5En. o- BULLETIN OF THE BRITISH MUSEUM (NATURAL HISTORY) GEOLOGY VOL. VI 1962 1963 PRINTED BY ORDER OF THE TRUSTEES OF THE BRITISH MUSEUM (NATURAL HISTORY) LONDON: 1963 DATES OF PUBLICATION OF THE PARTS No. i. lath June ...... 1962 No. 2. I2th June ...... 1962 No. 3. i4th February ..... 1963 PRINTED IN GREAT BRITAIN BY THOMAS DE LA RUE AND COMPANY LIMITED LONDON CONTENTS GEOLOGY VOLUME VI PAGE No. i. The Morphology and Systematics of some Cretaceous Cribrimorph Polyzoa (Pelmatoporinae). G. P. LARWOOD i No. 2. On Pteruchus, a microsporophyll of the Corystospermaceae. J. A. TOWNROW 287 No. 3. Revision of the Oligocene Floras of the Isle of Wight. M. E. J. CHANDLER 321 Index to Volume VI 385 THE MORPHOLOGY AND SYSTEMATICS OF SOME CRETACEOUS CRIBRIMORPH POLYZOA (PELMATOPORINAE) G. P. LARWOOD BULLETIN OF THE BRITISH MUSEUM (NATURAL HISTORY) GEOLOGY Vol. 6 No. i LONDON : 1962 THE MORPHOLOGY AND SYSTEMATICS OF SOME CRETACEOUS CRIBRIMORPH POLYZOA (PELMATOPORINAE) BY GILBERT POWELL LARWOOD Pp. 1-285 I Plates 1-23 ; 132 Text-figures BULLETIN OF THE BRITISH MUSEUM (NATURAL HISTORY) GEOLOGY Vol. 6 No. i LONDON: 1962 THE BULLETIN OF THE BRITISH MUSEUM (NATURAL HISTORY), instituted in 1949, is issued in five series corresponding to the Departments of the Museum, and an Historical series. Parts will appear at irregular intervals as they become ready. Volumes will contain about three or four hundred pages, and will not necessarily be completed within one calendar year. This paper is Vol. 6, No. i of the Geological (Palaeontological) series. Trustees of the British Museum, 1962 PRINTED BY ORDER OF THE TRUSTEES OF THE BRITISH MUSEUM Issued June, 1962 Price Six Pounds THE MORPHOLOGY AND SYSTEMATICS OF SOME CRETACEOUS CRIBRIMORPH POLYZOA (PELMATOPORINAE) By G. P. LARWOOD CONTENTS Page I. INTRODUCTION AND ACKNOWLEDGMENTS ..... 5 II. GENERAL STRATIGRAPHY ........ 7 Subdivisions of the English Chalk ...... 8 Foreign Upper Cretaceous Horizons . . . . . .14 III. NOTES ON THE COLLECTIONS STUDIED ..... 19 IV. PRESERVATION OF THE MATERIAL ...... 20 V. TECHNIQUES .......... 20 VI. MORPHOLOGY OF CRETACEOUS CRIBRIMORPH POLYZOA . . .21 VII. SYSTEMATIC DESCRIPTIONS . . . . . . . -51 Genus Aeolopora Lang ........ 54 Aeolopora distincta Lang ....... 55 ,, nebulosa Lang ....... 62 Genus Lagynopora Lang ....... 65 Lagynopora pustulosa sp. nov. ...... 67 ,, horsleyensis Lang ...... 68 ,, praecursor (Lang) nov. comb. .... 71 ,, saltdeanensis Lang ...... 73 ,, birlingensis Lang ...... 75 ,, amphora Lang ...... 77 ,, ampulla Lang ....... 79 ,, furcifera (Brydone) . . . . . .81 ,, ollula Lang . . . . . . .83 lagena Lang ....... 86 ,, urceolus Lang ....... 90 ,, vasculum Lang ...... 93 Species of uncertain systematic position previously assigned to Lagynopora ......... 95 Genus Hexacanthopora Lang ....... 97 Hexacanthopora sexspinosa Lang ..... 98 ,, viginticostata Voigt . . . . .102 Genus Leptocheilopora Lang . . . . . . .102 Leptocheilopora magna Lang . . . . . .103 ,, tenuilabrosa Lang . . . . .107 ,, filliozati (Brydone) . . . . .112 ,, vulnerata (Brydone) . . . . .116 Species of uncertain systematic position previously assigned to Leptocheilopora . . . . . . . . .118 GBOL. 6, i. i CRETACEOUS CRIBRIMORPH POLYZOA (PELM ATOPORIN AE) Page Genus Pelmatopora Lang . . . . . . .119 Pelmatopora calceata Lang . . . . . . .123 ,, crepidaria Lang . . . . . .125 solearis Lang . . . . . . .127 ,, gasteri Lang ....... 130 ,, chrysalis (d'Orbigny) . . . . .132 larva Lang ....... 134 ,, striata (d'Orbigny) ...... 136 " fragilis (d'Orbigny) . . . . . .138 ,, d'orbignyi Lang . . . . . .140 ,, quadrata Lang ...... 143 ,, fecampensis Lang . . . . . .145 ,, pero Lang ....... 148 ,, suffulta (Brydone) . . . . . .151 simplex Lang ...... 157 ,, plantaris Lang . . . . . .159 quadrivolucris Lang ...... 161 brydonei Lang . . . . . .164 coryli (Lang) ....... 168 ,, marsupitorum Lang . . . . .171 . gregoryi (Brydone) . . . . . .175 somptingensis Lang . . . . . .188 ,, palmata Lang ....... 196 sp. . ... 199 Species of uncertain systematic position previously assigned to Pelmatopora . . . . . . . . .200 Genus Castanopora Lang ....... 203 Castanopora armata sp. nov. . . . . . .206 ,, labiata (Levinsen) ...... 208 ,, retrorsa Lang ....... 209 ,, castanea Lang . . . . . .211 ,, dibleyi (Brydone) . . . . . .215 ,, guascoi (Ubaghs) . . . . . .219 spooneri (Butler & Cheetham) .... 220 ,, multicostata Voigt . . . . . .221 ,, jurassica (Gregory) . . . . . .223 ,, glandulosa Lang . . . . . .225 ,, aviculosa Lang . . . . . .226 magnifica (d'Orbigny) ..... 228 ,, faujasi (von Hagenow) ..... 236 ,, voigti sp. nov. ...... 236 Species of uncertain systematic position previously assigned to Rhiniopora and Castanopora . . . . . . .237 Genus Ubaghsia Jullien ....... 238 Ubaghsia ranunculus (Lang) ...... 242 ,, aurita (Lang) ....... 244 gasteri sp. nov. ....... 245 ,, langi sp. nov. ....... 247 ,, crassa (Lang) ....... 250 ,, coaxans (Lang) ....... 252 ,, perforata (Marsson) ...... 254 ocellata (Jullien) ...... 255 ,, meudonensis (Jullien) ...... 256 CRETACEOUS CRI BRIMORPH POLYZOA ( PELM ATOPORIN AE) 5 Page Ubaghsia demorgani (Jullien) ...... 256 reticulata (Ubaghs) ...... 257 ornata (Goldfuss) ...... 260 Species of uncertain systematic position previously assigned to Batrachopora ......... 264 Genus Andriopora Lang ....... 266 Andriopora minor sp. nov. ...... 266 major sp. nov. ...... 268 VIII. SYSTEMATIC BASIS, STRATIGRAPHY AND EVOLUTION OF THE GENERA AND SPECIES REVISED ........ 269 IX. REFERENCES .......... 275 SYNOPSIS Ten genera of Cretaceous cribrimorph Polyzoa, previously described by Lang, are considered to belong to the Pelmatoporinae. Some of these genera, and numerous species, are regarded as synonymous and all are diagnosed and revised. Seven new species are diagnosed and described. The morphology of Cretaceous cribrimorph Polyzoa is discussed and comparison made with Recent genera. Stratigraphical subdivisions of the English Chalk are reviewed and the distri- bution of the specimens from foreign Upper Cretaceous horizons is given. The Stratigraphical range of the revised genera and species is described and their probable evolution reviewed. I. INTRODUCTION AND ACKNOWLEDGMENTS SINCE the two catalogues on the Cretaceous cribrimorph Polyzoa by Dr. W. D. Lang were published in 1921 and 1922, the British Museum (Natural History) has received two very large collections of Chalk Polyzoa from Mr. C. T. A. Gaster. This has given the opportunity to examine and revise some of those results in the light of this added material, to re-assess the value of the cribrimorph Polyzoa as strati- graphical indices, and to reconsider the evidence for their evolution. It was found that, as in Recent cheilostomatous Polyzoa, there was much morphological variation in single species of the Cretaceous cribrimorphs, and far more in fact than Lang allowed for. As a result, many of his systematic subdivisions were found to be excessive. The study of Cretaceous cribrimorph Polyzoa is made difficult by the complexity of their structure. Confusion has also arisen from the unique terminology intro- duced by Lang, and from his attempts to assign systematic and Stratigraphical positions to species known only from earlier literature, where they were often poorly described and inadequately figured. Consequently I have not used Lang's termi- nology, but have used instead the more widely accepted terms which are generally applied to Recent and fossil Polyzoa. I have also rejected, as of uncertain systematic position, the ill-defined species just mentioned. Further, I have also rejected some of the hypothetical origins to which Lang attributed the development of certain structures, to which he gave evolutional significance, but to which the evidence appears opposed. All this has led to a general reduction in the number of genera and species recog- nized, to a revision of their Stratigraphical ranges, and to a great modification of the evolutionary sequences enunciated by Lang. CRETACEOUS CRIBRIMORPH POLYZOA (PELM ATO PORIN AE) 1 2 Z t 1 5 Griffith f. Rowe Brydone Brydone Caster 1 900 1911 1912 1914 19 24- 1 9 SI ente ' Sussex Hampshire Sussex Sussex i ^. ..I. Bm Bm Bm IsleofWiqht Hampshire Bm ^ Agu Aqu Aq Aq Scr Aq C7 a. o 4r * Opi Opi a. oi- - o O - 7. Ed 7 Ed Ed 7 E d o z M Ma VINO M Z M < Z M Ma 1 " U z U Z U Z U Mca " Mca * Mca Mca TB. Met Met Met Met Hp Hp Hp Hp o Tq z < Tq z < Tq z < Tl -3 z z z (. o o: ( a. Rc 13 i- II SRc ^ II D t- II 6Rc Ap Apl Apl z cr Z a < 7 Hjq < z X Hsq < Z X Hsq < T T O Z Sv&Rm z Sv z Sv u l_l < u oO NOT TO SCALE PI or Sc Sea Sea suggested Withers arrangement 1 9 J 5 SE NONI AN E CO Olu Bm cr A_gu Scr o. O 1 ii Ed M Ma. U Mca Met TURONIAN a. X Hp ~Hr~ Tl Rc CENOMANIAN Ap Hsq Sv Sc s: BICOI) SE NON IAN Bm cr 5 G'tfgu Scr CL 1 Ed M Ma U Mca TB. Met TURONIAN a. X Hp ~Hr" Tl II 6Rc A.p.M.. | CENOMANIAN Hsq ljT> Sv r Sca FIG. i. Key to the abbreviations : Ap Apl A.p.m. Aq Aqu G[A]pM G[A]q G[A]qu zone of Actinocamax plenus. Bm subzone of A . plenus. EC Actinocamax plenus Marls. zone of Actinocamax quadratus. Ed subzone of A . quadratus. Gonioteuthis [Actinocamax} plenus Hp Marls. Hsg zone of Gonioteuthis [A.] quadrata. II subzone of G. [A.] quadrata. M zone of Belemnella lanceolata (Ostrea Ma lunata Chalk). MAS = zone of Belemnitella mucronata. = subzone of Echinocorys scutata var. cincta. = subzone of Echinocorys scutata var. depressula. = zone of Holaster planus. = zone of Holaster subglobosus. = zone of Inoceramus labiatus. = zone of Marsupites testudinarius. = subzone of M. testudinarius. = Maastrichtian Stage. CRETACEOUS CRIBRIMORPH POLYZOA (PELM ATOPORIN AE) 7 By using modern binocular microscopes I have been able to study structures in the Cretaceous cribrimorph Polyzoa which must have been invisible to Lang or less well defined with the instruments available to him. I wish to record my high appreciation of the great value of the work done by Lang in his extensive studies of this group of Cretaceous Polyzoa. The present work 1 has been almost wholly carried out in the British Museum (Natural History) and my thanks are due to the Keepers of Palaeontology and Zoology for the facilities provided for my researches. I wish to record particularly my warm appreciation of the considerable assistance given to me by Dr. Anna B. Hastings and Dr. H. Dighton Thomas to whom I am indebted for their invaluable advice, interest, suggestions and criticisms. I am also much indebted to Dr. H. Dighton Thomas for reading a large part of my typescript. I also wish to acknowledge the help of the library staffs at the British Museum (Natural History) and to thank Miss P. L. Cook and Mr. R. F. Wise for their general assistance, Mr. M. G. Sawyers for the photography and Miss C. M. P. von Hayeck and Mr. A. C. Townsend for preparing translations. I am most grateful to Dr. J. F. Kirkaldy, Queen Mary College, University of London, for his supervision of my studies and for the criticisms he has given during the course of my work. My gratitude is also due to Mr. A. G. Brighton, Curator of the Sedgwick Museum, Cambridge, for the loan of material and for information on the R. M. Brydone Collection ; to Mr. R. R. Clarke, Curator of Norwich Castle Museum, for the loan of material ; to Mons. E. Buge, of the Laboratoire de Paleontologie, Museum National d'Histoire Naturelle, Paris, for photographs of, and information on, specimens from the d'Orbigny Collection and to the Editor of the Bulletin of the Zoological Society of France for permission to reproduce Plate 22, figs. 1-8. Finally, I record my gratitude to my wife for help and encouragement with many problems associated with this work. II. GENERAL STRATIGRAPHY Subdivisions of the English Chalk which have been established or adopted by previous authors are discussed below. The subdivisions followed here (column 7, Text-fig, i, p. 6) are based on a consideration of the extensive work of the authors mentioned. 1 A major part of the subject of a thesis for the degree of Doctor of Philosophy in the University of London. Mca = zone of Micr aster cor-anguinum. Sv Met = zone of Micr aster cortestudinarium. T.B. Olu = subzone of Ostrea lunata. Tg Op = zone of Offaster pilula. Tl Opi = subzone of O. pilula. U PI = zone of Plocoscyphia labrosa. i Re = zone of Rhynchonella cuvieri. a Rm = zone of Rhynchonella martini. Sc = zone of Stauronema carter i. 3 Sea = subzone of S. carteri. I Scr = subzone of Saccacoma cretacea. II = zone of Schloenbachia varians. = Trochiliopora Bed. = zone of Terebratulina gracilis. = zone of Terebratulina lata. = subzone of Uintacrinus westfalicus. = Lower belt of zone of Offaster pilula. = Belt of Echinocorys scutata var. cincta. = Upper belt of zone of Offaster pilula. = Horizon of Hagenowia rostrata. = Horizon of abundant Offaster pilula. 8 CRETACEOUS CRI BRIMO RPH POLYZOA (PELM ATOPORIN AE) The Ostrea lunata Chalk is contained well within the zone of Belemnella lanceolata and is Maastrichtian in age. Gaster's (1924-51) main subdivisions of the zones of Gonioteuthis [Actinocamax] quadrata and Off aster pilula are followed, but Brydone's (1912) upward extension of the zone of Micr aster cor-anguinum to include the Uintacrinus Chalk (usually placed in the zone of Marsupites testudinarius] has not been generally accepted and is not followed here. SUBDIVISIONS OF THE ENGLISH CHALK CENOMANIAN Zone of Schloenbachia varians The glauconitic, sandy marl, usually about one foot thick, which occurs at the base of this zone over much of southern England is here termed the subzone of Stauronema carteri ; this agrees with Brydone's and Gaster's general use of the term. Griffith & Brydone (1911) and Withers (1935) gave the unit zonal status ; it is not, however, sufficiently widespread or thick enough to be regarded as a true zone. Griffith & Brydone (1911) also suggested Plocoscyphia labrosa as an alternative narrie form, but apparently this sponge is only locally significant. The Chalk Marl, with the Totternhoe Stone at the top, succeeds the Stauronema carteri subzone giving a general thickness of about 160 ft. for the zone of Schloen- bachia varians. The thickness may be much less ; at Hunstanton, Norfolk, it is only 18-20 ft. The zone of Schloenbachia varians, as determined for southern England, is not recognized in the Chalk of Lincolnshire and Yorkshire. Bower & Farmery's (1910) division of the Lincolnshire Cenomanian was adopted for that of Yorkshire by C. W. & E. V. Wright (1942). They divided the stage into a lower zone of Holaster subglobosus and an upper zone of H. trecensis, and estimated an inland thickness of 70 ft. for the whole stage. Zone of Holaster subglobosus In southern England this zone has a general thickness of about 100 ft. Griffith & Brydone (1911) and Withers (1935) excluded from it the Actinocamax plenus Marls, which they regarded as a separate zone. Subsequently both Brydone and Gaster have described these Marls as a subzone of the Holaster subglobosus Zone. C. W. & E. V. Wright (1951 : 3, 4) also regarded the Actinocamax plenus Marls as a distinct subzone, but stated " Their cephalopod fauna is of Turonian affinities, and it therefore seems best to treat them as a subzone of the Inoceramus labiatus zone ". The Marls vary in thickness from a few to about 12 ft. and are here regarded only as a lithological marker of the base of the Turonian in some areas. TURONIAN Zone of Inoceramus labiatus and " Rhynchonella " cuvieri 1 Both name forms occur commonly in the zone which is about 70-90 ft. thick in southern England. In Yorkshire the zone is very thin only n ft. of gritty Chalk 1 Pettit (1954 : 29) placed the species in Orbirhynchia, CRETACEOUS CRI BRIMORPH POLYZOA (PELM ATOPORIN AE) 9 with broken Inoceramus labiatus shells is present. As mentioned above, the Actinocamax plenus Marls are a lithological marker of the base of the zone. Zone of Terebratulina lata Withers's (1935 : 54) estimate of the general thickness of this zone in southern England as about 160 ft. is probably a maximum. Dines and others (1954) recorded up to 140 ft. of T. lata Chalk in the Chatham district, Kent, and Wright (1947) estimated only 58 ft. for the zone in Dorset. In Yorkshire it is very much thicker (210 ft.). Zone of Holaster planus Although Brydone and Gaster excluded this zone from the Turonian (see below), it is generally regarded as the topmost zone of that stage. The base of the zone of H. planus is often well marked by the Chalk Rock. This hard, somewhat nodular, glauconitic, yellowish limestone, which is about 6 ft. thick, contains a shallow water fauna with Hyphantoceras reussianum. In the localities where the actual rock band is not developed, the fauna, although somewhat modified, is often present. This basal bed of the Holaster planus Zone is distinguished as the Hyphantoceras reussianum Subzone (see Withers, 1935 : 55). The zone is generally thin ; the maximum thickness given by Withers is about 60 ft., the minimum 14 ft. However, the zone thickens northwards, Dines and others (1954) recorded up to 70 ft. of Holaster planus Chalk in the Chatham area of Kent, Peake & Hancock (1961) estimate 75 ft. for the zone in north Norfolk and Rowe (1904 : 193) estimated 125 ft. as the thickness of the zone in Yorkshire. Wright (1947 : 202) drew attention to " a 2-foot band near the base of the zone [in Dorset] crowded with the polyzoan Bicavea rotaformis Gregory ". This very restricted occurrence of Bicavea contrasts with that of B. radiata Gaster and B. striata Gaster which are distributed throughout the zone of Gonioteuthis [Actinocamax] quadrata in the Senonian. SENONIAN Zone of Micraster cortestudinarium As mentioned above, Griffith & Brydone (1911), Brydone (1912) and Gaster (1924-51) placed the base of the Senonian at the bottom of the Holaster planus Zone. The first two authors also regarded the lowest third of the generally accepted zone of Micraster cor-anguinum as the uppermost unit of the Micraster cortestudinarium Zone. Withers (1935 : 57) estimated a general thickness of about 60 ft. for the M. cortestudinarium Chalk. Zone of Micraster cor-anguinum Griffith & Brydone (1911) and Brydone (1912) placed the lower boundary of this zone about 85 ft. above the generally accepted level (e.g., Rowe, 1900), and raised the upper boundary by about 60 ft. to include the Uintacrinus Chalk ; this arrange- ment has not been adopted by later authors. io CRETACEOUS CRIBRIMORPH POLYZOA (PELM ATOPORIN AE) Peake & Hancock (1961) record 170 ft. of M. cor-anguinum chalk in Norfolk. The upper boundary of the zone, as commonly denned at present, is the base of the Uintacrinus Chalk, its lower limit being placed about 260 ft. below that level. Gaster (1920 : 526) first drew attention to the Trochiliopora Bed near the base of the zone of Micr aster cor-anguinum in Sussex. He stated " the exact position in which it occurs ... is as follows : r Strong M. coranguinum tabular flint band. " Lower fourth of zone of J Chalk, about 35 feet. Micraster coranguinum ] Chalk with Trochiliopora sp., io feet. I Chalk, about 17 feet. " Chalk of zone of Micraster cortestudinarium ". This distinctive horizon in Sussex was not mentioned by Wright (1947) as recog- nizable in the Chalk of the M. cor-anguinum Zone of Dorset. The " strong Micraster cor-anguinum tabular [flint band] " of Rowe (1900 : 301) was mentioned previously by Whitaker (1872 : 50). In his work on the Sussex Chalk Gaster (e.g., 1937 : 361) also recognized this marker flint band near the base of the zone. C. W. & E. V. Wright (1942) adopted, for Yorkshire, Rowe's (1904) suggestion of a zone of Hagenowia rostrata which is abundant throughout Chalk equivalent to the Micraster cor-anguinum Zone in southern England. Zone of Marsupites testudinarius This zone, about 125 ft. thick, has been recognized generally, e.g., Rowe (1900), Gaster (1924-51), Withers (1935) as comprising two " bands " or subzones that of Marsupites testudinarius above (65 ft. thick) and that of Uintacrinus westphalicus below (60 ft. thick). As mentioned, Griffith & Brydone (1911) and Brydone (1912) did not include the Uintacrinus Chalk in their zone of Marsupites testudinarius. C. W. & E. V. Wright (1942 : 118) pointed out that Brydone's scheme avoids the anomaly of a " Marsupites Zone in one subzone of which Marsupites does not occur ". In the case of the Yorkshire Chalk they recognized a zone of Uintacrinus as have Peake and Hancock (1961) in Norfolk. Brydone (1915 : 13-15) added a few feet of Chalk, containing unusual crinoid plates, to the top of the Marsupites Zone ; this change was also adopted by Gaster (1937 : 362). Withers (1935 : 58) stated that " The Marsupites zone probably represents the maximum depth attained during the whole of the English Cretaceous period ". Zone of Off aster pilula 1 This zone, proposed by Brydone (1912 : 14), was established originally in the Chalk of Hampshire and later traced by him in Norfolk, Suffolk, Sussex, Dorset and the Isle of Wight (see Brydone, 19140, 19320, b). Blackmore was able to trace the 1 The original spelling of the specific name " pilula " was " pillula ", as Ananchytes pillula Lamarck (1816 : 27). Brydone (1912 : 7, footnote) stated with reference to the spelling pilula, " this name was deliberately spelt thus in ' The Zones ' (Griffith & Brydone, 1911) in deference to Mr. Griffith's scruples as a classical scholar against countenancing the spelling ' pillula ' . . ". CRETACEOUS CRIBRIMORPH POLYZOA (PELM ATOPORIN AE) n zone in Wiltshire, and other workers have established its presence throughout the rest of the English Chalk. Brydone divided the zone into a lower subzone of Echinocorys scutata var. depressula and an upper subzone of Off aster pilula. The depressula Subzone was not modified by Gaster, but for Brydone's Off aster pilula Subzone he (1924 : 94) substituted " subzone of Echinocorys scutata var. cincta ". In this subzone Gaster included the 60 ft. of Chalk comprising his " horizon of Hagenowia rostrata " ; the remainder of the subzone below it he termed the " horizon of abundant Off aster pilula " , almost equivalent to the three " belts " of the " subzone of Off aster pilula " of Brydone (191441). Brydone (1912 ; 19140) and particularly Gaster (1924 : 103-107 ; 1930 : 329 ; 1937 : 326) established a sequence of " belts " characterized by different varieties of Echinocorys scutata. These are not shown in columns 4 and 5 of Text-fig, i but are summarized in tabular form by Gaster as mentioned above. The thickness of the zone of Offaster pilula was estimated by Withers (1935 : 59) as about 160 ft. In Yorkshire, Chalk equivalent to the combined zones of Offaster pilula and Gonioteuthis [Actinocamax} quadrata, is characterized by the zonal form Inoceramus lingua with, at the top of the zone, a subzone of Scaphites binodosus regarded as the equivalent of the Gonioteuthis [Actinocamax] quadrata Zone of south-east England (C. W. & E. V. Wright, 1942 ; 1951 : 4). Peake & Hancock (1961) have not estab- lished this zone in Norfolk. Zone of Gonioteuthis [Actinocamax] quadrata Rowe's (1900) zone of A. quadratus was divided by Griffith & Brydone (1911) into three subzones. In 1912 Brydone combined the two lower subzones as the zone of Offaster pilula and restricted the Actinocamax quadratus Zone to the Chalk between his new zone and the base of the Belemnitella mucronata Zone. He included at the base of his restricted zone of Actinocamax quadratus about 60 ft. of Chalk which, in Sussex, Gaster (1924 : 93) regarded as the uppermost part of the underlying zone of Offaster pilula [i.e., the horizon of Hagenowia rostrata}. Gaster's arrangement was disputed by Brydone (1939) who re-stated his earlier opinion that the boundary between the zones of Offaster pilula and Actinocamax quadratus should be placed at the top of his " Planoconvexus Bed ". Gaster (1924 : 93) recognized a subzone of Saccacoma cretacea for the upper 125 ft. of his restricted zone of Actinocamax quadratus in Sussex. Saccacoma cretacea is not here regarded as a true subzonal form : the general thickness of the restricted zone of Gonioteuthis [Actinocamax'] quadrata was given by Withers (1935 : 59) as about 150 ft., so that Saccacoma cretacea extends through most of the zone. Simi- larly, the polyzoan species Bicavea radiata Gaster and B. striata Gaster occur through- out the whole zone and are not confined to separate horizons within it. Zone of Belemnitella mucronata The varying opinions on the position of the upper boundary of this zone are mentioned in the discussion of the overlying Ostrea lunata Chalk. 12 CRETACEOUS CRIBRIMORPH POLYZOA (PELM ATOPORIN AE) Apart from the inclusion, by some authors, of the 0. lunata Chalk (e.g., Withers, 1935 : 60), and the Parapachydiscan divisions proposed by Spath (1926), the zone of Belemnitella mucronata has not been generally subdivided. 1 The position of the lower boundary of the zone of Belemnitella mucronata as established, for example, by Rowe (1900), has not been queried. Variations in thickness are very marked : in a general estimate Withers (1935 : 60) gave the thickness as 250 ft. (excluding the Ostrea lunata Chalk) in Norfolk, 70 ft. in Hampshire, 250 ft. in Dorset, and 475 ft. in the Isle of Wight. The thick- ness in Norfolk has been more accurately estimated by Peake & Hancock (1961) as 325 ft. Uneven pre-Tertiary or recent erosion probably accounts for much of this variation, but the thickness which remains is great and more general subdivision would be of value. MAASTRICHTIAN Zone of Belemnella lanceolata In his original publication on the stratigraphy and fauna of the Trimingham Chalk, Brydone (1900 : n) concluded that " the great majority of forms . . . which appear in this [faunal] list . . . are characteristic of the Maastrichtian Stage on the Continent ". Subsequently, Brydone (i 908*2, b) described the Trimingham Chalk in detail. Since that date the Trimingham Chalk has been placed, by various authors, either as highest Senonian or as Maastrichtian in age. Boswell (1929 : 406, 4o8A) recognized Jukes-Browne's (1904 : 5, 12) zone of Ostrea lunata and regarded it as comprising " higher beds than those of the B. mucro- nata zone ". Withers (1935 : 40) discussed the limits of the " Maestrichtian and Upper Senonian (Campanian) " and some of the previous uses of the term " Maestrichtian ". He stated that it " was originally applied by Dumont ... to include the Tuffeau de Maestricht as exposed at Maestricht, Holland, and [that] this term corresponds to the Dordonian of Coquand ". He also mentioned Haug's (1910) extension of the term Maastrichtian to include the " Maestrichtian (s. str.) and the zone of B. mucro- nata ", and Spath's (1926) modification which included with the Maastrichtian only " the uppermost part of the B. mucronata zone ". Withers himself (1935 : 41) applied the term " Maestrichtian ... in its original sense to beds of the same age as the Tuffeau de Maestricht ", and retained as " Upper Senonian (Campanian) " the " Norwich Chalk ", the Skrivekridt of Denmark and the Schreibkreide of Riigen. The Chalk of Trimingham, Norfolk, he regarded (p. 60) as being " a little higher in the sequence of the B. mucronata zone . . . than that occurring in the neighbourhood of Norwich." 1 Wright (1947) mentioned " Lower, Middle and Upper Divisions " of the Belemnitella mucronata Zone in Dorset, the Middle Division being characterized by distinctive asteroid remains. C. W. & E. V. Wright (1951) adopted, in a slightly modified form, Spencer's (1913 : 145) division of the " mucro- nata " Chalk into Upper, Middle and Lower zones. They stated (1951 : 3) that of these divisions, "' the first [topmost] is now the zone of Belemnella lanceolata, and the other two are treated as subzones, as yet unnamed, of a restricted zone of Belemnitella mucronata " . CRETACEOUS CRIBRIMORPH POLYZOA (PELM ATOPORIN AE) 13 The " Maestrichtian " was suggested by Brydone (1938 : 16) as a " possible conti- nental equivalent " of the " Trimingham General Chalk ", i.e., his upper division of the zone of Ostrea lunata. More recently, Jeletzky (1951), in a comprehensive study of the use of the name Maastrichtian, considered that the Trimingham Chalk is of Lower Maastrichtian age, an opinion based largely on a study of the belemnite faunas of Trimingham and other Maastrichtian horizons on the Continent. The highest Belemnitella mucronata Chalk he regarded as that of the Norwich district, which he retained in the Senonian (see Jeletzky, 1951, table facing p. 208). Jeletzky's interpretation of Dumont's (1849) use f the term Maastrichtian has been questioned by van der Heide (1954). He stated (p. 509) that Dumont " considered the Maastrichtian Chalk and its equivalents as belonging to his Systeme Maestrich- tien : older beds were not included ". After a careful and detailed assessment of the evidence from Dumont's pre-i849 publications, his maps, and Mourlon's publi- cation (1878) based on Dumont's notes and manuscripts (Dumont died in 1857), van der Heide concluded that " the Systeme Maestrichtian of Dumont (1849) is equivalent to the Maastricht Chalk " of the type locality only, and that the newer interpretations, which enlarge the Maastrichtian (e.g. Jeletzky, 1951) are incorrect. Finally, van der Heide stated (p. 511) " the only conclusion at which we can arrive at the moment is that a detailed study of the stratigraphy and palaeontology of the type area of the Maastrichtian is indispensable ". It is desirable to establish, as van der Heide has done, the original meaning of a stratigraphical term, but this should not then preclude its use in a wider sense provided that the extended use is also clearly denned. Recently Jeletzky's enlarged use of the term Maastrichtian has been applied, with various modifications, by several continental authors. For example, Voigt (1951) has described polyzoan faunas of Lower and Upper Maastrichtian age from Holland and Germany ; the zone of Belemnitella mucronata being retained in the Upper Campanian. This is in agreement with the extensive work of Hiltermann & Koch (1950), Hiltermann (1952) and Wicher (1949, 1953^, I953&) which has shown that the top part of the previously so-called " Upper Senonian " of Denmark, Germany and other areas, may be regarded as a widespread boreal facies of the Maastrichtian (s. lato) characterized by a distinctive foraminiferal fauna. In a study of the foraminifera of the English Chalk Williams-Mitchell (1948) indicated that the foraminifera of the Trimingham Chalk differ considerably from those which characterize the underlying Senonian horizons. Barnard & Banner (1953 : 207) listed 24 species of arenaceous foraminifera which occur in the zone of Belemnitella mucronata ; of these, 6 are long-range forms occurring from the Cenoman- ian to the zone of Ostrea lunata, 5 range from the base of the zone of Belemnitella mucronata into the Ostrea lunata Chalk, and the remaining 13 species are all confined to the zone of Belemnitella mucronata, again indicating a change at the top of the latter zone. A sample collected in 1954 from a foreshore exposure of white chalk with Ostrea lunata, just north of Mundesley, was prepared and examined for its foraminiferal content by the late Mr. A. G. Davis. In a letter (20th September, 1954) he wrote i 4 CRETACEOUS CRIBRIMORPH POLYZOA (PELM ATOPORIN AE) " the foraminiferal content of this sample is quite unlike any from the zones below which are much better known. I find the foraminifera fauna is characterized by some species of Bolivina, species much like B. incrassata, B. " gigantea " and B. decussens. There are also some arenaceous agglomerated forms as also mentioned by Williams-Mitchell. The species of Bolivina present in the sample are characteristic of the Maastrichtian of Hemmoor and Liineburg. They are rare in the mucronata Zone, but do make an appearance and only become abundant higher up. They are abundant in the Mundesley sample. Other foraminifera are present, but not abundant, and they are of long range. The well-known Chalk foraminifera, Nodosarids, Globotruncana, etc., do not seem to be present." This evidence of a faunal change in the foraminifera is further supported by the distribution of species of Castanopora (see p. 274). Boswell (1923) estimated the total thickness of the Ostrea lunata Chalk at about no ft., and this is confirmed by Peake & Hancock (1961 : 320) in their precise study of the Trimingham Chalk. The boundary between it and the underlying zone of Bdemnitella mucronata has not been seen. C. W. & E. V. Wright (1951 : 3) have stated that " Ostrea lunata, the fossil used by Jukes-Browne as an index for the uppermost zone of the Chalk (at Trimingham), is not entirely appropriate [as a zonal name form], as it does not occur at all in a large part of the Trimingham Chalk. Now that Jeletzky has shown that the vast majority of the Trimingham belemnites are Belemnella lanceolata (Schlotheim) and not Belemnitella mucronata the former species can appropriately be used as a zone fossil, as it is over most of northern Europe ". Thus the authors referred (1951 : 3) to a zone of Belemnella lanceolata as an alternative to " zone of Ostrea lunata ". They also used the terms " Upper " and " Lower Senonian " as stages embracing the zones of Ostrea lunata down to, and including, the zone of Offaster pilula, and from the zone of Marsupites testudinarius down to, and including, the zone of Micr aster cortestudinarium respectively. They stated that the " Upper Senonian includes Campanian and Maastrichtian. Lower Senonian includes Coniacian and Santonian ". FOREIGN UPPER CRETACEOUS HORIZONS Most of the Polyzoa described here are from the English Chalk, but a number of specimens from various horizons of the Upper Cretaceous abroad have also been examined in order to complete the systematic revision of some genera. The following list of genera and species from such localities and horizons are included in the systematic revision of the Cretaceous cribrimorph Polyzoa described here. When no specimens are available, either in the collections of the British Museum (Natural History), or in the other collections studied, the species have been assessed from published works only. In these cases the name of the species is fol- lowed in the list by the reference to its original description [e.g., Castanopora [Rhinio- pora\ labiata (Levinsen) (1907 : 155, 156, 158, pi. opp. p. 160, fig. i, la-f). M0en, CRETACEOUS CRIBRIMORPH POLYZOA (PELM ATOPORIN AE) 15 Aalborg, Denmark. Lower Maastrichtian (as Senonian, zone of Belemnitella mucro- nata}}. Where specimens of species from foreign localities are available the name of the species is marked by an asterisk and is followed directly by its locality and horizon [e.g., * Castanopora glandulosa Lang. Riigen. Probably boreal Maastrich- tian (as Senonian, zone of Belemnitella mucronata)]. If a photograph only is available this is stated. Published records of the foreign occurrences of other species are also mentioned. AEOLOPORA Aeolopora nebulosa Lang. Also recorded by Voigt (1930 : 498, 542, 560, pi. 27, fig. i) from Ifo, Sweden. " Mammillatensenon." CASTANOPORA Castanopora [Rhiniopora] aviculosa (Lang). Photograph only of the holotype. Maastrichtian, Maastricht, Limbourg, Holland. *C. castanea Lang. Riigen. Also recorded by Voigt (1930 : 513, 561, pi. 30, fig. 17) from the same locality and horizon. Probably boreal Maastrichtian [as Senonian, zone of Belemnitella mucronata]. *C. dibleyi (Brydone). Also recorded by Voigt (1930 : 512, 561, pi. 30, fig. 18) from Riigen. Probably boreal Maastrichtian, and ? Voigt (1930 : 512, 561, pi. 30, fig. 20) as Castanopora sp. from Stafversvad, Schonen [as " Unteres Mukronatensenon "]. C. faujasi (von Hagenow) (1851 : 99, pi. 10, fig. 190, b). Also recorded by Voigt (1930 : 511, pi. 31, fig. 2) as Rhiniopora faujasi (von Hagenow), Maastricht, Limbourg, Holland. Maastrichtian [as " Ob. Mukronatensenon "]. *C. glandulosa Lang. Riigen. Probably boreal Maastrichtian [as Senonian, zone of Belemnitella mucronata]. C. guascoi (Ubaghs) (1865 : 51, pi. 2, figs. 3-c). Valkenburg (Fauquemont), east of Maastricht, Limbourg, Holland. Maastrichtian. Also recorded by Voigt (1930 : 512, 561, pi. 31, fig. i). Maastricht. Maastrichtian [as " Ob. Mukronatensenon "]. *C. [Rhiniopora] jurassica (Gregory). Recorded incorrectly from Ranville, Nor- mandy, France, as of Jurassic age. Very probably from Maastricht, Limbourg, Holland. Maastrichtian. C. [Rhiniopora] labiata (Levinsen) (1907 : 155, 156, 158, pi. opp. p. 160, fig. i, ia-/) = Cribrilina valida Levinsen (1925 : 376, pi. 5, fig. 5Sar-d). M0en, Aalborg, Denmark. Lower Maastrichtian, [as Skrivekridt, Senonian, zone of Belemnitella mucronata] . *C. magnifica (d'Orbigny). Holotype photograph only, either from Sainte Colombe, Manche, France, or from Royan, Charente Inferieure, France. Both localities Maastrichtian. [As Senonian, zone of Belemnitella mucronata.] Includes Rhiniopora aspera, R. asperula, R. cacus and R. horrida. Recorded by Voigt (1930 : 511) from Riigen and Blauen Bergen, Roslau. Probably boreal Maastrichtian [as " Ob. Mukronatensenon "]. Also recorded by lilies (1953) from Hemmoor, near Hanover, Germany. Maastrichtian. 16 CRETACEOUS CRIBRIMORPH POLYZOA (PELM ATOPORIN AE) C. multicostata Voigt (1930 : 512, 561, pi. 30, fig. 19). Riigen. Probably boreal Maastrichtian [as " Ob. Mukronatensenon "]. C. [Rhiniopora] spooneri (Butler & Cheetham) (1958 : 1154, text-figs, i, 2). ". . . from a chalk bed exposed at Rayburn's dome, Bienville Parish, Lousiana . . . equivalent to the Upper Cretaceous Saratoga chalk of Arkansas . . ." U.S.A. C. voigti sp. nov. (Voigt, 1930 : 511, pi. 31, fig. 6 as " Rhiniopora hispida Lang " which is indeterminate, see p. 238). M0en. Denmark. Lower Maastrichtian [as Oberes Mukronatensenon], and Riigen, probably boreal Maastrichtian. HEXACANTHOPORA *Hexacanthopora sexspinosa Lang. Also recorded by Voigt (1930 : 495, 542, 560, pi. 26, figs, n, 12) from " Gr. Biilten-Granulatensenon " (as H. brightonensis) and " Quadraten- oder Mukronatensenon " of Misburg, Germany. H. viginticostata Voigt (1930 : 495, 560, pi. 26, fig. 13 ; 1949 : 37, 43, pi. 9, figs, i, 2). Schwiecheldt, Hanover, Germany. " Quadraten- oder Mukronaten- senon ", and Lagerdorf, Holstein, Germany, Senonian, zone of Gonioteuthis [A ctinocamax] quadrata . LAGYNOPORA *Lagynopora furcifera (Brydone). Also recorded by Voigt (1930 : 495, 542, 560, pi. 26, fig. 10 ; 1949 : 36, 43, 44, pi. u, fig. i). Misburg, Germany " Quad- raten- oder Mukronatensenon ", and Lagerdorf, Holstein, Germany Senonian, zone of Gonioteuthis [A ctinocamax] quadrata. *L. horsleyensis Lang. A poorly preserved specimen has been recorded by Didon (1958 : 80, 84, text-fig. 2) from the Santonian of Le Trait, near Rouen, Seine Inferieure, France. L. lagena Lang. Also recorded by Voigt (1930 : 495, 542, 560, pi. 26, fig. 9). Balsburg. " Mammillatensenon." ?L. [? = Canupora] prima (Kiihn) (1930 : 65, pi. 26, fig. 13). Lithothamnienkalk. Haidhof, Ernstbrunn, Austria. Danian. LEPTOCHEILOPORA *Leptocheilopora filliozati (Brydone). Also recorded by Gillard (1943 : 187). "... a la cote 72 m. par le forage Font-de-Chevres . . . Royan ", France. Either Senonian, zone of Belemnitella mucronata, or Maastrichtian. *L. magna Lang. Holotype and paratype Luneberg, Hanover, Germany very probably boreal Maastrichtian [as Senonian, zone of Belemnitella mucronata]. Other specimens Hemmoor, Hanover, Germany Maastrichtian, either zone of Belemnella lanceolata mut. sumensis or zone of B. junior. Also recorded by Voigt (1930 : 496, pi. 27, fig. 5) ? Maastricht. Maastrichtian [as " Obere Mukronatenkreide "], and from Riigen, probably boreal Maastrichtian. The species is synonymous with Barroisina galeata Levinsen (1925 : 385, pi. 6, fig. CRETACEOUS CRIBRIMORPH POLYZOA (PELM ATOPORIN AE) 17 67). M0en, Aalborg, Denmark. Lower Maastrichtian [as Skrivekridt, Seno- nian, zone of Belemnitella mucronata]. The species is probably synonymous also with Leptocheilopora longuesensis Lang (igi6a : 396, 397 ; 1921 : 76) horizon recorded as " Campanian, Longuesse, France ". PELMATOPORA *Pelmatopora brydoneis [sic] Lang. Recorded by Didon (1958 : 83, 85, text-fig. 10) from the Santonian of Elbeuf, near Rouen, Seine Inferieure, France. *P. chrysalis (d'Orbigny). Photograph only. Villedieu, France. Senonian, Coni- acian. Also recorded by Gillard (1942 : 90) from the Upper Chalk between 24 m. 50 and 26 m. 80 (Division D) from a boring at Montbazon, south of Tours, Indre-et-Loire, France. P. ? daniensis Voigt (19256 : 99, 100, pi. 3, figs. 4-6 ; 1930 : 514, 561, pi. 31, fig. n). Cothen. Danian. *P. fecampensis Lang. Holotype and other specimens Fecamp north-east of Le Havre, Seine Inferieure, France. Senonian, Coniacian. Also recorded by Didon (1958 : 82, 84, text-fig. 9) from the Santonian of Le Trait, Elbeuf and Orival, near Rouen, Seine Inferieure, France. *P. fragilis (d'Orbigny). Lectotype the specimen figured by d'Orbigny (1851, pi. 717, fig. 9). Fecamp, north-east of Le Havre, Seine Inferieure, France. Senonian, Coniacian. Photograph only of a specimen from the same locality and horizon as the lectotype, and a specimen from St. Avertin, south-east of Tours, Indre-et-Loire, France. Senonian, Coniacian. Also recorded by Gillard (1942 : 90) from the Upper Chalk between 6 m. 50 and 7 m. 30 (Division A) from a boring at Montbazon, south of Tours, Indre-et-Loire, France. *P. larva Lang. Holotype and 0.28438 La Ribochere, Loir-et-Cher, east of La Chartre-sur-le-Loire, Sarthe, France. Senonian, Coniacian. *Pelmatopora cf. marsupitum [sic] Lang. Recorded by Didon (1958 : 83, 85, text- fig, n) from the Santonian of Moulineaux, near Rouen, Seine Inferieure, France. *P. d'orbignyi Lang. Holotype. St. Avertin, south-east of Tours, Indre-et-Loire, France. Senonian, Coniacian. Specimen also from La Ribochere, Loir-et- Cher, east of La Chartre-sur-le-Loir, Sarthe, France. Senonian, Coniacian. *P. quadrata Lang. Synonymous with P. filliozati Lang. Photograph only of the holotype of P. filliozati Lang, from Fecamp, north-east of Le Havre, Seine Inferieure, France. Senonian. Coniacian. *P. striata (d'Orbigny). Lectotype the specimen figured by d'Orbigny (1851, pi. 686, fig. 10). Nehou, south of Valoignes, east of Sainte Colombe, Manche, France. Senonian. Photographs only of a specimen from Villedieu, France. Senonian, Coniacian. Also recorded by Gillard (1942 : 90) from the Upper Chalk between 24 m. 50 and 26 m. 80 (Division D) from a boring at Montbazon, south of Tours, Indre-et-Loire, France. *P. suffulta (Brydone). Canu (1911 : 252, pi. 6, figs. 7-10) has also recorded " Cribrilina insignis " which is possibly synonymous with Pelmatopora suffulta. Roca, Argentine. Rocanean. GEOL. 6, I. 2 i8 CRETACEOUS CRIBRIMORPH POLYZOA (PELM ATO PORI N AE) UBAGHSIA Ubaghsia aurita Lang. Photograph only of the holotype. Royan, south of Rochefort, Charente Inferieure, France. Maastrichtian. *U. [Batrachopora] coaxans (Lang). Riigen. Probably boreal Maastrichtian [as " Upper Senonian "]. *U. [Batrachopora] crassa (Lang). Riigen. Probably boreal Maastrichtian [as Senonian, zone of Belemnitella mucronata] . U. [Steginopora] demorgani (Julh'en) (Jullien, 1886 : 615, pi. 19, figs. 4, 5, pi. 20, fig. i). Les Molineaux, Meudon, south-west of Paris, France. Senonian, zone of Belemnitella mucronata. U. [Steginopora] meudonensis (Jullien) (Jullien, 1886 : 614, pi. 17, figs. 1-5, pi. 18, figs. 1-3). Details as for U. demorgani. U. [Steginopora] ocellata (Jullien) (Jullien, 1886 : 614, pi. 19, figs. 1-3). Port Brehay, north-east of Gourbesville, north-west of Carenten, Manche, France. " Etage senonien " probably middle or lower part of zone of Belemnitella mucronata. *U. ornata (Goldfuss). Lectotype the specimen figured by Goldfuss (1826, pi. 9, fig. ib). St. Petersburg, Maastricht. Maastrichtian. Specimens from Valken- burg (Fauquemont) and Maastricht, Holland. Maastrichtian. Also recorded by Voigt (1930 : 513, pi. 31, fig. 20 only). Maastricht. Maastrichtian [as " Ob. Mukronatensenon "]. U. [Batrachopora] perforata (Marsson) (Marsson, 1887 : 98, 109, pi. 10, fig. n). Riigen. Probably boreal Maastrichtian [as " Schreibkreide "]. Also synony- mous with Cribrilina brachiata Levinsen (1925 : 377, pi. 8, fig. 24). M0en, Aalbourg, Denmark. Lower Maastrichtian [as Senonian, zone of Belemnitella mucronata]. *U. [Batrachopora] ranunculus (Lang). Riigen. Probably boreal Maastrichtian [as Senonian, zone of Belemnitella mucronata]. Also recorded by Voigt (1930 : 515, 561, pi. 31, fig. 17) from the same locality and horizon. *U. reticulata (Ubaghs). Lectotype the specimen figured by Ubaghs (1865, pi. 2a, fig. 70). Valkenburg (Fauquemont) or Geulem, Maastricht, Holland. Maastrichtian, " Ober Bryozoenschichte " (horizon / of Ubaghs). Specimens from Maastricht, Holland. Maastrichtian. Also recorded by Voigt (1930 : 515, pi. 31, figs. 18, 39 only). Maastricht, Holland. Maastrichtian [as " Ob. Mukronatensenon "]. The age of some Upper Cretaceous horizons abroad, e.g. that of the Riigen Chalk, has more recently been proved different from that originally stated by some authors. In the above list such revision of horizons is indicated by giving the old opinion enclosed in square brackets. Among the stratigraphical terms used in the above list " Coniacian " refers to beds equivalent in age to the zone of Micraster cortestudinarium, and " Santonian " to beds equivalent in age to the zones of M. cor-anguinum and Marsupites testudinaris. The following terms are revised or generally in use by foreign authors. CRETACEOUS CRIBRIMORPH POLYZOA (PELM ATOPORIN AE) 19 Granulatensenon. Chalk with Gonioteuthis granulata in Germany, approximately equivalent to the zone of Marsupites testudinarius in England. Lithothamnienkalk of Haidhof. Part of the Austrian Upper Cretaceous series of Danian age. Maastrichtian. The general use of this term as applied to English and foreign horizons has been discussed (p. 12). Mammillatensenon. Part of the Trummerkreide of Sweden, equivalent to the upper part of the zone of Gonioteuthis [Actinocamax] quadrata in Germany and England. Possibly also equivalent to part of the zone of Belemnitella mucronata in England (see Withers, 1935 : 71). Moen Chalk, Aalborg, Denmark. Referred by Levinsen (1925) and others to the Senonian, zone of Belemnitella mucronata, but now known to be Lower Maastrichtian. Oberes Mukronatensenon of Maastricht. Used by Voigt (1930) for the Cretaceous of the type locality of the Maastrichtian, termed subsequently by Voigt, and generally, Maastrichtian s. str. Rocanean. Part of the Argentine marine Upper Cretaceous. Feruglio (1949 : 218) gave an extensive survey of previous studies of the Rocanean and con- cluded that " after various considerations and a critical study of the data hitherto published by previous authors it is impossible, in the present state of knowledge, to decide whether these strata belong to the Upper Cretaceous or to the lower part of the Tertiary " [translation]. Rugen Chalk. Originally (e.g. Lang, 1921 ; 1922) regarded as Senonian, zone of Belemnitella mucronata, but subsequently shown (e.g. Voigt, 1951 ; Hiltermann, 1952) to be probably boreal Maastrichtian. III. NOTES ON THE COLLECTIONS STUDIED British Museum (Natural History] Most of the material described here is from the large collections of Chalk Polyzoa made by C. T. A. Gaster and presented by him in recent years. The total of Chalk Polyzoa in the Gaster Collections numbers many thousands, the majority of speci- mens coming from south-east England. Much of the material has been carefully cleaned, stained and mounted by the collector, and all specimens are accompanied by full and precise details of locality and horizon. A number of specimens have been studied which were obtained by earlier collectors. Such specimens, from collections other than the Gaster Collection, were incor- porated by Lang in his works on Cretaceous cribrimorph Polyzoa and have been re-examined here to complete the revision of some genera. The British Museum Collections also include photographs of specimens in the F. Canu Collection, Paris. Sedgwick Museum, Cambridge The R. M. Brydone Collection of Chalk Polyzoa in the Sedgwick Museum, Cam- bridge, includes many very well preserved cribrimorph Polyzoa. I have examined 20 CRETACEOUS CRIBRIMORPH POLYZOA ( PELM ATOPORIN AE) the type specimens of the species established by Brydone which belong to the genera revised here. Norwich Castle Museum All available specimens of cribrimorph Polyzoa in the R. M. Brydone Collection of Chalk fossils from Norfolk and adjacent areas have been examined. Where appropriate, these, and specimens from other collections in the Norwich Castle Museum, are incorporated in the present study. IV. PRESERVATION OF THE MATERIAL Cretaceous cribrimorph Polyzoa are often well preserved. They may, however, have been worn before interment so that projecting structures, such as avicularia, oral spines and median processes of the apertural bar, are eroded and rounded. Usually it is possible to find, in a zoarial fragment of average size, an area in which the zooecia are well preserved often through being at a slightly lower level than the general surface of the zoarium and thus escaping the general effects of wear. In contrast, some zoarial fragments entirely lack fine skeletal details, but retain, unbroken, projecting structures such as avicularia. General fine wear of this kind was possibly produced by solution effects on the surface of the skeleton before burial, rather than by mechanical abrasion. Phleger, Parker & Peirson (1953 : 117-119, pi. 12) have described and figured a number of Recent foraminifera with calcareous tests which exhibit similar primary solution effects. As only a few zoarial fragments of Cretaceous Polyzoa, from any given locality, may show such solution effects, it seems probable as with the Recent foraminifera that solution was predepositional rather than secondary. The secondary cause of loss of detail in Chalk Polyzoa is recrystallization of the calcium-carbonate of their skeletons. This seems to have occurred more commonly in specimens from earlier horizons of the English Chalk. Most polyzoan skeletons from the Chalk are composed of finely crystalline calcium- carbonate, but some may be perfectly replaced secondarily by silica. Siliceous specimens are usually very well preserved and may occur in the hollow centres of flint nodules forming part of the infilling " flint meal ". V. TECHNIQUES All the material has been examined with strong reflected light at high- and low- power magnifications under a binocular microscope. Lang's method of staining specimens with indigo water-colour has been used extensively (Lang, 1921 : Ixxv). Without staining, the detailed characters, such as the type and number of pelmata, are hardly visible, but the careful application of a fairly dark, temporary stain brings out such details and differentiates the polyzoan skeleton from any adherent Chalk matrix. Many specimens encrust fragments of echinoid test or pieces of Inoceramus shell. With such specimens, soaking in water and gentle brushing with a soft water-colour paint brush is usually an adequate cleaning method. Unattached zoarial fragments CRETACEOUS CRI BRIMORPH POLYZOA (PELM ATOPORIN AE) 21 may be freed from their Chalk matrix by repeated soaking in water and gentle brushing. The matrix may be harder and more closely adherent to the polyzoan skeletons. In these cases, soaking for a short time (10-30 minutes) in a saturated solution of salicylic acid was found to be sufficient to loosen the matrix without damaging the polyzoan. This treatment was always followed by careful washing in running water for 24-36 hours, the material being finally dried out very slowly. Specimens treated in this way have shown no signs of deterioration after five years. The material can be stained in the usual way. Where possible, the specimens have been mounted with gum tragacanth on mahogany microscope slides the system used generally in the Department of Palaeontology of the British Museum (Natural History). Accurate drawings of specimens have been made on koda-trace mounted on squared paper using a micrometer scale and squared graticule in the eyepiece of the micro- scope. All holotypes and some other specimens have been photographed by re- flected light generally at a magnification of X20, but occasionally at higher magni- fications up to X 100 to show minute detail. VI. MORPHOLOGY OF CRETACEOUS CRIBRIMORPH POLYZOA Zoarial Characters GROWTH HABIT. Many Cretaceous cribrimorph Polyzoa have encrusting zoaria firmly attached to a substrate such as an echinoid test or the shells of other organisms. Unattached zoarial fragments are also common, but many of these may have been encrusting during life on some perishable object which was destroyed during or after fossilization. Thus the distinction often made between encrusting and so-called " free " forms is very uncertain. Bassler (1953 : 67) pointed out that " although often described as free, only the upper branches actually are free, for most bryozoans are attached basally or by other parts of their surface to extraneous objects . . .". Encrusting zoaria are usually unilaminar, consisting of a relatively widespread, single layer of zooecia attached dorsally to a substrate. Much less commonly, successive layers of zooecia may be superimposed producing a multilaminar zoarium of hemispherical or nodular form : some species of Polycephalopora (Lang, 1922: 105) are of this type. Unattached zoaria may be uni-, bi- or multilaminar, and, as fossils, are almost invariably fragmentary. Unilaminar fragments may originally have encrusted a destructible substrate since lost. Their dorsal surfaces may be fairly even, with the basal wall of each zooecium smooth, slightly convex, and separated from adjacent zooecia by a slight furrow ; or they may be more irregular, the basal wall of each zooecium possessing small, scattered tubercles, with deeper furrows between adjacent zooecia, as in Pelmatopora gregoryi (Brydone), P. somptingensis Lang (PI. 15, fig. 4) and P. brydonei Lang (Text-fig. 77). Some Recent Polyzoa are attached to destructible substrates by means of tubercles protruding from their dorsal surfaces, and so their presence in fossil forms may indicate an originally adherent zoarium. Some zoaria are bilaminar, consisting of two layers of aligned zooecia growing back to back, their dorsal surfaces united. Bilaminar zoaria may be irregularly lobed expansions in one plane, or more complex, foliaceous and undulating. From very small fragments of fossil bilaminar zoaria it is usually not possible to decide what was the original form of whole colonies, though they were presumably like Recent bilaminar polyzoan colonies. Some zoaria of Pelmatopora larva Lang (p. 134) are bilaminar. Unattached fragments of multilaminar zoaria occur, but these may have been broken from encrusting masses. Castanopora voigti sp. nov. (p. 236) has an erect, cylindro-quadrate zoarium in which four adjacent rows of zooecia alternate : this zoarial form is apparently rare among cribrimorph Polyzoa. Other erect, cylindrical zoaria occur occasionally, as in Pnictopora suffocata Lang and P. strangulata Lang. Some genera, now largely archaic, were based on zoarial growth forms alone. There is often a considerable amount of variation in the growth habit of zoaria of the same genus or species. However, Lang (igi6a ; 1921 ; 1922) frequently used zoarial growth habit to distinguish species which are otherwise morphologically identical. In the material revised and described here, Pelmatopora affords several examples of species established by Lang on zoarial growth form alone. Thus he distinguished (1922 : 300) as P. roedeanensis , a species differing " only in colonial habit from P. marsupitum [sic]." P. lacuum Lang was described (1922 : 324) as " Pelmatopora ranunculoides, but with an erect unilaminar asty [zoarium] ", and P. promontoriorum Lang (1922 : 320) as having a structure which " resembles that of Pelmatopora saltdeanensis , but the asty is erect instead of incrusting ". Again, Lang stated (1922 : 308) " Pelmatopora damicornis differs from P. gregoryi and P. palmata in its colonial habit, which is bilaminar. The three species thus form a progressive series with regard to colonial habit and condition, culminating in the erect bilaminar P. damicornis ". Further examples may be cited, from genera not revised here. Among these are Sandalopora lavardinensis Lang distinguished (1922 : 330) on zoarial growth form from 5. gallica Lang, S. suppulosa Lang separated (1922 : 331) on the same basis from S. crepidata Lang and three species of Rhabdopora (R. virgata, R. virgulata and R. tigrina) distinguished (Lang, 19160 : 405 ; 1921 : 209) in the same way. Lang was aware of the uncertainty of describing unattached unilaminar zoarial fragments as " erect ". He stated (1919^ : 196) " It is hard to be certain . . . that an apparently erect unilaminar asty is not really incrusting, since an alga or other perishable substance may have formed its support ... it is unusual, however, to find an habitually-incrusting form in an apparently free condition, and, unless there are other reasons against it, I should advocate keeping incrusting and free, unilaminar forms specifically distinct ". Lang preceded this statement with the assertion that " in the Pelmatoporinae, and throughout the phylum, the direction of evolution is from an incrusting to an erect asty ". In some Recent Polyzoa it is possible to find species, such as Steganoporella buski Harmer, in which different parts of the same zoarium are encrusting or erect and uni- or bilaminar and, in some parts, even multilaminar. On such evidence, and CRETACEOUS CRIBRIMORPH POLYZOA ( PELM ATOPORIN AE) 23 in view of the uncertainty of establishing whether or not an unattached, unilaminar zoarial fragment had an encrusting mode of life, I do not agree with Lang's division of species on zoarial growth habit alone. On the same evidence, the suggested " direction of evolution " from encrusting to erect zoaria must also be questioned. ZOARIAL BUDDING. In an encrusting zoarium the zooecia may be developed uni- or multiserially. In Cretaceous cribrimorph Polyzoa the former condition is much rarer than the latter. Uniserial encrusting zoaria. Some genera, such as Corymbopora and Andriopofa (p. 266), are always uniserial, and the zooecia may possess caudae, as in A. major sp. nov. (p. 268). Generally, uniserial encrusting zoaria are more extensive than multiserial, though many more zooecia may be present in a multiserial zoarium which has developed uninterruptedly on a wide substrate. The angle of divergence of lines of uniserially budded zooecia may vary considerably. Multiserial encrusting zoaria. These are usually fan-shaped, tending ultimately to become circular as more and more zooecia are developed. The sequence of growth appears to be like that observed by Marcus (1926) [summarized by Harmer, 1931 : 122] in the Recent cheilostome polyzoan Electra pilosa (Linn.). Here three distal buds arise from the ancestrula producing the first generation of zooecia. Successive generations are budded off producing a young fan-shaped colony, the distal-lateral edges of which are early reflected and usually meet on the proximal side of the ancestrula. Where zooecia are crowded, usually only one bud is pro- duced, and in later stages there is a tendency to form adjacent, but distinct, uni- serial, radiating rows of zooecia (e.g., as in Aeolopora distincta Lang, PI. 2, figs, i, 2). Where sufficient space is available two or three buds may arise in Electra pilosa, and a new radiating row of zooecia is intercalated in the colony. This feature is commonly found in Cretaceous cribrimorph Polyzoa. In an adult zoarium, which has attained a more or less circular form, new zooecia are budded off from the periphery. This growing edge is seldom preserved in the Cretaceous cribrimorph Polyzoa ; presumably zooecia which have only just developed are more fragile than the preceding established, probably more calcified, adult zooecia. As a multiserial zoarium matures, particularly if its substrate is limited, the later stages of zoarial growth may obscure the ancestrular area, often by the development of secondary calcareous tissue. Frequently one part of a zoarium may develop more rapidly than another, and, especially where there is a limited substrate, two zoarial expansions may converge, producing distortion of zooecia where they meet. Bilaminar, erect, branching or foliaceous zoaria are apparently always multiserial. They may exhibit some of the features described for encrusting zoaria, but the modifications imposed by a limited substrate are usually absent, and the zoaria develop uninterruptedly. Zooecial Characters Certain structural features are common to the zooecia of all Cretaceous cribri- morph Polyzoa. They all possess calcified proximal, distal and lateral walls, and a 24 CRETACEOUS CRIBRIMORPH POLYZOA (PELM ATOPORIN AE) secondary front wall (the frontal shield) composed of costae. These over-arch an aperture which is divided by an apertural bar from a distal orifice with marginal oral spines. This basic arrangement may be complicated in various ways lateral costal fusions may develop between adjacent costae ; a median process, formed on the apertural bar, may fuse with the proximal pair of oral spines producing a proximal oral shield ; or the oral spines may be enlarged and bifurcated. The basic morph- ology is often further obscured by a general accumulation of secondary calcareous material which may fill the interzooecial valleys and, in some genera, encroach on to the frontal shields, or which may accumulate round the primary orifice producing a tubular secondary orifice. Ovicells and various heterozooecia may also obscure the form of zooecia. The following observations and remarks apply to adult zooecia, but many of the characters discussed are the same in younger stages of zoarial growth. Young zooecia and ancestrulae are discussed later. SIZE OF ZOOECIA. In the Cretaceous cribrimorph Polyzoa, as in other divisions of the Cheilostomata, the size of zooecia varies greatly, but some genera, compared with others, may have consistently small zooecia. For example, the zooecia of Aeolopora are always much smaller than those of Castanopora. However, for a given species there may be considerable differences in size between zooecia of separate zoaria, and often between zooecia in the same zoarium. Zooecial size, therefore, should seldom be used as a basis for differentiating species in the absence of more definite characters. But Lang has described (e.g. 1921 : 224-227) as separate species, forms such as Dishelopom binoculata and D. claviceps, which differ only very slightly in their zooecial length. SHAPE OF ZOOECIA. It is strictly correct to say that in the great majority of cribrimorph Polyzoa the zooecia are polygonal and not broadly oval or elliptical. This polygonal form is most easily seen on the dorsal surfaces of unattached uni- laminar zoaria (as in Pelmatopora somptingensis Lang, PL 15, fig. 4), or in encrusting zoaria in which the frontal shields have been destroyed, revealing the vertical walls of the zooecia. On the front of the zoarium interzooecial secondary tissue may obscure the true limits of each zooecium, or the frontal shields of adjacent zooecia may appear almost contiguous as in the specimens of Castanopora shown in PI. 17. The upper surfaces of zooecia may vary in shape from almost circular to almost quadrate, though they are most commonly longitudinally oval. In a given zoarium, most zooecia have approximately the same shape, but a few usually differ, possibly because of growth restrictions imposed by a limited substrate. Apparently, if only a limited amount of space is available for development, a zooe- cium tends to fill that space its shape being to some extent controlled by it. Zooecial Walls other than the Frontal Wall Basal walls. A distinction may be made between the zooecia of some unilaminar encrusting zoaria and those which are now unattached. In the former, where the frontal shield is removed by wear, or artificially, there is often no indication of a calcified basal wall. This is shown in broken zooecia of Lagynopora and Hexacantho- CRETACEOUS CRI BRIMORPH POLYZOA (PELM ATOPORIN AE) 25 pora (PL 5, figs, i, 4). In contrast, zooecia of unilaminar encrusting zoaria of Pelmatopora usually have a substantial calcified basal wall. The zooecia of unattached uni- and bilaminar, or erect cylindrical zoaria always possess calcified basal walls, which may be smooth on their lower surface or have a number of scattered tubercles, as in Pelmatopora somptingensis. Lateral, proximal and distal walls. These vary in height, and may slope as in Lagynopora and Leptocheilopora. Large distal and lateral communication pores may be visible in the distal and lateral walls respectively. These are often seen in Lagynopora, Hexacanthopora and Leptocheilopora and, less frequently, in other genera. The distal communication pores are usually large, single, circular or oval, and may be regarded as septula possibly covered originally by multiporous septular discs. Ordinary septula are usually smaller. The lateral communication pores are smaller than the distal, but more numerous. Often three or four occur in line along the middle of each lateral wall, or they may be scattered. Distal and lateral communication pores are visible in the specimen of Leptocheilopora magna shown in PL 6, fig. 5, and in the single zooecium of Castanopora magnifica shown in Text- fig. 112. In the latter their structure is unusual : small, circular pores occur in the centres of oval depressions surrounded by low rims. Communication pores have not been seen in Pelmatopora or other genera : septula are probably present but very minute. Dietellae occur in Lagynopora, Hexacanthopora and Leptocheilopora they are visible, for example, in some zooecia of Hexacanthopora sexspinosa Lang (PI. 5, ng. 3). FRONTAL WALL. Lang (1921 : xxxvi) described the frontal wall of membrani- morphs, from which the cribrimorphs are to be derived as a " composite structure. Laterally and proximally it is calcareous [the gymnocyst], and slopes outwards, gradually becoming continuous with the lateral walls ; but all the middle and distal parts [the aperture] are occupied by a flat and chitinous roof ". In the Cretaceous cribrimorph Polyzoa a secondary frontal wall of costae (the frontal shield) is formed over the aperture, the only part of the primary frontal wall to be retained being the calcareous gymnocyst surrounding the aperture. The frontal membrane, or chitinous part of the primary frontal wall originally covering the aperture, is not preserved. PRIMARY FRONTAL WALL GYMNOCYST. The gymnocyst is apparently always smooth. It is variable in width, usually wider proximally to the frontal shield and narrower along its sides. Occasionally a narrow band of gymnocyst may extend round the distal and lateral margins of the orifice. The amount of visible gymnocyst is commonly diminished by close growth of the zooecia, and, in many genera of Cretaceous cribrimorphs, it is totally concealed by plentiful interzooecial secondary tissue. As in some species of Pelmatopora, the secondary tissue may con- tain lacunae through which the gymnocyst is locally exposed. SECONDARY FRONTAL WALL FRONTAL SHIELD. The general and detailed features of the frontal shield, and its relationship to other zooecial characters, provide one of the most useful means of differentiating genera and species in the Cretaceous cribrimorph Polyzoa. Essentially, the frontal shield is composed of a series of costae which develop from the edge of the gymnocyst and overarch the aperture, 26 CRETACEOUS CRIBRIMORPH POLYZOA (PELM ATOPORIN AE) usually fusing along the mid-line of the zooecium. This basic arrangement is com- plicated in various ways. There is often considerable morphological similarity between the frontal shields of fossil cribrimorphs and those of some of the Recent Cribrilinidae. The development of some features in Recent species (observed by Harmer and others) shows that some analogous characters in the fossils may have had an origin different from that suggested by Lang. Development and structure of the costae. Hincks has described the costae of Recent Cribrilinidae, such as those of Membraniporella nitida (Johnston) as " probably the equivalent of the marginal spines on many of the Membraniporae ". Harmer (1902 : 292) agreed with Hincks's opinion and again mentioned M. nitida, suggesting that the modified, overarched, marginal spines developed by closure of embayments in the edge of the gymnocyst (Text-fig. 2A-C). Harmer also figured (1902, pi. 15, fig. 7) the ancestrula and some young zooecia of a specimen of Cribrilina radiata (Moll), in which he suggested the costae are analogous to horizontal calcareous lobes occurring on the inner sides of the marginal spines of the Membraniporid ancestrula. Norman (1903 : 91) described a more complex development of costae and has shown that lumen pores and lateral costal fusions may be formed as the costae develop. Costae of four of the species described by Norman are shown in Text-fig. 2D-G, p. 27. Other modes of formation of costae were recorded, somewhat obscurely, by Waters (1923 : 545-573). Apparently, in the Recent species Lepralia otto-mulleriana (Moll), a thin calcareous lamina may gradually spread from the proximal and lateral margins of the aperture leaving uncalcified pores. Subsequently, irregular ridges may separate costa-like areas, each with one pore (Text-fig. 3C). In other speci- mens, irregular " broad spines " with small " nodulations " may spread secondarily from the proximal and lateral margins of the aperture and so produce a costate appearance (Text-fig. $A, B, p. 28). Thus the costae of different and the same species of Recent Cheilostomata may differ structurally and have developed in different ways. In those forms in which the costae are produced by apparent closure of embayments in the edge of the gymnocyst the costae are continuous tubular structures. The costae of all the Cretaceous cribrimorph Polyzoa described here appear to be of this type. It is possible that a costa with the structure described by Norman (1903) is not a simple tubular outgrowth of the type described by Harmer. Lumen lines may have been present in the costae of some Cretaceous species, but fine detail of this kind is easily destroyed during fossilization. Harmer has pointed out that Lang's studies confirmed palaeontologically the supposed Membraniporid origin of Recent forms with costate frontal shields. Lang (1921 : 6, text-fig. 5) compared Membraniporid and cribrimorph Polyzoan structures his text-figure is reproduced here, somewhat modified, in Text-fig. ^A, B, p. 29. Number of costae. In the Recent Cribrilinidae and in the Cretaceous cribrimorph Polyzoa the number of costae in any single zooecium of a given zoarium may vary considerably. lilies (1953) even suggested that zooecial dimensions provide a better basis for specific diagnosis in species of Rhiniopora [Castanopora]. The number of costae is often greater in longer zooecia and fewer in shorter ones. Similarly, CRETACEOUS CRIBRIMORPH POLYZOA ( PELM ATOPORIN AE) 27 adult zooecia usually possess more costae than young zooecia in the same zoarium, though in some species the reverse may be true. Taken alone, the number of costae is thus of little diagnostic value, but, provided a sufficient number of speci- mens is available, the general range in number of the costae may be used, in con- Ip m D. d II Icf is m E ts FIG. 2. A-C. Diagram showing the development of continuous tubular costae from closure of bays in the edge of the gymnocyst. D " Cribrilina annulata Fabricus " based on Norman's figure 1903, pi. 8, fig. 10. E. " Cribrilina balzaci (Audouin) " based on Norman's figure 1903, pi. 9, fig. 6. F. " Gephyrotes nitido-punctata Smitt " based on Norman's figure 1903, pi. 8, fig. 13- G. " Cribrilina innominata Couch " based on Norman's figure 1903, pi. 9, fig. 3. g, edge of gymnocyst ; is, intercostal space or " lacuna " ; l.c.f, lateral costal fusion ; //, lumen line ; l.p, lumen pores or pelmata ; m, median line of frontal shield ; p, non- calcareous papillae. junction with all other available characters, to differentiate species. Lang's state- ment (1919^ : 197) that the number of costae " tends to increase during development [in the Pelmatoporinae] but may be very much reduced catagenically " indicates the variability of this character. Lumen pores : pelmata : pelmatidia. The lumen pores which occur along the mid- line of each costa in some of the Recent Cribrilinidae are closely analogous to the 28 CRETACEOUS CRIBRIMORPH POLYZOA ( PELM ATOPORIN AE) pores which occur in the same position on the costae of many Cretaceous cribrimorph Polyzoa. However, Lang (1921 : xli) termed the latter pelmata and pelmatidia, and described them as " hollow upturned prolongations, presumably continued in the living organism as free spines, but appearing in the fossil as a row of broken ends ". In some species, such as the more complex forms of Pelmatopora, he dis- tinguished " primary, secondary, tertiary and quaternary " pelmata and pelmatidia B. FIG. 3. Development of costa-like structures in the Recent species Lepralia otto- mulleriana Moll. A, B, C, based on parts of Water's figures, 1923, pi. 17, figs, i, 2 and 5 respectively. c.l, thin calcareous lamina ; irn, irregular ridges with " nodulations " ; isn, irregular broad " spines " with " nodulations " ; n, " nodulations" ; p, pores. corresponding in position to equivalent lateral costal fusions. The terms " primary, secondary " etc. were used with reference to the supposed order in which the pelmata developed and shifted outwards from the median area of the frontal shield. In agreement with Harmer (1926 : 471) I regard the pelmata and pelmatidia as lumen pores, which, as in the Recent Cribrilinidae, have developed during the formation of the costae bearing them. In Recent specimens, as a costa is formed, the lumen pores are apparently left as uncalcified, membranous areas on its upper surface. There is no indication that the pores are formed first at the inner end of the costa and subsequently migrate towards its outer end, an hypothesis with which Lang attempted to account for the position of pelmata and pelmatidia in most of the CRETACEOUS CRIBRIMORPH POLYZOA (PELM ATOPORIN AE) 29 Cretaceous forms. Thus Lang stated (1922 : 6) " It is convenient to consider that the primary [first formed] pelma has shifted proximally on the costa, carrying with it a part of the median line of fusion, and that the secondary pelma has been added at the distal [inner] end of the costa. . . . This process is repeated in more ad- oral spines orifice operculum apertural bar apertural spines cosfae cryptocysf =-"- qymnocyst A. B. FIG. 4. A, B. Diagram showing the development of a cribrimorph polyzoan (B) from a Membraniporid (A). Modified from Lang (1921, text-fig. 5). Chitinous parts stippled. C-F. Types of costae, pelmata, pelmatidia and lateral costal fusions in Cretaceous- cribrimorph Polyzoa. C. Simple Pelmatoporid costae with long, single intercostal spaces and each with a large, oval pelma at the inner end. The cross-section shows the slight rim round the pelmata. D. Costae of Castanopora with numerous equally small pelmatidia and a corres- ponding number of lateral costal fusions, each curved parallel to the edge of the gymnocyst producing rows of somewhat oblong intercostal spaces. E. Costae of Ubaghsia with two very large pelmata, short lateral costal fusions and irregular intercostal spaces. The cross-section shows that the costae are wider than in other genera. F. Costae of Aeolopora each with a single boss-like pelmatidium and no lateral costal fusions. The cross-section shows the extended rim of the pelmatidia. 30 CRETACEOUS CRIBRIMORPH POLYZOA (PELM ATOPORIN AE) vanced species ". He summarized the supposed process in a series of diagrams (1919^ : 198, text-figs. 2-5 ; 1922 : 6, text-fig. 2). Pelmata and pelmatidia, or lumen pores, were recorded by Lang (19160 : 83, 84 ; 1922 : i) in all the genera which he assigned to the Pelmatoporidae. In the material studied here they have also been found in Lagynopora, Hexacanthopora, Lepto- cheilopora and Aeolopora. There is no reason to suppose, as Lang has done (1922 : 8), that the pelmata in Diacanthopora are the broken ends of branched spines. In agreement with Harmer (1926 : 471), I regard them also as lumen pores. Lang (1921) has recorded minute pores in the costae of Pliophloea (p. 172), Dishelopora (p. 217) and Histricopom (p. 227). Although he did not call these minute pores " pelmata " or lumen pores, I regard them as such. It is very probable that minute pelmata, discernible only under high-power magnification, are, or were originally, present in most of the Cretaceous cribrimorph Polyzoa but have been lost during fossilization. Although Lang stated (1922 15), "It is not possible to impose a very rigid line of demarcation between a pelma and a pelmatidium ", he has used the supposed difference between the two to separate some subfamilies. Very often, as in the more complex species of Pelmatopora, a graded series occurs with the largest lumen pore (pelma) at the outer end, successive pores becoming gradually smaller towards the inner end of each costa. In the simpler species of Pelmatopora and in Tricephalopora, there is often a single, large, oval pelma near the inner end of each costa. In Castano- pora a series of up to seven or eight equally small pores may occur, or, as in Aeolopora, a single, minute, boss-like structure with a central pore may be present near the inner end of each costa. The pelmata may have a distinct rim produced by local thickening of the costal wall round the pore. This feature is also found in Recent forms ; Waters (1923) has recorded such thickened pore edges produced during the development of the secondary frontal wall in Lepralia otto-mulleriana (Text-fig. 3Q. In other genera of Cretaceous cribrimorph Polyzoa lumen pores may not occur in a continuous series and may lack distinct rims, as in Leptocheilopora magna Lang (PI. 6, fig. i). The different types of pelmata and pelmatidia which occur in the Cretaceous material described here are shown in Text-fig. ^C-F. Lang's terms " pelmata " and " pelmatidia " are retained in the systematic descriptions, but only for convenience of reference to the size of the pores : pelmata are interpreted as large lumen pores, and pelmatidia as small lumen pores. I do not accept in any way Lang's hypothesis of their origin. Lateral costal fusions. Lang's concept of a " proximal shift " of pelmata and lateral costal fusions presupposes that both features are secondary modifications of the costae. In some Recent forms, however, lateral costal fusions, like the pelmata or lumen pores, are developed during the primary growth of the costae (Text-fig. zD-G) ; in others they may develop subsequently between established costae and divide an originally long, single intercostal slit into a series of small intercostal spaces. It is difficult to decide whether the lateral costal fusions which occur in some Cretaceous cribrimorph Polyzoa are formed, like the pelmata, during the initial growth of the costae or subsequently. Pairs of lateral costal fusions usually coincide with the pelmata on the costae. Norman (1903) suggested that in some CRETACEOUS CRIBRIMORPH POLYZOA (PELM ATOPO RIN AE) 31 Recent forms adjacent costae produce lateral processes which meet half-way between the two costae and fuse (Text-fig. 2E). In other cases he suggested that adjacent, irregular costae may touch at various points along their length producing apparent lateral fusions, e.g., in Membraniporella nitida (Text-fig. 2.D). In the Cretaceous material most of the costae are regular and the lateral fusions between them are distinct tubular structures, often curved parallel with the edge of the gymnocyst (Text-fig. 4/)). In some species, such as Ubaghsia ornata, in which the pelmata may be very large, the costae expand at the levels of the pelmata and the lateral fusions are correspondingly short (Text-fig. 4#). Lateral costal fusions are not always present where pelmata are developed Lagynopora, Hexacanthopora and Leptocheilo- pora have pelmata but no lateral costal fusions. Although the number of lateral costal fusions on each costa of the same frontal shield is usually constant, the larger costae may possess extra fusions. Intercostal spaces. As in the Recent Cribrilinidae, the intercostal spaces of Creta- ceous cribrimorph Polyzoa vary widely in shape and size. In many genera the spaces between adjacent costae are elongate, single openings (Text-fig. 46"). In others a series of lateral costal fusions subdivides the space between adjacent costae into a number of smaller intercostal spaces termed, by workers on Recent forms, " lacunae ". The term " lacunae " is used here, however, to describe openings in the interzooecial tissue. In some species with lateral costal fusions the outermost inter- costal spaces may be fairly constant in shape, but little diagnostic value can be placed upon this feature. In general, the intercostal spaces of the earliest, simpler, Cretaceous cribrimorph Polyzoa are wider than the costae they separate, but in the majority of later forms the reverse is true. The intercostal spaces may be filled with secondary calcareous tissue which spreads outwards from the median area of the frontal shield : this is well shown by some species of Lagynopora. Median area of fusion. The size and shape of this area may vary considerably in a given species between zooecia of different zoaria and even between zooecia of the same zoarium. Many median areas of fusion are very narrow, involving only the inner tips of the costae and almost confined to the mid-line of the frontal shield ; others are wider and fusiform producing a flattened top to the arched frontal shield. In some species of Lagynopora and of other genera, the costae may be firmly united for about two-thirds of their length by an outward extension of the median area of fusion. Lang's concept of a proximal shift along the costae of the pelmata and lateral costal fusions led him, in his descriptions of some Pelmatoporid species, to use the term " median area of fusion " to include all the frontal shield inside the outermost lateral costal fusions, which he regarded as parts of the original median area of fusion. Thus he described (1922 : 301) Pelmatopora somptingensis as having " two paired rows of perforations [intercostal spaces] in the original median area of fusion (now comprising the greater part of the intraterminal front- wall [frontal shield]) ". The median area of fusion of P. somptingensis is, in fact, very narrow (Text-fig. 96). The same remarks apply to other species with lateral costal fusions : these structures are not part of the median area of fusion. Different types of median areas of fusion, as defined here, are shown in Text-fig, $a-d. 32 CRETACEOUS CRIBRIMORPH POLYZOA (PELM ATOPORIN AE) Apertural bars. Lang (1921 : 20) has shown that the apertural bar of the less complex, earlier genera of Cretaceous cribrimorph Polyzoa is asymmetrical but that in later more complex forms it is symmetrical and composed of two costae firmly fused in the mid-line. There is often considerable variation in its form between different genera and species, and occasionally between specimens of the same species. The apertural bar may be straight and relatively featureless, as in Andriopora minor sp. nov., or distinctly " V " shaped, as in Leptocheiloporafdliozati. In Hexacanthopora FIG. 5. Types of median area of fusion in Cretaceous cribrimorph Polyzoa. a, Narrow median area of fusion found in less complex species of Pelmatopora ; b, narrow median area of fusion typical of frontal shields with numerous lateral costal fusions found in the more complex species of Pelmatopora ; c, d, Langynoporid frontal shields, (c) narrow median area of fusion, (d) very wide median area of fusion. Median area of fusion shaded with horizontal lines. sexspinosa it is curved with a prominent median process. In Lagynopora the median process of the apertural bar is more pronounced and usually bifurcated, producing two hollow spine-like processes which curve outwards from the mid-line of the orifice and fuse with the proximal-lateral oral spines forming a " Y "-shaped proximal oral shield. The costae composing the apertural bar may also possess pelmata or pelmatidia if these are present in the costae of the frontal shield. Secondary calcareous tissue may accumulate on the apertural bar, as in some genera of the Tricephaloporinae, spreading proximally as a tongue of tissue covering the median area of the frontal shield. The whole apertural bar is easily modified by wear, median processes being particularly easily destroyed. Diagrams of different types of apertural bars developed in the material studied here are shown in Text-fig. 6a-q. CRETACEOUS CRIBRIMORPH POLYZOA (PELM ATOPORIN AE) 33 TERTIARY FRONTAL WALL. Continued upgrowth of interzooecial secondary tissue (p. 40), combined with lengthening and expansion of the tissue of tubular secondary orifices (p. 35), and parts of other secondary structures, produces a prominent, irregular tertiary frontal wall above the general level of the frontal shields. This composite type of tertiary frontal wall is well developed in some species of Ubaghsia (Pis. 21-23). A less complex tertiary frontal wall is developed in some species of Tricephalopora. In some a tongue of secondary tissue, spreading from the apertural bar, forms part FIG. 6. Types of apertural bars found in Cretaceous cribrimorph Polyzoa. a-d, Apertural bars of Pelmatopora. (a) P. solearis, (b) P. d'orbignyi, (c) P. sompting- ensis, (d) P. palmata. e-g, Apertural bars of Castanopora. (e) C. magnified, (f) C. castanea, (g) C. jurassica. h, Apertural bar of Ubaghsia ornata with four large pelmata. i, j, Apertural bars of (i) Andriopora major, (j) A. minor, k, I, Apertural bars of (k) Aeolopora distincta, (I) A. nebulosa. m, n, Apertural bars of (m) Leptocheilo- pora filliozati showing the median ridge which is continued along the mid-line of the frontal shield and (n) L. vulnerata in which there is a prominent median facet on the distal side of the " V "-shaped apertural bar. o, Apertural bar of Hexacanthopora sexspinosa with prominent median process, p, q, Apertural bars of two species of Langynopora showing the bifurcated median processes and their fusion with the proximal-lateral oral spines, (p) L. pustulosa, (q) L. ampulla. For convenient comparison each orifice and apertural bar is drawn at approximately the same scale, irrespective of actual size. GEOL. 6, i. 3 34 CRETACEOUS CRIBRIMORPH POLYZOA (PELM ATOPORIN AE) of a tertiary frontal wall, in others this structure is combined with a general up- growth of tubular secondary orifices and interzooecial secondary tissue to form a more complete tertiary frontal wall, which is less raised above the general level of the frontal shields than in Ubaghsia. Lang (1921 : xlix) has observed that " Hippi- opora appears to be the only described Cretaceous Cribrimorph outside the Pelmato- poridae which possesses a tertiary front- wall ". ORIFICES. The primary orifices of young zooecia vary in shape but are sharply denned, and, apart from being larger, may remain still sharply defined and other- wise unmodified in adult zooecia. Accumulation of secondary calcareous tissue round a primary orifice, or other medications, produces a secondary orifice. general ioss T of peculiar shape _____ SUPERCRIBRILINE ^..PLIOPHLOEAN ------ SUPER-SEMICIRCULAR Primitive jSC -SEMICIRCULAR im _____ SUB-SEMICIRCULAR FIG. 7. Evolution and terminology of orifices suggested by Lang. Diagram based on Lang (1921, text-fig. 10). PRIMARY ORIFICES. Lang (1921 : xlvi) suggested that the primary orifice in Cre- taceous cribrimorph Polyzoa, although varying in shape, tended to pass from a " primitive " so-called " sub-semicircular " or " semicircular " form to more com- plex shapes. This evolutionary sequence is summarized in Text-fig. 7 ; the terms used are those devised by Lang to describe ten different shapes which he recognized. He was well aware of the uncertainty of suggesting such a sequence, for he stated, " This evolution must not, however, be strained. It is easy to see how a normal aperture [orifice] may become distinctly pliophloean without passing through a cribriline stage ". The present work shows how, in most genera, and often within a given species, the shape of the orifice can be very variable. This feature is discussed and illustrated in some detail under the remarks on Leptocheilopora filliozati (p. 115), of which many specimens are available. Similar remarks apply to other species of Leptocheilopora and to species of other genera. Pelmatopora often has a comparable range of variation in shape of the primary orifice. Where proximal-lateral constrictions occur in an CRETACEOUS CRIBRIMORPH POLYZOA (PELM ATOPORIN AE) 35 orifice they may be more or less pronounced, and the shape of the proximal margin may vary according to the form of the apertural bar. Conversely, but in only a few species, the orifice may have a fairly constant shape, as in Leptocheilopora magna Lang. Thus the shape of the primary orifice is not usually of diagnostic value. It may vary in shape naturally or its form may be changed by wear ; probably the median proximal notch found in some orifices of Leptocheilopora tenuilabrosa (p. 107) is due to wear. No general evolutionary sequence in the shape of the primary orifice could be distinguished in the material studied here. In contrast to the variable shapes which may occur, the length and breadth of the orifice in a given species are often constant within a very small range. Lang (1919^ : 198) only briefly considered the size of the orifice in relation to that of the frontal shield, and suggested " This tends, as a rule, to increase ; but, in some cases . . . becomes smaller catagenetically ". In the genera studied here it is difficult to find evidence to support this view. It is apparent, however, that in a given species the length (hr) and the width (Ir) remain fairly constant although the shape may vary. This feature is again well shown by Leptocheilopora filliozati (p. 115) in which the dimensions of the orifice, irrespective of its shape, are fairly constant, even in ab- normal zooecia. Lang has suggested (1919^ : 197) that the shape of the orifice " tends to alter from being rather longer than wide to rather wider than long ", or, in other words, that Ir generally exceeds hr in later genera and species. In those genera revised here in which the form of the primary orifice is not secondarily modified in the adult stages, I can find no indication of this tendency. It is apparent that species with orifices which are wider than high predominate throughout. SECONDARY ORIFICES. In many genera the primary orifice is modified in adult zooecia by the marginal accretion of secondary calcareous tissue. A slightly thickened oral rim may be developed as in Pelmatopora, or increased accumulation may pro- duce a tubular secondary orifice, as in some species of Tricephalopora. Other struc- tures, such as oral spines and avicularia, may be incorporated in the general up- growth of calcium-carbonate round the orifice, as in Ubaghsia, or distinct distal and proximal oral shields may be produced, as in Lagynopora. Where a slightly thickened oral rim is developed the secondary tissue is usually accumulated fairly evenly round the distal and lateral margins. The proximal margin of the orifice, formed by the apertural bar, is seldom affected. Thus, although the dimensions of the orifice are slightly decreased they usually remain the same in proportion to one another and may be used, in conjunction with all other available characters, in specific diagnosis. In genera with a tubular upgrowth of calcareous tissue round the primary orifice the secondary orifice is often very different in shape and size, and is separated from the primary orifice by a peristome of variable length. The formation of distal and proximal oral shields, incorporating other structures, is considered later. ORAL SPINES. In some Recent cheilostome Polyzoa the shape and size of the oral spines varies widely even in a single species. Most oral spines are hollow in the centre, but they may be long, unbranched and rod-like, or bifurcated, or variously branched. 36 CRETACEOUS CRIBRIMORPH POLYZOA (PELM ATOPORIN AE) Frequently only the proximal-lateral pair of oral spines is branched, the remainder being unmodified. The oral spines are branched, for example, in some species of Chaperia, Scmpocellaria and AmphiUestrum (Text-fig. 9). The spines may be jointed near the base so that the upper part is easily removed by wear, leaving a small, hollow spine-base (Text-figs. 8c ; gk-n) . In most fossil specimens, including many of the Cretaceous cribrimorphs, only the bases of the oral spines are preserved. They may have been jointed near the base and have broken off at this point, or, as is more probable, they may have been un- FIG. 8. Oral spines in Recent species. a, b, Cribrilina alcicornis Jullien (1883, pi. 14, figs. 24, 25), (a) expanded, lobed oral spines preserved, (b) a worn orifice, the oral spines reduced to hollow spine-bases, and two worn avicularia. c, d, Chaperia " quadrispinosa " [B.M. (N.H.) Zool. Dept. Polyzoa Coll. slide 5490], (c) distal end of worn zooecium with four hollow oral spine- bases and distal-median avicularium, (d) distal end of unworn zooecium with four complete oral spines and distal-median avicularium. jointed and worn down to the base. Thus the apparent simplicity and similarity of the oral spines in many genera of Cretaceous cribrimorphs may be largely due to wear. However, bifurcated and branched oral spines are preserved in some genera : Ubaghsia may possess branched spines, and some species of Pelmatopora have dis- tinctive bifurcated oral spines. Jullien (1886, pis. 17-19) figured branched spines in Ubaghsia [Steginopora] meudonensis, U. [5.] ocellata, U. [S.] demorgani and in U. reticulata (see PL 22). All these species possess a substantial tertiary frontal wall which evidently protected the oral spines from wear. The variously modified oral spines which occur in some species of Pelmatopora were interpreted by Lang (1916^ : 102 ; 1919^ : 200 ; 1921 : xxxiii-xxxiv ; 1922 : 247) as secondary avicularia which have replaced the oral spines. I have examined a very large number of specimens of Pelmatopora, including those seen by Lang, and have found nothing to suggest CRETACEOUS CRIBRIMORPH POLYZOA (PELM ATOPORIN AE) 37 \m FIG. 9. Types of oral spines in three genera of Recent cheilostomatous Polyzoa. a-d, " Scrupocellaria frondis " [B.M. (N.H.) Zool. Dept. Polyzoa Coll. slide 31.12.19.76]. Branched oral spines from four zooecia of the same zoarium. e-g, " Scrupocellaria securifera " [B.M. (N.H.) Zool. Dept. Polyzoa Coll. slide 28.3.6.170]. Small oral spines tending to bifurcate, h, " Amphiblestrum cervicorne " [B.M. (N.H.) Zool Dept. Polyzoa Coll. slide 87.12.9.328]. Front view of paired, branched lateral oral spines and two unbranched distal oral spines, i-j, " Chaperia sp." [B.M. (N.H.) Zool Dept. Polyzoa Coll. slide TN 863 A]. Front and side views of paired, bifurcated lateral oral spines and four unbranched distal oral spines, k-m, " Chaperia cervicornis ". (K) [B.M. (N.H.) Zool. Dept. Polyzoa Coll. slide 99.5.1.548] stout, bifurcated oral spine, jointed at the base and with the central hollow visible ; (/) [B.M. (N.H.) Zool. Dept. Polyzoa Coll. slide 4440] branched oral spine, jointed at the base and with large central hollow; (m) [B.M. (N.H.) Zool. Dept. Polyzoa Coll. slide 99.7.1.1202] bifurcated oral spine, jointed at the base, n, " Chaperia galeata " [B.M. (N.H.) Zool. Dept. Polyzoa Coll. slide 536]. Unbranched oral spine, jointed at the base and with central hollow. 38 CRETACEOUS CRIBRIMORPH POLYZOA (PELM ATOPORIN AE) that the structures are avicularian. Their bifurcated form, as in Pelmatopora gregoryi, is a condition which is unknown in avicularia, and they lack true avicularian charac- ters. They occur consistently as part of the symmetrically arranged series of spines round the orifice, and they are most closely comparable with the expanded and bifurcated oral spines which occur in some Recent cheilostome Polyzoa. Lang (igi6a ; 1919) has referred to the structures as " avicularia " and later (1921) as a " kind of (supposed) aviculoecia [avicularia] ". In his fullest description of Pelmatopora (1922) he was evidently undecided as to their nature. In a discussion of " the elaboration of the aperture [orifice] " he has stated (p. 244) "... what appears to be a new structure [in Pelmatopora] occurred on the distal edge of the secondary apertural [oral] rim, corresponding in position to the obliterated distal pair of apertural [oral] spines, though probably lying just outside them ; it is even possible that the apparently new structure was a new development of the apertural [oral] spines, as the evidence of specimen D . 23397 f P- brydonei is not altogether conclusive. ... In this specimen the right distal apertural [oral] spine and the new structure on the same side are both present and seem to be separate. On the other hand, the astogenetic evidence of Pelmatopora saltdeanensis [= P. gregoryi] points to this supposed new structure being but a development of the distal pair of apertural [oral] spines. ... It is probable that, if not developments of apertural [oral] spines, these projections are aviculoecia [avicularia], and that the pointed depressions on their distal surfaces are the rostra. During evolution they enlarge, lengthen, and become bifid ...**. In his section on the systematics of Pelmatopora Lang referred to the structures as " secondary aviculoecia ". The structure in D . 23397 is discussed in detail under the remarks on P. brydonei (p. 166) and is figured (Text-fig. j8a, b). It is an enlargement of the unmodified oral spine, and regeneration of the whole orifice (see Lang, 1922 : 294) has not occurred. As Lang suggested in his reference to the " astogenetic evidence " of P. saltdeanensis [= P. gregoryi] and in his remarks on that species (1922 : 319), a comparison of oral spines of young and adult zooecia in a given zoarium points to his "secondary avi- culoecia " as only a development of the unmodified distal oral spines. In the species of Pelmatopora in which the adult zooecia possess enlarged oral spines, 1 the young zooecia have unmodified spines which gradually become expanded or bifurcated as the zooecia mature. In a given species of Pelmatopora, as in Recent cheilostome Polyzoa, the size and shape of the enlarged oral spines may vary considerably. This variation, which is produced largely by different degrees of wear, is shown particularly in Text-fig. Sia-d (P. marsupitorum) , Text-fig. 88a-/ (P. gregoryi), Text-fig. gja-g (P. somptingensis) , and in Text-fig. loia, b (P. palmata). It follows that variations in shape of the enlarged oral spines are not always suitable characters on which to differentiate species. The oral spines are always arranged symmetrically around the orifice, whatever their number. They are often equally spaced, but occasionally occur in paired groups of two or three. In the material studied, the adult zooecia in some genera have fewer 1 Pelmatopora coryli, P. quadrivolucris, P. brydonei, P. marsupitorum, P. gregoryi, P. somptingensis and P. palmata. CRETACEOUS CRIBRIMORPH POLYZOA (PELM ATOPORIN AE) 39 oral spines than the young zooecia (e.g., some species of Pelmatopora}. In other cases the number of oral spines is the same in adult and young zooecia. There is no indication that the later species tend to have fewer oral spines than the earlier ones. In the following Table, 15 species are listed in which it has been possible to compare the numbers of oral spines in young and adult zooecia. It can be seen that, in the four genera represented, the number of oral spines is more variable in the young stages, and that reduction in number, if any, is commonly to four oral spines in the adult zooecia. Horizon M. cortestudinarium and M. cor-anguinum Zones M. cor-anguinum Zone .... Marsupites Zone ..... O. pilula Zone ..... O. pilula and B. mucronata Zones G. [A.] quadrata Zone .... Marsupites and G. [A . ~\quadrata Zones O. pilula and G. [A.] quadrata Zones B. mucronata Zone and O. lunata Chalk B. mucronata Zone and Maastrichtian B. mucronata Zone and O. lunata Chalk Species Lagynopora lagena L. birlingensis L. praecursor L. ollula L. urceolus L. vasculum L. amphora L. ampulla L. furcifera Hexacanthopora sexspinosa Leptocheilopora filliozati L. vulnerata L. magna Castanopora castanea C. dibleyi Number of oral spines Young Adult zooecia zooecia 4. 5 or 6 4 4 4 6 4 6 or 7 4 or 5 5 or 6 4 4, 5 or 6 4 6 4 5 4 5 or 6 4 6 or 7 4, 5 or 6 4, 5 or 6 4 7 7 4 4 4 4 4 or 5 4 or 5 Lang (1921 : xliv) has stated that the oral spines " are primarily six in number " and that " In most families of Cretaceous Cribrimorphs the primary six apertural [oral] spines have been reduced to four ". He also mentioned a number of genera and species as not showing this tendency. From the exceptions mentioned by Lang, and from the evidence of the present work, it becomes difficult to recognize a general reduction in the number of the oral spines. The most that may be said is that some species of some genera show a variable reduction in the number of oral spines, others show no reduction, but none shows an increase. ORAL SHIELDS. Accumulation of secondary calcareous tissue round the orifice may conceal the oral spines or they may form a visible part of a distal or proximal oral shield. Occasionally, as in the species of Pelmatopora with enlarged distal oral spines, the space between the spines may be filled with secondary tissue forming a small distal oral shield. More frequently, as in Lagynopora, the proximal-lateral pair of oral spines fuse with the bifurcated median process of the apertural bar thus forming a prominent " Y "-shaped proximal oral shield (Text-fig. 6p, q). In Ubaghsia the proximal-lateral oral spines may be enlarged, but otherwise unmodified, and fused on to the distal side of large lateral oral avicularia. Lang (1921 : xlv) 4 o CRETACEOUS CRIBRIMORPH POLYZOA ( PELM AT O PO R I N AE) mentioned other kinds of proximal and distal oral shields in which the oral spines may be involved, but these are not found in the genera described here. In genera with prominent hyperstomial ovicells the distal pair of oral spines often flank the entrance to the ovicell ; in some cases they appear to be displaced by it (e.g., Text- fig. 67 Pelmatopora fecampensis). A projecting distal oral shield may be formed in species with endozooecial ovicells. In these the space between the distal oral spines may be filled with secondary calcareous tissue (e.g., Text-fig. 89 P. gregoryi). INTERZOOECIAL SECONDARY TISSUE. Lang has pointed out (1922 : 4) that the absence or extreme scarcity of interzooecial secondary tissue may be a useful diag- nostic character. Many of the genera he described (1921) are devoid of it, and in the present material, it is absent in Lagynopora, Hexacanthopora, Leptocheilopora and Aeolopora. When interzooecial tissue is present it may be very variable in amount. In the Pelmatoporidae, for example, a few genera, such as Castanopora, lack it, but in others, such as Pnictopora (Lang, 1922 : 145) the characters of the zooecia are almost totally concealed by it. Pelmatopora provides a good example of the extreme variation in amounts of secondary tissue which may be present in different species of the same genus and in different specimens of the same species. Thus in P. calceata there is no interzooecial secondary tissue ; in P. crepidaria it is only very slightly developed near the orifices ; and in P. solearis it may occur in contour-like ridges between the zooecia or it may be abundant, filling the interzooecial valleys. Other species of Pelmatopora may have extremely variable amounts of interzooecial secondary tissue, but it is generally abundant, either filling the interzooecial valleys or standing up as irregular ridges above the general level of the frontal shields. The amounts of interzooecial tissue vary so widely that it is not a character which is useful for specific differentiation. Thus, although Lang (1922 : 319) separated P. ccllium [= P. gregoryi] from P. saltdeanensis [P. gregoryi] solely on its sup- posedly greater accumulation in the former, the two species are alike in other characters and are here regarded as synonymous. Apparently there is a tendency, seen in some young zoaria, for interzooecial tissue to be concentrated near the orifices in the early stages of its accumulation. In later stages, if it is at all abundant, it is fairly evenly distributed in the interzooecial valleys. Its continued accumulation, spreading out from the adult parts of a zoarium, may almost obscure the young zooecia. The ancestrula is often thus covered. In the early stages of zoarial growth, before deposition of interzooecial tissue is complete, the gymnocysts of the zooecia may remain locally exposed. As accumu- lation continues, irregular openings or lacunae are maintained. These expose tissue which was deposited earlier or, occasionally, small areas of the gymnocyst may remain visible. Lang (1921, text-figs. 7-9) has summarized three stages in the accumulation of interzooecial secondary tissue. It is difficult to be certain whether the tissue is first deposited in a narrow band round the gymnocyst as Lang has shown (text-fig. 7). In the material described here, the interzooecial tissue is apparently not deposited in a narrow ridge near the edge of the gymnocyst, but in a thin layer spreading from isolated points in the lowest parts of the interzooecial furrows. Subsequently, CRETACEOUS CRIBRIMORPH POLYZOA (PELM ATOPORIN AE) 41 as shown by Lang (text-figs. 8, 9), lacunae remain in the accumulating tissue, but are gradually eliminated as it is built up into irregular interzooecial ridges. General upgrowth of interzooecial tissue may contribute to the formation of a tertiary frontal wall (p. 33). AVICULARIA. Workers on Recent and Tertiary cheilostome Polyzoa usually dis- tinguish two main types of avicularia : (a) " adventitious " forms which occupy various positions on the outside walls of normal zooecia, and (6) " vicarious " or " interzooecial " forms which occur in series with normal zooecia. The terms " interzooecial " and " vicarious " are usually regarded as interchangeable. In the Cretaceous cribrimorph Polyzoa, however, I distinguish between inter- zooecial and vicarious avicularia. The former are usually much smaller than the zooecia which they accompany and they do not occupy positions which would usually contain normal zooecia. The latter are often as large as, or larger than, the zooecia with which they occur, and occupy spaces which would otherwise be taken up by normal zooecia (Text-fig. ioa). Adventitious avicularia are rare in the Cretaceous cribrimorphs. Lang (1921 : 166) has recorded distal adventitious avicularia in Monoceratopora. In the material des- cribed here, larger, apparently adventitious, distal avicularia occur in Castanopora armata sp. nov. (Text-fig. 103). Vicarious avicularia are also infrequent in the Cretaceous cribrimorph Polyzoa. Some zoaria of Leptocheilopom tenuilabrosa (PL 7 ; Text-figs. 47, 48) possess very distinctive, large, spatulate, costate vicarious avicularia with distal apertural spines. Levinsen (1907 : 155, pi. opp. p. 160, figs, i, ib, ic) has recorded large, spatulate, vicarious avicularia of a more usual type in Castanopora [Cribrilina] labiata (Text- fig. io&). Interzooecial avicularia occur very commonly in many genera of the Cretaceous cribrimorphs. They vary considerably in size, shape, number and position, and they may be directed distally, proximally, or variously. Pelmatopora affords a good example of the variation in detail which may occur in the interzooecial avicularia of one genus (Text-fig. loc-g) and within a given species of one genus (Text-fig. g8a- / P. somptingensis) . The shape of interzooecial avicularia is easily modified by wear. Sharply pointed rostra, which occur in various species of Pelmatopora and Castanopora, are often removed by wear leaving an apparently oval avicularian aperture. It may thus be misleading to record as oval the avicularia of species of which only one or very few specimens are available. This may be so in the case of Pelmatopora calceata. Similarly the transverse bar which may divide the rostrum of an avicularian aperture from the proximal portion is often broken, and it is difficult to decide whether the remain- ing lateral constrictions are the broken ends of such a transverse bar or true condyles on which the mandible was hinged (Text-fig. loh). Interzooecial avicularia are often raised on fairly stout stalks, as in Pelmatopora somptingensis (Text-fig. 980, 6). In avicularia of this type, very little wear can remove the rostrum completely and reduce the visible structure to an oval cross-section of the stalk. Where the avicularia are paired, one on either side of an orifice, they are often secondarily thickened and raised on very stout stalks which may fuse above the 42 CRETACEOUS CRIBRIMORPH POLYZOA (PELM ATOPORIN AE) orifice, forming part of the proximal oral shield. This structure is well developed in Ubaghsia ranunculus (Text-fig. 117) and in other species of the same genus. Occa- sionally, as in Haplocephalopora (Lang, 1922 : 94), the avicularia may be very small and completely raised on the rim of a secondary tubular orifice. interzooecial vicarious T -5 adventitious f 9 rostrum distal. :end .calcareous shelf transverse bar. lateral constrictions: proximal end ^ FIG. 10. Types of avicularia in Cretaceous cribrimorph Polyzoa. a, Diagram showing the occurrence of the three main types, b, Vicarious avicularium of Castanopora labiata (Levinsen). c-g, Interzooecial avicularia of Pelmatopora, (c) P. gregoryi, (d) P. somptingensis , (e) P. calceata, (f, g) P. marsupitorum. h, General terminology of avicularia. In species with abundant interzooecial tissue the avicularia may be almost im- mersed, and it becomes difficult to decide whether they are interzooecial or adven- titious. Judging from the avicularia of species which lack interzooecial tissue the great majority appear to be truly interzooecial rather than adventitious. Waters (1923) has observed that Lang's text-figures of Cretaceous cribrimorph Polyzoa (1921 ; 1922) give the impression that most avicularia grow out of parts of gymno- cysts of the zooecia, but that in his plates Lang has not shown this relationship. There is no indication that the majority of avicularia are adventitious. CRETACEOUS CRIBRIMORPH POLYZOA (PELM ATOPORIN AE) 43 Waters (1923) has also pointed out that there is great variation in the avicularia of some Recent cheilostomatous Polyzoa, and that there are genera, and even species, in which they are sometimes present and sometimes not. It has already been men- tioned that in the Cretaceous cribrimorphs there is considerable variation in the interzooecial avicularia, but provided only well-preserved material is used and that avicularian characters are considered in relation to all other available features, the avicularia are certainly of value for differentiating species. In some species the avicularia are always distally pointed and directed and paired near the orifices, while in others they may have a noticeably sporadic distribution and be variously directed. Avicularia of two or more distinct sizes may be present, as in Hexacanthopora sexspinosa. In the material described here the general charac- ters of the avicularia of a given genus are fairly constant although the detailed characters may vary. Thus, in Leptocheilopora, apart from the large vicarious avi- cularia of L. tenuilabrosa, avicularia are absent. Those of Lagynopora are commonly very large and oval with lateral constrictions. In Castanopora they are usually long and pointed with somewhat spatulate rostra and often with transverse bars ; in Pelmatopora the unworn avicularia generally have pointed rostra and often lack transverse bars. The " secondary aviculoecia [avicularia] ", which Lang described as occurring in the more complex species of Pelmatopora, are modified oral spines. The structures have been discussed already (p. 38). In the interzooecial avicularia of the material described here no example has been found in which minute spines are present on the distal margin of the avicularian aperture. HETEROZOOECIA OTHER THAN AVICULARIA. These are apparently rare in the Cre- taceous cribrimorph Polyzoa. In some species of Pliophloea, Lang (1921 : 174) has recorded interzooecial " swoUen and hollow " tissue with small round pores and has suggested that the structures are " cenoecia " [kenozooecia] . In the present work, one specimen of Aelopora distincta, 0.40658, was found to have clusters of very small, convex, smooth heterozooecia with large oval apertures on their upper surfaces (PI. i, fig. 5). These structures may be kenozooecia. Heterozooecia other than avicularia have not been found in the other genera and species studied. OVICELLS. I agree entirely with the remarks made by Brown (1952 : 36) in a general discussion on the ovicells of the Cheilostomata. The present study shows that his remarks are completely applicable to the ovicells of Cretaceous cribrimorph Polyzoa. Brown stated " In the majority of the Cheilostomata the ovicells appear as glo- bular distal chambers sometimes resting lightly on and sometimes completely im- mersed in and covered by the frontal wall of the distal zooecium. Gradations between these two forms can be traced and no distinct boundary can be defined between the first or hyperstomial type (Text-fig, na), and the second or entozooecial [endozooecial] type (Text-fig. 116). In fact, Silen (1944) has shown that in the Anasca there is essentially no difference between these two forms so far as their structure is con- cerned, and I have no doubt that the same remarks will be found to apply to those ovicells of the Ascophora which are of the same type. . . . Thus it appears impossible 44 CRETACEOUS CRIBRIMORPH POLYZOA (PELM ATOPORIN AE) to sustain the view of some workers that the difference between " hyperstomial " and " entozooecial " ovicells can be used to subdivide not only genera but also families. . . . However, the terms are undoubtedly useful for descriptive purposes . . . ". The examples given by Brown of the occurrence of both types of ovicell in species of the same genus and of the use of the two forms for subdivision of families can be paralleled by examples from the Cretaceous cribimorph Polyzoa. In Pelmatopora the globular ovicells may be external, as in P. fecampensis (Text-figs. 66-68), or partly concealed by the wall of the distal zooecium, as in P. quadrata (Text-fig. 64), or completely concealed, producing externally only a distal transverse shelf over the orifice, as in P. marsupitorum (Text-fig. 82), P. somptingensis (Text-fig. 990, b) and P. gregoryi (Text-fig. 89). Lang (1921 : 4-6) has used the two types of ovicells to separate into two major groups the eleven families which he recognized in the Cretaceous cribrimorphs. One group with four families, including his Pelmato- dz, FIG. ii. Two types of ovicell in Cretaceous cribrimorph Polyzoa. a, Hyperstomial. b, Endozooecial. dz, distal zooecium ; ec, ectooecium ; ech, brood chamber ; en, endooecium ; mv, median vesicle ; op, operculum. (After Harmer, 1926, text-fig, i, and Brown, 1952, text-fig. 5.) poridae, he diagnosed as having endozooecial ovicells ; the remaining families he grouped together as having hyperstomial ovicells. Lang's statement (1921 : xxxv) that " the ovicell is of the same type throughout any given family of Cretaceous Cribrimorphs " is incorrect. Following general usage (e.g. Brown, 1952 : 37) the outer and inner layers which compose the wall of the ovicell are termed " ectooecium " and " endooecium " respectively " endooecium " is used in the present work as an alternative to " entooecium ". In the hyperstomial ovicells in the present material the endooecium is apparently always smooth and complete. The ectooecium may be complete, or marginal with a median-proximal fenestra which exposes part of the endooecium. The ectooecium is often smooth, but diagonal and median ridges may be present, or it may be costate as in Leptocheilopora tenuilabrosa (Text-figs. 46, 47), or corrugated as in some speci- mens of Aeolopora distinda (Text-fig. 16). The upper margin of the opening of the ovicell may have a distinct labellum bounded by lateral slits, as in Aeolopora, or it may be entire as in the majority of genera and species. The opening of the ovicell is frequently flanked by a pair of oral spines, but equally often these may be obscured by the growth of the ovicell. Occasionally the growth of hyperstomial ovicells may displace the oral spines this has apparently happened in some specimens of Pelmatopora fecampensis. CRETACEOUS CRIBRIMORPH POLYZOA (PELM ATOPORIN AE) 45 The presence of endozooecial ovicells is often completely concealed by interzooecial secondary tissue. Endozooecial ovicells may, however, produce a distal oral shield by the development of a distal transverse shelf filling the space between the distal pair of oral spines. Other types of ovicell have been distinguished by Levinsen (1909), Canu & Bassler (1920), Brown (1952) and by other authors. In the material studied here I have seen only hyperstomial and endozooecial types. YOUNG ZOOECIA AND ANCESTRULAE. Only two generalizations seem to be true of the young zooecia of all the Cretaceous cribrimorph Polyzoa. They are always smaller than the adult zooecia, and in any given zoarium the young zooecia never possess fewer oral spines than the adult zooecia. The general characters of young zooecia, compared with the equivalent characters of the adult zooecia in any given zoarium, may be summarized briefly as follows : (1) Size and shape of zooecia (2) Extent of gymnocyst . (3) Frontal shield (4) Number of costae (5) Number of pelmata and lateral costal fusions (6) Median area of fusion . Always smaller, but equally variable in shape. Often more widely exposed, due partly to the general absence of interzooecial secondary tissue. Often apparently more arched, again partly due to the absence of interzooecial second- ary tissue. Very commonly less, but occasionally the same or more. Very commonly less, but may be the same. Often narrower, but may be relatively as wide. Usually simpler, lacking secondary modifica- tions such as median processes or extra tissue. Always smaller and usually the same shape, but liable to exhibit the same degree of variation in relative hr : Ir values. Often greater or the same, but never less. Commonly absent or scanty. Usually smaller and sporadic, but otherwise similar. The majority of these remarks could be applied to the ancestrula of any given zoarium when it is compared with the young or adult zooecia. Measurements In each species studied, measurements are given where possible for the ancestrula, young and adult non-ovicelled zooecia and avicularia of parts of zoaria where normal growth appears to have taken place. It has been pointed out already (p. 24) that zooecial size may vary so greatly, often within a single zoarium, that in the absence (7) Apertural bar (8) Primary orifice (9) Number of oral spines . (10) Interzooecial secondary tissue (n) Avicularia .... 46 CRETACEOUS CRIBRIMORPH POLYZOA (PELM ATOPORIN AE) of more definite characters it should seldom be used as a basis for differentiating species. On the other hand, the length and breadth of the orifice in a given species are often constant within a very small range and when considered in relation to all other available characters are often of value for specific differentiation. The margins of the primary orifice are well defined and it is possible to make accurate measurements. In contrast, measurement of the zooecia is often made difficult by the fact that the distal and proximal walls may slope, and by the accumu- lation of interzooecial secondary tissue which obscures the true zooecial boundaries. The following abbreviations are used in the present work : Lz = length of zooecium. lz = width of zooecium. hr = length of orifice. lr = width of orifice. Lc = length of caudae. lc width of caudae. The first two abbreviations are also used for the length and width of avicularia. The last two are used in the description of Andriopora major sp. nov. (p. 268). Terminology Brown (1952 : 32) has already commented on the large number of new terms which Lang (1913-19 ; 1921 : xxvi-li) introduced in his studies on the Cretaceous cribri- morphs to describe the " skeleton as distinguished from the tissue which secretes it ". I agree that there is no need in practice for such a complete duplicate terminology, and accordingly follow the general usage of modern zoologists, although I retain a few of Lang's terms such as "apertural bar". See also Lagaaij (1952 : 12). ADULT ZOOECIA. See Zooecia. ANCESTRULA. The first zooecium of a zoarium, formed by the metamorphosis of the larva. APERTURAL BAR. Transverse proximal margin of the orifice formed by the fusion of the most distal pair of costae symmetrical in all but the earliest Cretaceous cribrimorph Polyzoa. APERTURE. The opening occupied in life by the frontal membrane. Used loosely by earlier workers and by Lang in the sense of the term " orifice " as defined here. AVICULARIA. Heterozooecia provided in life with a powerful musculature producing movement in a mandible. They may be (a) adventitious occupying various positions on the external walls of normal zooecia ; (b) vicarious as large as, or larger than, the zooecia with which they occur, and occurring in positions usually occupied by normal zooecia ; or (c) interzooecial usually much smaller than the zooecia which they accompany, not occupying positions which would usually contain normal zooecia. CAUDAE. Elongate, narrow, tubular, proximal part of the gymnocyst in some uni- serial genera. COMMUNICATION PORES. Pores perforating the walls separating two zooecia (see also dietettae}. [Syn., septulum (pi., septula] a single small pore. Some of the large, CRETACEOUS CRIBRIMORPH POLYZOA (PELM ATOPORIN AE) 47 single communication pores which occur in some genera of Cretaceous cribri- morph Polyzoa may have contained multiporous septular discs or thin disc-like structures with numerous small pores.] CONDYLES. The tooth-like pivots of the operculum or the mandible. COSTAE. [Syn., costulae.] Modified marginal spines, overarching the frontal membrane and forming the frontal shield in cribrimorph Polyzoa. CRYPTOCYST. A more or less horizontal calcareous lamina on the basal side of the frontal membrane developed from the edge of the gymnocyst, but not completely subdividing the body-cavity. DIETELLAE. Small enclosed spaces at the base of the distal and distal-lateral walls of the zooecia of certain Cheilostomata, and connected with the zooecia by communication pores. DISTAL. The portions of a structure on the side away from the origin of growth or from the ancestrula. DORSAL. The side of a zooecium opposite that composed of the frontal shield and orifice, or the side of a zoarium opposite that bearing the apertures [syn., back, reverse] . ECTOOECIUM. Outer layer of the ovicell wall. ENDOOECIUM. Inner layer of the ovicell wall [syn., Entooecium]. ENDOZOOECIAL. Type of ovicell which may be completely immersed in and covered by the frontal wall of the distally adjacent zooecium, while opening into the vestibular arch [syn., Entozooecial]. FENESTRA. Uncalcified area in the ectooecium of an ovicell through which the endooecium is exposed. FRONTAL MEMBRANE. Uncalcified part of the primary frontal wall a chitinous membrane covering the aperture in life. FRONTAL SHIELD. The secondary frontal wall in cribrimorph Polyzoa, formed above the aperture by the over-arching and fused costae. FRONTAL WALL. Chitinous or calcareous cover of the ventral surface of the zooecia. In the cribrimorph Polyzoa it may be (a) primary consisting of the calcareous gymnocyst, and in life of the chitinous frontal membrane, (b) secondary formed by the frontal shield, or (c) tertiary formed by an upgrowth and spread of secondary calcareous tissue above the primary and secondary frontal walls. GYMNOCYST. The part of the frontal wall which lies between the aperture and the upper edges of the vertical zooecial walls the calcified part of the primary frontal wall : it is usually most developed on the proximal side of the aperture. HETEROZOOECIA. Modified zooecia either (a) lacking a polypide, or with only a vestige of one, but provided with a musculature, as in avicularia, or (b) without polypide or a musculature, as in kenozooecia. HYPERSTOMIAL. Type of ovicell which rests on or indents the frontal wall of the distally adjacent zooecium. INTERCOSTAL SPACES. Openings between the costae they may be (a) single, long, slit-like spaces, or (6) subdivided into a series of smaller openings by lateral costal fusions. [Syn., lacunae of workers on Recent Polyzoa.] 48 CRETACEOUS CRIBRIMORPH POLYZOA (PELM ATOPORIN AE) INTERZOOECIAL. Term applied to any structure developed between zooecia of ad- jacent series, hence " interzooecial secondary tissue " is calcareous tissue accu- mulated between zooecia in the interzooecial valleys. KENOZOOECIA. See Heterozooecia. LABELLUM. The free tongue of the descending lamina of the ovicell. LACUNAE. Irregular openings in the interzooecial secondary tissue. LAMINA PERISTOMICA. Term introduced by Jullien and used by Lang, and here as synonymous with " tertiary frontal wall " see Frontal Wall. LATERAL COSTAL FUSIONS. Hollow cylindrical, lateral fusions between adjacent costae, usually arising at the levels of lumen pores. [Lang referred to the outer- most lateral costal fusions as " primary ", and to the successive inner ones as " secondary, tertiary ", etc.] LATERAL SLITS. The pair of slits at the sides of the labellum in some ovicells. LUMEN LINE. Clear, membranous, median line seen along the upper surface of the costae in some Recent Cribrilinidae. LUMEN PORES. Uncalcified, small, round, membranous areas on the upper surface of costae in some Recent Cribrilinidae. Lang's pelmata and pelmatidia of Cre- taceous cribrimorph Polyzoa are lumen pores. MANDIBLE. The triangular or rounded chitinous or calcareous structure which closes the orifice in the avicularium. Not preserved in the material studied here. MARGINAL SPINES. Spines, other than oral spines, which surround the aperture. Modified as costae in the Cretaceous cribrimorph Polyzoa. MEASUREMENTS. See p. 45. MEDIAN AREA OF FUSION. The imperforate area formed by the fusion of the inner ends of the costae, which extends laterally from the mid-line of the frontal shield and which is bounded by the innermost intercostal spaces. MEDIAN PROCESS. Median distal prolongation of the apertural bar. It may be a single, more or less pointed process, or it may bifurcate and fuse with the proximal pair of oral spines. MULTIPOROUS SEPTULAR DISCS. See Communication Pores. OPERCULUM. Chitinous or calcareous lamina, generally semicircular in shape, closing the orifice of the zooecium. OPESIA. The opening into the body cavity which remains after development of the cryptocyst. In the Cretaceous cribrimorph Polyzoa it usually coincides with the aperture. ORAL AVICULARIA. Avicularia which are associated with the orifice. In the Creta- ceous cribrimorph Polyzoa a pair of avicularia, termed " lateral oral avicularia ", may occur one on either side of the orifice. ORAL SHELF. The flattened rim round the distal and lateral margins of the orifice on which the operculum or mandible rests. ORAL SHIELDS. Structures, other than a peristome, which develop round the primary orifice. They may form a distal oral shield, usually a marginal upgrowth pro- duced by infilling of the space between distal oral spines with secondary tissue ; or a proximal oral shield, often formed by the fusion of the median process of CRETACEOUS CRIBRIMORPH POLYZOA (PELM ATOPORIN AE) 49 the apertural bar with the proximal pair of oral spines, or by the thickening, upgrowth and fusion of lateral oral avicularia. ORIFICE. The opening of the zooecium, covered by the operculum, for the extrusion of the polypide. It may be either (a) primary (the opening of the tentacular sheath covered by the operculum) leaving in the fossil state a well denned orifice with sharp limits and no marginal accumulation of secondary tissue, or (b) secondary when the primary orifice becomes surrounded by a peristome with a secondary orifice at its upper end. Lang introduced a series of terms such as "cribriline, normal, pliophloean" to describe various shapes of primary orifice (Text-fig. 7). OVICELL. The distal, globular, structure in the fertile cheilostomatous zooecia, which serves as a brood-chamber to the developing larvae. PELMA (pi., pelmata) and PELMATIDIUM (pi., pdmatidia). Large and small lumen pores respectively in the costae of Cretaceous cribrimorph Polyzoa. [Lang referred to the outermost pelmata and pelmatidia as " primary ", and succes- sively to the inner ones as " secondary, tertiary " etc.] I have retained these two terms merely for convenience of reference but with no implication of acceptance of Lang's hypothesis of their origin (see p. 28). PERISTOME. Tubular upgrowth of the rim of the primary orifice with the secondary orifice at its upper end. POLYPIDE. The polyzoan animal with its tentacles placed in the interior of the zooecium. PROXIMAL. The parts of a structure on the side near to the origin of growth or ancestrula. ROSTRUM. That part of an avicularium which is distal to the transverse bar or condyles and on which the mandible rests. SEPTULUM. See Communication Pores. TRANSVERSE BAR. Narrow calcareous bar in some avicularia, on which the mandible hinges. YOUNG ZOOECIA. See Zooecia. ZOARIUM. The entire polyzoan colony. ZOOECIUM. An individual member of the polyzoan colony. There is a difficulty in applying the terms " young " and " adult " to zooecia. They are here used as follows : Young zooecia are those formed in the early stages of growth of the zoarium, after the ancestrula. Adult zooecia are those formed in the late stages of growth of the zoarium. I reject the following terms used by Lang, and indicate for each, after the colon, the term used by me : Ancestroecium : ancestrula. Apertural spines : oral spines. [Also used correctly by Lang for the spines which may occur on the distal edge of the aperture in some avicularia.] A sty : zoarium. Aviculoecium : avicularium. GEOL. 6, I. 4 50 CRETACEOUS CRIBRIMORPH POLYZOA (PELM ATOPORIN AE) Cenoecia : kenozooecia. Costal spines : marginal spines. Cribriline : a term used by Lang to describe a particular shape of primary orifice (see Orifice). Epheboecium : adult zooecium. Extraterminal front-wall : gymnocyst. Fenestra : Lang used this term for openings in the calcareous tertiary frontal wall developed in some Cretaceous cribrimorph Polyzoa. Gerontoecium : adult zooecium. Heteroecia : heterozooecia. Interoecial : interzooecial. Intraterminal front-wall : frontal shield. Lamina : cryptocyst. Median lacunae : lacunae. Neanoecia : young zooecia. Normal : a term used by Lang to describe a particular shape of primary orifice (see Orifice). Oecium : zooecium. Orthoecium : zooecium. Pliophloean : a term used by Lang to describe a particular shape or primary orifice (see Orifice). Primary aperture : primary orifice. Termen : a term used by Lang for the edge of the gymnocyst surrounding the aperture. Note on the General Arrangement of the Systematics The scheme adopted in the systematic sections of the present work is as follows. Families and subfamilies. These are redefined where necessary. Synonymies pre- cede the diagnoses and any changes suggested are discussed under remarks on the families or subfamilies involved. Genera. The synonymy of each genus is given first, then the type species is cited and the genus diagnosed. Any changes are discussed under the remarks, and the stratigraphical range of the genus is given. Species. After the synonymy the type of each species is cited in detail and its status given. When no type has been previously selected lectotypes are chosen in order to establish the species firmly. The diagnosis which follows is based on struc- tures preserved in fossilization only, and the succeeding description is based on the characters of all material available to me. Where species are known from the literature only, or from photographs only, this is stated, and when the systematic position of a species is uncertain on this account, the species is listed as such and is not included in the general systematic assessment. Measurements are given where possible, and then general remarks on each species. The stratigraphical distribution is stated and all the specimens which have been examined are listed with full details of locality and horizon. Under the heading " Specimens " is listed all the appropriate material which is in the collections of the CRETACEOUS CRIBRIMORPH POLYZOA (PELM ATOPORIN AE) 51 Department of Palaeontology of the British Museum (Natural History), each speci- men with its registration number prefaced by the letter " D ". Material in the collections of other institutions is listed under " Other Material ". This includes specimens from the R. M. Brydone Collection in the Sedgwick Museum, Cambridge, the registration numbers of which are prefaced by the letters " S.M., B.". Specimens from the collections in the Norwich Castle Museum are denoted by the letters " N.C.M.". Unless otherwise stated all the specimens are from C. T. A. Gaster Collection. VII. SYSTEMATIC DESCRIPTIONS Phylum POLYZOA Class ECTOPROCTA Tribe GYMNOLAEMATA Order CHEILOSTOMATA Busk, 1852 Sub-Order ANASCA Levinsen, 1909 Division CRIBRIMORPHA Harmer, 1926 Family PELMATOPORIDAE Lang, 19160 19160 Pelmatoporidae Lang, p. 83. 1921 Pelmatoporidae Lang : Lang, pp. i, 6. 1922 Pelmatoporidae Lang : Lang, pp. 1-394. 1923 Pelmatoporidae Lang : Waters, pp. 547, 553. 19256 Pelmatoporidae Lang : Voigt, pp. 97, 98, 99. 1927 Pelmatoporidae Lang : Canu & Bassler, p. 18. 1930 Pelmatoporidae Lang : Voigt, pp. 537, 538. 1935 Pelmatoporidae Lang : Bassler, p. 31. Z 953 Pelmatoporidae Lang : Bassler, pp. 023, Gigo. 1958 Pelmatoporidae Lang : Didon, p. 82. DIAGNOSIS. Multiserial Cribrimorpha with one or more pelmata or pelmatidia on each costa. REMARKS. Lang (1921 : i) has stated that " If ovicells are present in the Pelma- toporidae, they are endozooecial ". In his key to the families of Cretaceous cribrimorph Polyzoa (1921 : 4), he divided into two groups the eleven families he recognized : group A was diagnosed as having hyperstomial ovicells and no pelmata or pelmatidia, group B as having endozooecial ovicells with pelmata or pelmatidia generally present. It is shown below that some genera of Lang's group A possess pelmata or pelma- tidia, and that both hyperstomial and endozooecial ovicells occur in the Pelmato- poridae. Brown (1952 : 43), in a brief discussion of the Membraniporidae, has stated that " although other workers (Canu & Bassler, 1920 ; Osburn, 1940) have used the difference between hyperstomial and entozooecial [endozooecial] ovicells to distinguish families, this is a very unreliable criterion, especially in the light of Silen's researches (1944) into the nature of the reproductive processes of the Polyzoa " (see also p. 43). It is apparent that the same remarks apply to the Cretaceous cribrimorph Polyzoa. Ovicells are not used here to distinguish families. 52 CRETACEOUS CRIBRIMORPH POLYZOA (PELM ATOPORIN AE) STRATIGRAPHICAL DISTRIBUTION. Turonian to Danian. Subfamily PELMATOPORINAE Lang, igi6a igi6a Castanoporinae Lang, pp. 83, 93. 19160 Pelmatoporinae Lang, pp. 84, 101. 191612 Andrioporinae Lang, p. 382 [partim Aeolopora only]. 19160 Lagynoporidae Lang, p. 393. 19160 Lagynoporinae Lang, p. 393. 19160 Leptocheiloporinae Lang, pp. 394, 396. 1919*2 Pelmatoporinae Lang : Lang, pp. 191-228. 1921 Castanoporinae Lang : Lang, pp. xxxv, xli, xliv, xlv, xlvii, 1, li, and p. i. 1921 Pelmatoporinae Lang : Lang, pp. xli, 1, li. 1921 Lagynoporidae Lang : Lang, pp. 5, 42. 1921 Lagynoporinae Lang : Lang, pp. 5, 44. 1921 Leptocheiloporinae Lang : Lang, pp. 5, 68. 1921 Andrioporinae Lang : Lang, p. 86 [partim Aeolopora only]. 1922 Castanoporinae Lang : Lang, pp. 5, 7, 10, 15, 154. 1922 Pelmatoporinae Lang : Lang, p. 235. 1927 Andrioporidae Lang : Canu & Bassler, p. 17 [partim Aeolopora only]. 1927 Lagynoporidae Lang : Canu & Bassler, p. 17. 1930 Lagynoporidae Lang : Voigt, p. 495. 1935 Andrioporidae Lang : Bassler, p. 30 [partim Aeolopora only]. 1935 Lagynoporidae Lang : Bassler, p. 30. 1943 Lagynoporidae Lang : Gillard, p. 186. 1953 Lagynoporidae Lang : Bassler, p. Gi88. 1953 Andrioporidae Lang : Bassler, p. Gi8g [partim Aeolopora only]. *953 Pelmatoporinae Lang : Bassler, p. 0192. J 953 Castanoporinae Lang : Bassler, p. Gig2. DIAGNOSIS. Pelmatoporidae with small or large zooecia ; with unmodified, or, enlarged or branched oral spines ; with or without oral shields ; apertural bar with or without a median process ; pelmata or pelmatidia present, either with one boss- like pelmatidium, or with one or more pelmata or pelmatidia on each costa ; with or without lateral costal fusions ; with or without a tertiary front wall ; with or without avicularia (if present these may be either sporadic, small and rounded, or paired, large and distally pointed) ; ovicells endozooecial or hyperstomial. REMARKS. The genera of Cretaceous cribrimorph Polyzoa which are revised here were placed by Lang (19160 ; 1921 ; 1922) in five subfamilies. This arrangement may be summarized as follows : Revised genera Subfamilies of Lang Castanopora ~\ Rhiniopora ( Castanopora} > Placed in the Castanoporinae [Lang, 1922 : 154]. Ubaghsia j > Placed in the Pelmatoporinae [Lang, 1922 : 235]. Batrachopora ( Ubaghsia} j Lagynopora ~\ Prodromopora (= Lagynopora} > Placed in the Lagynoporinae 1 [Lang, 1921 : 44]. Hexacanthopora Leptocheilopora . . . Placed in the Leptocheiloporinae 1 [Lang, 1921 : 68]. Aeolopora .... Placed in the Andrioporinae [Lang, 1921 : 89]. 1 Lang (1921 : 5, 44) placed these two subfamilies in the Lagynoporidae. CRETACEOUS CRIBRIMORPH POLYZOA (PELM ATOPORIN AE) 53 No distinction can be made between the Castanoporinae and the Pelmatoporinae. In his key to the subfamilies of the Pelmatoporidae Lang (1922 : 17) diagnosed them as follows : (a) Castanoporinae are Pelmatoporidae in which " costae bear pelmatidia 1 of several orders with lateral costal fusions corresponding in number and position to the pelmatidia ", (b) Pelmatoporinae are Pelmatoporidae in which " costae bear each one or more pelmata, 2 and lateral costal fusions correspond in number and position to the pelmata ". As it is not possible to distinguish clearly between pelmata and pelmatidia (see p. 30) the two subfamilies are not separable on the basis given by Lang, nor are there any other characters which clearly help to maintain the division. All genera previously assigned by Lang to the Lagynoporinae, and Leptocheilopora, the only genus which he placed in the Leptocheiloporinae, have distinct pelmata or pelmatidia and thus belong to the family Pelmatoporidae, and, according to Lang's definitions of its subfamilies, can be placed only in the Pelmatoporinae. Thus the subfamilies Lagynoporinae and Leptocheiloporinae, and the family Lagynoporidae which comprises them, are all synonymous with the subfamily Pelmatoporinae. Aeolopora possesses boss-like pelmatidia and consequently belongs to the family Pelmatoporidae and is excluded from the Andrioporinae which Lang (1921 : 86) diagnosed as lacking, on the costae, either " a median row of pores " or " a median slit ". Again, according to Lang's definitions of the subfamilies of the Pelmato- poridae, Aeolopora can be assigned only to the subfamily Pelmatoporinae. Thus all the genera listed in the above table are here regarded as belonging to the Pelmatoporinae. STRATI GRAPHICAL DISTRIBUTION. Turonian to Danian. KEY TO THE GENERA OF THE PELMATOPORINAE REVISED HERE (I) Pelmatoporinae lacking a tertiary front wall ; secondary orifice absent or only slightly developed. (A) Zooecia small ; a single boss-like pelmatidium at the inner end of each costa i. AEOLOPORA Lang (B) Zooecia large ; one or more normal pelmata or pelmatidia on each costa. (1) Proximal oral shield well developed formed by the bifurcation of the median process of the apertural bar and its fusion with the proximal pair of oral spines 2. LAGYNOPORA Lang (2) Proximal oral shield absent. (a) Median process of the apertural bar present and not bifurcated 3. HEXACANTHOPORA Lang (b) Median process of the apertural bar absent . 4. LEPTOCHEILOPORA Lang (i) Costae less numerous with fewer pelmata or pelmatidia and lateral costal fusions ; avicularia usually of one kind, either small, rounded and sporadic, where no distal oral shield is developed, or large, elongate, distally pointed and directed, paired where a slight distal oral shield is formed by the enlargement of the distal pair of oral spines .... 5. PELMATOPORA Lang (ii) Costae numerous with numerous pelmata or pelmatidia and lateral costal fusions ; avicularia large, variously directed, of one, two or three kinds 6. CASTANOPORA Lang (II) Pelmatoporinae with a well-developed secondary orifice and a tertiary front wall 7. UBAGHSIA (Jullien) 1 My italics. 54 CRETACEOUS CRIBRIMORPH POLYZOA (PELM ATOPORIN AE) Twelve other genera were placed by Lang (19160 ; 1922) in his subfamilies Castanoporinae and Pelmatoporinae. In the Castanoporinae he included seven genera other than those revised here. Provisionally I use Lang's definitions of these seven genera to distinguish them from those revised. Thus, according to Lang (1922 : 158), Carydiopora, Anornithopora, Hesperopora and Stichocados are distinguished from the other genera here placed in the revised subfamily of the Pelmatoporinae by their small size and fewer costae ; Phrynopora by its unusual type of " secondary aperture " [proximal oral shield] ; and Steginopora and Disteginopora by their types of tertiary front walls. Similarly, Lang (1922 : 240) included in his subfamily Pelmatoporinae Decurtaria, Murinopsia, Sandalopora, Ichnopora and Pachydera. Various characters of these five genera, particularly the types of oral shields which may be developed, distinguish them from other genera placed in the revised subfamily of the Pelmatoporinae. Genus AEOLOPORA Lang igida Aeolopora Lang, pp. 383, 390. 1921 Aeolopora Lang : Lang, p. 158. 1924 Aeolopora Lang : Gaster, second of three tables opp. p. no. 1927 Aeolopora Lang : Canu & Bassler, p. 23. 1930 Aeolopora Lang : Gaster, table opp. p. 340. 1930 Aeolopora Lang : Voigt, p. 498. 1935 Aeolopora Lang : Bassler, p. 43. J 953 Aeolopora Lang : Bassler, p. Gi8g. TYPE SPECIES (by original designation). Aeolopora distincta Lang, 19160 : 390. Senonian, zone of M. cor-anguinum. Upper Basildon, Berkshire. EMENDED DIAGNOSIS. Small Pelmatoporinae with a single boss-like pelmatidium near the distal end of each costa ; no lateral costal fusions ; ovicells hyperstomial, prominent, with labellum and lateral slits. REMARKS. As is mentioned below, the boss-like structure near the distal end of each costa, which is characteristic of the genus, is interpreted as an unusual form of pelmatidium. Lang (19160 : 382, 383) originally diagnosed Aeolopora as a multiserial, encrusting, Andrioporine genus lacking a " secondary aperture " [orifice], but with the " median area of fusion surrounded by a ring of solid spines ; [and with] apertural [oral] spines thickened ". This diagnosis remained almost unchanged in his subsequent key to the Andrioporine genera (1921 : 88, 89). Lang (1921 : 160), in his remarks on A. distincta, stated that " at the margin of the median area of fusion each costa bears a bead, which, to judge from comparable instances, is the original constricted distal end of the costa, which has retreated from the mid-line." It has been possible, using a magnification of XI4O, to see that the so-called " beads " are not solid but possess a minute central pore which apparently connects with the central hollow of the costa. The structure is therefore regarded as a pelmatidium with an unusually high rim. Remarking on the genus Aeolopora, Lang (1921 : 158, 159) also stated that " A tendency to this arrangement [the development of ' solid spines or beads ' round the CRETACEOUS CRIBRIMORPH POLYZOA (PELM ATOPORIN AE) 55 median area of fusion] has already been noticed in Andriopora gasteri . . . Eucheilo- pora . . . Pancheilopora, and again in the species Andriopora gallica and A. frequens." These species of Andriopora and all available specimens belonging to the other two genera have been examined for the feature mentioned. At the most, there is a tendency for irregular median ridges to form, but circlets of boss-like pelmatidia, or of " solid spines or beads ", are definitely not present. The presence of pelmatidia in Aeolopora removes the genus from both the sub- family Andrioporinae Lang, 1916^, and the family Andrioporidae Lang, 19160, and places it in the subfamily Pelmatoporinae. The boss-like pelmatidia particularly distinguish the genus, which is always small and lacks lateral costal fusions, but possesses frequent, prominent, hyperstomial ovicells. In the key to the families of Cretaceous cribrimorph Polyzoa Lang (1921 : 4-6) made a basic division of all families into (a) those with hyperstomial ovicells but without pelmata or pelmatidia and (b) those with endozooecial ovicells and pelmata or pelmatidia. Aeolopora is clearly a genus which has distinct hyperstomial ovicells and pelmatidia, though the latter are of an unusual form. The wider classification of the families and subfamilies of some of the Cretaceous cribrimorph Polyzoa is discussed elsewhere (p. 52). STRATIGRAPHICAL DISTRIBUTION. Senonian, lower part of zone of M. cor-anguinum to zone of B. mucronata. Of the two species A. distincta and A, nebulosa, here regarded as composing the genus, the former is apparently more abundant in the Senonian of southern England, ranging from the lower part of the zone of M. cor-anguinum into the zone of G. [A.] quadrata, while the latter has been recorded only from the zone of G. [A .] quadrata (or its equivalent, see Voigt, 1930 : 498) and from that of B. mucronata in the Isle of Wight. A . nebulosa is somewhat larger and more robust and may be regarded as a develop- ment from A. distincta. Apparently A. nebulosa occurs much less frequently. KEY TO SPECIES OF AEOLOPORA (A) Aeolopora with 10-16, often 11-13, costae ; apertural bar of variable thickness, with or without two distinct boss-like pelmatidia near the mid-line ; avicularia occa- sionally present ; ovicells hyperstomial with labella and lateral slits i. A. distincta Lang (B) Aeolopora with larger zooecia ; usually 9-12 costae ; apertural bar constantly thickened and prominent with a small median process above two indistinct boss-like pelmatidia ; avicularia apparently absent ; ovicells hyperstomial, with small labella and lateral slits 2. A. nebulosa Lang i. Aeolopora distincta Lang (PI. i ; PI. 2, figs. 1-7 ; Text-figs. 12-17) 191 6a Aeolopora distincta Lang, p. 390. 191 6a Aeolopora stellata Lang, p. 390. 1921 Aeolopora distincta Lang : Lang, p. 159, pi. 5, fig. 4 ; text-fig. 75. 1921 Aeolopora stellata Lang : Lang, p. 161, text-fig. 76. 1924 Aeolopora stellata Lang : Gaster, second of three tables opp. p. no. 56 CRETACEOUS CRI BRIMORPH POLYZOA (PELM ATOPORI N AE) 1930 Aeolopora stellata Lang : Gaster, table opp. p. 340. 1935 Aeolopora distincta Lang : Bassler, p. 43. !953 Aeolopora distincta Lang : Bassler, p. Gi8g, text-fig. 143, 2. HOLOTYPE. 0.28062. Zoarial fragment encrusting a piece of echinoid test. Senonian, high in the zone of M. cor-anguinum. Upper Basildon, north-west of Pangbourne, Berkshire. L. Treacher Collection. EMENDED DIAGNOSIS. Aeolopora with orifice of equal height and width, or hr exceeds Ir very slightly ; oral spines 6, costae 10-16, but very often 11-13 only ; apertural bar of variable thickness with or without two distinct boss-like pelmatidia 14 O I O-5mm. I FIG. 12. Aeolopora distincta Lang, 0.40599. Orifice and ovicell with complete ectooecium and well-formed labellum and lateral slits. FIG. 13. Aeolopora distincta Lang, D. 28062. Holotype. Ovicelled zooecium. FIG. 14. Aeolopora distincta Lang, 0.28911. Holotype of A. stellata Lang. Ovicelled zooecium. near the mid-line ; heterozooecia (? kenozooecia) occasionally present ; avicularia present ; ovicells abundant, hyperstomial, with labella and lateral slits. DESCRIPTION. Zoarium encrusting, unilaminar. Zooecia closely placed, oval. Orifice small, distally rounded, the sides straight, or tending to diverge proximally, the proximal-lateral corners may be somewhat rounded, proximal margin straight to widely " V "-shaped. Oral spines 6, apparently secondarily thickened, but small, arranged on the distal-lateral margins and sides of the orifice, usually paired sym- metrically. Frontal shield well arched. Costae variable from 10-16, but very often 11-13, fairly closely placed, widest at their proximal (outer) ends and tapered distally. Each costa bears near its distal (inner) end a small, prominent, boss-like pelmatidium. 1 There are no lateral costal fusions. The costae slope upwards to the 1 The " bead or solid spine " of Lang (1921 : 161). CRETACEOUS CRIBRIMORPH POLYZOA (PELM ATOPORIN AE) 57 pelmatidia and then flatten to join the median area of fusion, which is flat, of variable width, and may be occasionally absent. Apertural bar variable in thickness, often narrow, fairly straight or widely " V "-shaped, usually with, but sometimes ap- parently lacking, a pair of distinct boss-like pelmatidia near the mid-line. The apertural bar is never so consistently thickened as in A. nebulosa. Gymnocyst only slightly exposed. There is no interzooecial secondary tissue. FIG. 15. Aeolopora distincta Lang, 0.40578. Orifice and ovicell, the latter with a lateral growth of ectooecium. FIG. 16. Aeolopora distincta Lang. 0.40559. Two ovicelled zooecia and interzooecial avicularium. Both ovicells are damaged but that on the left shows the corrugated ectooecium. Avicularia interzooecial, occurring infrequently in any zoarium, fairly large, oval, distally directed and with slight lateral constrictions (Text-fig. 16). In most zoaria avicularia are absent. Heterozooecia (? kenozooecia) occasionally present, very small (one-fifth to one- quarter the size of the normal zooecia), convex, smooth, each with a large oval aperture on the upper surface, occurring singly or grouped in irregular clusters between the zooecia (seen only in 0.40658). Ovicells abundant, hyperstomial, prominent, globular, smooth, with a distinct labellum bounded by short lateral slits. The endooecium of the primary ovicell may be covered by a slightly corrugated ectooecium (Text-figs. 12, 15, 16). The ovicelled zooecia sometimes occur in linear series. 58 CRETACEOUS CRIBRIMORPH POLYZOA ( PELM ATOPORIN AE) MEASUREMENTS. Zooecia Lz = 0-27 to 0-33 mm. Iz = 0-19 to 0-25 mm. hr = 0-05 to 0-07 mm. lr = 0-05 to 0-06 mm. Avicularia Lz =0-05 mm. Iz = 0-03 mm. REMARKS. Lang (19160 : 390) originally referred two species, A. distincta Lang and A. stellata Lang, to Aeolopora, but the present revision shows that they are synonymous ; his later (1921) species, A. nebulosa, is clearly definable, however. O L FIG. 17. Aelopora distincta Lang, 0.40571. Zooecium, with very worn ovicell, showing arrangement of oral spine-bases. A. distincta and A. stellata were separated primarily on the number of "beads surrounding the median area of fusion " and on the form of the apertural bar. All the available specimens of Aeolopora, labelled by Lang as belonging to these species, have been re-examined, and the results may be tabulated briefly as follows : Lz Iz hr lr Number of costae Specimens assigned by Lang to A . distincta 0-30 to 0-33 mm. 0-20 to 0-25 mm. 0-05 to 0-07 mm. 0-05 to 0-06 mm. 10-16 (often 12 or 13) Specimens assigned by Lang to A . stellata 0-27 to 0-32 mm. 0-19 to 0-23 mm. 0-06 mm. 0-05 to 0-06 mm. 11-15 (often ii or 12) As Lang indicated (1921 : 159, 161), the dimensions of the two species are virtually the same. The apertural bar of A. distincta, according to Lang (1921 : 160), " is somewhat flattened in a vertical plane, and each of the costae of which it is composed retains the bead formed by its constricted distal end, and this takes its place in the ring of CRETACEOUS CRIBRIMORPH POLYZOA (PELM ATOPORIN AE) 59 beads ". In contrast, he stated (p. 161), the apertural bar of A. stellata " is con- siderably flattened in a vertical plane, and, unlike the apertural bar of A. distincta, does not normally bear a median pair of beads ". I have not found it possible to distinguish between the two by the form of the apertural bar. The structure is easily modified by wear, and is in itself variable both in the zooecia of a single zoarium and in those of different zoaria of each species recognized by Lang. The apertural bars of adjacent zooecia may be of varying thickness, and the boss-like pelmatidia, which are present near the mid-line, may or may not be distinct (cf. Text-figs. 13-16) : they are often visible in the specimens labelled by Lang stellata and are not, as he suggested, " not normally present ". The number of boss-like pelmatidia necessarily varies with the number of costae, and, as is apparent from the above table, the range in number of costae of A . stellata is contained within that of A . distincta. Thus the two species are regarded as synonymous, the name distincta being retained for them. Many new specimens, ranging from the zone of M. cor-anguinum to that of G. [A.} quadrata, have been assigned to the species, and although much of this material has been measured it has not proved necessary to extend the ranges established in the re-examination of Lang's specimens. Many specimens show the details of the ovicell, particularly 0.28062, 0.28911, 0.40578, 0.40559 and 0.40653. Heterozooecia are present in 0.40658, (PI. I, fig. 5). STRATIGRAPHICAL DISTRIBUTION. Senonian, zone of M. cor-anguinum to zone of G. [A.] quadrata. SPECIMENS. 0.28062. Holotype see above. 0.28911. Holotype of A. stellata Lang, encrusting a fragment of echinoid test. Senonian, zone of 0. pilula, subzone of E. scutata var. cincta. Pit 2 of Gaster, by reservoir, near Hill Barn, North Lancing, east of Worthing, Sussex. 0.21212-13. Two paratypes of A. distincta Lang. Horizon, locality and collection as for 0.28056 and 0.28052 respectively. 0.23326-28. Three paratypes of A. distincta Lang, 0.23326-27 encrusting Inocera- mus fragments, 0.23328 encrusting a piece of echinoid test. Senonian, top of zone of M. cor-anguinum. Medical College Pit, Epsom, Surrey. F. Mockler Collection. 0.23950. Paratype of A. distincta Lang, six well-preserved zooecia encrusting a very small shell fragment. Horizon, locality and collection as for 0.23326. 0.28052-55. Four paratypes of A. distincta Lang. Four or five incomplete zoaria encrusting one fragment of echinoid test [the fifth zoarial fragment numbered 0.21213]. Senonian, zone of M. cor-anguinum. Upper Basildon, north-west of Pangbourne, Berkshire. L. Treacher Col- lection. 0.28056-61 and 0.28063-66. Ten paratypes of A. distincta Lang. Ten of twelve incomplete zoaria encrusting one fragment of echinoid test [the other 6o CRETACEOUS CRIBRIMORPH POLYZOA (PELM ATOPO RIN AE) two zoarial fragments numbered D. 21212 and D. 28062 the latter the holotype]. Horizon, locality and collection as for the holotype. 0.28246. Paratype of A. distincta Lang, encrusting a fragment of Inoceramus. Senonian, zone of M. cor-anguinum, about 40 ft. from base of zone (20 ft. below the " strong cor-anguinum tabular " [flint band] of Whitaker and Rowe). Cliffs between Beltout and Birling Gap, west of Beachy Head, Sussex. 0.3248. Paratype of A. stellata Lang, encrusting a fragment of Inoceramus. Senonian, zone of G. [A.] quadrata. Romsey, south-west of Win- chester, Hampshire. H. P. Blackmore Collection. 0.28918-21. Four paratypes of A. stellata Lang, encrusting fragments of echinoid tests. Horizon, locality and collection as for 0.28911. 0.28965-66. Two paratypes of A. stellata Lang, encrusting one fragment of echinoid test. Senonian, zone of G. [A .] quadrata. Pit 7 of Gaster, in Lamb- leys Lane, Sompting, south of Lambleys Barn, north of Upton Cottages, north-west of Sompting Church (just above the 200 ft. contour) . 0.28986. Paratype of A. stellata Lang, encrusting a fragment of echinoid test. Senonian, zone of G. [A.] quadrata. Pit 10 of Gaster, Western Pit, Charman Dean, north of Broadwater, north of Worthing, Sussex. 0.29885. Incomplete zoarium labelled " 1A. stellata Lang", encrusting a fragment of echinoid test. Senonian, zone of 0. pilula, subzone of E. scutata var. depressula. Cliffs between last groyne east of Rotting- dean Gap and Saltdean, east of Brighton, Sussex. 0.29888. Specimen labelled "A. distincta Lang", encrusting a fragment of echinoid test. Senonian, zone of M. cor-anguinum. Coombs Pit, West Horsley, north-east of Guildford, Surrey. 0.29889-90. Two specimens labelled " A. stellata Lang ", the former encrusting a fragment of Ostrea, the latter a fragment of Inoceramus. Senonian, zone of 0. pilula, subzone of E. scutata var. cincta. Pit 2 of Gaster see 0.28911. 0.29891. Specimen labelled "A. stellata Lang", encrusting a fragment of Inoceramus. Senonian, zone of 0. pilula, subzone of E. scutata var. depressula. Pit 4 of Gaster. Western Pit, below Lancing Ring, west side of Boundstone Lane, north-east of Worthing, Sussex. 0.29892. Specimen labelled "A. stellata Lang", encrusting a fragment of echinoid test. Senonian, zone of 0. pilula, subzone of E. scutata var. depressula. Locality and collection as for 0.29885. 0.29893. Specimen labelled "A. stellata Lang", encrusting a fragment of echinoid test. Senonian, zone of Marsupites testudinarius , subzone of Uintacrinus westphalicus. Medical College Pit, Epsom, Surrey. 0.40555. Zoarial fragment encrusting part of a Pelmatopora zoarium. Senonian, zone of 0. pilula, subzone of E. scutata var. cincta. Pit 3 of Gaster, east pit at top of Boundstone Lane, North Lancing, near Worthing, Sussex. CRETACEOUS CRI BRIMO RPH POLYZOA (PELM ATOPORIN AE) 61 0.40556. One of two incomplete zoaria encrusting a fragment of echinoid test [ancestrula present]. Horizon as for 0.40555, Pit 4 of Gaster, western pit at top of Boundstone Lane, North Lancing, near Worthing, Sussex. 0.40559-61. Three incomplete zoaria 0.40559-60 encrusting the same Inoceramus fragment, 0.40561 encrusting a piece of echinoid test. Horizon as for 0.40555, Pit 2 of Gaster see 0.28911. 0.40562. Incomplete zoarium encrusting a small, whole valve of Ostrea. Horizon, locality and collection as for 0.40555. 0.40563-80. Eighteen specimens, all encrusting fragments of echinoid tests. Two specimens Senonian, zone of 0. pilula, subzone of E. scutata var. cincta, Pit 2 of Gaster (see 0.28911 above), the rest from the subzone of E. scutata var. depressula of Section 113 of Gaster cliffs between the last groyne east of Rottingdean Gap and Saltdean, east of Brighton, Sussex. 0.40581-94. Fourteen specimens, all encrusting fragments of echinoid tests, except 0.40581-83, 0.40587-88 and 0.40590-91 which encrust fragments of Inoceramus. Senonian, zone of 0. pilula, subzone of E. scutata var. cincta. Pits 2 and 4 of Gaster see 0.28911 and 0.29891 respectively. 0.40595-98. Four specimens encrusting fragments of Inoceramus. Senonian, zone of M. cor-anguinum (less than 10 ft. below strong cor-anguinum tabular). Cliffs, Beltout, near Eastbourne, Sussex. 0.40599. Specimen encrusting a fragment of Inoceramus. Senonian, zone of M. cor-anguinum. Southern England precise locality and collection unknown. 0.40600. Specimen encrusting a fragment of Inoceramus. Senonian, base of zone of M. cor-anguinum (about 20 ft. below the strong cor-anguinum tabular). Cliffs between Beltout and Birling Gap, west of Beachy Head, Sussex. 0.40601. Incomplete zoarium encrusting the same echinoid fragment as 0.40556. 0.40602-05. Four specimens, 0.40602-03 encrusting fragments of echinoid tests, 0.40604-05 encrusting fragments of Inoceramus. Senonian, zone of M. cor-anguinum (Trochiliopora Bed). Cliffs, Seaford district, Sussex. 0.40606-18. Thirteen specimens, all encrusting echinoid fragments. Senonian, zone of G. [-4.] quadrata. Pit 10 of Gaster, Charman Dean, near Worthing, Sussex. 0.40619. Specimen encrusting a fragment of echinoid test. Senonian, zone of G. [A.] quadrata. Pit 24 of Gaster, Warningcamp Hill, Warningcamp, north-east of Arundel, Sussex. 0.40620-23. Four specimens encrusting fragments of echinoid tests. Senonian, zone of G. [A.] quadrata. Pit 26 of Gaster, South Woodleighs Pit, east of gravel pit, north-east of Woodleighs Lodge, about half a mile west of Pit 24, Warningcamp, north-east of Arundel, Sussex. 62 CRETACEOUS CRIBRIMORPH POLYZOA (PELM ATOPORIN AE) 0.40624-26. Three specimens encrusting fragments of echinoid tests. Senonian, zone of G. [A.] quadrata. Locality, horizon and collection as for 0.40606. 0.40627. Specimen encrusting a fragment of echinoid test. Senonian, zone of 0. pilula, subzone of E. scutata var. cincta. Pit 2 of Gaster. Horizon, locality and collection as for 0.28911. 0.41064. Zoarial fragment encrusting a piece of Ostrea shell. Senonian, zone 0. pilula, subzone of E. scutata var. depressula. Section 113 of Gaster, cliffs Rottingdean, Sussex. 0.40628. Specimen encrusting a fragment of echinoid test. Senonian, zone of G. [A.] quadrata. Locality and collection as for 0.40606. 0.40629-31. Three specimens, encrusting fragments of echinoid test. Senonian, zone of G. [A.] quadrata. Pit 12 of Gaster, large pit north of Pumping Station, top of Waterworks Lane, north-east of " The Warren ", north of Broadwater and Worthing, Sussex. 0.40632-33. Two specimens encrusting fragments of echinoid tests. Senonian, either lowest part of zone of G. [A .] quadrata or topmost part of zone of 0. pilula, subzone of E. scutata var. cincta. Pit 3 of Gaster, eastern pit at top of Boundstone Lane, south of Lancing Ring, north of Fir Croft, North Lancing, Sussex. 0.40634-36. Three specimens, encrusting fragments of echinoid test. Senonian, zone of G. [A.] quadrata. Pit 15 of Gaster, large pit about one-third of a mile south-south-east of Salvington Windmill, and north of Hill Cottages, Salvington, Sussex. 0.40637-44. Eight specimens, all encrusting inner surfaces of fragments of echinoid tests. Senonian, zone of G. [A.] quadrata. South side of Pit 1143 of Brydone. Redhampton Limeworks Pit, Portsdown, Hampshire. 0.40645. Specimen encrusting a fragment of echinoid test. Senonian, zone of G. [A.] quadrata. Pit 16 of Gaster. Pit by main road, east of Swandean Isolation Hospital and half a mile south of Salvington Windmill, Durrington, Sussex. 0.40646-54. Nine specimens, all encrusting fragments of echinoid tests. Horizon, locality and collection as for 0.40606. 0.40655-57. Three specimens, encrusting one fragment of echinoid test. Horizon, locality and collection as for 0.40634. 0.40658. Incomplete zoarium with heterozooecia, encrusting a fragment of echinoid test. Horizon, locality and collection as for 0.28965. 0.38852. Zoarial fragment encrusting an Inoceramus. Upper Chalk. Grove Park Road, Bury St. Edmonds, Suffolk. J. L. Gilbert Collection. 2. Aeolopora nebulosa Lang (PI. 2, figs. 8, 9 ; Text-figs. 18, 19) 1921 Aeolopora nebulosa Lang, p. 163, pi. 5, fig. 5 ; text-fig. 77. 1924 Aeolopora nebulosa Lang : Gaster, second of three tables opp. p. no. 1930 Aeolopora nebulosa Lang : Voigt, pp. 498, 542, 560, pi. 27, fig. i. CRETACEOUS CRIBRIMORPH POLYZOA (PELM ATOPORIN AE) 63 HOLOTYPE. 0.29061. Zoarial fragment encrusting a piece of echinoid test. Senonian, zone of G. [A.] quadrata. Pit 7 of Gaster, in Lambleys Lane, Sompting, south of Lambleys Barn, north of Upton Cottages, north-west of Sompting Church, just above the 200 ft. contour. EMENDED DIAGNOSIS. Aeolopora with somewhat larger, more robust zooecia than those of A . distincta ; orifice of equal height and width, or br exceeds Ir very slightly or vice versa ; oral spines 6, considerably thickened ; costae usually 9-12 (occa- sional adult zooecia may have 8 or 13) ; apertural bar prominent, considerably thickened, wide, its distal face nearly vertical, noticeably produced upwards in the 19 O5 mm. FIG. 1 8. Aeolopora nebulosa Lang, 0.29061. Holotype. Zooecium with very thick apertural bar. FIG. 19. Aeolopora nebulosa Lang, 0.29061. Holotype. Zooecium with narrow apertural bar and well-developed oral spine bases. mid-line, with or without two distinct boss-like pelmatidia ; avicularia apparently absent ; ovicells prominent, hyperstomial, with small labellae and lateral slits. DESCRIPTION. Zoarium encrusting, unilaminar. Zooecia closely placed, oval, somewhat larger than those of A. distincta and more robust. Orifice small, always distally rounded, the sides straight, proximal margin slightly curved. Oral spines 6, prominent, considerably thickened but otherwise unmodified, usually paired and evenly spaced. Frontal shield well arched. Costae thicker and more robust than in A. distincta, usually 9-12, but occasionally adult zooecia may possess only 8, and less frequently may have 13. The costae narrow inwards, and each bears a small, prominent, boss-like pelmatidium fairly close to its distal (inner) end. There are no lateral costal fusions. The outline of the distal extremity of each costa may often be traced in the median area of fusion, which is relatively flat, and usually narrower than in A . distincta. Outwards from the boss-like pelmatidia the costae slope down to meet the gymnocyst less steeply than in A. distincta. Apertural bar prominent, considerably thickened, wide or very wide, its distal face vertical, produced upwards 64 CRETACEOUS CRIBRIMORPH POLYZOA (PELM ATOPORIN AE) in the mid-line to form a small median process. Beneath the median process and proximal to it, a pair of boss-like pelmatidia may or may not be distinct. The apertural bar is generally straighter than that of A. distincta. Gymnocyst only slightly exposed. There is no interzooecial secondary tissue. Avicularia apparently absent. Heterozooecia not seen. Ovicells prominent, hyperstomial, globular, smooth with a small labellum and lateral slits. If an ectooe- cium is present it is not corrugated as may be the case with A . distincta. MEASUREMENTS. Zooecia Lz = 0-30 to 0-40 mm. Iz = 0-20 to 0-30 mm. hr = 0-06 to 0-08 mm. Ir = 0-06 to 0-07 mm. REMARKS. The dimensions given by Lang for A . nebulosa (Lz = about 0-40 mm. and Iz = about 0-30 mm.) were maximum measurements. It is, however, apparent that A . nebulosa may be distinguished from A . distincta by its rather larger size, its more robust appearance, its definitely thicker oral spines, its thicker, and generally fewer costae, and its more constantly thickened apertural bar which may be very prominent (Text-figs. 18, 19). The labellum tends to be smaller than in A. distincta. Avicularia have not been seen in any of the specimens examined and their absence may again be of diagnostic value. Lang (1921 : 163) described the apertural bar of A. nebulosa as " thick, flattened in a vertical plane, and produced medianly in a spine-like projection ". This median projection may not always be present and is never very marked ; it is particularly prone to wear. The apertural bar of A. distincta also tends to be thickened medianly and this may occasionally produce a median projection. It is not true to describe the form of the orifice as " cribriline "* (Lang, 1921 : 163) ; the proximal-lateral constrictions characteristic of this type of orifice are not present. Voigt (1930 : 498, pi. 27, fig. i) very briefly recorded a specimen which he assigned to A. nebulosa Lang from the Mammillatensenon of Ifo, Sweden. Specimens 0.40660-65, from the zone of B. mucronata of the Isle of Wight extend the upward range of the species. The holotype, 0.29061, is from the zone of G. [A.] quadrata of Sussex and the paratype specimens from the same horizon in Wiltshire. No specimens of A. nebulosa have been discovered as yet below this horizon. Much new material belonging to the genus, has been examined, but apart from the specimens from the zone of B. mucronata all have proved to belong to A. distincta Lang. STRATIGRAPHICAL DISTRIBUTION. Senonian, zone of G. [A.] quadrata to zone of B. mucronata. SPECIMENS. 0.29061. Holotype see above. 0.3251. Paratype encrusting a fragment of Pechinoid test. [0.29052-53 are probably parts of the same specimen.] Senonian, zone of G. [A.] quadrata. East Harnham, south of Salisbury, Wiltshire. H. P. Blackmore Collection. 1 See Lang, 1921 : xlvii. CRETACEOUS CRIBRIMORPH POLYZOA (PELM ATOPORIN AE) 65 0.29052-53. Two paratypes [poorly preserved], encrusting. Horizon, locality and collection as for 0.3251. 0.40660. Zoarial fragment, encrusting a piece of echinoid test. Senonian, zone of B. mucronata. Pit 9 of Rowe, south of the Briary, between Alum Bay and Freshwater, Isle of Wight. 0.40661-65. Five incomplete zoaria, encrusting fragments of echinoid tests. Senonian, zone of B. mucronata. Pit 6 of Rowe, south of Newbarn, Afton Down, Isle of Wight. Genus LAGYNOPORA Lang ?i874 Lepralia : Reuss, p. 129 [partim]. 1877 non Lepralia : Novak, pp. 82, 93 [partim]. 1889 non Lepralia : Fric, p. 90. 1893 Cribrilina : Vine, pp. 316, 336 [partim]. ? 19006 Cribrilina : Canu, p. 445 [partim]. 1904 Cribrilina : Jukes-Browne, p. 490 [partim]. 1910 Cribrilina : Brydone, p. 391. 19160 Prodromopora Lang, p. 394. 19160 Lagynopora Lang, p. 394. 1921 Lagynopora : Lang, pp. Ixi, xci-v, 52. 1921 Prodromopora : Lang, pp. Ixiii, xciv, 50, 51. 1927 Lagynopora : Canu & Bassler, p. 17. 1927 Prodromopora : Canu & Bassler, p. 36. 1930 Prodromopora : Kiihn, p. 65. ?I93O Canupora Kiihn, p. 65. 1930 Lagynopora : Gaster, table opp. p. 340. 1930 Lagynopora : Voigt, pp. 495, 542, 560. ?i935 Canupora : Bassler, pp. 30, 64. J 935 Prodromopora : Bassler, pp. 30, 176. 1935 Lagynopora : Bassler, pp. 30, 135. 1949 Lagynopora : Voigt, pp. 36, 43, 44. ?i953 Canupora : Bassler, p. Gi88. I 953 Prodromopora : Bassler, p. Gi88. 1953 Lagynopora : Bassler, p. Gi88. 1958 Lagynopora : Didon, pp. 80, 84. TYPE SPECIES. Lagynopora lagena Lang, 19160 : 395. Senonian, zone of M. cortestudinarium or zone of M. cor-anguinum. Chatham, Kent. W. Gamble Collection. EMENDED DIAGNOSIS. Pelmatoporinae with a median process on the apertural bar which bifurcates and fuses with the proximal pair of oral spines producing a prominent oral shield ; avicularia usually present. REMARKS. Lagynopora may be clearly distinguished from other genera of the Pelmatoporinae by its distinctive proximal oral shield. In specimens which have been worn the proximal shield may often be destroyed. Usually, however, a few of these structures survive. Also it is possible to infer their presence originally in worn zooecia by the form of the apertural bar, and, in contrast to those of Hexa- canthopora, by the lengthened and enlarged proximal oral spines, originally fused to the median process. GEOL. 6, I. c 66 CRETACEOUS CRIBRIMORPH POLYZOA (PELM ATOPORIN AE) Prodromopora Lang is synonymous with Lagynopora. Lang (i9i6a : 394 ; 1921 : 50) regarded the few, narrow, widely spaced costae and the slight median area of fusion in Prodromopora as generically significant. Other characters were recognized as similar to those of Lagynopora. The characters of the frontal shield are, however, of specific value only, and Prodromopora praecursor Lang is placed in Lagynopora. Canupora prima Kiihn (1930 : 65) is here provisionally referred to Lagynopora and is listed and described as a species of uncertain systematic position (p. 96). I exclude from this genus Lepralia pediculus Reuss, which Lang doubtfully referred to Lagynopora (see p. 95). Excluding Lagynopora? prima (Kiihn), 12 species are recognized, one of which, L. pustulosa, is new. STRATIGRAPHICAL DISTRIBUTION. Senonian, zone of M. cortestudinarium to zone of B. mucronata in England, zone of G. [A.] quadrata in Germany, and PDanian in Austria. KEY TO THE SPECIES OF Lagynopora LANG (I) Lagynopora with boss-like pelmata . . . . i. L. pustulosa sp. nov. (II) Lagynopora in which the pelmata are minute pores. (A) Distinct lateral costal fusions present . . . 2. L. horsleyensis Lang (B) No lateral costal fusions. (1) Intercostal spaces wide, as long as the costae ; median area of fusion very slight; costae narrow (11-14) .... 3. L. praecursor (Lang) (2) Intercostal spaces narrower, but still distinct and nearly as long as the costae. (a) Zooecia small, Lz = 0-43 to 0-60 mm., lz = 0-25 to 0-37 mm. (i) Costae 11-14 avicularia occasional, fairly large, oval 4. L. saltdeanensis Lang (ii) Costae 17-18 ; avicularia abundant, small, oval 5. L. birlingensis Lang (b) Zooecia large, Lz = 0-64 to 0-75 mm., Iz = 0-37 to 0-50 mm. ; costae 13-17 ; frontal shield often with a median ridge . 6. L, amphora Lang (3) Intercostal spaces limited to the outer margins of the frontal shield. (a) Costae 12-14 7. L. ampulla Lang (b) Costae 20-23 8. L. furcifera (Brydone) (4) Intercostal spaces absent ; costae juxtaposed, outlined by furrows only, (a) Zooecia small, Lz = 0-48 to 0-68 mm., Iz = 0-35 to 0-51 mm. (i) Costae 9-11 ; oral spines 4 or 5 ; avicularia of one kind, large, prominent, oval 9. L. ollula Lang (ii) Costae 13-20 ; oral spines always 4 ; avicularia of two sizes 10. L. lagena Lang (6) Zooecia large, Lz 0-65 to 0-80 mm., Iz = 0-35 to 0-50 mm. (i) Median area of fusion extends only along the inner third of each costa ; costae 12-18 ; avicularia very large, broadly oval, pro- minent, fairly frequent, directed just proximally and outwards from the zooecia they accompany . .11. L. urceolus Lang (ii) Median area of fusion extends along the inner two-thirds of each costa; costae 15-17; avicularia rare or absent . 12. L. vasculum Lang CRETACEOUS CRIBRIMORPH POLYZOA (PELM ATOPORIN AE) 67 Lepralia pediculus Reuss 1 and Lagynopora Jprima (Kiihn) 2 are of uncertain systematic position and have therefore been omitted from the above key. i. Lagynopora pustulosa 3 sp. nov. (PI. 3, fig. i ; Text-figs. 20, 21) HOLOTYPE. 0.39419. Small zoarial fragment encrusting a piece of echinoid test. Senonian, zone of B. mucronata, Felpham Chalk, Bognor, Sussex. PARATYPES. 0.39420-22. Three zoarial fragments encrusting one piece of echinoid test. Senonian, zone of B. mucronata. Pit 8 of Rowe, near Nodewell, Freshwater, Isle of Wight. FIGS. 20, 21. Lagynopora pustulosa sp. nov., 0.39419. Holotype. Front and side view of adult zooecium. a.b, apertural bar ; d.o.s, distal oral spine-bases ; /, fusion between median process of apertural bar and proximal oral spines ; l.w, lateral wall ; m.p, median process of apertural bar ; o, orifice. DIAGNOSIS. Lagynopora with zooecia of small size (Lz = 0-50 to 0-53 mm., Iz = 0-27 to 0-32 mm.) ; proximal oral shield heavy, large, prominent, very obtusely ' Y "-shaped, with a marked median furrow ; frontal shield well arched ; costae 13- 16 ; each costa with a distinct small, boss-like pelma at its inner end ; ovicells hyperstomial, globular, small. DESCRIPTION. Zoarium encrusting, unilaminar. Zooecia elliptical, closely placed, each with a small, round, distal communication pore. Secondary orifice distally and laterally rounded, proximal margin straight. Oral spines 4, thickened, arranged 1 Lang (191 6a : 395 ; 1921 : 61) very tentatively placed this species in Lagynopora. * Canupora prima (Kiihn) (1930 : 65) may be a Lagynopora, but the available details are insufficient to place it with any certainty. * With reference to the form of the pelmata. 68 CRETACEOUS CRIBRIMORPH POLYZOA ( PELM ATOPORIN AE) symmetrically on the distal margin of the orifice. Proximal oral shield very prominent, large, very obtusely " Y "-shaped, with a straight distal margin and a marked median furrow, formed by the fusion of the bifurcated median process of the apertural bar with the proximal pair of oral spines. Frontal shield well arched. Costae 13-16, fairly narrow, tapering inwards and each with a small, boss-like pelma very close to its inner end. The pelmata produce two rows of small bosses, one on either side of the mid-line. Distinct, narrow intercostal spaces separate the costae. No lateral costal fusions. Median area of fusion slight. Apertural bar wider than the most distal costae, straight, the inner ends of its two component costae curve distally at the mid-line to form the prominent, wide median process which bifurcates to form part of the proximal oral shield. Gymnocyst concealed by the close placing of the zooecia. Avicularia apparently absent. Ovicells prominent but small, smooth, hyper- stomial, globular, of about equal height and width. MEASUREMENTS. Zooecia Lz = 0-50 to 0-53 mm. Iz = 0-27 to 0-32 mm. hr 0-09 mm. lr = 0-15 mm. [The majority of zooecia in the available specimens are ovicelled or slightly damaged, thus making accurate measurements based on non-ovicelled zooecia difficult.] REMARKS. This species is clearly distinguished by its boss-like pelmata and its large, prominent and distinctive proximal oral shield. In the holotype, 0.39419, young zooecia are present but not sufficiently well preserved to show whether 4 or 6 oral spines are typically developed at this stage of zoarial growth. The young zooecia apparently do not possess proximal oral shields. The same remarks apply to the young zooecia of the paratypes. In 0.39422 some ovicelled zooecia possess prominent, long, proximal oral spines these seem to be the remains of broken proximal oral shields. STRATIGRAPHICAL DISTRIBUTION. Senonian, zone of B. mucronata. SPECIMENS. 0.39419. Holotype see above. 0.39420-22. Paratypes see above. 2. Lagynopora horsleyensis Lang (PI. 3, figs. 2, 3 ; Text-fig. 22) igi6a Lagynopora horsleyensis Lang, pp. 395, 396. 1921 Lagynopora horsleyensis Lang : Lang, pp. xciii, 57, pi. 2, fig. 3 ; text-fig. 28. ?i958 Lagynopora horsleyensis Lang : Didon, pp. 80, 84, text-fig. 2. HOLOTYPE. 0.28908. Zoarial fragment encrusting a piece of echinoid test. Senonian, zone of M. cor-anguinum. Pit 264 of Young, Coombs Pit, West Horsley, north-east of Guildford, Surrey. EMENDED DIAGNOSIS. Lagynopora with 14-17 costae, each with 3, occasionally CRETACEOUS CRIBRIMORPH POLYZOA (PELM ATOPORIN AE) 69 only 2, distinct lateral costal fusions ; avicularia occasional, large, oval, interzooecial, directed distally and obliquely outwards from the zooecia they accompany. DESCRIPTION. Zoarium encrusting, unilaminar. Zooecia broadly oval, fairly closely placed, with large, oval distal communication pores. Secondary orifice wider than high, rounded distally with straight sides and a straight proximal margin. Proximal oral shield probably formed by the fusion of the lateral oral spines with the FIG. 22. Lagynopora horsleyensis Lang, N.C. 1^.247.956 (4/2). Adult zooecium with damaged apertural bar, the proximal oral shield worn away. A large interzooecial avicularium with proximal-lateral constrictions is shown to the left of the zooecium. median process of the apertural bar ; this structure is usually destroyed by wear. Oral spines 4, somewhat thickened, but otherwise unmodified. Frontal shield flatly arched. Costae 14-17, tapering inwards, each with 3, occasionally only 2, distinct lateral costal fusions. Outermost intercostal spaces long and slot-like, inner intercostal spaces small and regular. Median area of fusion narrow, outwards from the mid- line the costae are almost horizontal but turn down fairly steeply beyond the outer- most lateral costal fusions to meet the gymnocyst. Minute pelmatidia are present on the costae at the levels of the lateral costal fusions, and at least one other pelma- tidium apparently occurs near the outer end of each costa. Apertural bar a little wider than the most distal costae, distally bent at its outer ends and with a median yo CRETACEOUS CRIBRIMORPH POLYZOA ( PELM ATOPORIN AE) process. This probably fused with the lateral oral spines to produce a proximal oral shield. Gymnocyst apparently smooth, exposed proximally to some frontal shields, but generally obscured by the close placing of the zooecia. Interzooecial secondary tissue apparently absent. Avicularia interzooecial, of one kind, large, oval but somewhat parallel-sided, unpaired, with proximal-lateral constrictions separating a smaller proximal portion from a larger, rounded rostrum ; apparently directed distally and obliquely outwards from the zooecia they accompany. Ovicells prominent, smooth, hyperstomial, usually longer than wide, tending to be pointed distally. MEASUREMENTS. Zooecia Lz = 0-47 to 0-57 mm. lz = 0-30 to 0-40 mm. hr 0-09 to o-io mm. Ir = 0-12 to 0-15 mm. Avicularia Lz = 0-15 to 0-22 mm. lz == o-io to 0-17 mm. REMARKS. Lagynopora horsleyensis is easily distinguished from other species of the genus by its distinct lateral costal fusions. It is unfortunate that in the available specimens all the proximal oral shields have been destroyed by wear, only the worn median process of the apertural bar and the somewhat lengthened and thickened form of the lateral oral spines suggesting the original presence of this structure. 0.40942 extends the upward range of the species into the zone of G. [A.] quadrata. Lang (1921 : 57) slightly overestimated the dimensions of L. horsleyensis and its number of costae. His text-figure 28 and pi. 2, fig. 3, do not indicate the very distinct form of the lateral costal fusions. Didon (1958) has assigned to this species a poorly preserved specimen from the Santonian of Le Trait, near Rouen, France. STRATIGRAPHICAL DISTRIBUTION. Senonian, upper part of zone of M. cor- anguinum to zone of G. [A.] quadrata and ? Santonian of Le Trait, near Rouen, France. SPECIMENS. 0.28908. Holotype see above. 0.29899. Incomplete zoarium encrusting a shell fragment. Senonian, zone of M. cor-anguinum. Pit in Houndean Bottom, west of Lewes, Sussex. 0.40942. Incomplete zoarium encrusting a piece of echinoid test. Senonian, zone of G. [A.] quadrata. Pit 12 of Gaster, Broadwater Pit, north of waterworks pumping station, top of Waterworks Lane, north of Broadwater, near Worthing, Sussex. 0.41069. Small zoarial fragment of six young zooecia encrusting a piece of Inoceramus shell. Senonian, high in the zone of M. cor-anguinum. Locality and collection as for 0.29899. OTHER MATERIAL N.C.M.395I. Zoarial fragment with numerous ovicells encrusting the base of a whole test of Conulus albogalerus. Senonian, zone of M . cor-anguinum. Northfleet, Kent. A. W. Rowe Collection. 1921 1935 1953 CRETACEOUS CRIBRIMORPH POLYZOA (PELM ATOPORIN AE) 3. Lagynopora praecursor (Lang) nov. comb (PI. 3, fig. 5 ; Text-figs. 23, 24) Prodromopora praecursor Lang, p. 394. Prodromopora praecursor Lang : Lang, pp. Ixiii, xciv, 51, pi. 2, fig. i ; text-fig. 25. Prodromopora praecursor Lang : Bassler, p. 176. Prodromopora praecursor Lang : Bassler, p. Gi88, text-fig. 142, 8. 71 HOLOTYPE. 0.8351. Zoarial fragment with many damaged ovicelled zooecia and a broken ancestrular area, encrusting a piece of echinoid test. Senonian, zone do.s. FIGS. 23, 24. Lagynopora praecursor (Lang), D. 8351. Holotype. (23) Ovicelled adult zooecium, proximal oral shield worn away ; d.o.s, distal oral spines ; o, outline of ovicell of preceding zooecium. (24) Interzooecial avicularium, of the same zoarium, showing lateral constrictions. The avicularium is figured in the normal orientation to the zooecium directed distally and obliquely outwards. of M. cor-anguinum. Gillingham, north-east of Chatham, Kent. W. Gamble Collection. EMENDED DIAGNOSIS. Lagynopora with small zooecia (Lz = about 0-60 mm., Iz = 0-40 to 0-42 mm.) ; frontal shield well arched ; costae 11-13, narrow, separated 72 CRETACEOUS CRI BRIMORPH POLYZOA (PELM ATOPORI N AE) by wide intercostal spaces ; median area of fusion narrow ; avicularia frequent, apparently of one kind only, large (Lz = 0-23 mm., Iz = 0-15 to 0-20 mm.), oval or almost parallel-sided with proximal-lateral constrictions, directed distally and often obliquely outwards from the zooecia they accompany ; ovicells hyperstomial, often with a slight median ridge and small lateral slits. DESCRIPTION. Zoarium encrusting, unilaminar. Adult zooecia oval, fairly closely placed, each with a large, round distal communication pore. Secondary orifice wider than high, rounded distally and laterally with a straight proximal margin. Oral spines 4, arranged symmetrically ; the distal pair are smaller than the proximal- lateral pair and may flank the entrance to the ovicell when this is present. The proximal-lateral pair are enlarged ; they very probably fused with the median process of the apertural bar to form a proximal oral shield. Frontal shield well arched, sloping down steeply at the margins to meet the gymnocyst. Costae 11-13, narrow, fused only near the mid-line and separated by wide intercostal spaces. Some costae retain minute pelmatidia along their mid-line. Apertural bar well formed, only slightly wider than the most distal costae, with a median process which probably fused with the proximal-lateral oral spines to form the proximal oral shield. Gymno- cyst exposed proximally to most frontal shields and narrowly along their sides. No interzooecial secondary tissue. Aviculana of one kind, very large, frequent, directed distally and often obliquely outwards from the zooecia they accompany. The avicularia are oval or almost parallel-sided with well-marked proximal-lateral constrictions which may be the remains of worn transverse bars. Sometimes the constrictions may be completely removed by wear. Ovicells prominent, hyperstomial, globular, smooth, of medium size, often with a slight median ridge and with small lateral slits. Young zooecia smaller than the adult zooecia and with 6 oral spines. Ancestrula apparently with 6 oral spines. MEASUREMENTS. Adult zooecia Lz = about 0-60 mm. Iz 0-40 to 0-42 mm. hr = o-io to 0-12 mm. Ir = 0-14 to 0-15 mm. Avicularia Lz = 0-23 mm. Iz = 0-15 to 0-20 mm. Young zooecia Lz = 0-37 to 0-42 mm. Iz = 0-26 to 0-30 mm. hr I x measurable. Ancestrula Lz = 0-29 mm. Iz = 0-21 mm. , >Not measurable. REMARKS. Prodromopora praecursor Lang is placed in Lagynopora, as it apparently has a proximal oral shield formed by the fusion of the proximal-lateral oral spines with the median process of the apertural bar. Further, a prominent distal com- CRETACEOUS CRIBRIMORPH POLYZOA (PELM ATOPORIN AE) 73 munication pore is present, there are 4 oral spines in the adult zooecia, and large, distally directed oval avicularia are present. All these characters are typical of Lagynopom. Unlike most other species of Lagynopora, there are only a few widely spaced costae which fuse only along the mid-line of the frontal shield : this dis- tinctive frontal shield is only specifically diagnostic. Only one specimen, 0.8351, is available. Apart from three adult zooecia the zoarium is badly damaged. It is, however, possible, using high-power magnification, to distinguish minute pelmatidia on the costae of these zooecia. STRATIGRAPHICAL DISTRIBUTION. Senonian, zone of M. cor-anguinum. SPECIMEN. 0.8351. Holotype see above. 4. Lagynopora saltdeanensis Lang (PI. 3, fig. 4 ; Text-figs. 25, 26) igi6a Lagynopora saltdeanensis Lang, p. 395. 1921 Lagynopora saldeanensis Lang : Lang, pp. xcii, 56, text-fig. 27. 1930 Lagynopora saltdeanensis Lang : Gaster, table opp. p. 340. HOLOTYPE. 0.28896. Zoarial fragment encrusting a piece of echinoid test. Senonian, zone of 0. pilula, subzone of E. scutata var. depressula. Cliffs between last groyne east of Rottingdean Gap and Saltdean, east of Brighton, Sussex. O 26 O5mm. FIGS. 25, 26. Lagynopora saltdeanensis Lang, 0.28896. Holotype. (25) Adult ovicelled zooecium in which the proximal oral shield has been worn away. (26) Distal half of another adult ovicelled zooecium with two worn interzooecial avicularia. 74 CRETACEOUS CRIBRIMOKPH POLYZOA (PELM ATOPORIN AE) EMENDED DIAGNOSIS. Lagynopora with fairly small zooecia (Lz = 0-43 to 0-45 mm., Iz = 0-25 to 0-27 mm.) ; secondary orifice fairly small (hr = 0-08 mm., lr = 0-10 mm.) ; costae, 11-14, with distinct intercostal spaces, but no lateral costal fusions ; avicularia occasional, fairly large, oval ; ovicells hyperstomial. DESCRIPTION. Zoarium encrusting, unilaminar. Adult zooecia broadly oval, closely placed. Secondary orifice small, wider than high, rounded distally with straight sides and a straight proximal margin. Oral spines apparently 4, not much thickened. Proximal oral shield formed by the fusion of the lateral oral spines with the median process of the apertural bar. Nearly all zooecia are worn, retaining only the abraded median process on the apertural bar. Frontal shield well arched. Costae 11-14, narrow, tapering inwards, united along the mid-line in a narrow median area of fusion. Outwards from the median area the costae slope down fairly steeply to meet the gymnocyst. Two or three small pelmatidia are visible on the upper surfaces of most costae, but they may be obscured by wear. Apertural bar straight with a median process which is fused with the proximal-lateral oral spines to produce the proximal oral shield. Gymnocyst smooth, fairly widely exposed proximally to each frontal shield, but it may be concealed by the close placing of the zooecia or by the small amounts of interzooecial secondary tissue which may occur. Avicularia occasional, unpaired, fairly large, oval, and of uncertain orientation. Ovicells large, smooth, prominent, hyperstomial, globular, of about equal height and width and apparently without lateral slits. Young zooecia similar to the adult zooecia, but smaller and with fewer costae. MEASUREMENTS. Adult zooecia Lz 0-43 to 0-45 mm. Iz = 0-25 to 0-37 mm. hr 0-08 mm. lr = o-io mm. Young zooecia Lz = 0-30 to 0-33 mm. Iz = 0-20 to 0-25 mm. hr = 0-06 mm. lr = 0-09 mm. Avicularia Not measurable. REMARKS. L. saltdeanensis is smaller than L. birlingensis and possesses fewer costae, and has, apparently, fewer, larger, sporadic avicularia. The only available specimen of L. saltdeanensis is the holotype 0.28896. It possesses only a few well-preserved zooecia, at least two of which are representative of a young stage of zoarial growth. It might thus be argued that 0.28896 is merely an early growth stage of L. birlingensis. The problem can only be settled when new material becomes available. The form of the proximal oral shield in L. saltdeanensis is unknown, but this feature has generic rather than specific diagnostic value and its original presence can be determined with certainty from the form of the worn orifice. STRATIGRAPHICAL DISTRIBUTION. Senonian, zone of 0. pilula, subzone of E. scutata var. depressula. SPECIMEN. D. 28896. Holotype see above. 1921 1930 CRETACEOUS CRIBRIMORPH POLYZOA ( PELM ATOPORIN AE) 5. Lagynopora birlingensis Lang (PI. 3, fig. 6 ; Text-figs. 27, 28) Lagynopora birlingensis Lang, p. 395. Lagynopora birlingensis Lang : Lang, pp. xciv, 55, pi. 2, fig. 2 ; text-fig. 26. Lagynopora birlingensis Lang : Caster, table opp. p. 340. 75 HOLOTYPE. 0.28254. Incomplete zoarium encrusting a fragment of Inoceramus shell. Senonian, zone of M . cor-anguinum. Cliffs between Beltout and Billing Gap, west of Beachy Head, Sussex. FIGS. 27, 28. Lagynopora birlingensis Lang, 0.28254. Holotype. (27) Adult zooecium with worn orifice, the proximal oral shield worn away, and worn, oval avicularium. (28) Ovicell and orifice, partly obscured by matrix, of another adult zooecium the proximal oral shield is partly preserved ; m.p, median process of apertural bar ; p.o.s, proximal oral spine. EMENDED DIAGNOSIS. Lagynopora with fairly large zooecia (Lz = 0-50 to 0-60 mm., Iz = 0-30 to 0-37 mm.) ; secondary orifice of normal size (hr = o-io mm., Ir = 0-12 to 0-16 mm.) ; costae numerous (17-18) with distinct intercostal spaces ; no lateral costal fusions ; avicularia interzooecial, oval, fairly abundant ; ovicells hyperstomial, longer than wide. DESCRIPTION. Zoarium encrusting, unilaminar. Adult zooecia broadly oval, fairly closely placed. Secondary orifice wider than high, rounded distally and laterally, proximal margin fairly straight. Oral spines 4, somewhat thickened but otherwise unmodified, arranged in two pairs on the distal-lateral margins of the 7 6 orifice. Proximal oral shield very obtusely " Y "-shaped, formed by the fusion of the proximal-lateral pair of oral spines with the median process of the apertural bar. Frontal shield fairly well arched. Costae 17-18, narrow, tapering inwards and separated by distinct, narrow intercostal spaces : no lateral costal fusions present. The costae are united about the mid-line into a narrow median area of fusion in which may be traced the outlines of the inner ends of individual costae. Minute pelmatidia are present, possibly three or four on each costa. Apertural bar prominent with a median process forming part of the proximal oral shield it is often destroyed by wear leaving a straight apertural bar with a worn median process. Gymnocyst exposed proximally to some frontal shields but generally obscured by the small amount of irregular but widespread interzooecial secondary tissue. Avicularia interzooecial, unpaired, numerous, small, rounded to oval, of uncertain orientation. Ovicells hyperstomial, smooth, prominent, globular, somewhat longer than wide and without lateral slits. Young zooecia smaller than the adult zooecia, with fewer (n or 12) costae, but otherwise similar. MEASUREMENTS. Adult zooecia Lz = 0-50 to 0-60 mm. lz = 0-30 to 0-37 mm. hr = o-io mm. Ir = 0-12 to 0-16 mm. Young zooecium Lz = 0-35 mm. lz = O-22 mm. hr , ^,w,. measurable. Avicularia Lz = 0-08 to 0-12 mm. lz = 0-07 to o-n mm. REMARKS. Lagynopora birlingensis may be distinguished by its dimensions, the shape of the orifice which is wider than high, by the form of its proximal oral shield and by its numerous costae and avicularia. In his description of the species Lang (1921 : 55) described the orifices as normal to cribriline ; however, the marked proximal-lateral constrictions typical of cribriline orifices are not present. He also commented " aviculoecia [avicularia] dimorphic, both kinds fairly numerous, sporadically distributed, with more or less circular apertures, which, even in the larger kind, are decidedly smaller than those [i.e., the orifices] of the orthoecia [zooecia] and, at least in the larger kind, bear spines on the distal rim ". I have been unable to distinguish two kinds of avicularia and have not seen the spines which Lang mentioned. In his figure of the species (1921 : 12, text-fig. 2) Lang showed, at the lower left-hand side, a large round pore and a smaller one proximal to it. These might be avicularia, but as they are very worn this remains uncertain. The only complete proximal oral shield in the specimen is shown much improved in Lang's figure. Although it is more obscured by matrix than is indicated, it is possible to determine that it is much more obtusely " Y"- shaped than Lang has shown. He regarded L. birlingensis as a " very primitive form, approaching Prodromopora [= Lagynopora] in the thinness and distant spacing of the costae." See also remarks on L. saltdeanensis (p. 74). CRETACEOUS CRIBRIMORPH POLYZOA (PELM ATOPORI N AE) 77 STRATIGRAPHICAL DISTRIBUTION. Senonian, zone of M. cor-anguinum. SPECIMENS. 0.28254. Holotype see above. 0.41068 Zoarial fragment encrusting a piece of echinoid test. Senonian, zone of M. cor-anguinum (above the " strong cor-anguinum tabular flint band"). Cliffs between Birling Gap and Beltout, west of Eastbourne, Sussex. 6. Lagynopora amphora Lang (PI. 3, fig. 9 ; Text-fig. 29) igi6a Lagynopora amphora Lang, pp. 395, 396. 1921 Lagynopora amphora Lang : Lang, pp. xcii, 59, text-fig. 29. 1930 Lagynopora amphora Lang : Gaster, table opp. p. 340. HOLOTYPE. 0.28255. Incomplete zoarium encrusting a piece of echinoid test. Senonian, zone of 0. pilula, subzone of E. scutata var. cincta. Cliffs east of Telscombe Staircase, west of Newhaven, Sussex. O I FIG. 29. Lagynopora amphora Lang, 0.28255. Holotype. Orifice and broken ovicell of adult zooecium. The enlarged proximal oral spines fused originally with the prominent, broken median process of apertural bar. EMENDED DIAGNOSIS. Lagynopora with large zooecia (Lz = 0-64 to 0-75 mm., lz = 0-37 to 0-50 mm.) ; frontal shield often with a distinct median ridge ; costae 1 3-1 7 with distinct intercostal spaces ; avicularia interzooecial, small, oval, occasional ; ovicell hyperstomial, slightly pointed distally, slightly longer than wide. DESCRIPTION. Zoarium encrusting, unilaminar. Adult zooecia very closely placed, broadly oval, each with a large, oval distal, and a smaller, oval lateral communication pore. Secondary orifice wider than high, distally and laterally 78 CRETACEOUS CRIBRIMORPH POLYZOA ( PELM ATOPORIN AE) rounded with a straight proximal margin. Oral spines 4, slightly enlarged, arranged symmetrically on the distal and lateral margins of the orifice. Proximal oral shield developed, but form unknown, all the oral shields in the available specimens having been destroyed by wear. Frontal shield evenly arched, often with a distinct median ridge. Costae 13-17, tapering slightly inwards, separated by narrow but distinct intercostal spaces. No lateral costal fusions. Each costa possesses a series of minute pelmatidia on its upper surface. Median area of fusion slight, often consisting of the median ridge only, or extending only slightly on either side of it. The outline of the inner extremity of each costa is visible in the median area of fusion. Apertural bar wider than the most distal costae, somewhat triangular, with distally curved ends, and with a prominent, fairly wide median process which almost certainly fuses, when complete, with the proximal-lateral pair of oral spines to form a proximal oral shield. Gymnocyst not exposed, owing to the very close placing of the zooecia. No interzooecial secondary tissue. Avicularia interzooecial, occasional, small, with oval apertures. Ovicells hyper- stomial, prominent, smooth, globular, longer than wide, sometimes tending to be slightly pointed distally. Young zooecia generally resemble the adult zooecia, but are smaller and have 6 oral spines, and slightly fewer (11-14) costae. MEASUREMENTS. Adult zooecia Lz = 0-64 to 0-75 mm. lz = 0-37 to 0-50 mm. hr = O'i2 to 0-13 mm. lr = 0-15 to 0-16 mm. Young zooecia Lz = 0-40 to 0-47 mm. lz = 0-30 to 0-35 mm. hr = o-n to 0-12 mm. lr = 0-13 mm. Avicularia Not measurable. REMARKS. Lagynopora amphora is distinguished from other species of the genus particularly by the characters of its frontal shield, which, in contrast to that of L. ampulla, is evenly arched and unconsolidated. The median ridge is especially distinctive. STRATIGRAPHICAL DISTRIBUTION. Senonian, zone of 0. pilula, subzone of E. scutata var. cincta, and lower part of zone of B. mucronata (not yet recorded from the zone of G. [A.] quadrata}. SPECIMENS. 0.28255. Holotype see above 0.40943. Incomplete zoarial fragment with young and adult zooecia, some ovicelled, encrusting a piece of echinoid test. Horizon, locality and collection as for the holotype. OTHER MATERIAL N.C.M. 76. 937(32), 76.937(33). Two zoarial fragments encrusting one piece of echinoid test. Senonian, lower part of zone of B. mucronata, Wells, Norfolk. R. M. Brydone Collection. CRETACEOUS CRIBRIMORPH POLYZOA (PELM ATOPORIN AE) 79 7. Lagynopora ampulla Lang (PI. 3, figs. 7 , 8 ; Text-fig. 30) igi6a Lagynopora ampulla Lang, pp. 395, 396. 1921 Lagynopora ampulla Lang : Lang, pp. xcii, 60, text-fig. 31. 1930 Lagynopora ampulla Lang : Gaster, table opp. p. 340. HOLOTYPE. 0.28256. Specimen in five fragments. Incomplete zoarium en- crusting a cheilostome polyzoan. Senonian, zone of G. \_A.~\ quadrata. East side of Old Nore Point, west of Newhaven, Sussex. FIG. 30. Lagynopora ampulla Lang, 0.28256. Holotype. Adult ovicelled zooecium with small, round, worn avicularium (a). The ovicell is slightly damaged proximally ; the proximal oral shield is well preserved showing the slender fusions with lengthened proximal oral spines and wide median process of apertural bar. o, outline of the ovicell of the preceding zooecium. 8o CRETACEOUS CRIBRIMORPH POLYZOA (PELM ATOPORIN AE) EMENDED DIAGNOSIS. Lagynopora with large zooecia (Lz = 0-62 to 0-75 mm., Iz = 0-35 to 0-50 mm.) ; proximal oral shield obtusely " Y "-shaped, prominent, flat and wide in front with a distinct median furrow, and slender fusions with the proximal-lateral oral spines ; costae 12-14, closely placed, no lateral costal fusions. DESCRIPTION. Zoarium encrusting, unilaminar. Adult zooecia broadly oval, closely placed, with large, oval distal communication pores and smaller lateral com- munication pores. Secondary orifice wider than high, distally rounded with straight sides and a straight proximal margin, the sides of the orifice may converge slightly proximally. The form of the secondary orifice is often obscured by the well- developed proximal oral shield or by ovicells. Oral spines 4, slightly lengthened, somewhat thickened, arranged symmetrically on the distal rim of the orifice. Proximal oral shield very prominent, obtusely " Y "-shaped, flat and wide in front, composed of the bifurcated, enlarged median process of the apertural bar which fuses, on either side, with the proximal-lateral oral spines. Frontal shield very flatly arched, well consolidated. Costae 12-14 (often 13). Each costa is fairly flat and tapered inwards. Adjacent costae are in contact and horizontal for most of their length. At their outer ends they bend down steeply to meet the gymnocyst and are separated by short, narrow intercostal spaces. Although the costae are in contact with one another, their outlines remain distinct, even in the median area. Median area of fusion extremely wide. Minute pelmatidia are visible on the upper surfaces of some costae. Apertural bar wider than the most distal costae, straight, or slightly curved distally at either end, with a strong median process which bifurcates and fuses with the proximal-lateral oral spines to produce the proximal oral shield. Gymnocyst apparently smooth, but little exposed owing to the close placing of the zooecia. No interzooecial secondary tissue. Avicularia very occasional, small, circular, interzooecial. Ovicells hyperstomial, prominent, smooth, globular, of about equal height and width. The entrance to the ovicell may be prominently flanked by a pair of oral spines. Young zooecia similar to the adult zooecia, but smaller and with 5 oral spines, and generally fewer (10-12) costae. MEASUREMENTS. Adult zooecia Lz = 0-62 to 0-75 mm. Iz = 0-35 to 0-50 mm. hr = 0-14 to 0-15 mm. Ir = 0-15 to 0-17 mm. Young zooecia Lz = 0-40 to 0-47 mm. Iz = 0-25 to 0-32 mm. hr = 0-08 to o-io mm. Ir = 0-09 to 0-14 mm. Avicularia Lz = 0-04 mm. Iz = 0-04 mm. REMARKS. L. ampulla is distinguished from other species of Lagynopora by its well consolidated frontal shield, short intercostal spaces, and particularly by its proximal oral shield. Lang (1921 : 60) overestimated the zooecial dimensions of L. ampulla. CRETACEOUS CRIBRIMORPH POLYZOA (PELM ATOPO RIN AE) 81 STRATIGRAPHICAL DISTRIBUTION. Senonian, zone of G. [A.] quadrata. SPECIMEN. 0.28256. Holotype see above. 8. Lagynopora furcifera (Brydone) (PL 4, figs, i, 2 ; Text-figs. 31, 32) 1910 Cribrilina furcifera Brydone, pp. 391, 392, 482 [partim pi. 30, fig. 7 only, non fig. 6 (= Lagynopora vasculum), non fig. 8 (= L. ollula)]. igi6a Lagynopora [Cribrilina] furcifera (Brydone) : Lang, p. 395 [partim that referring to Brydone, 1910, pi. 30, fig. 7 only]. Cribrilina furcifera Brydone : Brydone, p. 492. Lagynopora furcifera (Brydone) Lang, pp. xci, 67. Lagynopora furcifera (Brydone) : Voigt, pp. 495, 542, 560, pi. 26, fig. 10. Lagynopora aft. furcifera (Brydone) : Voigt, pp. 36, 43, 44, pi. n, fig. i. LECTOTYPE. (Chosen by Lang, 1921 : 67.) S.M., 6.36165. An extensive, well- preserved zoarial fragment encrusting a piece of echinoid test. Senonian, zone of G. [A.] quadrata. Bramford, near Ipswich, Suffolk. R. M. Brydone Collection. 1917 1921 ?i930 ?I949 FIGS. 31, 32. Lagynopora furcifera (Brydone), S.M., 6.36165. Lectotype. (31) Adult zooecium and worn avicularium, the proximal oral shield destroyed. (32) Ovicell and orifice of another adult zooecium with complete proximal oral shield and part of an avicularium. EMENDED DIAGNOSIS. Lagynopora with very large zooecia (Lz = 0-75 to 0-85 mm., lz 0-50 to 0-56 mm.) ; proximal oral shield very prominent, very widely " Y "- shaped, composed of a wide median process which rises from the apertural bar, bifurcates, and fuses with the proximal-lateral pair of oral spines ; frontal shield well arched ; costae very numerous, 20-23, distinct, separated by intercostal spaces GEOL. 6, I. 6 82 CRETACEOUS CRIBRIMORPH POLYZOA ( PELM ATOPORIN AE) for at least half their length ; median area of fusion wide ; avicularia interzooecial, fairly frequent, oval. DESCRIPTION. Zoarium encrusting, unilaminar. Adult zooecia broadly oval, closely placed, each with a large, oval distal communication pore and one or two, somewhat smaller, oval lateral communication pores. Secondary orifice wider than high, rounded distally and laterally with a straight proximal margin. Oral spines 4, slightly enlarged, symmetrically arranged round the orifice. Proximal oral shield prominent, formed by the fusion of the proximal-lateral pair of oral spines with the wide, flat median process of the apertural bar. Frontal shield slightly flattened in the median area but otherwise well arched. Costae 20-23, narrow, well defined, separated at their outer ends, and for about half their length, by distinct intercostal spaces ; the outlines of their inner ends may be traced across the wide median area of fusion. No lateral costal fusions. Minute pelmatidia are visible on the upper surfaces of unworn costae. Apertural bar wide, somewhat swollen, triangular, the apex of the triangle pointing proximally. The outer ends of the apertural bar are slightly bent proximally to the frontal shield, but generally obscured by the close placing of the zooecia, or by avicularia. Interzooecial secondary tissue absent. Avicularia interzooecial, frequent, fairly large, oval. [In the lectotype all the avicularia are worn.] Ovicells hyperstomial, frequent, smooth, prominent, globular, some may be slightly pointed distally with a slight median ridge. The proximal- lateral margins of the ovicells normally incorporate the distal pair of oral spines. Young zooecia smaller than the adult zooecia but otherwise similar, except that some of the very young zooecia may possess 5 or 6 oral spines, and the orifice tends to be of equal height and width. MEASUREMENTS. Adult zooecia Lz =0-75 to 0-85 mm. lz = 0-50 to 0-56 mm. hr 0-15 to 0-16 mm. Ir = 0-18 to 0-20 mm. Young zooecia Lz = 0-57 to 0-63 mm. lz .= 0-40 to 0-52 mm. hr == 0-15 mm. Ir =r 0-15 mm. Avicularia Lz = About 0-20 mm. lz = About 0-13 mm. REMARKS. Brydone figured three specimens with his original description of Cribrilina furcifera, 1910, pi. 30, figs. 6-8). Lang (19160 : 395) placed these three specimens in a single species of Lagynopora. Subsequently (1921) he suggested that the material figured by Brydone as Cribrilina furcifera belonged to three separate species of Lagynopora (that shown in fig. 6 being L. vasculum, that in fig. 7 L. furcifera, and that in fig. 8 L. ollula}. Having examined Brydone's figured specimens, I agree that they are three separate species of Lagynopora. I have accordingly extended the brief diagnoses given by Lang [these were based solely on Brydone's somewhat inadequate figures] and have added full descriptions and measurements. CRETACEOUS CRIBRIMORPH POLYZOA (PELM ATOPORIN AE) 8$ Lagynopora furcifera (Brydone) possesses more costae than L. vasculum or L. ollula, and is larger. The degree of consolidation of the arched frontal shield and the avicularia also further distinguish Lagynopora furcifera from other species of the genus. Voigt (1930 : 495, pi. 26, fig. 10) assigned to the species a specimen from the " Quadraten-oder Mukronatensenon " of Misburg. Both the description, in which he stated only that there are about 20 costae and that Lz = 0-70 mm., and the figure, which is quite indistinct, are inadequate to place the material with any certainty. More recently (Voigt, 1949 : 36, pi. n, fig. i) has described and figured, as " Lagynopora aff. furcifera (Brydone) ", another specimen from the " Quadraten- kreide " of Lagerdorf, Holstein. It is slightly larger than the lectotype, with slightly fewer costae and with 7 oral spines in the youngest zooecia. STRATIGRAPHICAL DISTRIBUTION. Senonian, zone of G. [A.] quadrata of England and Germany. MATERIAL. S.M., 6.36165. Lectotype see above. 9. Lagynopora ollula Lang (PI. 4, fig. 3 ; Text-figs. 33~35) 1910 Cribrilina furcifera Brydone, p. 391 [partim pi. 30, fig. 8 only]. 19160 Lagynopora furcifera (Brydone) : Lang, p. 395 [partim that referring to Brydone, 1910, pi. 30, fig. 8 only]. 1921 Lagynopora ollula Lang, pp. xciv, 60. 1930 non Lagynopora furcifera (Brydone) : Voigt, pp. 495, 542, 560, pi. 26, fig. 10. 1949 non Lagynopora aft . furcifera (Brydone) : Voigt, pp. 36, 43, 44, pi. II, fig. i. LECTOTYPE. (Chosen by Lang, 1921 : 60.) S.M., 6.36166. The specimen figured by Brydone (1910, pi. 30, fig. 8). Zoarial fragment encrusting a piece of echinoid test. Senonian, zone of Marsupites, subzone of Uintacrinus. Kingsgate, Kent. R. M. Brydone Collection. EMENDED DIAGNOSIS. Lagynopora with large zooecia (Lz = 0-58 to 0-67 mm., Iz = 0-40 to 0-51 mm.) ; orifice of constant size (hr = 0-12 mm., Ir = 0-15 mm.) ; proximal oral shield very prominent, obtusely " Y "-shaped, the flat, wide median process standing out almost at right angles to the plane of the apertural bar ; frontal shield well consolidated ; costae 9-11, broad, closely placed, fused to neighbouring costae throughout most of their length ; avicularia interzooecial, unpaired, large, prominent, oval, with proximal-lateral constrictions. DESCRIPTION. Zoarium encrusting, unilaminar. Adult zooecia closely placed, very broadly oval, each with a very large, oval distal communication pore and several smaller, oval lateral communication pores. Secondary orifice wider than high, of constant size, distally rounded with straight sides and a straight proximal margin. The form of the orifice may be obscured by the proximal oral shield or by ovicells. Oral spines 4 or 5, arranged symmetrically round the orifice. The proximal-lateral pair of oral spines is often larger than the distal pair, all are slightly secondarily thickened. Proximal oral shield very prominent, obtusely " Y "-shaped, formed by the flat, wide median process of the apertural bar which bifurcates and fuses with 8 4 CRETACEOUS CRIBRIMORPH POLYZOA (PELM ATOPORI N AE) the lateral pair of oral spines. Frontal shield wide, flat, except at the margins where the costae descend steeply to meet the gymnocyst. Costae 9-11, distinct, wide, rounded, tapering inwards. Each costa is completely fused to its neighbouring costae for most of its length, but the outline of each costa is clearly visible up to the FIGS. 33-35. Lagynopora ollula Lang, S.M., 6.36166. Lectotype. (33) Adult ovicelled zooecium ; the proximal oral shield is broken on one side. (34) Orifice of another adult zooecium with a fifth distal-median oral spine-base the proximal oral shield broken. (35) Avicularium with proximal-lateral constrictions. mid-line of the frontal shield. Only at their outer ends are the costae clearly separate, and the frontal shield is well consolidated and the median area of fusion extremely wide. Minute pelmatidia are visible on the upper surfaces of unworn costae. Apertural bar straight, except for a distal curve at either end, swollen, wider than the most distal costae. A strong, flat, wide median process rises almost CRETACEOUS CRIBRIMORPH POLYZOA (PELM ATOPORIN AE) 85 perpendicularly from the centre of the apertural bar and forms part of the proximal oral shield. Gymnocyst smooth, but seldom exposed owing to the close placing of the zooecia ; usually visible round the interzooecial avicularia. No interzooecial secondary tissue. Avicularia interzooecial, unpaired, large, round or oval, probably with a transverse bar, now broken, and represented by proximal-lateral constrictions, originally divid- ing a smaller semicircular proximal portion from a larger, transversely oval rostrum. Apparently the avicularia are variously directed ; some are definitely distally directed obliquely away from the zooecia they accompany, others may be directed proximally and obliquely towards the zooecia they accompany. Ovicells hyperstomial, very prominent, smooth, globular, as wide as high. The proximal-lateral margin of the ovicell may incorporate or obscure the distal-lateral pair of oral spines. Some ovicells tend to be slightly pointed distally. Young zooecia smaller than the adult zooecia. Orifice of less constant size than in the adult stages. Oral spines 6 or 7. Proximal oral shield probably developed. Frontal shield more arched than in the adult. Costae more numerous, 10-12, but, as in the adult stages, fused for most of their length. Apertural bar wide, straight. Ancestrula [of lectotype]. Only the orifice is visible ; it is wider than high, and there are 8 closely spaced, symmetrically arranged oral spines. MEASUREMENTS. Adult zooecia Lz = 0-58 to 0-67 mm. Iz = 0-40 to 0-51 mm. hr = 0-12 mm. Ir = 0-15 mm. Avicularia Lz = 0-12 to 0-14 mm. Iz = 0-19 to 0-15 mm. Young zooecia Lz = 0-40 to 0-43 mm. Iz = 0-23 to 0-26 mm. hr = 0-07 to o-io mm. Ir = o-io to o-n mm. Ancestrula Lz^l XT , , , , >Not measurable. Iz/ hr = 0-07 mm. Ir o-io mm. REMARKS. Lagynopora ollula (Brydone) is clearly distinguished from other species of the genus by its much consolidated, wide frontal shield, its relatively few costae, the constant size of its orifice, and particularly by the characters of its avicularia. In the lectotype, S.M., 6.36166, where ovicells have been preserved they ap- parently afforded some protection for the proximal oral shield, for this is most complete in the ovicelled zooecia. In non-ovicelled zooecia, although the proximal oral shield is very prominent, it is frequently destroyed by wear so that the apertural bar appears as a straight, featureless structure with no trace of the very strong median process present in complete individuals. Very slight wear of the surfaces of the costae in this well-preserved specimen has been sufficient to obscure most of the 86 CRETACEOUS CRIBRIMORPH POLYZOA (PELM ATOPORIN AE) minute pelmatidia which may now be seen only occasionally on the upper surfaces of some costae. The lectotype zoarium, although small, is almost complete, for it possesses the ancestrula and its surrounding young zooecia, ovicelled adult zooecia, and, in one place, a small zooecium possibly close to part of the growing edge of the zoarium. Fewer oral spines are developed in the adult than in the young stages, and the ancestrula possesses the largest number of oral spines, 8. This reduction in the number of oral spines during growth is apparently accompanied by a slight reduction in the number of costae. Lang (1921 : 60) has suggested that L. ottula, apart from its well-consolidated frontal shield, shows " primitive characters ". Mr. A. G. Brighton has kindly informed me that Brydone (in litt. 23rd June, 1938) stated that the lectotype came from the " Uintacrinus Band " of Kingsgate, Kent. See also remarks under L. furcifera (Brydone), p. 82. STRATIGRAPHICAL DISTRIBUTION. Senonian, zone of Marsupites, subzone of Uintacrinus. MATERIAL. S.M., 6.36166. Lectotype see above. 10. Lagynopora lagena Lang (PI. 4, figs. 4-6 ; Text-figs. 36, 37) 1893 Cribrilina nitidiformis Vine, pp. 316, 336 [nomen nudum vide Lang, 1921 : 62]. 1904 Cribrilina nitidiformis Vine : Jukes-Browne, p. 490 [vide Lang, 1921 : 62]. 191 6a Cribrilina nitidiformis Vine : Lang, p. 410 [vide Lang, 1921 : 62]. 191 6a Lagynopora lagena Lang, p. 395. 1921 Lagynopora lagena Lang : Lang, pp. Ixi, xciv, 62, pi. 2, fig. 4 ; text-fig. 30. ?i93o Lagynopora aff. lagena Lang : Voigt, pp. 495, 542, 560, pi. 26, fig. 9. 1935 Lagynopora lagena Lang : Bassler, p. 135. 1953 Lagynopora lagena Lang : Bassler, p. Gi88, text-fig. 142, 9. HOLOTYPE. 0.4042. Zoarial fragment encrusting a piece of echinoid test. Senonian, either zone of M. cortestudinarium or zone of M. cor-anguinum. Chatham, Kent. W. Gamble Collection. EMENDED DIAGNOSIS. Lagynopora with zooecia of medium size (Lz = 0-48 to 0-68 mm., Iz = 0-35 to 0-46 mm.) ; proximal oral shield more acutely " Y "-shaped than in other species of Lagynopora, formed by a fairly narrow median process of the apertural bar which fuses with large, robust proximal-lateral oral spines ; frontal shield evenly arched ; costae 13-20 (often 15-19), juxtaposed but delimited for their whole length by distinct furrows and united only in the narrow median area of fusion which may form a slight ridge ; avicularia frequent, apparently of two sizes, inter- zooecial, oval with proximal-lateral constrictions ; ovicells hyperstomial, often with a slight median ridge, occasionally with small lateral slits. DESCRIPTION. Zoarium encrusting, unilaminar. Adult zooecia broadly oval, fairly closely placed, each with an oval distal communication pore. Secondary orifice wider than high, rounded distally and laterally with a straight proximal margin. Oral spines 4, symmetrically arranged round the orifice, the proximal-lateral pair CRETACEOUS CRIBRIMORPH POLYZOA ( PELM ATOPORIN AE) 87 slightly larger than the distal pair. Proximal oral shield prominent, more acutely " Y "-shaped than in other species of Lagynopora, formed by the narrow median process of the apertural bar which fuses with the proximal pair of robust oral spines. Frontal shield well arched, with a slight, often ridge-like, narrow median area of 36 O I O*5mm. FIGS. 36, 37. Lagynopora lagena Lang. (36) 0.4042. Holotype. Adult ovicelled zooecium with complete proximal oral shield and small oral, worn avicularium of type b. The distal oral spines are unusually long. (37) 0.2633. Paratype. Large interzooecial avicularium of type a, shown in relation to Fig. 36 in the usual orientation for the species directed distally and obliquely outwards from the zooecium. fusion. Costae 13-20, variable in number but often 15-19, narrow, juxtaposed but denned along their whole length by distinct furrows and properly fused only along the mid-line of the frontal shield. No lateral costal fusions. Minute pelmatidia are visible on the upper surfaces of some well-preserved costae. Apertural bar wider than the most distal costae, straight, with a slight distal bend at either end, and with 88 CRETACEOUS CRIBRIMORPH POLYZOA ( PELM ATOPORIN AE) a narrow median process which forms part of the proximal oral shield. Gymnocyst smooth, only slightly exposed proximally to some frontal shields or more extensively round some avicularia, but generally concealed by the close placing of the zooecia. No interzooecial secondary tissue. Avicularia of one kind, but, in some zoaria, of two sizes, interzooecial, oval with proximal-lateral constrictions which are, apparently, the broken ends of straight transverse bars. Where avicularia of both sizes are developed, the larger type (a) occurs near the orifice and is directed distally and obliquely outwards from the zooecium it accompanies. The small type (b) occurs less frequently and always distal to the orifice or distal to the ovicell when this is present, and is distally directed. In zoaria with both types the avicularia occur frequently, but they are less numerous in zoaria with only the larger form. Where only the larger form of avicularium occurs it may also be placed distally to the orifice. Occasionally avicularia are rare or even absent in a zoarium. No example has been seen in which only the smaller type of avicularium occurs. Ovicells hyperstomial, small but prominent, smooth, globular, wider than high and often with a median ridge. Occasional ovicells may have small lateral slits. Young zooecia resemble the adult zooecia, but are smaller and may have from 4 to 6 oral spines and fewer costae. Often the youngest zooecia have the most oral spines. Ancestrulae lack the proximal oral shield which occurs throughout young and adult zooecia. Some ancestrulae possess 6 oral spines, that of D.I 1280, however, has only 4. MEASUREMENTS. Adult zooecia Lz = 0-48 to 0-68 mm. lz = 0-35 to 0-46 mm. hr = o-io to 0-13 mm. lr == 0-13 to 0-18 mm. Avicularia : Type a Lz = 0-18 to 0-20 mm. lz = 0-15 to 0-17 mm. Type b Lz = o-io to o-n mm. lz = 0-07 to 0-08 mm. Young zooecia Lz = 0-40 to 0-45 mm. lz = 0-26 to 0-33 mm. hr = 0-07 mm. lr = o-ii mm. Ancestrula (of D. 11280) Lz 0.30 mm. lz = 0-23 mm. hr = 0-07 mm. lr = o-io mm. REMARKS. Lagynopora lagena, the type species, was regarded by Lang (1921 : 63) as " the lowest term in a series " which, he suggested, exhibits an increasing consolida- tion of the frontal shield and a gradual loss of avicularia, first of the smaller kind [type (b) in L. lagena] and finally of the larger kind also. Certainly L. lagena is the only species of Lagynopora which possesses more than one size of avicularium, and it also exhibits, though not necessarily in a single zoarium, the widest range in CRETACEOUS CRI BR IMO RPH POLYZOA (PELM ATOPORIN AE) 89 number of costae. Like other species, it undergoes, in the early stages of zoarial growth, a rapid reduction in the number of oral spines. L. lagena is distinguished by its large number of costae, its well-arched frontal shield and narrow, ridge-like median area of fusion, and by its avicularia and small ovicells. STRATIGRAPHICAL DISTRIBUTION. Senonian, zones of M. cortestudinarium and M. cor-anguinum in England. ? Upper part of zone of G. [A.] quadrata in Germany. SPECIMENS. 0.4042. Holotype see above. 0.4027-28. Two paratype zoarial fragments, the former encrusting an erect cheilostome polyzoan, the latter with only one complete zooecium and now unattached. Horizon, locality and collection as for the holotype. 0.4046. Paratype. Zoarial fragment encrusting a piece of echinoid test. Horizon, locality and collection as for the holotype. 0.4238. Paratype. Zoarial fragment encrusting a piece of Inoceramus shell. Horizon, locality and collection as for the holotype. 0.4969-70, 0.4974-76, 0.27978-79. Seven paratypes. Zoarial fragments encrust- ing pieces of echinoid tests. Horizon, locality and collection as for the holotype. 0.2633. Paratype. Zoarial fragment encrusting part of an erect cheilostome polyzoan. Labelled " Syntype of Cribrilina nitidiformis Vine 1893 ". Horizon and locality as for the holotype. G. R. Vine Collection. 0.2640. Paratype. Zoarial fragment encrusting a piece of Inoceramus shell. Labelled " Syntype of Cribrilina nitidiformis Vine 1893 ". Horizon and locality as for the holotype. G. R. Vine Collection. 0.11280. Paratype. Zoarial fragment encrusting a piece of test of Micr aster precursor Rowe. Senonian, top of zone of M . cortestudinarium or base of zone of M . cor-anguinum. Chatham, Kent. W. Gamble Collection. 0.21209. Paratype. Zoarial fragment with young zooecia possessing six oral spines encrusting a small fragment of echinoid test. Senonian, zone of M. cor-anguinum. Woburn Green, south-west of Beaconsfield, Buckinghamshire. L. Treacher Collection. 0.24236-38. Three paratypes. Zoarial fragments encrusting pieces of echinoid test. Senonian, high in zone of M. cortestudinarium. Luton, south- east of Chatham, Kent. W. Gamble Collection. 0.24385. Paratype. Extensive zoarial fragment encrusting a piece of echinoid test. Senonian, zone of M . cor-anguinum. Locality and collection as for 0.24236-38. 0.24519-20. Two paratypes. Zoarial fragments encrusting pieces of echinoid test, the former with small avicularia of type (&). Senonian, zone of M. cor- anguinum. Gillingham, north-east of Chatham, Kent. W. Gamble Collection. 0.24525. Paratype. Zoarial fragment with numerous avicularia of type (a) and with a regenerated and reversed zooecium, encrusting a piece of echinoid test. Horizon, locality and collection as for 0.24519-20. CRETACEOUS CRIBRIMORPH POLYZOA ( PELM ATOPORI N AE) 0.8135, D. 24136, 0.24541. Three paratypes. Zoarial fragments ; 0.8135 encrust- ing an erect polyzoan, the remainder encrusting pieces of echinoid test. Horizon, locality and collection as for 0.24519-20. 0.24539, 0.24592. Two paratypes. Zoarial fragments, the former encrusting an erect cyclostome polyzoan, the latter encrusting an erect cheilostome polyzoan. Horizon, locality and collection as for 0.24519-20. 0.27039-40. Two paratypes. Zoarial fragments encrusting the dorsal surface of pieces of unattached cheilostome polyzoan zoaria. Senonian, zone of M. cortestudinarium. Lower Pit, Slines Oak, Worms Heath, Warling- ham, Surrey. F. Mockler Collection. 0.27854-56. Three paratypes Zoarial fragments encrusting pieces of echinoid tests. Senonian, zone of M. cortestudinarium (upper part). Locality and collection as for 0.24519-20. 0.29102. Paratype. Zoarial fragment encrusting three pieces of echinoid test. Senonian, zone of M. cor-anguinum. Keston, Kent (south-east of Croydon, Surrey). R. Jones Collection. ii. Lagynopora urceolus Lang (PL 4, ng. 7 ; PI. 5, fig. i ; Text-figs. 38, 39) 1916* Lagynopora urceolus Lang, pp. 395, 396. 1921 Lagynopora urceolus Lang : Lang, p. 65, pi. 2, fig. 5 ; text-fig. 32. 1930 Lagynopora urceolus Lang : Gaster, table opp. p. 340. HOLOTYPE. 0.28889. Zoarial fragment with ancestrula and ovicelled adult zooecia encrusting a piece of echinoid test. Senonian, zone of 0. pilula, subzone of E. scutata var. depressula. Cliffs between last groyne east of Rottingdean Gap and Saltdean, Sussex. EMENDED DIAGNOSIS. Lagynopora with zooecia of large size (Lz = 0-65 to 0-78 mm., Iz = 0-35 to 0-50 mm.) ; orifice just wider than high ; frontal shield well arched ; costae 12-18, closely placed ; no marked intercostal spaces ; avicularia larger than the orifice, interzooecial, fairly frequent, directed just proximally and outwards from the zooecia they accompany ; ovicells large. DESCRIPTION. Zoarium encrusting, unilaminar. Adult zooecia broadly oval, each with a large, circular distal communication pore and one or more smaller, oval lateral communication pores. Secondary orifice just wider than high, rounded distally and laterally with a straight proximal margin. Oral spines 4, occurring in two distinct pairs, the proximal pair larger. Proximal oral shield obtusely " Y "-shaped, formed by the fusion of the proximal oral spines with the bifurcated median process of the apertural bar. Frontal shield well arched, but flattened in the median area. Costae 12-18, closely placed, separated by furrows rather than definite intercostal spaces, but with their outlines distinct. Median area of fusion not very wide, extending along the inner half of the costae at the maximum. The mid-line of the frontal shield may be marked by a slight, irregular ridge. No lateral costal fusions. Minute pelmatidia are visible on the upper surfaces of well-preserved costae. Apertural bar CRETACEOUS CRIBRIMORPH POLYZOA (PELM ATOPORIN AE) 91 widely triangular, the apex pointing proximally, with a median ridge and a prominent median process which forms part of the proximal oral shield. Gymnocyst smooth, almost completely concealed by the close placing of the zooecia and by ovicells and avicularia. No interzooecial secondary tissue. O I Q-5 mm. FIG. 38. Lagynopora urceolus Lang, D. 40944. Adult ovicelled zooecium and inter- zooecial avicularium. The proximal oral shield is destroyed ; the avicularium, with proximal-lateral constrictions, is directed typically outwards from the zooecium it accompanies. Avicularia very prominent, larger than the orifice, interzooecial, directed just proximally and outwards from the zooecia they accompany, broadly oval with proximal-lateral constrictions dividing the wider semicircular proximal portion from the somewhat pointed longer rostrum. Ovicells very prominent, frequent, hyper- stomial, large, smooth, globular, without lateral slits. Young zooecia similar to the adult zooecia, but smaller and with 5 or 6 oral spines and 12-16 costae. Ancestrula (of holotype) very small, with 7 oral spines. Number of costae unknown. 92 CRETACEOUS CRIBRIMORPH POLYZOA (PELM ATOPORIN AE) MEASUREMENTS. Adult zooecia Lz = 0-65 to 0-78 mm. lz = 0-35 to 0-50 mm. hr = 0-13 to 0-15 mm. Ir = 0-15 to 0-17 mm. Avicularia Lz = 0-16 to 0-21 mm. lz = 0-14 to 0-17 mm. Young zooecia Lz = 0-35 to 0-47 mm. lz = 0-23 to 0-30 mm. hr = o-io mm. Ir = o-io to 0-12 mm. Ancestrula (of holotype) Lz = 0-30 mm. lz = 0-18 mm. hr = 0-09 mm. Ir = o-io mm. O L O-4mm. FIG. 39. Lagynopora urceolus Lang, D. 28889. Holotype. Ovicell and orifice of adult zooecium with proximal oral shield broken on one side. REMARKS. Lang (1921 : 65) apparently placed very little diagnostic value on the very distinctive avicularia of L. urceolus for he did not mention them in his diagnosis of the species. L. urceolus is distinguished particularly by its avicularia and to a lesser extent by the dimensions of its zooecia, its number of costae and its well-arched frontal shield. The outline of individual costae may be traced across the median area of fusion which is narrow rather than " wide " as Lang has stated. In 0.40944, a well-preserved specimen, an avicularium is apparently replaced by a small, reversed, but otherwise normal zooecium. CRETACEOUS CRIBRIMORPH POLYZOA (PELM ATOPORIN AE) 93 STRATIGRAPHICAL DISTRIBUTION. Senonian, zone of 0. pilula, subzone of E. scutata var. depressula, and zone of Marsupites, subzone of Uintacrinus. SPECIMENS. 0.28889. Holotype see above. 0.29898. Ovicelled zoarial fragment encrusting a piece of echinoid test. Senonian, zone of 0. pilula, subzone of E. scutata var. depressula. Cliffs west of Chimney Shaft, Roedean, east of Brighton, Sussex. 0.40944. Ovicelled zoarial fragment encrusting a piece of echinoid test. Horizon, locality and collection as for 0.29898. 0.41064. Lagynopora cf. urceolus. Somewhat damaged ovicelled zoarial fragment encrusting a piece of echinoid test. Senonian, zone of Marsupites, subzone of Uintacrinus. Pit 49 of G. W. Young Medical College Pit, Epsom, Surrey. 0.41067. Well-preserved, ovicelled zoarial fragment possibly close to part of the growing edge, encrusting a fragment of echinoid test. Senonian, zone of 0. pilula, subzone of E. scutata var. depressula. Section 113 of Gaster, cliffs east of Rottingdean Gap to Saltdean, Sussex. 12. Lagynopora vasculum Lang (PI. 5, fig. 2 ; Text-figs. 40, 41) 1910 Cribrilina furcifera Brydone, p. 391 [partim pi. 30, fig. 6 only ; non fig. 7 ( Lagynopora furcifera) ; non fig. 8 (= L. ollula)]. 19160, Lagynopora [Cribrilina] furcifera (Brydone) : Lang, p. 395 [partim Brydone, 1910, pi. 30, fig. 6 only]. 1921 Lagynopora vasculum Lang, pp. xciii, 66, text-fig. 33. LECTOTYPE. (Chosen by Lang, 1921 : 67.) S.M., 6.36164. A well-preserved zoarial fragment encrusting a piece of echinoid test. Senonian, zone of O. pilula, subzone of E. scutata var. depressula. Lower part of old pit and road cutting at Mount Pleasant, Andover, Hampshire. R. M. Brydone Collection. EMENDED DIAGNOSIS. Lagynopora with large zooecia (Lz = 0-73 to 0-80 mm., Iz 0-45 to 0-50 mm.) ; proximal oral shield very prominent, obtusely " Y "- shaped ; median process of the apertural bar very wide ; costae numerous, 15-17, indistinct except towards the margins of the otherwise consolidated frontal shield ; intercostal spaces between the outer ends of the costae only ; ovicells hyperstomial, large, globular, smooth. DESCRIPTION. Zoarium encrusting, unilaminar. Adult zooecia large, broadly oval, very closely placed, each with a large, prominent, round distal communication Pore and two or more smaller, oval lateral communication pores. Secondary orifice wider than high, rounded distally and laterally with a straight proximal margin. Oral spines 4, arranged symmetrically round the orifice, the proximal-lateral pair slightly larger than the distal pair. Proximal oral shield very prominent, consisting of a very wide median process of the apertural bar ; the process bifurcates and fuses with the proximal-lateral pair of oral spines producing a very obtusely " Y "-shaped oral shield. The proximal oral shield when fully developed obscures most of the 94 CRETACEOUS CRIBRIMORPH POLYZOA (PELM ATOPORIN AE) orifice. Frontal shield flatly arched. Costae 15-17, fairly narrow. At their outer ends the costae are separated by distinct intercostal spaces which extend about one- third of the distance towards the mid-line of the frontal shield. On either side of the mid-line a wide median area of fusion is developed, but the outlines of the inner d.cp. O5 mm. I FIGS. 40, 41. Lagynopora vasculum Lang, S.M., B. 36164. Lectotype. (40) Adult ovicelled zooecium with complete proximal oral shield. (41) Orifice of another adult zooecium in which the proximal oral shield is broken ; d.c.p. distal communication pore in sloping distal wall of zooecium ; m.p, median process of apertural bar. ends of individual costae can be seen in this well-consolidated part of the frontal shield. Minute pelmatidia are visible on the upper surface of some unworn costae. No lateral costal fusions. No median ridge on the frontal shield. Apertural bar somewhat swollen, straight except for a slight distal bend at either end, wider than the most distal costae, with a strong, wide median process which forms part of the proximal oral shield. Gymnocyst smooth, only very occasionally exposed in small, triangular areas proximal to the frontal shields, generally obscured by the very close placing of the zooecia. No interzooecial secondary tissue. Avicularia are present occasionally. They are apparently interzooecial and fairly large, but in the lectotype only three worn avicularian-like structures have been seen. Ovicells hyperstomial, large, prominent, smooth, globular, occasionally slightly pointed distally, their proximal-lateral margins usually incorporating the distal pair of oral spines. Young zooecia smaller than the adult zooecia but otherwise similar. Only the first ring of young zooecia have 5 or 6 oral spines ; all successive young and adult zooecia possess only 4 oral spines. Ancestrula (almost obscured in the lecto- type), with 6 long, narrow oral spines. MEASUREMENTS. Adult zooecia Lz = 0-73 to 0-80 mm. Iz = 0-45 to 0-50 mm. hr = 0-12 to 0-15 mm. lr = 0-15 to 0-18 mm. ? Avicularia Not measurable. Young zooecia Lz = 0-43 to 0-46 mm. Iz = 0*30 mm. hr = o-io to o-n mm. lr = O'li to 0-12 mm. Ancestrula Lz, Iz, hr = Not measurable, lr = 0-12 mm. REMARKS. Lang (1921 : 66) based his diagnosis of Lagynopora vasculum on Brydone's figure of the species (1910, pi. 30, fig. 6). The median process of the apertural bar is much wider than is shown in Lang's text-figure 33 (1921 : 66), and the frontal shield is less consolidated. As in L. ollula Lang, there is a rapid reduction in the number of oral spines during the growth of the zoarium, but, unlike L. ollula, this is apparently accompanied by a slight increase in the number of costae. L. vasculum is distinguished mainly by its large size, its numerous costae, and the width of its median area of fusion which extends across about two-thirds of the frontal shield. Avicularia are apparently rare, contrasting with the prominent presence of avicularia in L. ollula. See also remarks under L. furcifera (Brydone), p. 82. STRATIGRAPHICAL DISTRIBUTION. Senonian, zone of 0. pilula, subzone of E. scutata var. depressula. MATERIAL. S.M., 6.36164. Lectotype see above. SPECIES OF UNCERTAIN SYSTEMATIC POSITION PREVIOUSLY ASSIGNED TO LAGYNOPORA (i) Lepralia pediculus Reuss 1874 Lepralia pediculus Reuss, p. 129, pi. 24, fig. 16. 1921 [Lagynopora] pediculus (von Reuss) Lang, p. 61. REMARKS. Lang himself (1921 : 61) regarded the systematic position of this species as uncertain, for he placed the name in square brackets and stated (p. 62) 96 CRETACEOUS CRI BRIMORPH POLYZOA (PELM ATOPO RIN AE) " Lepralia pediculus, if a Lagynopora, appears to be closely related to L. lagena ; but the widely-spaced oecia [zooecia] at once distinguish it from that species ". In his diagnosis (1921 : 61) he described the species as a " [Lagynopora} of large size (oecia about -66 mm. long) ; with about 16 closely-approximated costae ; lateral costal fusions rare or absent ; intraterminal front-wall [frontal shield] fairly well-arched ; oecia widely-spaced ". This description was presumably based on that of Reuss (1874 : 129, pi. 24, fig. 16). There are no indications of lateral costal fusions in the figure, nor is there the slightest suggestion of a proximal oral shield an essential generic character of Lagynopora. There is no evidence to suggest that Lepralia pediculus Reuss should be placed in Lagynopora. The spacing of the zooecia is not of diagnostic value, and Reuss's figure is very stylized showing, at the most, a multiserial cribrimorph polyzoan with a well-arched frontal shield, numerous costae, 6 or 7 oral spines, and hyperstomial, smooth, globular ovicells. Gillard (1942 : 91) has referred a specimen from a boring at Montbazon, France, to " Lagynopora pediculus var. Reuss ". Its horizon may be Upper Turonian. (2) Lagynopora ? prima (Kiihn) nov. comb. 1930 Canupora prima Ktihn, p. 65, pi. 26, fig. 13. 1935 Canupora prima Kiihn : Bassler, p. 64. 1953 Canupora prima Kiihn : Bassler, p. Gi88. LECTOTYPE. (Here chosen.) The specimen figured by Kiihn, 1930, pi. 26, fig. 13. Danian, Lithothamnienkalk. Haidhof, near Ernstbrunn, Austria. DIAGNOSIS. (Based on Kuhn's description and figure.) ^Lagynopora with encrusting zoarium ; zooecia of large size (Lz = 0-90 to i-oo mm., Iz = 0-56 to 0-58 mm.) ; orifice very large (hr 0-28 mm., Ir = 0-25 to 0-28 mm.), rounded distally and laterally with a straight proximal margin ; oral spines 6 ; frontal shield fairly well arched ; costae 8-n, separated for half their length by wide intercostal spaces ; median area of fusion extends about half-way along the costae ; apertural bar fairly wide, straight ; avicularia rare their form unknown. REMARKS. Kiihn (1930 : 65) has commented "... our genus [Canupora] has great similarity to Prodromopora [ Lagynopora}, but is distinguished by the presence of 6 oral spines, which is a more primitive condition than the 4 oral spines of Prodro- mopora, so that one may regard it as the most primitive genus of the Lagynoporidae. Always assuming that Lang's developmental series is correct " [translation]. It is difficult to interpret Kuhn's figure, and in his description he did not state whether or not his material possessed proximal oral shields or large distal communica- tion pores. The occurrence of 6 oral spines in the adult zooecia by no means justifies placing the species in a separate genus, and it is therefore provisionally referred to Lagynopora, especially as this, in its young stages, often has 6 oral spines. Also, if the age of the Lithothamnian Chalk is correctly established as Danian, it is very unlikely that Lagynopora^ prima may be regarded as the most primitive unit in a developmental series of species which are otherwise confined to the Senonian. No specimens of Lagynopora^ prima are available in the collections of the British Museum (Natural History). CRETACEOUS CRIBRIMORPH POLYZOA (PELM ATOPORIN AE) 97 Genus HEXACANTHOPORA Lang Hexacanthopora Lang, p. 394. 1921 Hexacanthopora 1924 Hexacanthopora 1927 Hexacanthopora 1930 Hexacanthopora 1930 Hexacanthopora 1935 Hexacanthopora 1949 Hexacanthopora 1 95 3 Hexacanthopora Lang, pp. Ixi, xcii, xciii, 44 Gaster, second of three tables opp. p. no. Canu & Bassler, pp. 17, 31. Gaster, table opp. p. 340. Voigt, pp. 495, 542, 560. Bassler, pp. 30, 126. Voigt, pp. 37, 43. Bassler, p. Gi88. TYPE SPECIES. Hexacanthopora sexspinosa Lang, igi6a : 394. Senonian, zone of Marsupites [subzone unspecified] . Roke Farm, south-east of Odiham, Hampshire. L. Treacher Collection. EMENDED DIAGNOSIS. Pelmatoporinae with a small median process on the apertural bar this process never fuses with the proximal-lateral oral spines to form a proximal oral shield ; oral spines often 6 ; avicularia large, prominent, often frequent. REMARKS. Hexacanthopora Lang is distinguished from Lagynopora Lang primarily by the absence of a proximal oral shield, and from Leptocheilopora by the presence of a median process on the apertural bar and numerous, large avicularia. Hexacanthopora is better distinguished on these characters than solely on the number of oral spines in its adult zooecia. Lang (1921 : 44) diagnosed Hexacantho- pora as " Lagynoporinae [= Pelmatoporinae] in which (at least) some epheboecia [adult zooecia] have six apertural [oral] spines ". The genus may possess from 4 to 6 oral spines in the adult zooecia : in two specimens, 0.28890 and 0.29897, it was not possible to find any zooecium with 6 oral spines. It is, however, still true to say that the 4-6 (commonly 6) oral spines which occur in Hexacanthopora contrast with the number of oral spines in Leptocheilopora. In the latter there are 4 oral spines only, except in L. vulnerata (Brydone) where there are consistently 7 in each adult zooecium. Lagynopora, with the exception of L. ollula (4, occasionally 5) and L.? prima (6), consistently has only 4 oral spines in the adult zooecia. Only two species of Hexacanthopora are recognized here : H. sexspinosa Lang, and H. viginticostata Voigt from the Senonian of Germany. STRATIGRAPHICAL DISTRIBUTION. Senonian, zones of M. cor-anguinum to B. mucronata. KEY TO THE SPECIES OF HEXACANTHOPORA LANG (I) Hexacanthopora with 4-6 oral spines in the adult zooecia ; costae 11-18 ; median area of fusion not obscuring the inner ends of the costae ; avicularia usually frequent, of two sizes in the adult zoarial stage . . i. H. sexspinosa Lang (II) Hexacanthopora always with 6 oral spines in the adult zooecia ; costae 20 (average) ; median area of fusion wide, obscuring the outlines of the inner ends of the costae ; avicularia large, frequent, apparently of one size in the adult zoarial stage 2. H. viginticostata Voigt GEOL. 6. I. 7 98 CRETACEOUS CRIBRIMORPH POLYZOA (PELM ATOPORIN AE) i. Hexacanthopora sexspinosa Lang (PI. 5, figs. 3-6) 191 6a Hexacanthopora sexspinosa Lang, p. 394. 19160 Hexacanthopora kintburiensis Lang, p. 394. I9i6a Hexacanthopora brightonensis Lang, p. 394. 1921 Hexacanthopora sexspinosa Lang : Lang, Ixi, xciii, 45, pi. i, fig. 8 ; text-fig. 21. 1921 Hexacanthopora kintburiensis Lang : Lang, pp. xcii, 47, pi. i, fig. 9 ; text-fig. 23. 1921 Hexacanthopora brightonensis Lang : Lang, pp. xcii, 48, text-fig. 24. 1924 Hexacanthopora kintburiensis Lang : Gaster, second of three tables opp. p. no. 1924 Hexacanthopora brightonensis Lang : Gaster, second of three tables opp. p. no. 1930 Hexacanthopora sexspinosa Lang : Gaster, table opp. p. 340. 1930 Hexacanthopora kintburiensis Lang : Gaster, table opp. p. 340. 1930 Hexacanthopora brightonensis Lang : Gaster, table opp. p. 340. 1930 Hexacanthopora brightonensis Lang : Voigt, pp. 495, 542, 560, pi. 26, fig. u. 1930 Hexacanthopora sexspinosa Lang : Voigt, pp. 495, 542, 560, pi. 26, fig. 12. 1935 Hexacanthopora sexspinosa Lang : Bassler, p. 126. 1953 Hexacanthopora sexspinosa Lang : Bassler, p. Gi88, text-fig. 142, u. HOLOTYPE. D. 21205. Well-preserved zoarial fragment encrusting a piece of echinoid test. Senonian, zone of Marsupites [subzone unspecified]. Roke Farm, south-east of Odiham, Hampshire. L. Treacher Collection. EMENDED DIAGNOSIS. Hexacanthopora with fairly large zooecia (Lz = 0-55 to 0-80 mm., Iz = 0-35 to 0-55 mm.) ; orifice wider than high (hr = o-io to 0-15 mm., Ir = 0-12 to 0-17 mm.) ; oral spines 4-6 ; costae 11-18, visible individually up to the mid-line of the frontal shield ; avicularia of two kinds, (a) a large oval form with small constrictions near the proximal end, (b) a smaller, similar form ; one type of avicularium may be more numerous than the other, or occasionally only one type may be visible, or, even more rarely, both types may be absent. DESCRIPTION. Zoarium encrusting, unilaminar. Adult zooecia fairly large, broadly oval, each with a very prominent, large distal communication pore and smaller lateral communication pores. Dietellae are present in the distal-basal angles of the zooecia, and revealed where the upper part of the zooecium has been worn away (see PI. 5, fig. 3) . Orifice wider than high, evenly rounded distally and laterally, with a straight or slightly proximally curved proximal margin. Oral spines 4-6, symmetrically arranged round the orifice. In a given zoarium 6 oral spines may be consistently developed in the adult zooecia, as in the holotype ; or 4, 5 or 6 oral spines may be present, as in 0.21204 ; or only 4 or 5 may occur, as in 0.28890. The proximal-lateral pair of oral spines are not enlarged as in Lagynopora. Frontal shield well arched, but flattened in the median area. Costae 11-18, separated for two-thirds of their length by distinct intercostal spaces. The costae are united in the median area of fusion, but the outlines of the inner ends of individual costae remain clearly visible. Median area of fusion narrow. Minute pdmatidia may be seen along the mid-line of well-preserved costae. Apertural bar straight, somewhat curved distally at either end, with a distinct, though fairly small, median process which apparently never fuses with the proximal-lateral pair of oral spines to form a proximal oral shield as in Lagynopora. Gymnocyst smooth, often slightly exposed CRETACEOUS CRIBRIMORPH POLYZOA (PELM ATOPORIN AE) 99 proximally to the frontal shields and occasionally very narrowly along their sides. No interzooecial secondary tissue. Avicularia of two sizes. Type a is a larger form, usually a little longer than wide, but occasionally the reverse is true, oval, or slightly pointed distally, with slight proximal-lateral constrictions dividing a small proximal portion from a very large rostrum. Tybe b is smaller, but otherwise similar to type a. Both types may be variously orientated usually distally and very obliquely outwards from the zooecia they appear to accompany. None has been seen which is directed proximally. In a given zoarium one type or the other may be more frequent, or, very occasionally, only one form may be developed. Even more rarely avicularia may be absent. Ovicetts hyperstomial, prominent, globular, smooth, without lateral slits. A pair of oral spines may flank the entrance to the ovicell. Young zooecia smaller than the adult zooecia, often with fewer (11-14) costae and more numerous oral spines. Paratype 0.21207 possesses at least one young zooecium with 7 oral spines, and 0.29895-96 have young zooecia with 6 oral spines and adult zooecia with only 4 or 5. Ancestrula small, often obscured. In the holotype the ancestrula has 6 oral spines and 12 costae. MEASUREMENTS. Adult zooecia Lz = 0-50 to 0-80 mm. Iz = 0-35 to 0-55 mm. hr = o-io to 0-15 mm. Ir = o-io to 0-15 mm. Young zooecia Lz = 0-35 to 0-50 mm. Iz = 0-21 to 0-33 mm. hr = 0-09 to o-n mm. lr = o-io to 0-13 mm. Ancestrula (of holotype) Lz = 0-32 mm. Iz = 0-20 mm. hr = 0-07 mm. lr = 0-09 mm. Avicularia : Type a Lz = 0-18 to 0-25 mm. Iz = 0-17 to 0-25 mm. Type b Lz o-n to 0-18 mm. Iz = 0-09 to 0-16 mm. REMARKS. Hexacanthopora kintburiensis Lang and H. brightonensis Lang are synonymous with H. sexspinosa Lang. Thirteen specimens of Hexacanthopora, labelled by Lang, are available in the collections of the British Museum (Natural History). Lang (19160 : 394 ; 1921 : 45) divided this material into three species, basing his division principally on the number of oral spines commonly developed in adult zooecia, the number of costae, and the length of zooecia. In addition he stated (1921 : 45) that H. sexspinosa possesses two types of avicularia, " both kinds, especially the smaller, rare ; the smaller kind are more or less distally directed, and have somewhat elongate, slightly constricted, and blunt apertures ; the larger vary ioo CRETACEOUS CRIBRIMORPH POLYZOA (PELM ATOPORIN AE) in size, but generally have an aperture as large as that of an orthoecium [zooecium] ; they are indifferently oriented, little longer than wide, with a somewhat pointed aperture divided by a constriction into a very much smaller proximal portion and a very large rostrum ". The avicularia of H. kintburiensis he described (1921 : 47) as " occasional, large, with blunt, indifferently orientated apertures, nearly as large as those of the orthoecia, with a very slight constriction near the proximal end ". H. brightonensis (1921 : 49) was stated to have " aviculoecia [avicularia] apparently of the large kind only, fairly numerous, irregularly distributed, with indifferently orientated, nearly circular apertures of nearly the same size as those of the orthoecia, and with a constriction nearer the proximal end ". Both large and small avicularia are, however, present in each of the species of Hexacanthopora recognized by Lang. The larger avicularia (type a) may be more numerous than the smaller (type b). Normally avicularia occur infrequently, but in one specimen, 0.28890 the holotype of H. brightonensis Lang, they are unusually abundant. The type and variable number of the avicularia do not aid specific division of the material. Similarly the dimensions of the zooecia and the ranges in number of costae, in the three species recognized by Lang, overlap or are the same. These characters and the number of oral spines are compared in the following table : Specimens labelled by Lang as : Measurements in mm. 1. H. sexspinosa 2. H. kintburiensis 3. H. brightonensis r Lz Iz hr Ir o 55 to o 75 0-35 to o 45 o-iotoo-i3 O-I2 to O-I5 0-55 to o 80 0-35 to o 55 o- 10 to o- 15 0-14 to o- 17 0-60 to o 67 0-38 to O' 50 0-13 0-15 Costae Oral spines I. 14-18 6 2. 11-18 4-6 3- 11-13 4-5 All adult zooecia in the specimens labelled by Lang " H. sexspinosa " possess 6 oral spines, whereas those labelled " H. kintburiensis " have adult zooecia with 4 or 5 as well as commonly 6 oral spines. In the specimens labelled " H. brightonensis " a few adult zooecia have only 4 oral spines, the majority have 5 and no definite instance could be found of 6 oral spines. Voigt (1930 : 495) has recorded specimens of H. sexspinosa and H. brightonensis from Germany in chalk equivalent in age to the zones of Marsupites and G. [A.] quadrata. STRATIGRAPHICAL DISTRIBUTION. Senonian, zones of Marsupites to G. [A.~\ quadrata in England and Germany, ?also zone of M. cor-anguinum in England. SPECIMENS. 0.21205. Holotype see above. D. 21206. Paratype. Zoarial fragment encrusting a piece of echinoid test. Horizon, locality and collection as for the holotype. 0.21207. Paratype. Zoarial fragment with ancestrula and mainly young zooecia encrusting a piece of echinoid test. Senonian, ? zone of Marsupites. Odiham, Hampshire. L. Treacher Collection. CRETACEOUS CRIBRIMORPH POLYZOA (PELM ATOPORIN AE) 101 0.29101. Paratype. Zoarial fragment encrusting a piece of echinoid test. Senonian, zone of Marsupites [subzone unspecified]. Margate, Kent. N. T. Wetherell Collection. 0.21204. Holotype of Hexacanthopora kintburiensis Lang. Well-preserved zoar- ium, two zooecia with undamaged ovicells, encrusting a piece of echinoid test. Senonian, zone of G. [A.] quadrata. Kintbury, west of Newbury, Berkshire. L. Treacher Collection. 0.29070. Paratype of H. kintburiensis Lang. Zoarial fragment encrusting a piece of ?Inoceramus shell. Senonian, zone of G. [A.] quadrata. Romsey, south-west of Winchester, Hampshire. H. P. Blackmore Collection. PD.263I Paratype of H. kintburiensis Lang. A worn zoarial fragment with about ten abraded zooecia only. It is not possible to distinguish the number of oral spines, nor to measure the orifice. Encrusting a shell fragment. Upper Senonian [zone unspecified]. Salisbury, Wiltshire. G. R. Vine Collection. 0.28890. Holotype of H. brightonensis Lang. Zoarial fragment with fairly well preserved zooecia and very frequent avicularia, encrusting a piece of echinoid test. Senonian, zone of Marsupites [subzone unspecified]. Brighton, Sussex. ?D. 28891. Paratype of H. brightonensis Lang. A very small, worn zoarial fragment encrusting a piece of echinoid test. Senonian, zone of 0. pilula, subzone of E. scutata var. depressula. Cliffs between last groyne east of Rotting- dean Gap and Saltdean, east of Brighton, Sussex. 0.29896. Zoarial fragment with ancestrula and numerous adult ovicelled zooecia. Encrusting a piece of echinoid test. Labelled by Lang " H. kint- buriensis ". Senonian, zone and subzone of Marsupites. West pit, in top of Hangleton Lane, Highdown Hill, east of Angmering, Sussex. ?D. 21208. Very poorly preserved zoarial fragment encrusting a piece of echinoid test. Labelled by Lang " H. kintburiensis ". Senonian, zone of M. cor- anguinum. Woburn Green, south-west of Beaconsfield, Buckingham- shire. L. Treacher Collection. 0.29895. Zoarial fragment with ancestrula and adult ovicelled zooecia encrusting a piece of echinoid test. Labelled by Lang " H. kintburiensis ". Senonian, zone of 0. pilula, subzone of E. scutata var. depressula. Pit 4 of Gaster, western pit, south of Lancing Ring and west of Boundstone Lane, north-east of Worthing, Sussex. 0.29897. Worn zoarial fragment with obscured ancestrula. Encrusting a piece of echinoid test. Senonian, zone of 0. pilula, subzone of E. scutata var. depressula. Cliffs, west of Chimney Shaft, Roedean, east of Brighton, Sussex. 0.41065. Very small zoarial fragment with young zooecia encrusting a piece of echinoid test. Senonian, zone and subzone of Marsupites. Section 75 of Gaster, Brighton Cliffs, Sussex. 102 CRETACEOUS CRIBRIMORPH POLYZOA (PELMATOPORIN AE) 2. Hexacanthopora viginticostata Voigt 1930 Hexacanthopora viginticostata Voigt, pp. 495, 560, pi. 26, fig. 13. 1949 Hexacanthopora viginticostata Voigt : Voigt, pp. 37, 43, pi. 9, figs, i, 2. NEOTYPE. (Designated by Voigt, 1949 : 37, pi. 9, fig. 2.) Sample 142. Senonian, zone of G. [A.] quadrata. Lagerdorf, Holstein, Germany. DIAGNOSIS. (Based on Voigt's descriptions and figures, 1930 ; 1949.) Hexacan- thopora with zooecia of fairly large size (Lz = 0-60 to 0-70 mm., Iz = about 0-40 mm.) ; orifice small, higher than wide (hr about 0-12 mm.) ; oral spines constantly 6 ; costae 20 (average) ; median area of fusion wide, obscuring the outlines of the inner two-thirds of the costae ; avicularia variable in occurrence, large (0-20 to 0-30 mm. diameter), with a slit-like or irregularly polygonal aperture, smaller in the young than in the adult stages of zoarial growth ; ovicells hyperstomial, large, globular ; young zooecia with fewer (about 14-16) costae ; ancestrula about 0-30 mm. long. REMARKS. Voigt recently (1949 : 37) designated a neotype for the species, the holotype having been lost in a fire. The well-preserved new material, from the same horizon and the same and different localities as the original specimens, differs mainly in the number of avicularia present. They are apparently much more numerous than in the original material in which they were " rare ". H. viginticostata Voigt is distinguished from H. sexspinosa Lang by its larger number of costae and its wide median area of fusion. Also the orifice of the former is apparently higher than wide, contrasting with that of H. sexspinosa which is consistently wider than high. STRATIGRAPHICAL DISTRIBUTION. Senonian, zones of G. [A.] quadrata and B. mucronata in Germany. SPECIMENS. None in the collections. Genus LEPTOCHEILOPORA Lang ?i852 Reptoporella d'Orbigny, pi. 717, figs. 6, 7 ; 1853, p. 474 ; 1854, p. 1097. ?i857 Repteporella [sic] : Pictet, p. in. 19006 Cribrilina (Typica) : Canu, p. 447 [partim]. 19006 non Membranipora : Canu, p. 449. 1910 Cribrilina : Brydone, p. 391 [partim]. 1912 Cribrilina : White, p. 43 [partim]. 19146 Cribrilina : Brydone, p. 97 [partim]. igi6a Leptocheilopora Lang, p. 396. 1917 Cribrilina : Brydone, p. 51 [partim C. tumuliformis only]. ?J9i7 Reptoporella : Lang, p. 172. 1917 Leptocheilopora : Lang, p. 172. 1921 Leptocheilopora : Lang, pp. Ixii, Ixv, 68. ?i92i Reptoporella: Lang, p. Ixv. 1925 Barroisina : Levinsen, p. 384 [partim B. galeata only]. 1930 Leptocheilopora : Voigt, p. 496. 1930 Leptocheilopora : Gaster, table opp. p. 340. 1935 Leptocheilopra : Bassler, pp. 30, 138. 1943 Leptocheilopora : Gillard, pp. 186, 187 [probably partim ? nonL. regularis (d'Orbigny)]. 1953 Leptocheilopora : Bassler, p. Gi88. CRETACEOUS CRIBRIMORPH POLYZOA (PELMATOPORIN AE) 103 TYPE SPECIES. Leptocheilopora tenuilabrosa Lang, igi6a : 397. Senonian, zone of Marsupites testudinarius (subzone unspecified). Brighton, Sussex. EMENDED DIAGNOSIS. Pelmatoporinae with no median process on the apertural bar ; no proximal oral shield ; avicularia absent or only very occasionally developed. REMARKS. Lang (1921 : 71), followed by Bassler (1953 : Gi88), suggested that Reptoporella d'Orbigny may be a synonym of Leptocheilopora Lang, but this cannot be decided until d'Orbigny's material of Reptoporella regularis d'Orbigny (1853 : 475, pi. 717, figs. 6, 7), the type species of Reptoporella, has been restudied. (See discus- sion of species of uncertain systematic position p. 118.) Leptocheilopora. as here defined is placed in the subfamily Pelmatoporinae. Four species are recognized : L. magna Lang and L. vulnerata (Brydone) are, as yet, known only from the Lower Maastrichtian or highest Senonian, L.filliozati (Brydone) occurs throughout the zones of G. [A.] quadrata and 0. pilula, and L. tenuilabrosa Lang is recorded from the zones of Marsupites and Micraster cor-anguinum. STRATIGRAPHICAL DISTRIBUTION. Senonian, zone of M. cor-anguinum to zone of B, mucronata, and Maastrichtian, zone of Ostrea lunata in England, zone of Belemnella lanceolata mut. sumensis or zone of B. junior in Germany. KEY TO THE SPECIES OF LEPTOCHEILOPORA (I) Leptocheilopora with zooecia of large size (Lz = 0-80 to i-oo mm., Iz = 0-50 to 0-66 mm.) ; orifice of constant form with marked proximal-lateral constrictions i. L. magna Lang (II) Leptocheilopora with zooecia of small size (Lz = less than 0-75 mm.). (A) Primary ovicells costate ; costae 17-22, (11-15 in young zooecia) ; intercostal spaces distinct ; apertural bar broadly triangular, usually somewhat curved proximally ; large, vicarious, spatulate avicularia may occur in the adult stages of some zoaria . . . . . 2. L. tenuilabrosa Lang (B) Primary ovicells smooth. (1) Lz 0-55 to 0-75 mm., Iz = 0-35 to 0-55 mm. ; orifice of variable shape, but often with proximal-lateral constrictions (hr = 0-12 to 0-17 mm., Ir = oi2 to 0-16 mm.); oral spines 4; costae 12-18, well defined; often with a median ridge on the frontal shield ; ovicells without lateral slits . . . . . . . -3- L.filliozati (Brydone) (2) Lz = 0-42 to 0-50 mm., Iz = 0-31 to 0-35 mm. ; orifice small, of fairly constant size (hr = o-io to 0-12 mm., Ir = 0-09 to o-n mm.) ; usually lacking proximal-lateral constrictions ; oral spines 7 ; frontal shield flatly arched without a median ridge; costae 11-15, fl a ^, closely placed; ovicell with small lateral slits . . . . 4. L. vulnerata (Brydone) Reptoporella regularis d'Orbigny, previously assigned to Leptocheilopora, and cheilopora longuessensis Lang are of uncertain systematic position and are omitted from the above key. i. Leptocheilopora magna Lang (PI. 6, figs. 1-7 ; Text-figs. 42, 43) I9i6a Leptocheilopora magna Lang, p. 396. ?igi6a Leptocheilopora languessensis [sic] Lang, pp. 396, 397. io 4 CRETACEOUS CRIBRIMORPH POLYZOA (PELM ATOPORIN AE) ?i92i Leptocheilopora longuessensis Lang : Lang, p. 76. 1921 Leptocheilopora magna Lang : Lang, p. 77, pi. 2, fig. 9 ; text-fig. 38. 1925 Barroisina galeata Levinsen, p. 385, pi. 6, fig. 67. 1930 Leptocheilopora magna Lang : Voigt, p. 496 [partim], pi. 27, fig. 5 [probably non fig. 4]- HOLOTYPE. 0.19623. Incomplete zoarium with ancestrula, encrusting a frag- ment of echinoid test. Horizon given as " Senonian, Campanian, zone of B. mucro- nata, Liineburg, Hanover ", Germany very probably Maastrichtian. F. Mockler Collection. O5 mm. i FIG. 42. Leptocheilopora magna Lang, 0.38919. Adult zooecium with widely exposed gymnocyst and marked proximal-lateral constrictions in the orifice. EMENDED DIAGNOSIS. Leptocheilopora with zooecia of large size (Lz = 0-80 to i -00 mm.) ; costae 12-17 ; orifice with marked proximal-lateral constrictions. DESCRIPTION. Zoarium encrusting, unilaminar. Adult zooecia large, broadly oval, each with a single, fairly large, distal communication pore. Orifice higher than wide, rounded distally and laterally with marked proximal-lateral constrictions, the proximal margin often well curved proximally. Oral spines 4, small, unmodified. Frontal shield wide and flat. Costae 12-17, flat, tapering inwards where their distal ends may be traced across the wide median area of fusion. No lateral costal fusions. Very small pdmata, usually obscured by wear, along the mid-line of each costa. Apertural bar usually a little wider than the most distal costae, flat, smooth and curved proximally, with no median process. Gymnocyst often almost obscured by CRETACEOUS CRIBRIMORPH POLYZOA (PELM ATOPORIN AE) 105 the close placing of the zooecia, but usually visible proximally to the frontal shield, and occasionally widely exposed all round the frontal shield (Text-fig. 42). No interzooecial secondary tissue. Avicularia absent. Primary ovicells large, prominent, hyperstomial, smooth, globular, apparently composed of a smooth endooecium and a costate ectooecium which is usually incomplete and marginal. Young zooecia small, with only 10 costae. The orifice lacks the proximal-lateral constrictions characteristic of the orifices of O5mm. FIG. 43. Leptocheilopora magnet. Lang, 0.38918. Orifice and broken ovicell resting on the proximal part of frontal shield of succeeding zooecium. The specimen is partly obscured by matrix. adult zooecia, and is less markedly higher than wide. Oral spines 4, more prominent than in the adult zooecia. Frontal shield flatly arched, with only a very small amount of gymnocyst exposed proximally to it. MEASUREMENTS. Adult zooecia Lz = 0-80 to i-oo mm. lz = 0-50 to 0-66 mm. hr = 0-21 to 0-24 mm. lr = 0-18 to 0-21 mm. Young zooecia Lz = 0-50 mm. lz = 0-27 mm. hr = 0-15 mm. lr = 0-12 mm. io6 CRETACEOUS CRI BRIMORPH POLYZOA (PELM ATOPORIN AE) REMARKS. The holotype, 0.19623, and paratype, 0.19622, have been re- examined. The former has the ancestrula imperfectly preserved, and outside the first ring of zooecia the range in number of costae, 12-17, is the maximum yet recorded for L. magna. In this specimen the measurements are : Lz = 0-90 to i-oo mm., Iz = 0-56 to 0-66 mm., hr = 0-21 mm., Ir = 0-18 mm. The dimensions of the orifice are very constant. All zooecia of the holotype are apparently non- ovicelled. Paratype 0.19622 is a much damaged and worn zoarium with only the ancestrula and surrounding rings of young zooecia preserved ; the majority of the zooecia are thus small. Two specimens, 0.38918 and 0.38919, labelled by Voigt as L. magna Lang, have also been re-examined. The zooecia of the former are slightly larger and possess a few more costae than those of the latter. Imperfectly preserved ovicells are present in both specimens. Voigt (1930 : 496, pi. 27, figs. 4, 5) assigned two specimens to L. magna Lang. I accept the specimen shown in fig. 5 as belonging to the species, but that shown in fig. 4 has a very marked series of short, slot-like intercostal spaces, a feature which I have not found in the specimens of L. magna available to me. I have therefore tentatively excluded that specimen from the synonymy of the species. In agreement with Voigt (1930 : 496), Barroisina galeata Levinsen is regarded as synonymous with Leptocheilopora magna Lang. Levinsen (1925 : 385, pi. 6, fig. 67) referred to the " rib area [frontal shield] ... of 7-9 pairs of flat ribs ", to its " high, rounded, strongly arched " ovicells, and to the absence of avicularia all characteristic of L. magna. The imperfectly preserved ovicells which occur in 0.38918 and 0.38919 are apparently ribbed or costate marginally, and seem to consist of two layers interpreted as a smooth endooecium partly covered by a costate ectooecium. The primary ovicell of L. magna Lang is smooth, but this primary layer (the endooecium) may be partly covered secondarily by an outer layer (the costate ectooecium). This feature could lead to confusion with L. tenuilabrosa Lang, in which the primary ovicell is costate, consisting of one layer only. However, the very large size of L. magna Lang and its very distinctively shaped orifice (pliophloean) 1 serve to dis- tinguish it clearly from other species of Leptocheilopora. Leptocheilopora longuessensis Lang is provisionally included in the synonymy of L. magna Lang. The diagnoses given by Lang (1916^ : 396 ; 1921 : 76) are based only on the interpretation of a poor photograph of the holotype in the Canu Collec- tion. From the photograph it is possible to determine only that the zoarium is that of an encrusting, unilaminar Leptocheilopora ; the zooecia are broadly oval with flatly arched frontal shields possessing fairly numerous (probable about 16) costae ; the orifice is longitudinally elongate and distally and laterally rounded with proximal- lateral constrictions and 4 somewhat enlarged oral spines. It is very probable that the zooecia shown in the photograph are close to the ancestrula, as those near the base of the zoarial fragment are much smaller than those near the outer edges. This being so it is very uncertain whether the smaller size of the zooecia can have much 1 See Lang, 1921 : xlvii, fig. log. CRETACEOUS CRIBRIMORPH POLYZOA (PELM ATOPORIN AE) 107 diagnostic significance Lang (1921 : 76) gave Lz as about 0-60 mm. and Iz as 0-48 mm. The specimen could well be part of the young stage of zoarium of Lepto- cheilopora magna Lang. However, this opinion can only be tentative. STRATIGRAPHICAL DISTRIBUTION. Maastrichtian, either zone of Belemnella lanceolata mut. sumensis or zone of B. junior, and Senonian, zone of Belemnilella mucronata. SPECIMENS. 0.19623. Holotype see above. 0.19622. Paratype. Damaged and worn zoarial fragment encrusting a piece of echinoid test. Horizon, locality and collection as for the holotype. 0.38918. Zoarial fragment encrusting a piece of siliceous sponge. Maastrichtian, either zone Belemnella lanceolata mut. sumensis or zone of B. junior. Cement factory (loose on floor), Hemmoor, Hanover, Germany. E. Voigt Collection. 0.38919. Zoarial fragment encrusting a belemnite guard. Horizon, locality and collection as for 0.38918. 0.39431. Two damaged zooecia only, encrusting a fragment of echinoid test. Senonian, zone of Belemnitella mucronata. Felpham Chalk [foreshore], Bognor, Sussex. 2. Leptocheilopora tenuitabrosa Lang (PI. 6, figs. 8-n ; PI. 7, figs, i, 2 ; Text-figs. 44-48) 191 6a Leptocheilopora tenuilabrosa Lang. pp. 396 397. 1917 Leptocheilopora tenuilabrosa Lang : Lang p. 172. 1917 Cribrilina tumuliformis Brydone, p. 51, pi. 3, figs. 7, 8. 1921 Leptocheilopora tenuilabrosa Lang : Lang, pp. Ixii, xciii, 73, pi. 2, fig. 7 ; text-fig. 35. 1921 Leptocheilopora gasteri Lang, pp. xciv, 71, pi. 2, fig. 6 ; text-fig. 34. 1930 Leptocheilopora tenuilabrosa Lang : Gaster, table opp. p. 340. 1935 Leptocheilopora tenuilabrosa Lang : Bassler, p. 138. 1953 Leptocheilopora tenuilabrosa Lang : Bassler, p. Gi88, text-fig. 142, 10. HOLOTYPE. 0.28892. Zoarial fragment, probably with fairly young zooecia. encrusting a piece of echinoid test. Senonian, zone of Marsupites testudinarius (subzone unspecified). Brighton, Sussex. EMENDED DIAGNOSIS. Leptocheilopora with costate primary ovicell ; costae 17- 22, (11-15 in younger zooecia) ; intercostal spaces distinct ; large, spatulate, vicarious avicularia may occur in the adult stages of some zoaria. DESCRIPTION. Zoarium encrusting, unilaminar. Adult zooecia broadly oval, with a single, oval distal communication pore. Orifice small, of variable shape ; always rounded distally and usually rounded laterally, but occasionally with straight sides, and often with slight, but distinct, proximal-lateral constrictions ; proximal margin straight or slightly curved proximally. A distinct median notch, probably produced by wear, may be present in the proximal margin of the orifice. Oral spines 4, very small, indistinct, grouped on the distal margin of the orifice. Frontal shield flatly arched, the costae curving down gently from the mid-line to meet the gymnocyst. Costae 17-22, flat, tapering inwards, and separated by narrow, but distinct, intercostal io8 CRETACEOUS CRIBRIMORPH POLYZOA (PELM ATOPORIN AE) spaces. No lateral costal fusions. Very small pdmaia occur along the mid-line of the upper surface of each costa. Apertural bar straight, or slightly curved proximally when it is very broadly triangular (the apex of the triangle directed proximally), flat, with no median process, and only slightly wider than the distal costae ; a very slight median ridge may be present and this may be prolonged on to the frontal shield as I I FIG. 44. Leptocheilopora tenuilabrosa Lang, 0.28892. Holotype. Adult zooecium with broken, worn, costate ovicell ; the apertural bar is slightly damaged. an irregular median ridge. Gymnocyst smooth, usually well exposed, except where the close placing of zooecia may obscure it. No interzooecial secondary tissue. Avicularia very large, occasional, sporadic, vicarious and spatulate with costate frontal shields covering the proximal part of the aperture (about 8-13 costae are present). The distal end of the spatulate rostrum may include a narrow calcareous shelf (Text-fig. 47), but, in some cases, this may be absent (Text-fig. 48). Avicularia have been seen only in the adult stages of two zoaria : they apparently do not occur in the younger stages of zoarial growth and may be absent even in the adult zones CRETACEOUS CRI BRIMORPH POLYZOA (PELM ATOPORIN AE) 109 of a zoarium. Primary ovicells prominent, frequent, hyperstomial, costate, tending to be longer than wide. The 11-13 flat, hollow costae which cover the ovicell apparently possess occasional minute pores along their mid-lines : the costae may form an ectooecium, but this is uncertain. Young zooecia smaller than the adult zooecia, with fewer (11-15) costae, and apparently not associated with vicarious avicularia. O O3ntm. 1 i i | FIG. 45. Leptocheilopora tenuilabrosa Lang, D. 28892. Holotype. Orifice and complete costate ovicell of adult zooecium ; the apertural bar is broken in the middle. MEASUREMENTS. Adult zooecia Lz = 0-57 to 0-66 mm. lz = 0-32 to 0-50 mm. hr = 0-12 to 0-13 mm. Ir 0-13 tg 0-14 mm. Avicularia Lz = 0-80 to 0-83 mm. lz = 0-33 to 0-36 mm. Young zooecia Lz = 0-43 to 0-52 mm. lz = 0-30 to 0-45 mm. hr == 0-08 to o-io mm. Ir = o-io to 0-12 mm. REMARKS. Leptocheilopora gasteri Lang is synonymous with L. tenuilabrosa Lang. The only apparent difference between the two species, which may be estab- lished on the specimens available in the collections of the British Museum (Natural History), is in the range in number of costae : 16-18 for the former and 11-15 f r the latter. The dimensions of the zooecia, and particularly of the orifices, are very similar and both species have costate ovicells. Lang (1921 : 71, 72) mentioned and figured what he regarded as " rather obvious, irregular lateral costal fusions " in L. gasteri. The available specimens labelled by him as L. gasteri are worn, but the costae are clearly separated by narrow slit-like intercostal spaces (Text-fig. 46). Uneven wear, possibly combined with a certain amount of secondary calcification no CRETACEOUS CRIBRIMORPH POLYZOA (PELM ATOPORIN AE) during fossilization, has apparently produced small hollows and slight, irregular accumulations of calcium-carbonate in the narrow spaces between the costae. These might easily be misinterpreted as incipient lateral costal fusions The same feature occurs occasionally in the specimens which he assigned to L tenuilabrosa O FIG. 46. Leptocheilopora tenuilabrosa Lang, 0.29901. Holotype of L. gasteri Lang. Adult zooecium with costate ovicell, with four minute oral spine-bases grouped on distal margin of orifice. Lang (1921 : 73) regarded Cribrilina tumuliformis Brydone (1917 : 51, pi. 3, figs. 7, 8) as synonymous with Leptocheilopora tenuilabrosa. Examination of Brydone's figured specimens of Cribrilina tumuliformis confirms this opinion. The range in number of costae in Brydone's specimens, S.M., 6.36338-39, is, however, 17-22, and in both zoaria large, spatulate, vicarious avicularia are present. Young zooecia are also preserved and these are more closely similar to the zooecia of the holotype of L. tenuilabrosa (0.28892) and to those of the paratype (D. 21210) than are the adult zooecia. It seems probably that Lang's specimens lack the fully developed adult CRETACEOUS CRIBRIMORPH POLYZOA (PELM ATOPORIN AE) in stages of zoarial growth. In S.M., 6.36339 a complete but small normal zooecium is regenerated inside a larger, damaged individual. The very unusual vicarious, costate avicularia which may be present are particu- larly diagnostic of L. tenuilabrosa. Even where avicularia are absent, as they may be in some zoaria, the costate primary ovicell clearly distinguishes the species. Dr. Hastings kindly sent me the following note : " Vicarious avicularia with a costulate frontal shield are found in some recent species of Figularia. I have seen 47 O O-5 FIGS. 47, 48. Leptocheilopora tenuilabrosa Lang. (47) S.M., 13.36339. Figured Brydone (1917, pi. 3, fig. 8) as Cribrilina tumuliformis. Adult zooecium with costate ovicell (the ovicell of the preceding zooecium is also shown covering the proximal end of the zooecium) and a large, vicarious avicularium with costate frontal shield. (48) S.M., 6.36338. Figured Brydone (1917, pi. 3, fig. 7) as Cribrilina tumuliformis. Vicarious avicularium with typically spatulate rostrum and costate frontal shield. Small spine-bases may occur near the distal end of the aperture. them in the type material of F. philomela Busk sp., where they were also observed by Harmer (1902 : 239) ; and in the specimen of F. spatulata (Calvet) collected by the Discovery Expedition (Stat. 47, I mile west of Shag Rocks, South Georgia, 199 m.)." Osburn (1950, p. 188, pi. 29, fig. i) described and figured a new Recent species, Cottetosia bellula, in which " the primary ovicell is small . . . smooth . . . ; it soon becomes covered by an ectooecium which is composed of three or four pairs of radiating costules similar to those of the front and with similar lacunae [intercostal spaces]. ..." STRATIGRAPHICAL DISTRIBUTION. Senonian, zones of M. cor-anguinum and Marsupites. SPECIMENS. 0.28892. Holotype see above. H2 CRETACEOUS CRIBRIMORPH POLYZOA (PELM ATOPORIN AE) D.2I2IO. Paratype. Zoarial fragment encrusting a piece of echinoid test. Senonian, zone of Marsupites [subzone unspecified]. Roke Farm, south- east of Odiham, Hampshire. L. Treacher Collection. D. 2990 1. Holotype of L. gasteri Lang. Zoarial fragment encrusting a piece of Inoceramus shell. Senonian, zone of M. cor-anguinum. Pit in Houndean Bottom, west of Lewes, Sussex. 0.29902. Paratype of L. gasteri Lang. Zoarial fragment encrusting a piece of Inoceramus shell. Horizon, locality and collection as for 0.29901. 0.40931. Another fragment of 0.29902. OTHER MATERIAL S.M., 6.36338. Large, well-preserved zoarial fragment, encrusting a piece of echinoid test. Figured by Brydone (1917, pi. 3, fig. 7) as Cribrilina tumuliformis. Senonian, zone of M. cor-anguinum. Leaves Green, Kent. R. M. Brydone Collection. S.M., 6.36339. Large, well-preserved zoarial fragment encrusting a piece of echinoid test. Figured by Brydone (1917, pi. 3, fig. 8) as Cribrilina tumuliformis. Senonian, horizon and collection as for S.M., 6.36338. Gravesend, Kent. 3. Leptocheilopora filliozati (Brydone) (PI. 7, figs. 3, 4 ; PL 8 ; Text-figs. 49, 50) 1910 Cribrilina filliozati Brydone, p. 391, pi. 30, figs. 9, 10. 1912 Cribrilina filliozati Brydone : White, p. 43. 191 6a Leptocheilopora filliozati (Brydone) Lang, p. 396. igi6a Leptocheilopora arcuata Lang, pp. 396, 397. 1921 Leptocheilopora filliozati (Brydone) : Lang, pp. xcii, 76. 1930 Leptocheilopora arcuata Lang : Gaster, table opp. p. 340. 1930 Leptocheilopora filliozati (Brydone) : Gaster, table opp. p. 340. 1943 Leptocheilopora arcuata Lang : Gillard, p. 187. LECTOTYPE. (Chosen by Lang, 1921 : 77.) S.M., 6.36167, the specimen figured by Brydone, 1910, pi. 30, fig. 9. Zoarium, with ancestrula, encrusting a fragment of echinoid test. Senonian, zone of 0. pilula, subzone of E. scutata var. depressula. Locality 932 of Brydone, lower part of old pit and road cutting at Mount Pleasant, on the road to Micheldever, Andover, Hampshire. R. M. Brydone Collection. EMENDED DIAGNOSIS. Leptocheilopora with zooecia of variable size (Lz = 0-55 to 0*75 mm., Iz = 0-35 to 0-55 mm.) ; orifice of variable shape but usually with proximal-lateral constrictions ; frontal shield fairly well arched with 12-18 well- defined costae and often with a median ridge ; ovicells smooth, without lateral slits. DESCRIPTION. Zoarium unilaminar, encrusting. Adult zooecia broadly oval, closely placed. A large distal communication pore and two or three round lateral communication pores are present. Orifice always slightly higher than wide, of fairly constant dimensions, rounded distally and laterally, with proximal-lateral constric- CRETACEOUS CRIBRIMORPH POLYZOA (PELM ATOPORINAE) 113 tions present but seldom pronounced as in Leptocheilopora magna, proximal margin usually gently curved proximally. The shape of the orifice varies proximally, where the proximal-lateral constrictions may not be distinct and the proximal margin may vary from straight to proximally curved or, occasionally prominently " V "-shaped : the absence of the constrictions may be due to wear. Oral spines 4, slightly thick- ened, equally spaced on the margin of the orifice. Frontal shield gently arched. Costae 12-18, distinct, but often very closely placed, rounded at their outer ends and O I O*5mm. FIG. 49. Leptocheilopora filliozati (Brydone), D. 28294. Holotype of L. arcuata Lang. Adult zooecium with median ridge on frontal shield and large distal and lateral communication pores. tapering inwards where they may be traced across the median area of fusion which is of variable width. No lateral costal fusions. In well-preserved specimens some costae show three (possibly four) very small pelmata along their mid-line. This feature is easily obscured by wear and possibly also by deposition of calcium- carbonate during fossilization, and may thus not be visible. Apertural bar often V "-shaped, the apex pointing proximally, not much wider than the distal costae, smooth except for a slight median ridge which is often prolonged down the mid-line of the frontal shield. Gymnocyst not much exposed laterally, but often visible proximally to each frontal shield. No interzooecial secondary tissue. Avicularia apparently absent. Ovicells prominent, globular, but tending to be slightly pointed distally and flattened in front, hyperstomial, smooth, without lateral slits, and generally longer than wide. The lateral pair of oral spines may flank the GEOL. 6, I. 8 ii4 CRETACEOUS CRIBRIMORPH POLYZOA (PELM ATOPORIN AE) entrance to the ovicell. Young zooecia and ancestrulae smaller than the adult zooecia, usually with 6 oral spines, and less often 5 or 4 in the slightly later stages of zoarial growth. There are generally fewer costae (8-12) than in the adult. The orifices, in the young stages, tend to have less marked proximal-lateral constrictions. MEASUREMENTS. Adult zooecia Lz 0-55 to 0-75 mm. lz = 0-35 to 0-55 mm. hr = 0-12 to 0-17 mm. lr = 0-12 to O'i6 mm. Young zooecia Lz = 0-33 to 0-54 mm. lz = 0-22 to 0-37 mm. hr = 0-09 to 0-15 mm. lr = 0-08 to 0-13 mm. Ancestrulae Lz = 0-28 to 0-36 mm. lz = 0-17 to 0-25 mm. hr = 0-09 to o-io mm. lr = 0-07 to o-io mm. REMARKS. Leptocheilopora arcuata Lang is a junior synonym of L. filliozati (Brydone). Of the specimens in the British museum (Natural History) collections available to Lang, he assigned only 0.29900 to L. filliozati (Brydone). The specimen was presented in December, 1919 but was not mentioned by Lang in his 1921 catalogue. Measurement and comparison of this specimen with those assigned by Lang to L. arcuata suggested their synonymy, and this was confirmed by a detailed examination of Brydone's figured specimens of L. filliozati, S.M., 6.36167-68. Among the nineteen zoaria examined, the adult zooecia of 0.39425 and 0.39432 were found to be slightly larger than normal and to possess slightly more costae (16-18). These specimens are therefore only tentatively referred to L. filliozati (Brydone). It is of interest to note that the number of costae is not necessarily greater in more adult zooecia, but that occasionally the reverse may be true. For example, in the ancestrula of 0.28894 there are apparently 12 costae, but the zooecia of the first growth ring, although larger, have only 9 or 10 costae each ; again, the largest zooecia of the holotype, and of paratypes 0.4279, 0.28893 and 0.28895 have the fewest costae. The zooecium shown in PI. 8, fig. i is distorted and of exceptional length (Lz = 1-30 mm., lz = 0-30 mm., hr = 0-16 mm., lr = 0-14 mm.), in this case there are 35 costae. In Leptocheilopora filliozati (Brydone) Lz appears to vary less than lz, possibly because the width of a zooecium is more directly affected by restrictions imposed on it over a limited substratum. Apparently the development of the orifice is not usuaUy restricted by normal growth conditions : thus, not only does hr slightly exceed lr, except in a very few instances where the two measurements are equal, but the maximum measurements also vary only a little and usually in proportion to one another. Even in the case of the abnormally long zooecium mentioned above the dimensions of the orifice are normal. The measurements of the orifice are therefore important diagnostically, although the orifices of zooecia of the same and of different CRETACEOUS CRIBRIMORPH POLYZOA (PELM ATOPORIN AE) 115 zoaria may apparently vary in shape. This feature is illustrated by the following diagram (Text-fig. 50) of orifices from some of the specimens examined. Variation also occurs in the shape of the apertural bars. In both cases, some of the variation may be due to wear. Leptocheilopora filliozati (Brydone) is smaller than L. magna, and lacks the constant form of the orifice of that species. It is easily distinguished from L. tenuilabrosa which has costate ovicells. The greater size and number of costae, and the fewer (4) oral spines in the adult zooecia of L. filliozati distinguish it from L. vulnerata (Brydone), which also has a different apertural bar and small lateral slits in the ovicell. L. filliozati is also characterized by the frequent development of an irregular median ridge on the frontal shield. D.39429 D.39430 D.29900 D.39428 D.28294 D.39424 FIG. 50. Leptocheilopora filliozati (Brydone) variation in the shape of the orifice. STRATIGRAPHICAL DISTRIBUTION. Senonian, (? zone of B. mucronata], zones of G. [A.] quadrata and 0. pilula, subzones of E. scutata var. cincta and E. scutata var. depressula. SPECIMENS. 0.28294. Holotype of L. arcuata Lang. Incomplete zoarium with ancestrula encrusting a fragment of echinoid test. Senonian, zone of G. [A.] quadrata. Cliffs between Rottingdean and Saltdean, east of Brighton, Sussex. 0.4279. Paratype of L. arcuata Lang. Zoarial fragment with ancestrula encrusting a piece of echinoid test. Senonian, zone of G. [A.} quadrata. East Harnham, south of Salisbury, Wiltshire. W. Gamble Collection. 0.4290. Paratype of L. arcuata Lang. Zoarial fragment encrusting a piece of echinoid test. Horizon, locality and collection as for 0.4279. 0.4296. Paratype of L. arcuata Lang. Zoarial fragment encrusting a piece of echinoid test. Horizon, locality and collection as for 0.4279. 0.28893-94. Two paratypes of L. arcuata Lang. Zoarial fragments encrusting pieces of echinoid test. Senonian, zone of 0. pilula, subzone of E. scutata var. depressula. Cliffs between last groyne east of Rottingdean Gap and Saltdean, east of Brighton, Sussex. 0.28895. Paratype of L. arcuata Lang. Zoarial fragment encrusting a piece of echinoid test. Senonian, zone of 0. pilula, subzone of E. scutata var. cincta. Pit on East Hill, Rottingdean, east of Brighton, Sussex. 0.29900. Zoarial fragment encrusting a piece of echinoid test. Horizon, locality and collection as for 0.28893-94. 0.39424, 0.39426-28. Four zoarial fragments encrusting pieces of echinoid test (0.39424 with ancestrula). Senonian, zone of G. [A.] quadrata. u6 CRETACEOUS CRIBRIMORPH POLYZOA (PELM ATOPORIN AE) Pit 15 of Gaster, about one-third of a mile south-south-east of Salvington Windmill, and north of Hill Cottages, Salvington, Sussex. ?D. 39425. Zoarial fragment encrusting a piece of echinoid test. Horizon, locality and collection as for 0.39424. 0.39429. Zoarial fragment encrusting a piece of echinoid test. Senonian, zone of G. [A.] quadrata. Pit 26 of Gaster, South Woodleighs Pit, east of gravel pit, north-east of Woodleighs Lodge, about half a mile west of Pit 24 of Gaster, Warningcamp, north-east of Arundel, Sussex. 0.39430. Zoarial fragment encrusting a piece of echinoid test. Horizon, locality and collection as for 0.39424. PD.39432. Incomplete zoarium encrusting a piece of echinoid test. Senonian, zone of B. mucronata. Pit 8 of Rowe, south of Nodewell, Freshwater, Isle of Wight. 0.40932. Incomplete zoarium encrusting a piece of echinoid test. Senonian, zone of 0. pilula, subzone of E. scutata var. cincta. Pit 87 of Gaster, near cart-track to Newlands Barn, north end of East Hill, Rotting- dean, Sussex. 0.40933-35. Three incomplete zoaria encrusting fragments of echinoid test, the latter poorly preserved. Senonian, zone of 0. pilula, subzone of E. scutata var. depressula. Section 113 of Gaster, cliffs between last groyne east of Rottingdean Gap and Saltdean, Sussex. 0.40936-38. Three incomplete zoaria encrusting fragments of echinoid tests. Senonian, zone of G. [A.] quadrata. Pit 200 yards north of Trumley Copse, Lavant, Sussex. 0.40939. Incomplete zoarium encrusting a piece of echinoid test. Senonian, zone of G. [A.] quadrata. Halnaker Chalk Pit, half a mile south of Halnaker Windmill, Boxgrove, Sussex. OTHER MATERIAL. S.M., 6.36167. Lectotype, labelled by Mr A. G. Brighton. " Cribrilina filliozati Brydone [Syntype] ". See above. S.M., 6.36168. Zoarial fragment encrusting a piece of echinoid test. Labelled by Mr. A. G. Brighton " Cribrilina filliozati Brydone [Syntype] ". Senonian, zone of G. [A.] quadrata. Locality 1054 of Brydone, Pit near a lane about one-eighth of a mile north-east of the Black Horse Inn, West Titherley, Hampshire. R. M. Brydone Collection. 4. Leptocheilopora vulnerata (Brydone) (PL 9, figs, i, 2 ; Text-fig. 51) 19146 Cribrilina vulnerata Brydone, p. 97, pi. 4, figs. 3, 4. igi6a Leptocheilopora vulnerata (Brydone) Lang, p. 396. 1921 Leptocheilopora vulnerata (Brydone) : Lang, pp. xc, 70. LECTOTYPE. (Chosen by Lang, 1921 : 70.) S.M., 6.36271, the specimen figured by Brydone, 1914, pi. 4, fig. 3. Maastrichtian, zone of Belemnella lanceolata (0. lunata Chalk). Trimingham, Norfolk. R. M. Brydone Collection. CRETACEOUS CRIBRIMORPH POLYZOA (PELM ATOPORIN AE) 117 EMENDED DIAGNOSIS. Leptocheilopora with small zooecia (Lz = 0-42 to 0-50 mm., lz = 0-31 to 0-35 mm.) ; orifice small, of fairly constant size (hr = o-io to 0-12 mm., lr = 0-09 to o-ii mm.) ; oral spines 7 ; costae 11-13, wide, distinct ; no intercostal spaces ; apertural bar triangular, produced slightly in the mid-line and sloping down to the proximal margin of the orifice ; ovicells smooth with small lateral slits. DESCRIPTION. Zoarium encrusting, unilaminar. Adult zooecia broadly oval, closely placed, with a single, large, oval distal communication pore and one or more I O4mm. _J FIG. 51. Leptocheilopora vulnerata (Brydone), S.M., 6.36271. Lectotype. Adult zooecium with seven oral spine-bases, prominent curved facet on apertural bar, distinctly rimmed small pelmata, and large distal and smaller lateral communica- tion pores. smaller, oval lateral communication pores. Orifice small, distally and laterally rounded with a straight proximal margin ; slight proximal-lateral constrictions may be present. Oral spines 7, symmetrically and evenly spaced. Frontal shield flat or very gently arched, but descending steeply at the margins to meet the gymnocyst. Costae 11-13, wide, tapering inwards, distinct, closely placed. No intercostal spaces or lateral costal fusions. Three or four small pelmata with distinct, low rims occur on each costa ; they decrease in size inwards from the outer ends. Apertural bar triangular, with the apex pointing proximally and produced slightly in the mid-line : there is a prominent, curved facet on its descending distal side. Gymnocyst occa- sionally slightly exposed proximally to the frontal shield, but often obscured by the close placing of the zooecia. n8 CRETACEOUS CRIBRIMORPH POLYZOA (PELM ATOPORIN AE) Avicularia apparently absent. Ovicells smooth, large, prominent, hyperstomial, globular, with small lateral slits. Young zooecia smaller than the adult zooecia, but otherwise similar, with 7 oral spines and 9-12 costae ; the orifice is only slightly smaller than in the adult zooecia. Ancestrula very small, generally obscured. MEASUREMENTS. Adult zooecia Lz = 0-42 to 0-50 mm. lz = 0-31 to 0-35 mm. hr = o-io to 0-12 mm. lr = 0-09 to o-n mm. Young zooecia Lz = 0-30 to 0-32 mm. lz = 0-19 to 0-25 mm. hr = o-io mm. lr = 0-07 to o-io mm. Ancestrula Not measurable. REMARKS. Leptocheilopora vulnerata (Brydone) is distinguished from other species of the genus particularly by its small zooecial size, its constant number of oral spines, its relatively constant number of costae, and by the form of its apertural bar. The small lateral slits in the ovicell are also apparently peculiar to L. vulnerata (Brydone). The lectotype, S.M., 6.36271, and the other specimen originally figured by Brydone (19146, pi. 4, fig. 4) S.M., 6.36272, have been examined. Both are exceptionally well preserved and therefore retain very detailed characters such as the small, rimmed pelmata on the costae. Lang (1921 : 70) doubted whether this species should be included in Leptocheilopora, but examination of Brydone's specimens shows that the species is accurately placed there and that Lang was mistaken in classifying the genus in the group of the cribrimorph Polyzoa lacking pelmata. STRATIGRAPHICAL DISTRIBUTION. Maastrichtian, zone of Belemnella lanceolata (Ostrea lunata Chalk) and ? upper part of zone of B. mucronata Brydone (19146 : 97) stated " This species is abundant in the Trimingham Chalk and occurs sparingly in the Weybourne Chalk ". MATERIAL. S.M., 6.36271. Lectotype, labelled " Cribrilina vulnerata (Brydone) [Syntype] ". See above. S.M., 6.36272. Zoarium, with ancestrula, encrusting a piece of echinoid test. Labelled " Cribrilina vulnerata (Brydone) [Syntype] ". Horizon, locality and collection as for the lectotype. PN.C.M. 76.937 (28/1). Zoarial fragment with young zooecia encrusting a test of Cardiaster ananchytis (Leske). Senonian, zone of B. mucronata. Thorpe St. Andrews, Norwich, Norfolk. R. M. Brydone Collection. SPECIES OF UNCERTAIN SYSTEMATIC POSITION PREVIOUSLY ASSIGNED TO LEPTOCHEILOPORA (i) Leptocheilopora longuessensis Lang. 19160 Leptocheilopora languessensis [sic] Lang, pp. 396, 397. See remarks under Leptocheilopora magna Lang (p. 106). CRETACEOUS CRIBRIMORPH POLYZOA (PELM ATOPORIN AE) 119 (2) Reptoporella regularis d'Orbigny. 1852 Reptoporella regularis d'Orbigny, p. 717, figs. 6, 7. 1853 Reptoporella regularis d'Orbigny : d'Orbigny, p. 475. 1854 Reptoporella regularis d'Orbigny : d'Orbigny, p. 1097. REMARKS. Lang (19160 : 397 ; 1921 : 70) tentatively referred Reptoporella regularis d'Orbigny to Leptocheilopora. However, the placing of d'Orbigny's species cannot be at all certain without actual material being examined. The figures show a cribrimorph polyzoan with prominent hyperstomial ovicells and distal to each a smaller round structure with a median proximal pore. Lang (19160) regarded this as the distal communication pore, but this is usually only visible at the edges of a zoarium where the distal walls of the zooecia may be clearly exposed. The structure might even be avicularian. As Lang stated (1921 : 71), " The structure and systematic position of the species, ... as of the genus Reptoporella of which R. regularis is the genotype, remains conjectural ". I do not agree that Membranipora crenulata d'Orbigny (1852, pi. 728, figs. 13-15 ; J 853 : 547 ; 1854 : 1093) is, as suggested by Canu (19006 : 449) synonymous with Reptoporella regularis d'Orbigny. Gillard (1943 : 186) also disagreed with Canu on this point, and stated " la figure de d'Orbigny a ete exagerement retouche au point de preter aux plus graves confusions. Les septules distales ont ete reproduites a 1'extremite de chaque zoecie, si bien que Canu a pu supposer que chaque lignee zoeciale debutait par un avicellaire intercale." Evidently Gillard assigned several specimens, from the Upper Campanian of the Royan area, to Leptocheilopora regularis (d'Orbigny) as he also stated (1943 : 186), " Plusieurs zoaria recueillis a Port-Marant et a la base de la falaise E. de Talmont, se rapportent a cette espece dont les zoecies montrent des traces d'epines areales tres tenues. Lz = 700-800 /*, Iz = 350-375 /*, La [=hr] = 80 jn, la [= lr] = 100 u." Genus PELMATOPORA Lang 1851 1852 1852 1853 1854 1854 1860 1860 Escharipora d'Orbigny, pis. 603, 684-687, 700, 703 [partim] Escharipora : d'Orbigny, p. 221 [partim]. Semiescharipora d'Orbigny, pis. 717719 [partim]. Semiescharipora : d'Orbigny, p. 479 [partim]. Escharipora : d'Orbigny, p. 1097 [partim]. Semiescharipora : d'Orbigny, p. 1097 [partim]. Escharipora : Coquand, p. 121. Semiescharipora : Coquand, p. 150. 1885 Semiescharipora: Vine, pp. 116, 156. ? 18890 Cribrilina Pergens, pp. 61, 69. 1893 Cribrilina Pergens, pp. 202, 216. 1893 Cribrilina Vine, pp. 316, 323, 336. igooa Cribrilina Canu, p. 409. 19006 Cribrilina Canu, p. 445 [partim]. 19006 Escharipor a : Canu, p. 457 [partim]. 1900 Cribrilina Rowe, p. 341. 1904 Cribrilina Jukes-Browne, p. 490. 1906 Cribrilina Brydone, p. 300. 1910 Cribrilina White, pp. 55, 56. 120 CRETACEOUS CRIBRIMORPH POLYZOA (PELM ATOPORIN AE) 1911 Cribrilina : Canu, pp. 252 [partim], 280. 1912 Cribrilina : White, pp. 35, 43. 1912 Cribrilina : Brydone, pp. 20, 53, 70-89, 95. 1913 Cribrilina : Brydone, p. 436 [partim]. ?I9I3 Cribrilina : White, pp. 24, 27, 30, 32, 38 [partim]. 1913 Cribrilina : Lang, p. 171. igi6a Carydiopora Lang, p. 94 [partim]. igi6a Pelmatopora Lang, p. 101. 1917 Cribrilina : Brydone, p. 495. 19196 Pelmatopora igigd Pelmatopora 1921 Pelmatopora 1921 Cribrilina : Lang, p. Ivii [partim]. 1922 Pelmatopora 1923 Pelmatopora 1924 Pelmatopora 19246 Pelmatopora Lang, p. 107. Lang, pp. 191, 197, 204, 210. Lang, pp xcvi-xcv. Lang, p. 240. Cribrilina : Waters, p. 546 [partim]. Waters, p. 555. Cribrillina [sic] : Bohm, p. 101. Gaster, second of three tables opp. p. no. Voigt, p. no. Cribrilina : Voigt, p. 236 [partim]. 1924 Cribrilina : White, pp. 55, 62. ?I925# Cribrilina : Voigt, p. 25 [partim]. ?I925& non Pelmatopora : Voigt, pp. 98-102. 1927 Pelmatopora : Canu & Bassler, pp. 18, 35. 1930 Pelmatopora : Gaster, table opp. p. 340. 1930 non Pelmatopora : Voigt, pp. 515, 544, 561. J 935 Pelmatopora : Bassler, pp. 31, 165. 1939 non Pelmatopora : Voigt, p. 93. 1942 Pelmatopora : Gillard, p. 90. J 953 Pelmatopora : Bassler, p. Gig2. 1958 Pelmatopora : Didon, pp. 80, 82-85. TYPE SPECIES. Pelmatopora pero Lang, 19160 : 101. Senonian, top of zone of M. cor-anguinum. Medical College Pit, Epsom, Surrey. F. Mockler Collection. EMENDED DIAGNOSIS. Pelmatoporinae with or without a secondary orifice where present it comprises a distal oral shield of secondary tissue tending to envelope the unmodified oral spines, or the oral shield may be partly formed by a pair, occasionally two pairs, of enlarged oral spines ; apertural bar lacking a median process ; avicularia variable, relatively small, rounded, sporadically distributed in the species in which the distal oral shield is not developed, but commonly paired near the orifice, large, distally pointed and directed in the species with distal oral shields. REMARKS. All the material originally assigned to Pelmatopora by Lang has been re-examined. Similarly, all the specimens figured by Brydone which Lang regarded as Pelmatopora species have been examined. In addition a large number of speci- mens, particularly from the upper zones of the Senonian, in the C. T. A. Gaster Collection, have been incorporated in the revision. Lang (1922 : 241), in his remarks on Pelmatopora, was concerned primarily with tracing the stratigraphical relationships of the species which he recognized. The present revision shows that several of the species which he described are synonymous, CRETACEOUS CRIBRIMORPH POLYZOA (PELM ATOPORIN AE) 121 and that their stratigraphical relationships are, in some cases, different from those on which Lang based some of his evolutionary theory. Lang (19160 : 102 ; 1922 : 251) originally distinguished 38 species of Pelmatopora. Voigt (19256 : 99, 100 ; 1930 : 514) subsequently described two more. Voigt's species are here not definitely assigned to Pelmatopora (see p. 200), and only 22 of the species recognized by Lang are maintained here. It has not proved necessary to establish any new species of Pelmatopora. The revision is summarized by the following comparative list of Lang's and present identifications. Only those specimens probably available to Lang when he prepared volume 4 of the Catalogue of Cretaceous Bryozoa (1922) are considered. The species are listed in the same order as that used by Lang in 1922. Lang's identifications (1922) 1. P. calceata, Lang 2. P. crepidaria Lang . 3. P. solearis Lang 4. P. larva, sp. n. 5. P. chrysalis (d'Orbigny) 6. P. striata (d'Orbigny) 7. P. d'orbignyi Lang . 8. P. pauciclavia Lang 9. P. fragilis (d'Orbigny) 10. P. quadrata Lang 11. P. filliozati Lang 12. P. insignis (Canu) 13. P. suffulta (Brydone) 14. P. gasteri Lang 15. P. repleta (Brydone) 16. P. interrupta (d'Orbigny) 17. P. simplex Lang 1 8. P. coryli Lang 19. P. fecampensis Lang 20. P. plantaris Lang 21. P. pero Lang .... 22. P. brydonei Lang 23. P. quadrivolucris Lang 24. P. marsupitum [sic] Lang . 25. P. roedeanensis Lang 26. P. somptingensis Lang 27. P. gregoryi (Brydone) 28. P. palmata Lang 29. P. damicornis Lang . 30. P. danktonensis Lang 31. P. bidens Lang 32. P. lancingensis Lang 33. P. saltdeanensis Lang Present identifications P. calceata Lang, p. 123. P. crepidaria Lang, p. 125. P. solearis Lang, p. 127. P. larva Lang, p. 134 ; and P. d'orbignyi Lang [partim], p. 140. P. chrysalis (d'Orbigny), p. 132 ; and P. larva Lang [partim], p. 134. P. striata (d'Orbigny), p. 136. P. d'orbignyi Lang, p. 140. P. fragilis (d'Orbigny), p. 138. P. fragilis (d'Orbigny), p. 138. P. quadrata Lang, p. 143. P. quadrata Lang, p. 143. ? P. suffulta (Brydone), p. 151. P. suffulta (Brydone), p. 151. P. gasteri Lang, p. 130. P. suffulta (Brydone), p. 151. P. chrysalis (d'Orbigny), p. 132 ; and P. larva Lang, p. 134. P. simplex Lang, p. 157. P. coryli Lang, p. 168. P. fecampensis Lang, p. 145. P. plantaris Lang, p. 159. P. pero Lang, p. 148 ; and P. brydonei Lang [partim], p. 164. P. brydonei Lang, p. 164. P. quadrivolucris Lang, p. 161. P. marsupitorum Lang, p. 171. P. marsupitorum Lang, p. 171. P. somptingensis Lang, p. 188. P. gregoryi (Brydone), p. 175 ; and P. pal- mata Lang [partim], p. 196. P. palmata Lang, p. 196. P. palmata Lang, p. 196. P. somptingensis Lang, p. 188. P. gregoryi (Brydone), p. 175. P. gregoryi (Brydone), p. 175. P. gregoryi (Brydone), p. 175. 122 CRETACEOUS CRIBRIMORPH POLYZOA (PELM ATOPORIN AE) 34. P. collium Lang . . . . .P. gregoryi (Brydone), p. 175. 35. P. promontoriorum Lang . . . .P. gregoryi (Brydone), p. 175. 36. P. ranunculoides Lang . . . .P. gregoryi (Brydone), p. 175. 37. P. lacuum Lang . . . - . P. gregoryi (Brydone), p. 175. 38. P. gyrinoides Lang . . . . .P. gregoryi (Brydone), p. 175. Pelmatopora is distinguished from other genera of the Pelmatoporinae by the type of avicularia which are commonly present, and particularly by the absence of prominent distal or proximal oral shields. STRATIGRAPHICAL DISTRIBUTION. Senonian, zones of M. cortestudinarium to G. [A.] quadrata, Pzone of B. mucronata and PDanian. KEY TO THE SPECIES OF PELMATOPORA LANG (I) Pelmatopora with unmodified oral spines. (A) Median area of fusion narrow ; frontal shield arched ; orifice often with proximal-lateral constrictions ; no lateral costal fusions ; gymnocyst well exposed ; large pelmata only. (1) Interzooecial secondary tissue entirely absent ; avicularia small, rounded, sporadic . . . . . . . . . i. P. calceata Lang (2) Interzooecial secondary tissue present. (a) Interzooecial secondary tissue only slightly developed ; avicularia small, rounded, tubular, in two pairs near the orifice 2. P. crepidaria Lang (b) Interzooecial secondary tissue abundant ; avicularia small, rounded, one pair near orifice . . . . . . 3. P. solearis Lang (B) Median area of fusion wider. (1) Orifice small (hr = Ir), with marked proximal-lateral constrictions ; lateral costal fusions present . . . . . . 4. P. gasteri Lang (2) Orifice without marked proximal-lateral constrictions. (a) Lateral costal fusions absent ; interzooecial secondary tissue abundant with marked lacunae ; gymnocyst concealed. (i) Large pelmata only ; frontal shield flat. (a') Orifice higher than wide ; avicularia small, rounded, sporadic 5. P. chrysalis (d'Orbigny) (b f ) Orifice wider than higher. (a") Avicularia large, pointed ... 6. P. larva Lang (b") Avicularia small, rounded, sporadic, occasionally tending to be paired ; 25 or more costae 7. P. striata (d'Orbigny) (ii) Pelmata and pelmatidia present ; frontal shield arched ; 10-15 costae 8. P. fragilis (d'Orbigny) (b) Lateral costal fusions present ; interzooecial secondary tissue abundant. (i) Orifice higher than wide ; frontal shield flat ; avicularia relatively large, pointed, paired .... 9. P. d'orbignyi Lang (ii) Orifice wider than high. (') Avicularia large, pointed, paired. (a") Frontal shield arched ... 10. P. quadrata Lang (b") Frontal shield relatively flat. (a'"} Apertural bar wide with slight median furrow ; zooecia small, costae well spaced 1 1 . P. fecampensis Lang CRETACEOUS CRIBRIMORPH POLYZOA (PELM ATOPORIN AE) 123 (b'") Apertural bar narrow with slight median ridge ; zooecia large ; costae closely placed ; pematidia occasionally present . . . 12. P. pero Lang (b'} Avicularia small, rounded, paired. (a") Pelmata and pelmatidia present ; 15-20 costae ; large zooecia ; amount of interzooecial secondary tissue vari- able but never markedly developed 13. P. suffulta (Brydone) (b") Pelmatidia more numerous ; Lz less than i oo mm. ; interzooecial secondary tissue markedly developed with conspicuous lacunae. (a"') Costae narrow, 16-18 . . 14. P. simplex Lang (b'"} Costae wide, 13-16 . . 15. P. plantaris Lang (II) Pelmatopora with enlarged oral spines. (A) Two pairs of enlarged oral spines present . . 16. P. quadrivolucris Lang (B) Only the distal pair of oral spines enlarged. (1) Proximal pair of unmodified oral spine bases often still visible 17. P. brydonei Lang (2) Unmodified oral spines entirely obscured by secondary tissue accumulated round the margin of the orifice (may be visible in early growth stages). (a) Avicularia small, rounded, occasional, sporadic ; zooecia small; 11-14 costae. . . . . . . . .18. P. coryli Lang (b) Avicularia large, distally pointed and directed usually paired. (i) Enlarged distal oral spines relatively short and peg-like ; 14-20 costae . . . . . . 19. P. tnarsupitorum Lang (ii) Enlarged distal oral spines elongate, pointed, relatively slender, with a strong tendency to bifurcate the outer horn of the bifurcation curving away laterally and proximally . 20. P. gregoryi (Brydone) (iii) Enlarged distal oral spines laterally flattened and distally expanded, with a marked tendency to bifurcate .21. P. somptingensis Lang (iv) Enlarged distal oral spines very broad distally and distinctly bilobed . . . . . . 22. P. palmata Lang The following species are omitted from the above key and are regarded as of uncertain systematic position : Pelmatopora incerta Voigt (19256 : 99, 100), P. grandiporosa Voigt (1930 : 514), Pelmatopora sp. Voigt (1930 : 514), Pelmatopora daniensis Voigt (19256 : 99, 100). They are discussed on p. 200. i. Pelmatopora calceata Lang (PL 9, fig. 3 ; Text-fig. 52) 191 6a Pelmatopora calceata Lang, p. 102. igigd Pelmatopora calceata Lang : Lang, pp. 191, 196, 210, 218, 223, text-figs, i, 49. 1921 Pelmatopora calceata Lang : Lang, p. xciv. 1922 Pelmatopora calceata Lang : Lang, p. 254, pi. 5, fig. 6 ; text-fig. 74. HOLOTYPE. 0.4032. Well preserved zoarial fragment encrusting a piece of echinoid test. Senonian, either base of zone of M. cor-anguinum or top of zone of M. cortestudinarium. Chatham, Kent. W. Gamble Collection. EMENDED DIAGNOSIS. Pelmatopora with no distal oral shield ; oral spine bases unmodified, in two pairs ; median area of fusion narrow ; pelmata present but no 124 CRETACEOUS CRIBRIMORPH POLYZOA (PELM ATOPORIN AE) pelmatidia ; frontal shield strongly arched ; no interzooecial secondary tissue ; avicularia small, apparently rounded, sporadic. DESCRIPTION. Zoarium encrusting, unilaminar. Zooecia broadly oval, small. Orifice evenly rounded distally, the sides and proximal margin straight, occasionally with proximal-lateral constrictions, the rim not secondarily thickened. Oral spine bases 4, not enlarged, unmodified, the proximal-lateral pair placed on the distal- lateral curves of the orifice and not indenting its outline. Frontal shield strongly arched. Costae 10-14, widely spaced at the outer ends, with no lateral costal fusions. Each costa bears a prominent, large pelma near its inner end. The outlines of the inner ends of individual costae may be traced in the narrow median area of fusion. Apertural bar straight, slightly thickened, with two prominent pelmata near the O'Smm. I FIG. 52. Pelmatopora calceata Lang, 0.4032. Holotype. Adult zooecium and three small, oval, sporadic avicularia. mid-line ; no median process. Gymnocyst well exposed laterally and particularly proximally to the frontal shield. No interzooecial secondary tissue. Avicularia numerous, probably variously directed, sporadic, small, rounded, possibly adventitious on the sides of the zooecia rather than interzooecial, though this is not certain. Ovicells not seen. MEASUREMENTS. Zooecia Lz = 0-54 to 075 mm. lz = 0-33 to 0-39 mm. hr = 0-12 mm. Ir = 0-12 mm. Avicularia Not measurable. REMARKS. The only available specimen of P. calceata, the holotype, has been re-examined. Lang slightly underestimated the dimensions, those of the orifice are particularly constant. The range in number of costae is 10-14 and not 14-16 as stated (Lang, 1922 : 254). The avicularia are very small and it is not possible to determine whether they are proximally or distally directed ; there is a slight sugges- tion of proximal-lateral constrictions in some avicularian apertures, possibly CRETACEOUS CRIBRIMORPH POLYZOA (PELM ATOPORIN AE) 125 indicating distally directed rostra which are larger than the proximal portions of the apertures. Lang regarded this species as a radical form. STRATIGRAPHICAL DISTRIBUTION. Senonian, either base of zone of M. cor- anguinum or top of zone of M. cortestudinarium. SPECIMEN. 1X4032. Holotype see above. 2. Pelmatopora crepidaria Lang (PL 9, fig. 4 ; Text-figs. 53, 54) 19160, Pelmatopora crepidaria Lang, p. 102. 1919^ Pelmatopora crepidaria Lang : Lang, pp. 211, 222, 224, text-fig. 47. 1921 Pelmatopora crepidaria Lang : Lang, p. xciv. 1922 Pelmatopora crepidaria Lang : Lang, p. 255, pi. 5, fig. 7 ; text-fig. 75. HOLOTYPE. D. 21200. Well-preserved zoarial fragment. Senonian, zone of M. cor-anguinum. Woburn Green, south-west of Beaconsfield, Buckinghamshire. L. Treacher Collection. EMENDED DIAGNOSIS. Pelmatopora with unmodified oral spine-bases ; no pelmatidia ; frontal shield very well arched ; interzooecial secondary tissue irregu- larly developed in small amounts particularly near the orifices ; avicularia small, rounded, prominent, tubular, occurring in one or two pairs near the orifice. DESCRIPTION. Zoarium unilaminar, probably always encrusting. Zooecia some- what elongate, oval. Orifice of equal height and width, large, evenly rounded distally and laterally with slight proximal-lateral constrictions and a straight proximal margin ; the outline of the orifice is not obscured by the accumulation of secondary calcareous tissue. Oral spine-bases 4, in two pairs, widely placed, well developed, but unmodified and not enlarged, not indenting the outline of the orifice. Secondary closure of the orifice may occur, as in the holotype. An irregular, curved, calcareous shelf may be formed deep in the distal half of the orifice and extend proximally along the lateral margins. In other zooecia the orifice may be com- pletely closed by an irregular lamina of secondary calcareous tissue, see PL 9, fig. 4 and Text-fig. 54. Frontal shield well arched, elongate. Costae 11-14, closely spaced ; no lateral costal fusions. Each costa bears a large pelma very close to its inner end. Median area of fusion narrow. Apertural bar prominent, very wide, thickened, with a very slight median ridge and two prominent, large pelmata, one on either side of and close to the mid-line ; no median process developed. Gymnocyst smooth, somewhat obscured by the irregular, small amounts of interzooecial secondary tissue which are developed particularly near the orifices. The gymnocyst is usually exposed laterally and especially proximally to the frontal shields. The interzooecial valleys are deep and sharply defined. Avicularia very prominent but small, apparently directed distally and obliquely outwards from the zooecia they accompany, rounded and raised on elongate, stout, tubular stalks which project above the general level of the arched frontal shields. The avicularia are usually arranged in a proximal-lateral and a distal-lateral pair near the margins of the orifice : but proximal-lateral pairs occur more frequently 126 CRETACEOUS CRIBRIMORPH POLYZOA (PELM ATOPORIN AE) than distal-lateral pairs. Other similar, sporadic avicularia are occasionally present. Ovicells not seen. MEASUREMENTS. Zooecia Lz = 0-66 to 0-81 mm. lz = 0-35 to 0-39 mm. hr = 0-15 to 0-18 mm. Ir = 0-15 to 0-18 mm. Avicularia Not measurable. REMARKS. The holotype, D. 21200, and the paratype, 0.4110, have been re- examined. The former is a very well preserved zoarial fragment which is now unattached, the latter is a worn zoarial fragment encrusting a piece of echinoid test. O5mm. I O O O2mm. FIGS. 53, 54. Pelmatopora crepidaria Lang, D. 2 1200. Holotype. (53) Adult zooecium with two pairs of tubular avicularia near the orifice. (54) Distal part of adult zooecium, the tubular avicularia abraded and an irregular calcareous lamina developed in the distal and distal-lateral parts of the orifice. Lang's measurements for the species are, apparently, maximum dimensions ; gener- ally the zooecia are smaller, usually about 0-35 mm. wide and about twice as long. The range in number of costae is 11-14, but usually less than 14. It is not possible to determine whether all the avicularia are distally directed outwards from the zooecia they accompany. The avicularia project and are thus often worn at their upper ends. Compared with the zooecia of P. calceata those of P. crepidaria are more closely spaced, their median areas of fusion are not so wide, their costae have less rounded outer ends, and their intercostal spaces are narrower and longer. STRATIGRAPHICAL DISTRIBUTION. Senonian, zone of M. cor-anguinum. SPECIMENS. D. 21200. Holotype see above. 0.4110. Paratype. Worn zoarial fragment encrusting a piece of echinoid test. Senonian, (zone unspecified). Chatham, Kent. W. Gamble Collection. CRETACEOUS CRIBRIMORPH POLYZOA (PELM ATOPORIN AE) 127 3. Pelmatopora solearis Lang (PI. 9, figs. 5, 6 ; Text-figs. 55, 56) 19160, Pelmatopora solearis Lang, p. 102. 1919^ Pelmatopora solearis Lang : Lang, pp. 210, 213, 218, 223, text-fig. 50. 1921 Pelmatopora solearis Lang : Lang, pp. xciv, xcv. 1922 Pelmatopora solearis Lang : Lang, p. 257, pi. 5, fig. 8 ; text-fig. 76. 1930 Pelmatopora solearis Lang : Caster, table opp. p. 340. HOLOTYPE. D.2I2H. Zoarial fragment encrusting a piece of echinoid test. Senonian, zone of M. cor-anguinum. Hurley Bottom, Berkshire, south-east of Henley, Oxfordshire. L. Treacher Collection. FIG. 55. Pelmatopora solearis Lang, D. 2763. Paratype. Adult zooecium and two worn avicularia ; there is no interzooecial secondary tissue round the zooecium. EMENDED DIAGNOSIS. Pelmatopora with unmodified oral spine-bases ; median area of fusion may be narrow or wide ; no well-developed pelmatidia ; interzooecial secondary tissue relatively abundant ; avicularia small, rounded, sporadic, tending to be paired, one near each proximal-lateral corner of the orifice. DESCRIPTION. Zoarium unilaminar, probably always encrusting. Adult zooecia broadly oval, often nearly parallel-sided and elongate. Orifice generally a little wider than high, evenly rounded distally, with straight sides and a straight proximal margin. Occasionally very slight proximal-lateral constrictions occur. The outline of the orifice is not obscured by the accretion of secondary calcareous tissue. Oral spine-bases 4, unmodified, the lateral pair tending to be larger than the distal pair, but not indenting the outline of the orifice. Frontal shield well arched, but often flat in the median area. Costae 14- 24, usually 14-19, fairly closely spaced with no lateral costal fusions. Each costa bears a large pelma very close to its inner end. 128 CRETACEOUS CRIBRIMORPH POLYZOA (PELMATOPORIN AE) Very occasionally a small pdmatidium may also occur. The pelmata often form a prominent " rim " to the median area of fusion which may be narrow and elongate, with the double row of large pelmata lying close together, or it may be wide, with the two rows of pelmata further away from the mid-line of the frontal shield. When the median area of fusion is wide the outlines of the inner ends of individual costae may be traced across it. Apertural bar straight and somewhat triangular, prominent, wide, rounded on its upper surface and thickened, with two large, but shallow, pelmata, one on either side of, and close to, the mid-line ; no median process. FIG. 56. Pelmatopora solearis Lang, 0.19510. Paratype. Two adult zooecia and orifice of a proximally adjacent third zooecium and five worn avicularia. The contour-like development of interzooecial secondary tissue is apparent. The frontal shield of the zooecium on the right has a wide median area of fusion, contrasting with that of the zooecium on the left where the pelmata are close to the mid-line. Gymnocyst smooth, often well exposed, particularly proximally to the frontal shield, but it may be considerably, and even completely, obscured by interzooecial secondary tissue accumulated in contour-like ridges and eventually filling the interzooecial furrows. Irregular lacunae occur in this secondary tissue. Avicularia numerous, small, oval to rounded, occasionally somewhat pointed distally, sporadic, or tending to occur in pairs, one avicularium occurring near each proximal-lateral corner of the orifice. Ovicells not seen. Young zooecia smaller than the adult zooecia. Orifice of the same size and shape as in the adult zooecia. Oral spine-bases 4. Frontal shield more arched than in the adult stages, with about 12 costae. Each costa has a large pelma at its inner end close to the mid-line, the median area of fusion always being very narrow. The apertural bar is stout with two prominent pelmata near the mid-line, and the gymnocyst is well exposed. Interzooecial secondary tissue is scanty or absent in the young stages. The avicu- CRETACEOUS CRIBRIMORPH POLYZOA (PELM ATOPORIN AE) 129 laria are small, rounded and generally sporadic, but tend to occur in the paired arrangement found more commonly in the adult stages. MEASUREMENTS. Adult zooecia Lz 0-63 to i-oo mm. Iz = 0-32 to 0-50 mm. hr 0-12 to 0-18 mm. Ir = 0-12 to 0-21 mm. Young zooecia Lz =0-50 mm. Iz = 0-30 mm. hr = 0-12 to 0-15 mm. Ir 0-15 to 0-18 mm. Avicularia Not measurable. REMARKS. Lang's description was based mainly on the holotype. This, with all paratypes, has been re-examined, as well as several other specimens. In the many zooecia measured, costae were found to be more numerous in the larger than in the smaller ones. 0.2813 possesses one abnormally long zooecium (Lz = 1-45 mm., Iz = 0-33 mm.) with about 35 costae. The most variable feature is the amount of interzooecial secondary tissue which may be developed. It may be absent or very abundant in different specimens, and occasionally varies from scarce to abundant in the same zoarium. As Lang has suggested, the young zooecia of P. solearis are similar to the adult zooecia of P. calceata, the radical form, according to Lang, from which P. solearis may be derived. Most of the specimens assigned by Lang to P. solearis encrust fragments of echinoid test. 0.24542, 0.27043-46, 0.28265 an d 0.4221 are now unattached. STRATIGRAPHICAL DISTRIBUTION. Senonian, zones of M. cortestudinarium and M. cor-anguinum. SPECIMENS. 0.21211. Holotype see above. 0.28267. Paratype. Zoarial fragment encrusting a piece of echinoid test. Senonian, zone of M. cor-anguinum, Trochiliopora Bed (about 20 ft. above base of zone). Hindover, north-east of Seaford, Sussex. 0.28268. Paratype. Zoarial fragment encrusting a piece of echinoid test. Senonian, zone of M. cor-anguinum, Trochiliopora Bed. Cliff End, east side of Cuckmere Haven, Sussex. 0.24542. Paratype. Zoarial fragment, now unattached. Senonian, zone of M . cor-anguinum. Gillingham, north-east of Chatham, Kent. W. Gamble Collection. 0.27042-46. Paratypes. Five fragments of the same unattached zoarium. Senonian, zone of M. cortestudinarium. Lower pit, Slines Oak, Worms Heath, Warlingham, Surrey. F. Mockler Collection. 0.19510. Paratype. Zoarial fragment encrusting a piece of echinoid test. Senonian, zone of M. cortestudinarium. Seaford, Sussex. F. Mockler Collection. 0.28269. Paratype. Zoarial fragment encrusting a piece of echinoid test. Senonian, zone of M. cortestudinarium. Cliffs between Hope Gap and Cuckmere Haven, Sussex. GEOL. 6, I. O 130 CRETACEOUS CRIBRIMORPH POLYZOA (PELM ATOPORIN AE) 0.2763, 0.2813, 0.2817, 0.27980. Four paratypes. Zoarial fragments now unattached. Senonian, either base of zone of M. cor-anguinum or top of zone of M. cortestudinarium. Chatham, Kent. G. R. Vine Collection. 0.4026, D. 4971, 0.4978. Three paratypes. Zoarial fragments, now unattached. Horizon and locality as for 0.2763. W. Gamble Collection. 0.4030, 0.4221, 0.4965. Three poorly preserved zoarial fragments, now un- attached. Horizon and locality as for 0.2763. W. Gamble Collec- tion. 0.28265-66. Two zoarial fragments, the former now unattached, the latter encrusting a piece of echinoid test. Senonian, zone of M. cor- anguinum, Trochiliopora Bed, Summit of the Downs, Mount Harry, near Lewes, Sussex. 0.40134. Zoarial fragment encrusting a piece of echinoid test. Lower Senonian, zone unspecified. ? Chatham, Kent. W. Gamble Collection. 0.40135. Zoarial fragment encrusting a piece of echinoid test. Lower Senonian, zone unspecified. PChatham, Kent. Collection unspecified. 0.40722-27. Six unattached zoarial fragments. Horizon, locality and collection as for 0.28265 see above. 0.40728-31. Four unattached zoarial fragments. Senonian, zone of M. cor- anguinum, Trochiliopora Bed. Cliffs, Beltout, west of Eastbourne, Sussex. 0.40732-33. Two unattached zoarial fragments. Senonian, zone of M. cor- anguinum, Trochiliopora Bed. Cliffs, east side of Cuckmere Haven, east of Seaford, Sussex. 0.40734-35. Two zoarial fragments encrusting pieces of echinoid tests. Senonian, zone of M. cortestudinarium. Cliffs between Hope Gap and Cuckmere Haven, east of Seaford, Sussex. 4. Pelmatopora gasteri Lang (PI. 9, fig. 8 ; Text-fig. 57) igi6a Pelmatopora gasteri Lang, pp. 102, 105. igigd Pelmatopora gasteri Lang : Lang, pp. 211, 218, 222, 226, text-fig. 44. 1921 Pelmatopora gasteri Lang : Lang, p. cxiv. 1922 Pelmatopora gasteri Lang : Lang, p. 278, pi. 5, fig. 12 ; text-fig. 84. HOLOTYPE. 0.28274. The only specimen. Fragment of a well-preservec zoarium, now unattached. Senonian, zone of M. cor-anguinum, Trochiliopora Bed about 20 ft. above base of zone. Cliffs, east side of Cuckmere Haven, Sussex. EMENDED DIAGNOSIS. Pelmatopora with unmodified oral spine-bases ; pelmatidia present ; avicularia tend to be paired but are occasionally sporadic ; costae 15-17 zooecia small (Lz = 0-60 to 0-72 mm., Iz = 0-33 to 0-36 mm.) ; orifice with markec proximal-lateral constrictions. DESCRIPTION. Zoarium unilaminar, now unattached. Zooecia oval, small Orifice of equal height and width, rounded distally and laterally, with a straight CRETACEOUS CRIBRIMORPH POLYZOA (PELM ATOPORIN AE) 131 proximal margin and with marked proximal-lateral constrictions. Oral spine-bases unmodified, occurring in two pairs, the proximal-lateral pair slightly larger. The outline of the orifice may be very slightly indented by the oral spine bases. Frontal shield steeply arched, but with a flat median area of fusion. Costae 15-17, each with a fairly prominent pelma near its inner end, and, closer to the mid-line of the frontal shield, often with an obscure pelmatidium. Lateral costal fusions occur at the level of the pelmata only. Median area of fusion fairly narrow, spindle-shaped. Apertural bar prominent, flat, very wide, with two pelmata, one on each side of and close to the mid-line. Gymnocyst obscured by interzooecial secondary tissue, which, though 0-5 mm. FIG. 57. Pelmatopora gasteri Lang, 0.28274. Holotype. Adult zooecium and paired, worn avicularia. The two avicularia at the proximal end belong to adjacent zooecia. abundant, does not encroach on to the frontal shields. Slight, irregularly elongate depressions are present in the interzooecial secondary tissue. Avicularia tend to occur just proximally to the proximal-lateral corners of the orifice, often paired. Other occasional, sporadic, interzooecial avicularia occur. All are small, elongate-oval and probably distally directed. Ovicells not seen. MEASUREMENTS. Zooecia Lz = 0-60 to 0-72 mm. lz = 0-33 to 0-36 mm. hr = 0-12 mm. lr = 0-12 mm. Avicularia Not measurable. REMARKS. The unique holotype has been re-examined. The oral spine-bases are larger than is suggested by Lang's figure (1922, text-fig. 84), and the avicularia tend to be paired rather than sporadic. The pelmatidia lie very close to the mid-line in the median area of fusion and are generally obscured by slight extra-calcification or by wear along the mid-line. The form and constant small size of the orifice, the 132 CRETACEOUS CRIBRIMORPH POLYZOA (PELM ATOPORIN AE) relatively small zooecia, and the restricted range in number of costae particularly distinguish this species. No other specimens have been found in the large amount of material examined from the C. T. A. Gaster Collection. STRATIGRAPHICAL DISTRIBUTION. Senonian, zone of M. cor-anguinum. SPECIMEN. 0.28274. Holotype see above. 5. Pelmatopora chrysalis (d'Orbigny) (PI. 9, fig. 7; Text-fig. 58) 1851 Escharipora chrysalis d'Orbigny, pi. 686, figs. 6-8 (as chrisalis [sic]) ; 1852, p. 228 ; 1854, p. 1097. 1852 Semiescharipora interrupta d'Orbigny, pi. 719, figs. 5-8 ; 1853, p. 487 ; 1854, p. 1098. 1860 Escharipora chrysalis d'Orbigny : Coquand, p. 121. 1860 Semiescharipora interrupta d'Orbigny : Coquand, p. 150. igooa Cribrilina interrupta (d'Orbigny) : Canu, p. 409. 19006 Cribrilina interrupta (d'Orbigny) : Canu, p. 449. 19006 Escharipora chrysalis d'Orbigny : Canu, p. 449. igi6a non Pelmatopora interrupta (d'Orbigny) : Lang, p. 102. igi6a Pelmatopora chrysalis (d'Orbigny) Lang, p. 102. 1917 Semiescharipora interrupta d'Orbigny : Brydone, p. 495. 1919^ non Pelmatopora interrupta (d'Orbigny) : Lang, pp. 211, 223, text-fig. 42. 1919^ Pelmatopora chrysalis (d'Orbigny) : Lang, pp. 212, 223. 1921 Pelmatopora chrysalis (d'Orbigny) : Lang, p. xciii. 1921 Pelmatopora interrupta (d'Orbigny) : Lang, p. xciii. 1922 Pelmatopora chrysalis (d'Orbigny) : Lang, p. 263 [partim 0.28438 and 0.28439 excl.]. 1922 Pelmatopora interrupta (d'Orbigny) : Lang, p. 281, text-fig. 85. ?i942 Pelmatopora chrysalis (d'Orbigny) : Gillard, p. 90. EMENDED DIAGNOSIS. Pelmatopora with unmodified oral spine-bases ; median area of fusion narrow ; pelmatidia apparently absent ; frontal shield flat ; inter- zooecial secondary tissue abundant, with marked lacunae ; avicularia small, rounded, sporadic, unpaired. DESCRIPTION. Zoarium uni- or bilaminar, now unattached. Zooecia elongate, elliptical. Orifice higher than wide, evenly rounded distally with straight sides and a straight proximal margin ; slight proximal-lateral constrictions may occur. The outline of the margin of the orifice is apparently somewhat obscured by the accretion of secondary calcareous tissue. Number of oral spine-bases indeterminate, probably 4, but obscured by secondary calcareous tissue. Frontal shield flat. Costae 19-22, closely spaced. No lateral costal fusions. Each costa bears a prominent pelma near its inner end : these pelmata tend to form a slight " ridge " on either side of the narrow, lens-shaped median area of fusion. No pelmatidia visible. Apertural bar wide, apparently straight and thickened, with a slight median furrow, and probably carrying two large pelmata near the mid-line ; no median process present. Gymnocyst apparently obscured by plentiful interzooecial secondary tissue which fills the inter- zooecial valleys and contains rather regular, elongate, narrow lacunae which are wider at their rounded proximal ends. Avicularia not very frequent, unpaired, sporadic, small, rounded to slightly elongate. Ovicells not seen. CRETACEOUS CRIBRIMORPH POLYZOA (PELM ATOPORIN AE) 133 MEASUREMENTS. [Based on Canu's measurements for " Cribrilina interrupta (d'Orbigny) ", (Canu, 19006 : 449).] Zooecia Lz = 0-92 to i-oo mm. Iz = 0-42 to 0-50 mm. hr = 0-24 to 0-26 mm. Ir = 0-17 to 0-21 mm. REMARKS. Only a photograph (according to Lang, 1922 : 264, the middle speci- men of three on a slide labelled " Escharipora striata d'Orbigny, Coniacian, Villedieu " in the Canu Collection) is available. The diagnosis and description are based on this photograph (PI. 9, fig. 7). This specimen compares closely with d'Orbigny's O5mm. FIG. 58. Pelmatopora chrysalis (d'Orbigny). Drawn from a photograph, in the British Museum (Natural History), of the middle specimen of three on a slide labelled "Escharipora striata d'Orbigny, Coniacian, Villedieu." F. Canu Collection, Paris. An adult zooecium and one worn avicularium surrounded by interzooecial secon- dary tissue with characteristically elongate lacunae. figure of Escharipora chrysalis except for the very regular pairing of the avicularia on each zooecium in d'Orbigny's figure. Canu (19006 : 449), who regarded Semiescharipora interrupta d'Orbigny and Escharipora chrysalis d'Orbigny as synonymous, based his opinion on a comparison of d'Orbigny's actual specimens and gave measurements for the material. Un- fortunately he retained the name interrupta for the species, although chrysalis has priority by one year. d'Orbigny's figures of both species are highly stylized, but Lang (1922) rigidly interpreted them and disagreed with Canu's conclusions, keeping the two species separate. Lang did not choose a lectotype for Escharipora chrysalis, but did so for Semiescharipora interrupta. Such rigid interpretation of stylized figures is not desirable, nor is it advisable to choose a lectotype from them in the absence of actual specimens. Canu's conclusions (19006) based on an examination of d'Orbigny's specimens, are therefore accepted in preference to those founded on such questionable interpretations. 134 CRETACEOUS CRIBRIMORPH POLYZOA (PELM ATOPORIN AE) 0.28438 and 0.28439 were labelled by Lang " Pelmatopora chrysalis (d'Orbigny) ", but the former has prominently paired, distally pointed and directed avicularia and is here assigned to P. larva Lang : the latter has very numerous narrow costae and has been assigned also, with a query, to P. larva Lang. STRATIGRAPHICAL DISTRIBUTION. Senonian, Coniacian of France. SPECIMENS. None in the collections. Photograph the middle specimen of three on a slide labelled " Escharipora striata d'Orbigny, Coniacian, Villedieu ". F. Canu Collection. 6. Pelmatopora larva Lang (PI. 9, fig. 9 ; Text-figs. 59, 60) 1852 non Semiescharipora interrupta d'Orbigny, pi. 719, figs. 5-8 ; 1853, p. 487 ; 1854, p. 1098. ?i9i6a Pelmatopora interrupta (d'Orbigny) : Lang, p. 102. ?i9i9^ Pelmatopora interrupta (d'Orbigny) : Lang, pp. 211, 223, text-fig. 42. 1921 Pelmatopora larva Lang, p. xcv [nom nud.~\. 1922 Pelmatopora larva Lang, p. 260, pi. 5, fig. 9 ; text-fig. 77. 1922 Pelmatopora chrysalis (d'Orbigny) : Lang, p. 263 [partim 0.28438-39 only]. HOLOTYPE. 0.28440. Small fragment of unilaminar zoarium, now unattached. Senonian, Coniacian. La Ribochere, Loir et Cher, east of La Chartres-sur-le-Loir, Sarthe, France. F. Canu Collection. O*5 mm. FIG. 59. Pelmatopora larva Lang, D. 28438. Distal end of adult zooecium with two distally pointed avicularia, showing their paired occurrence proximal to the orifice. EMENDED DIAGNOSIS. Pelmatopora with unmodified oral spine-bases ; median area of fusion narrow ; no pelmatidia ; frontal shield flat ; interzooecial secondary tissue abundant ; avicularia elongate, distally pointed and directed, tending to be paired, one near each proximal-lateral corner of the orifice. DESCRIPTION. Zoarium uni- or bilaminar, now unattached. Zooecia elliptical, long and narrow. Orifice wider than high, rounded distally with a straight proximal margin, the sides straight or converging slightly proximally. The outline of the CRETACEOUS CRIBRIMORPH POLYZOA (PELM ATOPORIN AE) 135 margin of the orifice may be slightly obscured by accretion of secondary calcareous tissue. Oral spine-bases apparently 4, unmodified, often obscured by secondary calcareous tissue, and not indenting the outline of the orifice. Frontal shield flat, of variable length. Costae about 17, fairly closely spaced. No lateral costal fusions. Each costa bears a large pelma near its inner end close to the narrow median area of fusion. No pelmatidia. Apertural bar wide, but not very thick, bearing two large pelmata very close to the mid-line; there is no median process. Gymnocyst almost O5mm. FIG. 60. Pelmatopora larva Lang, D. 28440. Holotype. Adult zooecium and two distally pointed and directed avicularia. entirely obscured by plentiful interzooecial secondary tissue which fills the inte- zooecial valleys to a level generally equal to, or a little above, that of the flat frontal shields. Irregular, elongate, shallow lacunae occur frequently in the interzooecial tissue, occasionally descending deeply to expose the gymnocyst. Avicularia relatively large, prominent, elongate, distally pointed and directed ; generally paired, one near each proximal-lateral corner of the orifice or a little proximal to this position. Ovicells not seen. MEASUREMENTS. Zooecia Lz = 0-87 to i-oo mm. lz = 0-33 to 0-36 mm. hr = 0-18 mm. lr = 0-18 to o-2i mm. Avicularia Lz = 0-12 to 0-15 mm. lz 0-06 to 0-09 mm. 136 CRETACEOUS CRIBRIMORPH POLYZOA (PELM ATOPORIN AE) REMARKS. P. larva Lang, P. interrupta (d'Orbigny) and P. chrysalis (d'Orbigny), as interpreted by Lang (1922), have been reconsidered. P. interrupta and P. chrysalis are synonymous, and P. larva is distinguished from them mainly by the type and position of the avicularia. In the holotype of P. larva, 0.28440, the avicularia always lie proximally to the apertural bar at or near the proximal-lateral corners of the orifice. Nowhere do they occur on the lateral margins of the orifice as in P. d'orbignyi Lang, nor are they of the smaller, rounded, sporadic type which are seen in photographs of a specimen here assigned to P. chrysalis (d'Orbigny). 0.28438, labelled by Lang " P. chrysalis (d'Orbigny) ", also belongs to P. larva, for it possesses paired, distally pointed and directed avicularia which lie proximally to the proximal-lateral corners of the orifice. 0.28439, similarly labelled by Lang, is also probably better assigned to P. larva. Although its costae are constant in number at 21, the dimensions of the zooecia, the well-developed, distally pointed and directed, paired avicularia (one proximal to each proximal-lateral corner of the orifice), and the abundant interzooecial secondary tissue with shallow, elongate lacunae are all features which are more characteristic of P. larva than of P. chrysalis. The measurements of the specimen are as follows : Zooecia Lz = 0-87 mm. lz = 0-36 mm. hr = 0-15 to 0-18 mm. Ir = 0-18 to 0-21 mm. Avicularia Lz = 0-15 mm. lz = 0-09 mm. STRATIGRAPHICAL DISTRIBUTION. Senonian, Coniacian of France. SPECIMENS. 0.28440. Holotype see above. 0.28438. Small unattached fragment of bilaminar zoarium, labelled by Lang " P. chrysalis (d'Orbigny) ". Horizon, locality and collection as for the holotype. ?D. 28439. Small zoarial fragment, now unattached, labelled by Lang " P. chrysalis (d'Orbigny) ". Horizon, locality and collection as for the holotype. 7. Pelmatopora striata (d'Orbigny) (PI. 9, %. 10) Escharipora striata d'Orbigny, pi. 686, figs. 9-12 ; 1852, p. 229 ; 1854, p. 1097. 1851 Escharipora mumia d'Orbigny, pi. 687, figs. 4-6 ; 1852, p. 233 ; 1854, p. 1097. 1851 non Escharipora elegans d'Orbingy, pi. 684, figs. 13-15 ; 1852, p. 222 ; 1854, p. 1097. 19006 Cribrilina (Decurtaria] striata (d'Orbigny) Canu, p. 450. 19006 non Escharipora elegans (d'Orbigny) : Canu, p. 457. 191601 Pelmatopora striata (d'Orbigny) Lang, pp. 102, 104. 19196? Pelmatopora striata (d'Orbigny) : Lang, pp. 212, 222. 1921 Pelmatopora striata (d'Orbigny) : Lang, p. xciii. 1922 Pelmatopora striata (d'Orbigny) : Lang, p. 264. ?I942 Pelmatopora striata (d'Orbigny) : Gillard, p. 90. CRETACEOUS CRI BRIMORPH POLYZOA (PELM ATOPO RIN AE) 137 LECTOTYPE. (Chosen by Lang, 1922 : 265.) The specimen figured by d'Orbigny, 1851, pi. 686, fig. 10. Nehou, south of Valoignes, east of Ste. Colombe, Manche, France. Senonian. EMENDED DIAGNOSIS. Pelmatopora with unmodified oral spine-bases ; apparently no pelmatidia ; frontal shield flat ; about 25 costae. DESCRIPTION. Zoarium uni- or bilaminar, now unattached. Zooecia large, elliptical. Orifice rounded distally and laterally, with a straight proximal margin, apparently higher than wide. Number and form of oral spine-bases not determin- able, but definitely not enlarged, probably obscured by the accretion of secondary calcareous tissue. Frontal shield apparently flat. Costae about 25 or 26, narrow, closely spaced, each with a large pelma near its inner end close to the median area of fusion. This is somewhat wider than in P. chrysalis (d'Orbigny). The outlines of the inner ends of individual costae may be traced into the narrow median area of fusion. No pelmatidia and no lateral costal fusions visible. Apertural bar prominent, rather wide, with a slight median furrow, and with two large pelmata, one on either side of the mid-line. Gymnocyst apparently entirely concealed by the very abundant interzooecial secondary tissue which completely fills the interzooecial valleys and stands up as ridges between the zooecia. Irregular elongate lacunae occur in the secondary tissue. Avicularia are possibly present but the photograph on which the present diagnosis and description are based is not clear enough to show them with certainty. Ovicells not seen. MEASUREMENTS. [From Canu (19006 : 450).] Zooecia Lz = 1-14 to 1-35 mm. lz = 0-50 to 0-64 mm. hr = 0-20 to 0-30 mm. lr = 0-21 to 0-25 mm. REMARKS. The diagnosis and description for P. striata (d'Orbigny) are only tentative. Canu (19006 : 450) based his conclusions on an examination of d'Orbigny's actual specimens and regarded Escharipora striata and E. mumia as synonymous. This interpretation is followed here, since d'Orbigny's stylized figures have little systematic value. As Lang has remarked (1922 : 265), there are no indications of pelmata in either of d'Orbigny's figures of the two species which Canu regarded as synonymous, and therefore the placing of E. striata in the genus Pelmatopora can only be tentative. However, the slide in the Canu Collection, labelled " Escharipora striata d'Orbigny ", holds three specimens : the outermost specimens compare closely with the d'Orbigny figures and are definitely Pelmatopora. A photograph of one of these outer specimens is in the collections of the British Museum (Natural History). The middle specimen on the slide has been assigned to P. chrysalis (d'Orbigny). STRATI GRAPHICAL DISTRIBUTION. Senonian, Coniacian of France. SPECIMENS. A photograph only one of the outer specimens of three on a slide labelled " Escharipora striata d'Orbigny, Coniacian, Villedieu ". F. Canu Collection. 138 CRETACEOUS CRIBRIMORPH POLYZOA (PELM ATOPORIN AE) 8. Pelmatopora fragilis (d'Orbigny) (PI. 10, figs, i, 2 ; Text-fig. 61) 1851 Semiescharipora fragilis d'Orbigny, pi. 717, figs. 8-n ; 1853, p. 480; 1854, p. 1097. 1885 Semiescharipora fragilis d'Orbigny : Vine, pp. 116, 156. 1893 Cribrili na fragilis (d'Orbigny) Pergens, pp. 202, 216. 1893 Cribrilina fragilis (d'Orbigny) : Vine, pp. 316, 323, 336. 19006 Cribrilina fragilis (d'Orbigny) : Canu, pp. 448/458. 1904 Cribrilina fragilis (d'Orbigny) : Jukes-Browne, p. 490. igiba Pelmatopora fragilis (d'Orbigny) Lang, pp. 102, 104. igi6a Pelmatopora pauciclavia Lang, pp. 102, 104. Pelmatopora fragilis (d'Orbigny) : Lang, pp. 212, 222. Pelmatopora pauciclavia Lang : Lang, p. 211, text-fig. 41. 1921 Pelmatopora pauciclavia Lang : Lang, p. xciv. 1921 Pelmatopora fragilis (d'Orbigny) : Lang, p. xcv. 1922 Pelmatopora pauciclavia Lang : Lang, p. 267, pi. 5, fig. n ; text-fig. 80. 1922 Pelmatopora fragilis (d'Orbigny) : Lang, p. 269. 1942 Pelmatopora fragilis (d'Orbigny) : Gillard, p. 90. LECTOTYPE. (Chosen by Lang, 1922 : 269.) The specimen figured by d'Orbigny, 1851, pi. 717, fig. 9. Senonian, Coniacian. Fecamp, Seine Inferieure, France. O'Smm. FIG. 61. Pelmatopora fragilis (d'Orbigny), D. 28273. Holotype of P. pauciclavia Lang. Adult zooecium and paired avicularia. The avicularia at the proximal end belong to adjacent zooecia. EMENDED DIAGNOSIS. Pelmatopora with unmodified oral spine-bases ; median area of fusion narrow ; pelmatidia often present ; frontal shield high, flat on top ; costae 9-15 ; orifice relative!} 7 large ; avicularia often paired. CRETACEOUS CRI BRIMORPH POLYZOA ( PELM ATOPORIN AE) 139 DESCRIPTION. Zoarium unilaminar, encrusting or now unattached. Zooecia broadly oval or with somewhat parallel sides, of variable length. Orifice relatively large, usually higher than wide, rounded distally with straight sides and a straight proximal margin. Occasionally the orifice may narrow slightly at the proximal end ; there are no proximal-lateral constrictions. Oral spine-bases 4, widely spaced, unmodified, possibly very slightly enlarged, but not indenting the outline of the margin of the orifice. Frontal shield high, flat on top. Costae wide, 9-15 (often 10-11), each with a prominent, raised pelma near the inner end at the edge of the median area of fusion : an inner pelmatidium is often also present on each costa. Lateral costal fusions occur at the level of the pelmata. The area within the pelmata is flat ; outside it the costae slope down fairly steeply. Median area of fusion narrow. Apertural bar thick, prominent, with two large pelmata, one immediately on either side of the mid-line which is marked by a slight median ridge. Gymnocyst largely concealed by fairly abundant interzooecial secondary tissue which contains irregularly elongate, well-defined lacunae. Avicularia interzooecial, tubular, prominent, often paired one on either side of each zooecium and placed just proximally to the apertural bar, or well proximal to this position. Apparently the avicularian apertures are small, rounded to oval, and, in less worn examples, may be slightly pointed distally. Ovicells not seen. MEASUREMENTS. [Based partly on Canu's measurements for " Cribrilina fragilis (d'Orbigny) ", 19006 : 448.] Zooecia Lz = 0-71 to 0-81 mm. Iz = 0-39 to 0-50 mm. hr = 0-14 to 0-18 mm. Ir == o-n to 0-18 mm. REMARKS. P. fragilis was poorly figured by d'Orbigny. Lang (1922 : 269) interpreted the species from a photograph provided by Canu of a specimen in the d'Orbigny Collection. That specimen was one of three on a slide : one of the other two specimens is specifically distinct and was made the type of P. filliozati Lang. Although it is difficult to interpret the photograph of P. fragilis it is apparent that the frontal shields are not flat, as suggested by Lang in his diagnosis of the species, but are high and sloping outwards, and that the avicularia tend to occur one on either side of each frontal wall near the apertural bar. The measurements of the holotype of P. pauciclavia Lang, 0.28273, are as follows : Zooecia Lz = 0-78 to 0-81 mm. Iz = 0-39 to 0-47 mm. hr = 0-18 mm. Ir = 0-15 to 0-18 mm. The range in number of costae in the specimen is 9-12. Comparing this with the measurements given by Canu (19006 : 448) for " Cribrilina fragilis (d'Orbigny) ", it is apparent that the dimensions of the two are closely similar. Canu recorded the dimensions of the latter species as Lz = 0-71 to 0-78 mm., Iz = 0-42 to 0-50 mm., hr = 0-14 mm. and Ir = o-n mm. The range in number of costae discernible in i 4 o CRETACEOUS CRIBRIMORPH POLYZOA ( PELM ATOPORIN AE) the photograph of Pelmatopora fragilis is 13-15, and the amount of interzooecial secondary tissue present also compares closely with that in 0.28373. 0.28452, labelled by Lang " Pelmatopora 1 fragilis (d'Orbigny) ", is rather badly worn but is tentatively retained in the species. 0.28441-42, included in P. fragilis by Lang, are, however, here excluded from the species. The former has a flat frontal shield with at least 16 narrow costae, and an amount of interzooecial secondary tissue different from that in P. fragilis. Other details are destroyed in this badly damaged specimen and, like 0.28442, it is indeterminate. STRATIGRAPHICAL DISTRIBUTION. Senonian, Coniacian in France, zone of M. cor- anguinum in England. SPECIMENS. 0.28452. Worn zoarial fragment encrusting a piece of molluscan shell. Senonian, Coniacian. St. Avertin, south-east of Tours, Indre-et- Loire, France. F. Canu Collection. 0.28273. Holotype of P. pauciclavia Lang. Very well preserved zoarial fragment. Senonian, zone of M. cor-anguinum, Trochiliopora Bed (about 20 ft. above base of zone). East side of Cuckmere Haven, cliffs, Sussex. Photograph one of three specimens on a slide labelled " Cribrilina \Semiescharipora} fragilis d'O.". Senonian, Emscherian. Fecamp, Seine Inferieure, France. F. Canu Collection. Excluded from the species indeterminate 0.28441, 0.28442. 9. Pelmatopora d'orbignyi Lang (PI. 10, fig. 3 ; Text-figs. 62, 63) 191 6a Pelmatopora d'orbignyi Lang, pp. 102, 104. 1919^ Pelmatopora d'orbignyi Lang : Lang, pp. 211, 222, 225, text-fig. 48. 1921 Pelmatopora d'orbignyi Lang : Lang, p. xcv. 1922 4 Pelmatopora larva Lang, p. 260 [partim paratype 0.28443 only]. 1922 Pelmatopora d'orbignyi Lang : Lang, p. 266, pi. 5, fig. 10 ; text-fig. 79. HOLOTYPE. 0.28453. Small fragment of erect, bilaminar zoarium. Senonian, Coniacian. St. Avertin, south-east of Tours, Indre-et-Loire, France. F. Canu Collection. EMENDED DIAGNOSIS. Pelmatopora with unmodified oral spine-bases ; pelmatidia occasionally present ; frontal shield flat ; interzooecial secondary tissue abundant ; avicularia prominent, large, distally pointed and directed, paired at the proximal- lateral corners of the orifice. DESCRIPTION. Zoarium unilaminar and probably encrusting, or bilaminar and erect. Zooecia long, elliptical, somewhat pointed proximally. Orifice higher than wide, evenly rounded distally and laterally with a straight proximal margin, proximal- lateral constrictions variably developed. The outline of the margin of the orifice is somewhat obscured by secondary tissue and is indented laterally by a pair of large avicularia. Oral spine-bases probably 4, the distal pair are often visible though somewhat immersed in secondary tissue : the lateral pair, if present, are concealed by the large, lateral, oral avicularia or by secondary tissue. Frontal shield apparently flat, the outer ends of the costae descend sharply, but are largely obliterated by the CRETACEOUS CRIBRIMORPH POLYZOA (PELM ATOPORIN AE) 141 abundant interzooecial secondary tissue. Costae 14-20, each with a large pelma near the inner- end. Some costae may also possess a pelmatidium nearer to the mid-line of the zooecium. Lateral costal fusions are often present at the level of the pelmata, producing an irregularly developed row of intercostal spaces very close to the mid-line and a series of outer intercostal spaces which are slot-like. Median lO mm FIG. 62. Pelmatopora d'orbignyi Lang, D. 28443. Paratype of P. larva Lang. Adult zooecium with two worn lateral oral avicularia and adjacent broken zooecium with two well-preserved lateral oral avicularia. area of fusion very narrow and irregular. Apertural bar somewhat triangular, wide, but not very thick, with two prominent pelmata one on each side of and close to the mid-line ; a slight median ridge is present, but there is no median process. Gymno- cyst almost entirely concealed by plentiful interzooecial secondary tissue which contains irregular but sharply denned elongate lacunae through which the smooth gymnocyst may be locally exposed. Avicularia prominent, large, paired at the proximal-lateral corners of the orifice, almost as long as the orifice, raised, elongate, pointed, directed distally and obliquely i 4 2 CRETACEOUS CRI BRIMORPH POLYZOA (PELM ATOPORIN AE) inwards, divided by a transverse bar into a larger, rounded, proximal portion and a small, triangular rostrum. They are not deeply immersed in the interzooecial secondary tissue. Ovicells not seen. MEASUREMENTS. Zooecia Lz = 0-94 to 1-15 mm. Iz 0-46 to 0-50 mm. hr = 0-21 to 0-24 mm. lr = 0-15 to 0-18 mm. Avicularia Lz = 0-15 to 0-24 mm. Iz -- 0-12 mm. FIG. 63. Pelmatopora d'orbignyi Lang, 0.28453. Holotype. Adult zooecium and three avicularia surrounded by very abundant interzooecial secondary tissue. REMARKS. The holotype (0.28453) has been re-examined. 0.28443, a paratype of P. larva Lang, has been assigned to P. d'orbignyi also. Occasional pelmatidia are present on the costae in the median area of the frontal shield in 0.28443, and its dimensions and range in number of costae are similar to those of the holotype of P. d'orbignyi. 0.28443 also has two particularly well-preserved lateral oral avicu- CRETACEOUS CRIBRIMORPH POLYZOA (PELM ATOPORIN AE) 143 laria which are large, raised, and distally pointed and directed. Lang described the specimen as " much worn " ; however, it is not as worn as the holotype of P. d'orbignyi, in which the avicularia are considerably abraded but regularly paired close to the proximal-lateral corners of the orifice. The position of these avicularia was regarded by Lang as diagnostic for the species, and 0.28443 accordingly may be placed in P. d'orbignyi Lang. The holotype has a bilaminar zoarium, but the two laminae of zooecia are not aligned, as is usually the case with normally bilaminar forms, but cross obliquely. STRATI GRAPHICAL DISTRIBUTION. Senonian, Coniacian of France. SPECIMENS. 0.28453. Holotype see above. 0.28443. Paratype of P. larva Lang. Small fragment of unilaminar zoarium. Coniacian. La Ribochere, Loir-et-Cher, east of La Chartre-sur-le-Loir, Sarthe, France. F. Canu Collection. 10. Pelmatopora quadrata Lang (PI. 10, figs. 4, 5 ; Text-fig. 64) igi6a Pelmatopora quadrata Lang, pp. 102, 104. igi6fl Pelmatopora filliozati Lang, pp. 102, 105. 1919^ Pelmatopora quadrata Lang : Lang, pp. 197, 211, 222, text-fig. 40. 1919^ Pelmatopora filliozati Lang : Lang, pp. 197, 212, 222. 1921 Pelmatopora quadrata Lang : Lang, p. xciv. 1921 Pelmatopora filliozati Lang : Lang, p. xciv. 1922 Pelmatopora quadrata Lang : Lang, p. 270, text-fig. 8ia, b. 1922 Pelmatopora filliozati Lang : Lang, p. 272, text-fig. 8ic. HOLOTYPE. 0.28271. Well-preserved zoarial fragment with numerous ovicells. The fragment is now unattached. Senonian, zone of M. cor-anguinum, Trochiliopora Bed (about 20 ft. above base of zone). Cliffs, east side of Cuckmere Haven, Sussex. EMENDED DIAGNOSIS. Pelmatopora with unmodified oral spine-bases ; pelmatidia present ; costae 15-20 ; frontal shield well arched ; avicularia elongate, distally pointed and directed, tending to be paired. DESCRIPTION. Zoarium unilaminar, now unattached. Zooecia broadly oval, of variable length. Orifice wider than high, evenly rounded distally and laterally, with a straight proximal margin ; there are no proximal-lateral constrictions. Where an ovicell is present the orifice is transversely rectangular in outline. Oral spine-bases 4, often obscured by the accretion of secondary tissue near the orifice or by the development of ovicells. The oral spines do not indent the outline of the margin of the orifice. Frontal shield well arched, but slightly flattened on top in the median area. Costae 13-20 (often 15 or 20), each with a prominent pelma near the inner end at the edge of the median area of fusion and a pelmatidium almost at the extreme inner end. Lateral costal fusions occur at the level of the pelmata. Median area of fusion of variable width. Apertural bar not very wide, relatively flat, with a marked median furrow and carrying a pair of prominent pelmata, one on either side of the mid-line. Gymnocyst almost completely concealed by abundant interzooecial secondary tissue which lacks well-formed lacunae. 144 CRETACEOUS CRIBRIMORPH POLYZOA ( PELM ATOPORIN AE) Avicularia not very large, but prominent, distally pointed and directed ; a transverse bar divides a small, semicircular proximal portion from a long, narrow rostrum. There is a strong tendency for the avicularia to be paired, one near each proximal-lateral corner of the orifice ; occasional sporadic avicularia also occur. Ovicells apparently endozooecial, well immersed. Where ovicells are developed a distal oral shield is formed by the infilling of the space between the distal oral spines by a transverse shelf of calcareous tissue. This transverse shelf reduces the size of the orifice which becomes transversely oblong. The lateral pair of oral spines may O O'Smm. FIG. 64. Pelmatopora quadrata Lang, 0.28271. Holotype. Ovicelled adult zooecium with paired avicularia. The avicularium at the proximal end belongs to an adjacent zooecium. be displaced proximally, appearing at the distal-lateral corners of the ovicelled orifice and not, as is sometimes the case, obscured by the calcareous tissue. MEASUREMENTS. Zooecia Lz = 0-81 to 0-85 mm. Iz = 0-39 to 0-43 mm. hr = 0-12 mm. lr = 0-15 mm. Avicularia Lz =0-15 mm. Iz = 0-09 mm. REMARKS. The holotype of P. filliozati Lang is the specimen nearest to the label on a slide with three specimens from the F. Canu Collection labelled " Cribrilina [Semiescharipora] fragilis d'O." (see Lang, 1922 : 273). A photograph of this specimen is in the collections of the British Museum (Natural History). Careful comparison of this photograph with the holotype of P. quadrata Lang shows that the two species are synonymous ; in the photograph most zooecia possess 18-20 costae, and in the holotype of P. quadrata the range is apparently 13-16, most zooecia having 15 costae. This is the principal difference between the two. Ovicells CRETACEOUS CRIBRIMORPH POLYZOA (PELM ATOPORIN AE) 145 are developed in the Canu specimen producing the same oblong, modified orifice. The median area of fusion is similar and the avicularia apparently pointed and tending to be paired. It has not been possible to discover the evidence for the measurements which Lang gave for the Canu specimen. The photograph has no scale. STRATIGRAPHICAL DISTRIBUTION. Senonian, Emscherian in France ; zone of M . cor-anguinum, Trochiliopora Bed, in England. SPECIMENS. 0.28271. Holotype see above. 0.28272. Paratype. Fragment of a well-preserved, now unattached, zoarium. Horizon, locality and collection as for the holotype. Photograph of a specimen in the F. Canu Collection. The specimen is mounted nearest to the label on a slide containing three specimens labelled " Cribri- lina [Semiescharipora} fragilis d'O.". The specimen was chosen by Lang as the holotype of his species Pelmatopora filliozati. Senonian, Ems- cherian. Fecamp, north-east of Le Havre, Seine Inferieure, France. ii. Pelmatopora fecampensis Lang (PI. 10, fig. 6 ; Text-figs. 65-68) iQi6a Pelmatopora fecampensis Lang, pp. 102, 105. 1919^ Pelmatopora fecampensis Lang : Lang, pp. 211, 222, text-fig. 43. 1921 Pelmatopora fecampensis Lang : Lang, p. xcv. 1922 Pelamtopora fecampensis Lang : Lang, p. 286, pi. 6, fig. 3 ; text-fig. 88. 1958 Pelmatopora fecampensis Lang : Didon, pp. 82, 84, text-fig. 9. HOLOTYPE. 0.28473. Zoarial fragment, now unattached. Senonian, Coniacian. Fecamp, north-east of Le Harvre, Seine Inferieure, France. F. Canu Collection. EMENDED DIAGNOSIS. Pelmatopora with unmodified oral spine-bases ; orifice wider than high, larger than in P. gasteri ; costae 16-21 (often 18 or 19) ; pelmatidia present ; outermost intercostal spaces long and slit-like ; interzooecial secondary tissues abundant, lacking well-marked lacunae ; avicularia distally pointed and directed, generally two to each zooecium. DESCRIPTION. Zoarium unilaminar, probably encrusting but now unattached; Zooecia elliptical, the frontal shields fairly closely spaced. Orifice a little wider than high, of very constant size, lacking proximal-lateral constrictions, rounded distally and laterally with a straight proximal margin, its outline not obscured by secondary calcareous tissue. Oral spine-bases 4, small and unmodified. Frontal shield flatly arched, the median area of fusion depressed and narrow. Costae 16-21 (often 18 or 19), each with a prominent pelma about half-way along its length, coinciding with the edge of the median area. In addition, each costa usually carries a pelmatidium closer to the mid-line of the zooecium. Lateral costal fusions are developed at the level of the pelmata. Outermost intercostal spaces long and slit-like. Apertural bar fairly wide, with two large pelmata near the mid-line which is marked by a slight furrow. Gymnocyst concealed by abundant interzooecial secondary tissue which fills the interzooecial valleys and partly immerses some avicularia. There are usually no well-defined lacunae in the interzooecial tissue. GEOL. 6, I. 10 146 CRETACEOUS CRI BRIMORPH POLYZOA (PELM ATOPORIN AE) Avicularia small but prominent, distally pointed and directed, the apertures semi- circular proximally, narrowing distally into very elongate triangular rostra. Trans- verse bars are apparently absent. Very commonly, two variably placed avicularia are associated with each zooecium ; occasionally other sporadic avicularia of the same type occur. Ovicells apparently endozooecial, but globular and often promi- nent, tending to reduce the size of the orifice, either obliterating the oral spines or o O5mm. FIG. 65. Pelmatopora fecampensis Lang, D. 28473. Holotype. Adult zooecium and three avicularia. developing apparently within the orifice without displacing the oral spines (Text-figs. 66-68). MEASUREMENTS. Zooecia Lz = 0-75 to 0-90 mm. lz = 0-39 to 0-50 mm. hr = 0-15 mm. Ir = 0-18 mm. Avicularia Lz = 0-12 to 0-15 mm. lz = 0-06 mm. REMARKS. The holotype and five paratype zoarial fragments of P. fecampensis have been re-examined. The avicularia tend to occur regularly, two associated with each zooecium, but they are not constantly developed in the same position. The ovicells, though probably endozooecial, are very prominent and lack the thickened edge characteristic of the endozooecial ovicells of other species, such as P. somptingensis Lang and P. gregoryi (Brydone). CRETACEOUS CRIBRIMORPH POLYZOA (PELM ATOPORIN AE) 147 Paratype 0.28472 consists of only four zooecia of normal dimensions one of which is ovicelled. The ovicell is developed apparently within the orifice of the zooecium without displacing the oral spines (Text-fig. 68). Lacunae are quite well developed in the interzooecial secondary tissue of this specimen. O O5mm. I i 1 FIG. 66. Pelmatopora fecampensis Lang, D. 28475. Paratype. Distal end of ovicelled zooecium, three avicularia, and part of dntally adjacent zooecium, the ovicell has a proximally extended calcareous lamina which almost closes the orifice. Paratypes 0.28274 an d 0.28477 are fragments of zoaria which are now unattached. The former is well preserved with one zoarial lamina encrusting another ; 0.28477 is a very small fragment with well-preserved avicularia. 0.28476 is another para- type zoarial fragment with only one complete zooecium preserved and no unworn avicularia. O5mm. FIG. 67. Pelmatopora fecampensis Lang, 0.28475. Paratype. Distal end of ovicelled zooecium showing apparent displacement of the lateral oral spines by the ovicell. Paratype 0.28475 is a larger zoarial fragment with prominent oral spine bases and well-preserved avicularia. At least three of its zooecia have ovicells which are apparently endozooecial, but very prominent and globular. In one case the edge of the ovicell is apparently prolonged by a lamina which almost completely closes the orifice, and a thickened, transverse band of tissue runs across the ovicell, possibly 148 CRETACEOUS CRIBRIMORPH POLYZOA (PELM ATOPORIN AE) marking its normal limit. Several of the zooecia have developed thin calcareous laminae entirely sealing the orifices, and it is possible that the prolongation associated with the ovicell just mentioned is part of such a lamina. In this case the develop- ment of the ovicell has obliterated the oral spines, but in an adjacent zooecium two of the oral spines, probably the lateral pair, have been displaced by the develop- ment of the ovicell but still remain visible. FIG. 68. Pelmatopora fecampensis Lang, 0.28472. Paratype. Distal end of ovicelled zooecium with two avicularia, showing the apparent development of an ovicell inside the orifice, but not displacing the oral spines. STRATIGRAPHICAL DISTRIBUTION. Senonian, Coniacian of France. SPECIMENS. 0.28473. Holotype see above. 0.28472, 0.28474-77. Five paratypes. Zoarial fragments now unattached. Horizon, locality and collection as for the holotype. 12. Pelmatopora pero Lang (PL 10, fig. 7 ; Text-fig. 69) 19160 Pelmatopora pero Lang, pp. 102, 105. igigc Pelmatopora pero Lang : Lang, pv 107. ,.->-> 19190" Pelmatopora pero Lang : Lang, pp. 210, 213, 216, 218, 220, 222, text-fig. 52. 1921 Pelmatopora pero Lang : Lang, pp. Ixiii, xciii. " j 1922 Pelmatopora pero Lang: Lang, p. 296, pi. 6", "fig. 5; text-fig. 90 [partim 0.29861 excl. = P. brydonei], j-. *935 Pelmatopora pero Lang : Bassler, p. 165. T 953 Pelmatopora pero Lang : Bassler, p. 0192, text-fig. 144, 7. HOLOTYPE. 0.23405. Zoarial fragments, now unattached. Senonian, extreme top of zone of M. cor-anguinum. Medical College Pit, Epsom, Surrey. F. Mockler Collection. EMENDED DIAGNOSIS. Pelmatopora with unmodified oral spine-bases ; zooecial length about i-oo mm. ; costae 13-20 (often 16-18) ; two avicularia to each zooe- cium, usually not symmetrically paired, large, prominent, distally pointed and directed. CRETACEOUS CRIBRIMORPH POLYZOA (PELM ATOPORIN AE) 149 DESCRIPTION. Zoarium unilaminar, encrusting, but may now be unattached. Zooecia elongate, elliptical, tending to be somewhat pointed proximally. Orifice wider than high, rounded distally and laterally with a straight proximal margin, of very constant size, without proximal-lateral constrictions. Oral spine-bases 4, unmodified, sometimes slightly obscured by secondary tissue. Frontal shield flat. Costae 13-20 (often 16-18), fairly closely spaced but well defined, each with a prominent pelma about half-way along its length and a pelmatidium nearer to its O'Smm. FIG. 69. Pelmatopora pero Lang, D. 23411. Paratype. Adult zooecium with paired, damaged avicularia just proximal to the orifice and, at the proximal end, two un- damaged avicularia belonging to adjacent zooecia. inner end. Lateral costal fusions are developed at the levels of both the pelmata and pelmatidia, producing a paired row of intercostal spaces on either side of the median area. Occasionally a second paired row of irregularly developed intercostal spaces may be present close to the mid-line, when a second series of minute pelmatidia is also developed. The median area of fusion is thus of variable width but generally narrow. It is commonly level with, but may occasionally be depressed slightly below, the level of the rest of the frontal shield. Apertural bar not very wide, with a very slight median ridge and two indistinct pelmata, one on either side of the mid-line. Gymnocyst concealed by plentiful interzooecial secondary tissue which almost fills the interzooecial valleys and contains shallow, irregularly elongate depressions. i 5 o CRETACEOUS CRIBRIMORPH POLYZOA (PELM ATOPORI N AE) Avicularia prominent, large, elongate, distally pointed and directed, rounded proximally with a long, triangular rostrum. There are two avicularia to each zooecium, but they are not symmetrically paired. Ovicells not seen. MEASUREMENTS. Zooecia Lz = 0-81 to 1-12 mm. lz = 0-39 to 0-63 mm. hr = 0-15 to 0-18 mm. lr = 0-18 to 0-21 mm. Avicularia Lz = 0-15 to 0-24 mm. lz = 0-09 mm. REMARKS. The holotype, fifteen paratypes and two other specimens labelled by Lang Pelmatopora pero have been re-examined and retained in this species, but one, 0.29861, also labelled as that species, is referred to P. brydonei Lang. Where possible the zooecia of all specimens have been measured. Their dimensions vary considerably, but those of the orifice remain very constant. The avicularia, where unworn, are always elongate and sharply pointed distally. Well-preserved avicularia are present in several specimens, especially in the holotype, and in para- types 0.23404, 0.23408-09 and 0.23411. Paratype 0.23410 possesses lacunae which are more deeply developed than in the other specimens. 0.23414 and 0.23428 have two definitely paired rows of intercostal spaces in the median area ; the inner paired row is imperfectly developed in several zooecia of paratype 0.23415. The occurrence of a second paired row of intercostal spaces close to the mid-line is possibly the most variable feature of the species. All zoarial fragments are now unattached except 0.29908 which encrusts a fragment of echinoid test. No young zooecia have been seen. 0.29861 is here assigned to Pelmatopora brydonei Lang. It compares closely with the holotype of that species ; the distal oral spines of each zooecium are undoubtedly enlarged, the lateral oral spines are visible and unmodified, the length of the zooecia is over i-oo mm., the paired avicularia are small and oval, and there are 16-20 costae. STRATIGRAPHICAL DISTRIBUTION. Senonian, zone of M. cor-anguinum. SPECIMENS. 0.23405. Holotype see above. 0.23402-04, 0.23406-16, D 23428. Fifteen paratypes. Zoarial fragments, all now unattached. Horizon, locality and collection as for the holotype. 0.29858. Zoarial fragment, now unattached. Senonian, zone of M. cor- anguinum. Pit between Cliff End and Exceat Farm, near Seaford, Sussex. 0.29908. Large fragment of zoarium encrusting a piece of echinoid test. Senonian, zone of M. cor-anguinum. Meopham, south of Gravesend, Kent. G. E. Dibley Collection. 0.40744. Zoarial fragment encrusting a piece of echinoid test. Senonian, high in the zone of M. cor-anguinum. Pit 264 of Young, Coombs Pit, West Horsley, Surrey. 0.40745-46. Two unattached zoarial fragments. Senonian, zone of M. cor- anguinum. Locality and collection as for 0.29858. CRETACEOUS CRIBRIMORPH POLYZOA (PELM ATOPORIN AE) 151 13. Pelmatopora suffulta (Brydone) (PI. 10, figs. 8, 9 ; PI. n, fig. i ; Text-figs. 70, 71) Cribrilina insignis Canu, pp. 252, 280, 282, pi. 6, figs. 7-10. 1913 Cribrilina suffulta Brydone, p. 436, pi. 14 [partim fig. 4 only]. ?igi6a Pelmatopora insignis (Canu) Lang, pp. 102, 104. igi6a Pelmatopora suffulta (Brydone) Lang, pp. 102, 104. 1917 Cribrilina suffulta Brydone : Brydone, p. 495. 1917 Cribrilina repleta Brydone, p. 495 [partim -non pi. 32, fig. 9]. ?igigd Pelmatopora insignis (Canu) : Lang, pp. 211, 218, 222, 224, text-fig. 39. 1919^ Pelmatopora suffulta (Brydone) : Lang, pp. 198, 211, 218, 222, 226, text-fig. 45. 1921 Pelmatopora suffulta (Brydone) : Lang, pp. xciii, xciv. ?i92i Pelmatopora insignis (Canu) : Lang, p. xciv. 1921 Pelmatopora repleta (Brydone) Lang, p. xciv [MOW. nud.~\. 1922 Pelmatopora insignis (Canu) : Lang, p. 273, text-fig. 82. 1922 Pelmatopora suffulta (Brydone) : Lang, p. 277, text-fig. 83. 1922 Pelmatopora repleta (Brydone) Lang, p. 280. 1930 Pelmatopora repleta (Brydone) : Gaster, table opp. p. 340. LECTOTYPE. (Chosen by Lang, 1922 : 277.) The specimen figured by Brydone (1913, pi. 14, fig. 4). S.M., 6.36262. A large zoarial fragment encrusting a piece of echinoid test. Senonian, zone of M. cor-anguinum. Gravesend, Kent. R. M. Brydone Collection. EMENDED DIAGNOSIS. Pelmatopora with unmodified oral spine-bases ; costae 14- 22 ; pelmatidia usually present ; avicularia small, distally pointed and directed, often paired, one near each proximal-lateral corner of the orifice ; interzooecial secondary tissue very variably developed, the gymnocyst may be widely exposed or secondary tissue may almost fill the interzooecial valleys. DESCRIPTION. Zoarium unilaminar, encrusting. Adult zooecia usually elongate- oval, some with almost parallel sides ; occasionally very wide zooecia occur. Orifice rounded distally, often with straight sides, but occasionally somewhat rounded laterally, proximal margin straight, no proximal-lateral constrictions. The outline of the orifice is not obscured either by the oral spines or by secondary calcareous tissue. Oral spine-bases 4, possibly very occasionally 5, arranged symmetrically on the distal margin of the orifice. Frontal shield variably arched, either low, with a flat, fairly wide, depressed median area, or with fairly steeply sloping costae and a narrower median area ; occasionally the whole frontal shield may be flat. Costae 14-22, each with a prominent pelma about half-way along its length at the edge of the median area, and, nearer the mid-line, a pelmatidium. Lateral costal fusions always occur at the level of the pelmata producing a paired row of intercostal spaces ; occasionally, when distinct lateral costal fusions arise also at the level of the pelma- tidia, a second row of intercostal spaces may occur in the median area nearer to the mid-line. The median area of fusion is narrow and fusiform, or wider with an almost oval outline ; it is often depressed below the general surface level of the frontal shield. Apertural bar prominent, but not very wide, with two large pelmata, one immediately on either side of the mid-line ; there is often a very slight median ridge, but no median process. Gymnocyst very variably exposed, smooth. Interzooecial secondary tissue may be absent in a few cases, but is commonly abundant. Where 152 CRETACEOUS CRIBRIMORPH POLYZOA (PELM ATOPORIN AE) interzooecial secondary tissue is absent the gymnocyst is widely exposed laterally, and particularly proximally, to the frontal shield. Shallow lacunae may be devel- oped in the interzooecial tissue. Avicularia small, distally pointed and directed, often paired, one near each proximal-lateral corner of the orifice, but sporadic avicularia of the same type also occur frequently. The avicularian aperture is rounded proximally, where it is almost semicircular, and is constricted distally in the triangular rostrum. In many O O-Smm. FIG. 70. Pelmatopora suffulta (Brydone), 50466 (old collection number). Adult zooecium and three avicularia of specimen labelled by Lang " P. insignis (Canu)." specimens the avicularia are worn and apparently oval it is only when they have not been worn that they retain distally acute rostra. Ovicetts apparently endozooecial. When present they are marked by a straight, low distal oral shield which is produced by the infilling with secondary tissue of the space between the distal oral spines. The orifices of ovicelled zooecia thus have an oblong outline. Young zooecia (of S.M., 6.36263) are smaller than the adult zooecia of the same zoarium, but otherwise similar, except that there are fewer costae (10-12), a second series of lateral costal fusions is not present near the mid-line, and the avicularia are not paired. CRETACEOUS CRIBRIMORPH POLYZOA (PELM ATOPORIN AE) 153 MEASUREMENTS. Adult zooecia Lz == 0-77 to 1-12 mm. Iz = 0-43 to 0-65 mm. hr = 0-14 to 0-19 mm. Ir = 0-18 to 0-22 mm. Young zooecia (measurements based on the young zooecia of S.M., 6.36263 only) : Lz = 0-53 to 0-62 mm. Iz = 0-30 to 0-35 mm. hr = 0-12 to 0-14 mm. Ir 0-12 to 0-14 mm. Avicularia among adult zooecia : Lz = 0-09 to 0-12 mm. Iz = 0-06 mm. REMARKS. Pelmatopora suffulta (Brydone) and P. repleta (Brydone) are synony- mous. P. insignis (Canu) has been doubtfully included in the synonymy and is discussed more fully below. The specimens, S.M., 6.36262-63, which Brydone (1913 : 436, pi. 14, figs. 4, 5) figured as Cribrilina suffulta, have been re-examined. The latter specimen, shown in his fig. 5, was later separated by Brydone (1917 : 495) as Cribrilina repleta. Lang (19160; : 102, 104) placed both specimens in Pelmatopora suffulta (Brydone). Subse- quently he followed Brydone's separation of the specimens (Lang, 1922 : 280) making S.M., 6.36263 the lectotype of P. repleta (Brydone). The dimensions and other characters of S.M., 6.36262 and S.M., 6.36263 are compared below. Adult zooecia A vicularia . Number of costae Oral spine-bases Other characters S.M., 6.36262 Lectotype of Pelmatopora suffulta (Brydone) Lz = o 95 to i 10 mm. Iz = 0-43 to 0-65 mm. hr = 0-14 to 0-19 mm. Ir = 0-18 to 0-22 mm. Lz = Not measurable Iz = Not measurable 14-20 4 Gymnocyst generally widely exposed ; interzooecial secondary tissue absent ; one (occasionally two) la- teral costal fusions on each costa ; avicularia usually paired, all worn S.M., 6.36263 Lectotype of Pelmatopora repleta (Brydone) Lz = 0-77 to 0-90 mm. Iz = 0-43 to 0-53 mm. hr = 0-17 to 0-18 mm. Ir = o'i8 to 0-20 mm. Lz = o' 12 mm. Iz = o - o6 mm. 14-16. 4- Gymnocyst usually concealed ; interzooecial secondary tis- sue plentiful ; two (occasion- ally only one) lateral costal fusions on each costa ; avi- cularia usually paired, dist- ally pointed and directed. Although the gymnocyst is frequently well exposed in the lectotype of P. suffulta there are also numerous zooecia in which it is concealed or only slightly exposed. Conversely, some zooecia in the lectotype of P. repleta have exposed gymnocysts. Apart from differences in the amounts of interzooecial secondary tissue which may 154 CRETACEOUS CRIBRIMORPH POLYZOA (PELM ATOPORI N AE) be developed the two species are clearly similar. Brydone (1917 : 495) said of his species Cribrilina suffulta and C. repleta, " The relationship between the two is, however, so very close that each is liable to display here and there a considerable measure of the distinguishing character of the other ". This statement is confirmed by an examination of the specimens which Lang assigned to Pelmatopora suffulta and to P. repleta. One encrusting zoarial fragment, 0.29907, is labelled as an ideotype of P. suffulta (Brydone). As in the lectotype, each of its zooecia possesses only four oral spine- bases, not " five in number normally " as suggested by Brydone (1913 : 436). Its avicularia are all worn, but Brydone, basing his opinion on the well-preserved lectotype, rightly stated that the avicularia of suffulta correspond " very closely in shape, size and disposition with those of Cribrilina [= Pelmatopora] gregoryi." Some zooecia of 0.29907 are ovicelled ; the range in number of costae is 16-18, and the dimensions of the adult zooecia are as follows : Lz = 0-87 to 0-95 mm. Iz = 0-45 to 0-50 mm. hr 0-15 to 0-18 mm. Ir = 0-18 to 0-21 mm. There are slight amounts of interzooecial secondary tissue. 50466 [Old Collection number], which Lang (1922 : 274) placed in Pelmatopora insignis (Canu), is regarded as P. suffulta (Brydone), its measurements are : Lz = i-oo to 1-12 mm. Iz = 0-45 to 0-59 mm. hr 0-15 mm. Ir = 0-18 to 0-21 mm. The avicularia of 50466 are 0-09 mm. long and 0-06 mm. wide. The main difference from 0.29907 is the absence of interzooecial secondary tissue, while the avicularia are more regularly paired. Ovicelled zooecia occur occasionally ; the zoarium is encrusting. The frontal shields of the zooecia are less closely spaced and the gymnocyst generally more widely exposed than in 0.29907. Unfortunately the horizon and locality of the specimen are unknown. 0.29857 and 0.28275-77, labelled by Lang " P. repleta (Brydone) ", are also here referred to P. suffulta. The first is a fragmentary encrusting zoarium with a poorly preserved ancestrula and younger zooecia only. Interzooecial secondary tissue is fairly abundant, and each zooecium has about 17 costae and paired avicularia. Describing the avicularia of P. repleta, Lang (1922 : 280) referred to them as " spor- adically distributed ". They show, however, a strong tendency to be paired, one just proximal to each proximal-lateral corner of the orifice. 0.28275-77 are not well preserved, but each zooecium has apparently 16 or 17 costae. Lang (1922 : 281) also recorded as P. repleta one other specimen, 0.28290, which has 22 costae in some zooecia and a flat frontal shield. The amount of interzooecial secondary tissue which may be present in a given zoarium is not a useful diagnostic character. The specimens in the British Museum (Natural History), previously recorded by Lang as P. suffulta or as P. repleta, show CRETACEOUS CRIBRIMORPH POLYZOA (PELM ATOPORIN AE) 155 particularly the variable amounts of tissue which may occur, both in different parts of the same zoarium and in separate zoaria of otherwise similar specimens. In their development of interzooecial secondary tissue the lectotypes of P. suffulta (S.M., 6.36262) and P. repleta (S.M., 6.36263) lie near the extremes of a wide varia- tion which encompasses 50466, 0.29907, 0.29857, 0.28275-77 and 0.28290 the other characters of all these specimens being similar, or, as with the range in number of costae which may be present, having a wide variation. Cribrilina insignis Canu has been doubtfully included in the synonymy of P. suffulta, though it is certainly a Pelmatopora. The specimen is of Rocanean age, I'Omm. FIG. 71. Pelmatopora suffulta (Brydone), D. 29907. Labelled bv Lang " Idiotype ". Parts of five adult zooecia with five worn avicularia : showing the slight amount of interzooecial secondary tissue developed. from the type locality of Roca, Argentine. Canu (1911 : 252, pi. 6, figs. 7-10) referred to the zooecia as distinct, separated by deep furrows, large, though the dimensions given are very variable one of the figured zooecia is 0-50 mm. wide. The range in number of costae is apparently 16-20, and the median area [= "plastron" of Canu] is fusiform and " irregularly perforate ". Canu noted, however, that the " perforations " in the median area are aligned with the " prolongation of the intercostal spaces ". There are, in fact, two paired rows of intercostal spaces with others occurring occasionally nearer to the mid-line. It is not possible to discern pelmatidia in Canu's figures they are certainly present in 50466, which Lang assigned to Canu's species, and which is here referred to P. suffulta. The avicularia of Cribrilina insignis were described by Canu as oval, not constantly placed, and with small, elliptical somewhat elongate apertures. Although very similar to P. suffulta, P. insignis (Canu) has narrower zooecia and smaller orifices than those of the former species. 156 CRETACEOUS CRIBRIMORPH POLYZOA (PELM ATOPORIN AE) It is unfortunate that the horizon of Cribrilina insignis Canu is of uncertain age (see p. 19). Feruglio (1949) gave a very full discussion of the conflicting views on the age of the type series of the Rocanean. It has been placed as low as the Cenomanian and as high as the Eocene. The presence of a species of Pelmatopora, apparently of the less complex type, possibly suggests a horizon in the Lower Senonian for part, at least, of the type section. However, it is unwise to attempt too firm a comparison of material from such widely separated provinces. STRATIGRAPHICAL DISTRIBUTION. Senonian, zone of M. cor-anguinum in England ; Rocanean in Argentina. SPECIMENS. 50466. Old Collections number. A well-preserved zoarial fragment encrusting a piece of echinoid test. Labelled by Lang " Pelmatopora insignis (Canu) ". Horizon and locality unknown, possibly Senonian of southern England. Prof. Morris Collection. 0.29907. Zoarial fragment with many broken zooecia encrusting a piece of echinoid test. Labelled by Lang " Ideotype ". Senonian, zone of M. cor-anguinum. Grays, Essex. G. E. Dibley Collection. 0.29857. Zoarial fragment with poorly preserved ancestrula and young zooecia only, encrusting a shell fragment. Recorded by Lang as P. repleta (Brydone). Senonian, zone of M. cor-anguinum. Pit in Houndean Bottom, west of Lewes, Sussex. 0.28275-77, 0.28290. Four zoarial fragments now unattached. Recorded by Lang as P. repleta (Brydone). Senonian, zone of M. cor-anguinum, Trochiliopora Bed, about 20 ft. above base of zone. Cliff End, east side of Cuckmere Haven, Sussex. 0.40736. Zoarial fragment encrusting a piece of Inoceramus hinge. Senonian, zone of M. cor-anguinum (less than 10 ft. below the " strong cor- anguinum tabular flint band"). Cliffs, first of Seven Sisters, Cuckmere end, east of Seaford, Sussex. 0.40737-38. Two unattached zoarial fragments. Senonian, zone of M. cor- anguinum. Pit between Cliff End and Exceat Farm, east of Seaford, Sussex. 0.40739-41. Three unattached zoarial fragments. Senonian, zone of M. cor- anguinum, Trochiliopora Bed. Cliffs, Beltout, west of Eastbourne, Sussex. 0.40742. Unattached zoarial fragment. Senonian, zone of M. cor-anguinum, Trochiliopora Bed. Summit of Downs, Mount Harry, near Lewes, Sussex. OTHER MATERIAL. S.M., 6.36262. Lectotype see above. S.M., 6.36263. Large, well-preserved zoarial fragment with young and adult zooecia, some with ovicells, encrusting a piece of echinoid test. Figured by Brydone (1913, pi. 14, fig. 5) as Cribrilina repleta, chosen by Lang (1922 : 280) as lectotype of Pelmatopora repleta (Brydone). Senonian, zone of M. cor-anguinum. Gravesend, Kent. R. M. Brydone Collection. CRETACEOUS CRIBRIMORPH POLYZOA (PELM ATOPORIN AE) 157 14. Pelmatopora simplex Lang (PI. n, figs. 2, 3 ; Text-figs. 72, 73) jgi6a Pelmatopora simplex Lang, pp. 102, 105. 1919^ Pelmatopora simplex Lang : Lang, pp. 210, 218, 221, 224, 226, text-fig. 46. 1921 Pelmatopora simplex Lang : Lang, p. xcii. 1922 Pelmatopora simplex Lang : Lang, p. 282, pi. 6, fig. i ; text-fig. 86. 1924 Pelmatopora simplex Lang : Gaster, second of three tables opp. p. no. 1930 Pelmatopora simplex Lang : Gaster, table opp. p. 340. HOLOTYPE. 0.28281. Well-preserved zoarium, with ancestrula, encrusting a piece of echinoid test. Senonian, zone of G. [A.] quadrata. Cliffs, east side of Old Nore Point, west of Newhaven, Sussex. EMENDED DIAGNOSIS. Pelmatopora with unmodified oral spine-bases ; Lz less than i -oo mm. ; costae 16-18 ; a second series of pelmatidia may be developed close to the mid-line ; interzooecial secondary tissue conspicuous, with large, well-defined lacunae ; avicularia paired, one at each proximal-lateral corner of the orifice. DESCRIPTION. Zoarium encrusting, unilaminar. Adult zooecia oval. Orifice rounded distally and laterally with a straight proximal margin, without proximal- lateral constrictions ; its outline may be obscured by a high ring of secondary tissue developed particularly on the distal margin. Oral spine-bases 4, tending to be obscured by the ring of secondary tissue, the more distal pair slightly enlarged, otherwise unmodified and not completely immersed. Frontal shield flat. Costae 16-18, well defined, narrow, each with a pelma about half-way along its length, and, nearer to the mid-line, at least one, and often two, pelmatidia. Lateral costal fusions occur at the levels of the pelmata and pelmatidia, producing two paired rows of intercostal spaces. Apertural bar fairly wide, flat, or sloping down towards the proximal edge of the orifice, with two poorly developed pelmata (one near each end), and a very slight median ridge. Gymnocyst frequently exposed through the very conspicuous, deep, well-defined, large and irregular lacunae in the interzooecial secondary tissue. The latter is abundant, and in some cases more than fills the interzooecial valleys, overflowing on to the frontal shields. Avicularia paired, one near each proximal-lateral corner of the orifice, small, rounded or somewhat elongate, probably distally directed, and usually deeply immersed in the interzooecial secondary tissue. Ovicells not seen. Young zooecia much smaller than the adult zooecia, with smaller, but well-defined, orifices, the margins of which are not obscured by secondary tissue. Oral spine- bases four, small and unmodified. Frontal shield slightly more arched than in the adult zooecia. Costae n, well defined, narrow, each with a pelma about half-way along its length and a pelmatidium nearer to the mid-line. Lateral costal fusions occur at the level of the pelmata only. Apertural bar very well defined, with a marked pelma near each end. The gymnocyst is exposed through large, irregular lacunae which occur frequently in the plentiful interzooecial secondary tissue. The latter tends to fill the interzooecial valleys and to encroach on to the frontal shields. Avicularia are generally paired, small, round or slightly elongate, and are probably distally directed. 158 CRETACEOUS CRIBRIMORPH POLYZOA (PE LM ATOPORI N AE) 0-5 Omm. FIGS. 72,73. Pelmatopora simplex Lang, D. 28281. Holotype. (72) Adult zooecium and three avicularia, showing very deep, large lacunae in the interzooecial secondary tissue. (73) Young zooecium and avicularium. An expansion of secondary tissue partly obscures the frontal shield. MEASUREMENTS. Adult zooecia Lz = 0-69 to 0-84 mm. lz = 0-39 to 0-45 mm. hr = 0-15 to 0-18 mm. Ir = 0-18 mm. Young zooecia Lz = 0-50 mm. lz = 0-24 to 0-27 mm. hr = 0-12 mm. Ir = 0-12 to 0-15 mm. REMARKS. The holotype and 0.29859-60 have been re-examined. The measure- ments given by Lang (1922 : 282) for adult zooecia of P. simplex were slightly over- estimated. 0.29859 is an encrusting, unilaminar zoarium with a poorly preserved ancestrula. 0.29860 is another fragment of a unilaminar encrusting zoarium, probably a young stage. Most zooecia of this specimen are small and have rather CRETACEOUS CRIBRIMORPH POLYZOA (PELM ATOPORI N AE) 159 more interzooecial secondary tissue than is present in the ancestrular area of the holotype. STRATIGRAPHICAL DISTRIBUTION. Senonian, zone of G. [A.] quadrata and zone of 0. pilula, subzone of E. scutata var. depressula and subzone of E. scutata var. cincta. SPECIMENS. 0.28281. Holotype see above. 0.29860. Zoarial fragment with poorly preserved ancestrula, encrusting a piece of echinoid test. Senonian, zone of 0. pilula, upper part of subzone of E. scutata var. depressula. Pit 4 of Gaster, west of Boundstone Lane, south of Lancing Ring, north-east of Worthing, Sussex. 0.29859. Zoarial fragment with young zooecia, encrusting a piece of echinoid test. Senonian, zone of 0. pilula, subzone of E. scutata var. cincta. Pit on East Hill, Rottingdean, east of Brighton, Sussex. 0.40743. cf. simplex. Zoarial fragment encrusting a piece of echinoid test. Senonian, zone of 0. pilula, subzone of E. scutata var. cincta. Pit 87 of Gaster, near track to Newlands Barn, north end of East Hill, Rottingdean, east of Brighton, Sussex. 0.40945. Small, well-preserved zoarial fragment with young zooecia, encrusting a piece of echinoid test. Senonian, zone of 0. pilula, subzone of E. scutata var. depressula. Pit i of Gaster, pit near Bridle Road, south of Lancing College and College (or Bunwell's) Farm, west of Pad Farm, Lancing, Sussex. 15. Pelmatopora plantaris Lang (PL n, fig. 4 ; Text-fig. 74) igi6a Pelmatopora plantaris Lang, pp. 102, 105. Pelmatopora plantaris Lang : Lang, pp. 199, 210, 213, 216, 218, 222, 224, text-figs. 6-8, 1921 Pelmatopora plantaris Lang : Lang, p. xciv. 1922 Pelmatopora plantaris Lang : Lang, p. 288, pi. 6, fig. 4 ; text-fig. 89. HOLOTYPE. 0.19620. Zoarial fragment, with young zooecia, encrusting a piece of echinoid test. Senonian, zone of M. cor-anguinum. Wivelrod, west of Alton, Hampshire. H. O. White Collection. EMENDED DIAGNOSIS. Pelmatopora with unmodified oral spine-bases ; Lz less than i-oo mm. ; costae 13-16, slightly thicker than in P. simplex ; a second series of pelmatidia may be developed near the mid-line ; interzooecial secondary tissue conspicuous with large well-defined lacunae ; two avicularia to each zooecium but not usually symmetrically paired. DESCRIPTION. Zoarium unilaminar, probably encrusting but now unattached. Adult zooecia broadly oval. Orifice rounded distally and laterally, with a straight proximal margin, without proximal-lateral constrictions ; its outline may be obscured by secondary tissue. Oral spine-bases 4, unmodified, the distal pair seldom show the slight thickening which is more characteristic of the distal oral spines of P. simplex. Frontal shield flat. Costae 13-16 (often 14), well-defined, slightly wider than the costae of P. simplex. Each costa bears a pelma about half-way along its length, and, nearer the inner end, one (occasionally two) pelmatidia very close to the 160 CRETACEOUS CRIBRIMORPH POLYZOA ( PELM ATOPORIN AE) mid-line. Lateral costal fusions occur at the levels of the pelmata and the outermost pelmatidia producing two paired rows of intercostal spaces. Apertural bar not quite so wide as in P. simplex, with two prominent pelmata and a very slight median furrow. Gymnocyst extensively exposed through very conspicuous, deep, large, well-defined, irregular lacunae in the abundant interzooecial secondary tissue, which occasionally encroaches slightly on to the edges of the frontal shields of some zooecia. Avicularia, two to each zooecium, but not symmetrically paired as in P. simplex, small, rounded (probably by wear), or slightly elongate and probably distally directed ; not deeply immersed in the interzooecial secondary tissue. Ovicells not seen. O'Smm. FIG. 74. Pelmatopora plantaris Lang, D. 19620. Holotype. Adult zooecium and paired avicularia. The proximal pair belong to adjacent zooecia. Young zooecia are smaller than the adult zooecia and have more arched frontal shields with fewer (n) costae and less interzooecial secondary tissue ; the gymnocyst is more exposed. Avicularia occur singly in the young stages, or there are two associated with each zooecium, although they are not symmetrically paired. MEASUREMENTS. Adult zooecia Lz = 0-78 to 0-87 mm. Iz = 0-42 to 0-50 mm. hr = 0-15 mm. Ir = 0-18 mm. Young zooecia Lz = 0-50 mm. Iz = 0-31 mm. hr = 0-12 mm. Ir = 0-12 mm. Avicularia Not measurable. CRETACEOUS CRIBRIMORPH POLYZOA (PELM ATOPORIN AE) 161 REMARKS. In the description emphasis has been laid on the differences between P. simplex and P. plantaris. At most these differences are relatively slight, but there is also a difference in the stratigraphical occurrence of the two species. All the material assigned to P. simplex is from the zones of G. [A.] quadrata and 0. pilula, whereas the material referred to P. plantaris is of M. cor-anguinum age. Until more material is available from the intervening horizons it seems advisable to retain the two species as separate, basing the division principally on (i) the lack of symmetrically paired avicularia in P. plantaris compared with the common occur- rence of evenly placed pairs in P. simplex, and (ii) on the smaller number of slightly wider costae in the former compared with the higher number of narrower costae in the latter. 0.28291, an encrusting zoarium, was labelled by Lang " Pelmatopora ^plantaris ", but it has 15-17 costae and its avicularia tend to be symmetrically paired. STRATIGRAPHICAL DISTRIBUTION. Senonian, zone of M. cor-anguinum. SPECIMENS. 0.19620. Holotype see above. 0.28288-89. Two paratypes, zoarial fragments, now unattached. Senonian, zone of M. cor-anguinum, Trochiliopora Bed, about 20 ft. above base of zone. Cliffs, east side of Cuckmere Haven, Sussex. ?D. 28291. Zoarial fragment encrusting a piece of echinoid test. Labelled by Lang " Pelmatopora ? plantaris ". Senonian, zone of M. cor-anguinum. Cliffs, westernmost of Seven Sisters, east of Cuckmere Haven, Sussex. 0.40747. Incomplete zoarium encrusting a fragment of Inoceramus shell. Senonian, zone of M. cor-anguinum, 4 ft. below the " strong cor- anguinum tabular flint band ". Cliffs, Beltout, west of Eastbourne, Sussex. 16. Pelmatopora quadrivolucris Lang (PI. n, figs. 5, 6 ; PI. 12, fig. i ; Text-fig. 75) 1913 Cribrilina gregoryi Brydone : Brydone, p. 436 [partim pi. 14, fig. 3 only]. 1913 Cribrilina suffulta Brydone, p. 436 [partim pi. 14, fig. 5 only]. igi6a Pelmatopora quadrivolucris Lang, pp. 102, 105. 1917 Cribrilina galanthis Brydone, p. 495. 1917 Cribrilina repleta Brydone : Brydone, p. 495 [partim pi. 32, fig. 9 only]. igigd Pelmatopora quadrivolucris Lang : Lang, pp. 200, 213, 216, 222. 1921 Pelmatopora quadrivolucris Lang : Lang, p. xciii. 1922 Pelmatopora quadrivolucris Lang : Lang, p. 295, text-fig. 92. HOLOTYPE. 0.28907. Zoarial fragment encrusting a piece of echinoid test. Senonian, zone of M. cor-anguinum. Coombs Pit (Pit 264 of Young), West Horsley, north-east of Guildford, Surrey. EMENDED DIAGNOSIS. Pelmatopora with two pairs of exposed enlarged oral spines. DESCRIPTION. Zoarium unilaminar, encrusting, although it may now be un- attached. Zooecia long, elliptical or almost parallel-sided. Orifice rounded distally and laterally with a straight proximal margin ; its outline is often indented by the two pairs of enlarged oral spines, and its size may be reduced by the accumulation of secondary tissue round its margin. Oral spines 4, symmetrically arranged in two GEOL. 6, I. II 162 CRETACEOUS CRIBRIMORPH POLYZOA (PELM ATOPORIN AE) pairs, all enlarged, and somewhat greater in size than the peg-like distal oral spines of P. brydonei. Frontal shield flat, of variable length, often just over twice as long as wide. Costae 14-19, well defined, each with a pelma about half-way along its length and a pdmatidium nearer the mid-line ; very occasionally a second pelma- tidium may occur very close to the mid-line. Lateral costal fusions arise at the level of the pelmata, and less frequently at the level of the pelmatidia. Apertural bar wide, flat, with two well-defined pelmata. Gymnocyst concealed by plentiful interzooecial O5 mm. FIG. 75. Pelmatopora quadrivolucris Lang, 0.28907, Holotype. Adult zooecium with paired, worn avicularia and four enlarged oral spine-bases. secondary tissue which fills the interzooecial valleys. Slight depressions are present in the surface of the interzooecial tissue. Avicularia distinct, distally pointed and directed, usually paired, one near each proximal-lateral corner of the orifice, occasionally single. The avicularian aperture is constricted distally in the triangular rostrum and is wider, almost semicircular, proximally. Ovicells not seen. MEASUREMENTS. Zooecia Lz = i-oo to 1-25 mm. Iz = 0-35 to 0-60 mm. hr = 0-15 to 0-21 mm. lr = 0-21 to 0-27 mm. Avicularia Lz = 0-12 to 0-15 mm. Iz = 0-07 to 0-09 mm. CRETACEOUS CRIBRIMORPH POLYZOA (PELM ATOPORIN AE) 163 REMARKS. 0.28907, the holotype, has been re-examined. Five specimens from the R. M. Brydone Collection in the Sedgwick Museum, Cambridge, have also been assigned to the species ; these are S.M., 13.36261, S.M., 13.36363, S.M., 6.71538-39 and S.M., 6.75867. The first of these is a well-preserved encrusting zoarium. Part of it was figured by Brydone (1913, pi. 14, fig. 3) originally as Cribrilina gregoryi, and later (1917 : 495) distinguished by him as Cribrilina galanthis. There is no doubt that it is a specimen of Pelmatopora quadrivolucris. Lang (1922 : 293) provisionally included the specimen in his synonymy of P, brydonei, presumably basing his opinion on Brydone's figure only. Each zooecium in S.M., 6.36261 has four definitely enlarged oral spines, the range in number of costae is 14-16, there is less interzooecial secondary tissue than in the holotype of P. quadrivolucris, and the avicularia are more markedly paired, although single avicularia are also frequent. No ovicells or young zooecia are preserved. Part of the zoarial fragment is shown here (PL n, fig. 5). Brydone (1913 : 436, pi. 14, figs. 4, 5) originally designated Cribrilina suffulta [=Pelmatopora suffulta] to include his " coarse form " shown in fig. 5. Later (1917 : 495), Brydone separated this coarse form as Cribrilina repleta and figured part of another specimen which he also assigned to the latter species. Of this specimen, S.M., 6.36363, he stated (1917 : 495, pi. 32, fig. 9) " I have figured an exceptionally well-preserved specimen which shows that the tubercles on the anterior lip [oral spines] are typically four in number, long and tapering, but very brittle ". I have re-examined this specimen, each zooecium of which has four enlarged oral spines, and confirm Lang's opinion (1922 : 295 in synon.) that it belongs to Pelmatopora quad- rivolucris. The measurements and other details of the specimen are as follows : Zooecia Lz = i-n to 1-25 mm. lz = 0-50 to 0-60 mm. hr = 0-20 to o-2i mm. Ir = 0-26 to 0-27 mm. Range in number of costae = 16-19. Number of lateral costal fusions on each costa = i (occasionally 2). Avicularia Lz = 0-15 to 0-16 mm. lz = 0-07 to 0-09 mm. It is noticeable that the dimensions of S.M., 6.36363 are generally greater than those of the holotype of P. quadrivolucris, suggesting that the latter may be a slightly younger stage of zoarial growth. The avicularia of S.M., 6.36363, which are well preserved, are distally pointed and directed, unlike the apparently oval avicularia of the holotype which is somewhat worn. Part of S.M., 6.36363 is shown in PL 12, fig. i. STRATIGRAPHICAL DISTRIBUTION. Senonian, zone of M . cor-anguinum. SPECIMEN. 0.28907. Holotype see above. OTHER MATERIAL. S.M., 6.36261. Holotype (by monotypy) of Cribrilina galan- this 6rydone. A well-preserved zoarial fragment encrusting a piece of echinoid test. Senonian, zone of M. cor-anguinum. Locality 199 of 6rydone, siding east of junction, railway cutting, 6asingstoke, Hampshire. R. M. 6rydone Collection. 164 CRETACEOUS CRIBRIMORPH POLYZOA (PELM ATOPORIN AE) S.M., 6.36363. Zoarial fragment, now unattached, but partly embedded in a small block of chalk. The specimen figured by Brydone (1917, pi. 32, fig. 9) as Cribrilina repleta. Senonian, zone of M. cor-anguinum. Locality 559 of Brydone, excavations for tank at fold yard, one quarter mile west of Lower Grenville Copse, Soberton, Hampshire. R. M. Brydone Collection. S.M., 6.71538. Zoarial fragment, now unattached, but partly embedded in a small block of chalk. Senonian, zone of M. cor-anguinum. Locality 502 of Brydone, pit in lane one quarter mile south-east of Grasmere Cottage, Easton, Hampshire. R. M. Brydone Collection. S.M., 6.71539. Zoarial fragment, now unattached, but partly embedded in a small block of chalk. Horizon, locality and collection as for S.M., 6.36363. S.M., 6.75867. Zoarial fragment encrusting four pieces of echinoid test. Senonian, zone of M. cor-anguinum. Locality 328 of 6rydone, Hurstbourne Priors (6eehouse Pit), Hampshire. R. M. 6rydone Collection. 17. Pelmatopora brydonei Lang (PI. 12, fig. 3 ; Text-figs. 76-78) 1906 non Cribrilina gregoryi Brydone, pp. 290, 300, text-fig. 13. 1913 non Cribrilina gregoryi Brydone : Brydone, p. 436, pi. 14, figs. 1-3. igi6a Pelmatopora brydonei Lang, pp. 103, 105. 1917 non Cribrilina galanthis Brydone, p. 495. 1919^ Pelmatopora brydonei Lang: Lang, pp. 199, 210, 213, 220, 222, 225, text-figs. 9-11, 53. 54- 1921 Pelmatopora brydonei Lang : Lang, p. xciii. 1922 Pelmatopora brydonei Lang : Lang, p. 293, text-fig. 91. 1922 Pelmatopora pero Lang : Lang, p. 290, pi. 6, fig. 5, text-fig. 90 [partim 0.29861 only]. ?i958 Pelmatopora cf. brydoneis [sic] Lang : Didon, pp. 83, 85, text-fig. 10. HOLOTYPE. 0.23396. Small zoarial fragment, now unattached. Senonian, top of zone of M . cor-anguinum. Epsom, Surrey. F. Mockler Collection. EMENDED DIAGNOSIS. Pelmatopora with a pair of enlarged distal oral spines, the unmodified pair of lateral oral spines not entirely concealed by secondary thickening on the margin of the orifice. DESCRIPTION. Zoarium unilaminar, encrusting, but may now be unattached. Zooecia elongate, elliptical, tending to be parallel-sided and somewhat pointed proximally. Orifice wider than high, rounded distally and laterally, with a straight proximal margin ; the outline of the orifice often indented by the enlarged distal oral spines. Two pairs of oral spines visible the distal pair are enlarged and peg- like and point proximally, the lateral pair are unmodified and almost obscured by the development of secondary tissue. Frontal shield variable in length, usually narrow, flat. Costae 15-19, well defined, each with a pelma about half-way along its length, a pelmatidium near its inner end, and, occasionally, a second very small CRETACEOUS CRIBRIMORPH POLYZOA (PELM ATOPORIN AE) 165 pelmatidium very close to the mid-line. Lateral costal fusions occur at the levels of the pelmata and the outermost pelmatidia, producing a paired row of irregular intercostal spaces and a variably developed second paired row closer to the mid-line Median area of fusion narrow. Apertural bar wide and flat, with obscure pelmata. FIGS. 76, 77. Pelmatopora brydonei Lang, 0.23396. Holotype. (76) Very long adult zooecium with normal, enlarged distal oral spines, unmodified lateral oral spine-bases and paired avicularia near the proximal-lateral corners of the orifice. The two more heavily calcified and worn avicularia, near the proximal end of the zooecium, belong to adjacent zooecia. (77) Dorsal surface of adult zooecium with irregularly spaced solid bosses. Gymnocyst concealed by plentiful interzooecial secondary tissue which fills the inter- zooecial valleys and which contains slight lacunae. Avicularia distinct, large, distally directed, oval, about two- thirds as wide as long ; there is a strong tendency for them to occur near the proximal-lateral corners of the orifice, either singly or paired. Usually two avicularia are associated with each zooecium. Ovicells not seen. 166 CRETACEOUS CRIBRIMORPH POLYZOA (PELM ATOPORIN AE) MEASUREMENTS. Zooecia Lz = i-oo to 1-45 mm. lz = 0-39 to 0-56 mm. hr = 0-18 mm. Ir = 0-21 mm. Avicularia Lz = 0-09 mm. lz = 0-06 mm. REMARKS. The holotype, eight paratypes, and one other specimen, all labelled by Lang " P. brydonei ", have been re-examined. st FIG. 78. Pelmatopora brydonei Lang, D. 23397. Paratype. (a) Side view of part of a damaged orifice, (b) Front view of same orifice, m, hard matrix ; o.s, apparently unmodified " primary " oral spine ; r.p, rim of primary orifice ; r.s, rim of secondary orifice ; s.t, secondary tissue of enlarged oral spine. The dorsal surface of the zoarial lamina of the holotype is covered by small, apparently solid, conical bosses which are irregularly distributed and by which the zoarium may have been attached (Text-fig. 77). The form of these dorsal bosses contrasts with the hollow dorsal " spines " developed in P. gregoryi, and particularly with those illustrated (Text-figs. 91, 92). It was stated by Lang (1922 : 294], with reference particularly to 0.23397, that " both the right distal apertural [oral] spine and the right secondary aviculoecium CRETACEOUS CRIBRIMORPH POLYZOA (PELM ATOPORIN AE) 167 are present, the latter lying outside the former. But the primary apertural rim in this specimen is so distinct as to suggest that the whole aperture has been renewed. If this has happened, this specimen cannot be used to demonstrate that the secondary aviculoecium is a new structure, and not a development of the distal apertural spine, as has been assumed hitherto. ... If the secondary aviculoecia are rightly regarded as developments of no pre-existing structures, the species P. brydonei must be considered as arising from a saltation . . . ". Here Lang referred to the nature of the oral spines and orifices of the specimen which is shown here in side and front views respectively (Text-fig. 780;, b). From a careful examination of the specimen under high-power magnification it is apparent that the rim of the primary orifice is undamaged but partly concealed by hard matrix. Distal to the rim of the primary orifice an apparently unmodified " primary " oral spine is preserved. This structure is, however, intimately fused to a localized accumulation of secondary calcareous tissue on its distal side, here termed " secondary tissue of the enlarged oral spine ". This enlarged oral spine protrudes above the general level of the rim of the secondary orifice which is very much broken, but which normally, in undamaged zooecia, obscures the rim of the primary orifice and the unmodified oral spines. The left- hand distal oral spine has been destroyed. I regard the smaller " primary " unmodified right-hand distal oral spine and the localized accumulation of secondary tissue on its distal side as parts of the same enlarged distal oral spine which has been broken and worn obliquely along its length. Damage to the distal end of the zooecium has largely removed secondary tissue, exposing the sharply defined distal margin of the primary orifice and the originally small base of the oral spine. This arrangement does not necessarily indicate renewal of the orifice, but does show that the so-called " secondary aviculoecia " of Lang are, in fact, enlarged oral spines : that is, spines which are developed round the margin of the orifice and which have increased in size during the localized accumulation of secondary tissue. It is thus incorrect to represent P. brydonei (vide Lang, 1922 : 295, text-fig. 91) as possessing two pairs of unmodified oral spines in addition to the so-called " second- ary aviculoecia ". The species has only one pair of lateral unmodified oral spines and one pair of enlarged distal oral spines. (See also the general remarks on oral spines, p. 35.) In the adult zooecia of P. brydonei the number of costae varies from 15 to 19 and is most often 16. The avicularia, described by Lang as " sporadic ", occur almost invariably two to each zooecium. They are often symmetrically paired, one on either side, near the proximal-lateral corners of the orifice. 0.29861, recorded by Lang (1922 : 292) as P. pero, is actually a specimen of P. brydonei. The specimen is discussed on p. 150. STRATIGRAPHICAL DISTRIBUTION. Senonian, upper part of the zone of M. cor- anguinum. SPECIMENS. 0.23396. Holotype see above. 0.23397-401, 0.23429-31. Eight paratypes. Zoarial fragments, now unattached. Senonian, extreme top of the zone of M. cor-anguinum. Medical College Pit, Epsom, Surrey. F. Mockler Collection. 168 CRETACEOUS CRIBRIMORPH POLYZOA (PELM ATOPORIN AE) 0.23325. Small zoarial fragment, now unattached. Horizon, locality and collection as for the paratypes. 0.29861. Zoarial fragment encrusting a piece of echinoid test. Recorded by Lang as P. pero. Senonian, high in the zone of M. cor-anguinum. Coombs Pit (Pit 264 of Young), West Horsley, north-east of Guildford, Surrey. 18. Pelmatopora coryli (Lang) (PL 12, fig. 4 ; Text-fig. 79) 19160. Carydiopora coryli Lang, p. 94. 1921 Pelmatopora coryli (Lang) Lang, pp. xcii, xciii \norn. nud.]. 1922 Pelmatopora coryli (Lang) : Lang, p. 285, pi. 6, fig. 2 ; text-fig. 87. 1923 Pelmatopora corylii [sic] (Lang) : Waters, p. 555. 1924 Pelmatopora coryli (Lang) : Gaster, second of three tables opp. p. no. 1930 Pelmatopora coryli (Lang) : Gaster, table opp. p. 340. HOLOTYPE. 0.28998. Small zoarial fragment of only eight zooecia, encrusting a piece of echinoid test. Senonian, zone of 0. pilula, subzone of E. scutata var. cincta. Pit 2 of Gaster, by reservoir, near Hill Barn, north of North Lancing village, south- east of Lancing Ring, north-east of Worthing, Sussex. EMENDED DIAGNOSIS. Pelmatopora with small zooecia ; distal oral spines en- larged, lateral oral spines unmodified and concealed by secondary thickening on the margin of the orifice ; costae 11-14 avicularia occasional, sporadic. DESCRIPTION. Zoarium unilaminar, encrusting. Adult zooecia small, broadly oval. Orifice rounded distally and laterally, with a straight proximal margin, wider than high, not much obscured by secondary tissue. Oral spines four, but in the adult zooecia the lateral pair are unmodified and completely covered by secondary tissue. The distal pair of oral spines is enlarged. Frontal shield steeply sloping outwards at the margins but flat on top. Costae 11-14, eacn w i*h a pelma at the middle and a pelmatidium near the inner end. A second pelmatidium may occur occasionally very close to the mid-line. Lateral costal fusions are developed at the levels of the pelmata and the outermost pelmatidia, producing two irregularly paired rows of intercostal spaces. Median area of fusion narrow. The costae are charac- teristically rounded where they turn down to meet the gymnocyst. Apertural bar fairly wide, sloping down to the proximal edge of the orifice, with two very prominent, large pelmata and a very slight median furrow. Gymnocyst not exposed. The interzooecial valleys are apparently lined with secondary tissue, the edges of this lining tissue standing up as a small but distinct ridge round each frontal shield. The " lacunae " are apparently deep hollows in the interzooecial secondary tissue ; they occur only over the deepest parts of the interzooecial valleys. Avicularia occasional, sporadic, small, rounded, possibly distally directed, fre- quently much obscured by secondary tissue. Ovicells not seen. Young zooecia smaller than the adult zooecia, with an orifice of the same shape, but with four unmodified oral spines, none of which is obscured by secondary tissue. Frontal shield more often arched, costae 10 or n, well defined, each with a pelma near the middle and a pelmatidium near the inner end near the mid-line. Only one CRETACEOUS CRIBRIMORPH POLYZOA (PELM ATOPORIN AE) 169 lateral costal fusion occurs regularly at the level of the pelmata, though lateral fusions may occasionally be developed at the level of the pelmatidia. Apertural bar narrower than in the adult zooecia, with two very large pelmata. The gymno- cyst is well exposed proximally to the frontal shield and slightly exposed laterally. Interzooecial secondary tissue, if present, is small in amount and is confined to the region of the orifice. Paired avicularia have been seen associated with only one O O'Smm. FIG. 79. Pelmatopora coryli (Lang), 0.28998. Holotype. Adult zooecium with enlarged distal oral spine-bases and single avicularium near the proximal end. young zooecium, where they occur one near each proximal-lateral corner of the orifice. Apart from this example, the avicularia occur sporadically in the young zoarial stages. MEASUREMENTS. Adult zooecia Lz = 0-60 to 0-75 mm. lz = 0-39 to 0-45 mm. hr = 0-12 to 0-15 mm. Ir = 0-15 to 0-18 mm. Young zooecia Lz = 0-51 to 0-59 mm. lz 0-27 to 0-33 mm. hr = 0-09 to 0-12 mm. lr = 0-12 to 0-15 mm. Avicularia Not measurable. 170 CRETACEOUS CRIBRIMORPH POLYZOA (PELM ATOPORIN AE) REMARKS. The holotype and three paratypes, 0.28996-97 and 0.28999, have been re-examined. In these specimens it is possible to find only one adult zooecium, in the holotype, in which the distal margin of the orifice is complete and unworn. Only three other adult zooecia are present in the holotype in each case the distal margin is worn but still retains the bases of the enlarged distal oral spines which are well preserved in the unworn adult zooecium. On this evidence the specimen is here grouped with the more complex species of Pelmatopora which possess a pair of enlarged distal oral spines. The remaining zooecia of the holotype are smaller, and each has two pairs of unmodified oral spine-bases. It seems probable that Lang based his diagnosis and description on these young zooecia. In paratype 0.28996 only three zooecia retain complete frontal shields and all have worn or damaged distal margins. The zoarium is unilaminar and encrusting. Paired avicularia occur in two of the more complete zooecia, and there are at least two lateral costal fusions arising from each of the 12 or 13 costae which are present. The gymnocyst is variably exposed. The dimensions of this specimen are : Lz = 0-60 to 0-69 mm. lz = 0-39 to 0-42 mm. hr About 0-12 mm. Ir = 0-15 mm. Paratype 0.28997 is also worn, but there is more abundant interzooecial secondary tissue than in the holotype or in 0.28996. The avicularia are generally paired. The adult zooecia are a little larger than in the holotype, with 13 or 14 costae. 0.28999 was labelled by Lang as a paratype of P. coryli. It is, however, very badly worn and cannot be placed with certainty in that species. It is the only specimen recorded from the zone of Marsupites. Comparison has also been made between all specimens referred by Lang to P. coryli and all species of Carydiopora from which it was removed by Lang (1922). None of the remaining species of Carydiopora possesses pelmata or distal oral spines typical of Pelmatopora, STRATIGRAPHICAL DISTRIBUTION. Senonian, zone of 0. pilula, subzone of E. scutata var. depressula and subzone of E. scutata var. cincta, and Pzone of Marsupites (subzone unspecified). SPECIMENS. 0.28998. Holotype see above. 0.28996. Paratype. Worn zoarial fragment, encrusting a piece of echinoid test. Senonian, zone of 0. pilula, subzone of E. scutata var. cincta. Pit 4 of Gaster, Western Pit (close to Pit 3 of Gaster), at top of Boundstone Lane, south of Lancing Ring, east of Halewick Lane, Sompting, Sussex. 0.28997. Paratype. Worn zoarial fragment encrusting a piece of echinoid test. Senonian, zone of 0. pilula, subzone of E. scutata var. depressula. Cliffs, between last groyne east of Rottingdean Gap and Saltdean, east of Brighton, Sussex. ?D. 28999. Paratype. Very badly worn zoarial fragment. Senonian, zone of Marsupites (subzone unspecified). Cliffs, Brighton, Sussex. CRETACEOUS CRIBRIMORPH POLYZOA (PELM ATOPORIN AE) 171 19. Pelmatopora marsupitorum Lang (PL 12, figs. 2, 5 ; Text-figs. 80-83) 19160 Pelmatopora marsupitorum Lang, pp. 103, 105. Pelmatopora roedeanensis Lang, pp. 103, 105. Pelmatopora marsupitum [sic] Lang : Lang, pp. 214, 216, 222, text-figs. 55, 56. Pelmatopora roedeanensis Lang : Lang, pp. 215, 222. 1921 Pelmatopora marsupitum [sic] Lang : Lang, pp. xcii, xciii. 1921 Pelmatopora roedeanensis Lang : Lang, pp. xcii, xciii. 1922 Pelmatopora marsupitum [sic] Lang : Lang, p. 297, pi. 6, fig. 6 ; text -figs. 736, 93. 1922 Pelmatopora roedeanensis Lang : Lang, p. 299. 1924 Pelmatopora marsupitum [sic] Lang : Gaster, second of three tables opp. p. no. 1924 Pelmatopora roedeanensis Lang : Gaster, second of three tables opp. p. no. 1930 Pelmatopora marsupitum [sic] Lang : Gaster, p. 336, table opp. p. 340. 1930 Pelmatopora roedeanensis Lang : Gaster, table opp. p. 340. ?I958 Pelmatopora cf. marsupitum [sic] Lang : Didon, pp. 83, 85, text-fig, n. HOLOTYPE. 0.28867. Zoarial fragment encrusting a piece of echinoid test. Senonian, zone of Marsupites (subzone unspecified), Brighton, Sussex. EMENDED DIAGNOSIS. Pelmatopora with a pair of relatively short and peg-like enlarged distal oral spines ; the unmodified lateral oral spine-bases always concealed by secondary tissue ; costae 14-20. DESCRIPTION. Zoarium unilaminar, encrusting, but may now be unattached. Zooecia elliptical, of variable length. Orifice rounded distally and laterally, with a straight proximal margin, its outline often indented by the pair of enlarged distal oral spines. Oral spines 4, only the enlarged distal pair visible. Compared with the enlarged distal oral spines of other species these are relatively short and peg-like, occasionally rather broad, and very occasionally tending to widen slightly at their distal ends. The unmodified pair of lateral oral spines is always obscured by second- ary tissue accumulated on the margins of the orifice. Frontal shield flat, of variable length. Costae 14-20 (often 18), well defined, each with a pelma near the outer end, a smaller pelma towards the inner end, and often a pelmatidium close to the mid-line. Lateral costal fusions arise at the levels of the pelmata producing two paired rows of intercostal spaces. Occasionally a single line of intercostal spaces may be developed along the mid-line of the frontal shield when opposite intercostal spaces coalesce. Even less frequently, lateral costal fusions may arise at the levels of the pelmatidia giving a third paired row of intercostal spaces. Median area of fusion very narrow or absent. Apertural bar low and wide, with two well-defined, large pelmata and often with less obvious, smaller pelmata nearer the mid-line. The distal edge of the apertural bar is frequently indented by a minute median furrow. Gymnocyst frequently concealed by plentiful interzooecial secondary tissue which fills the inter- zooecial valleys and which contains irregularly elongate lacunae. Avicularia large, prominent, distally pointed and directed, usually paired, one near each proximal-lateral corner of the orifice, but sporadic avicularia of the same type also occur frequently. In unworn avicularia the aperture may be either divided by a straight transverse bar, separating a semicircular proximal portion from a triangular rostrum, or there may be no transverse bar, the aperture being 172 CRETACEOUS CRIBRIMORPH POLYZOA (PELM ATOPORIN AE) O*5 mm. 80 8! Q-5 mm- 82 83 FIGS. 80-83. Pelmatopora marsupitorum Lang. (80) D. 39400. Normal adult zooecium with well-preserved enlarged distal oral spines and paired avicularia near the orifice. The two avicularia near the proximal end belong to adjacent zooecia. (81) Orifices of four adult zooecia showing variation in form of enlarged distal oral spines. The variation is due largely to different degrees of wear : (a) 0.39400 ; (b) 0.39363 ; (c) D. 28866, Paratype ; (d) D. 28868, holotype of P. roedeanensis Lang. (82) D. 39363. Orifice with well-buttressed and thickened distal oral shield typical of ovicelled zooecia. Paired, worn, proximal-lateral avicularia are present. (83) Avicularia. (a) 0.39369. Somewhat worn, secondarily thickened avicularium with robust transverse bar. (b) D. 39400. Well-preserved stalked avicularium. CRETACEOUS CRIBRIMORPH POLYZOA (PELM ATOPORIN AE) 173 narrow and slit-like for the distal two-thirds of its length. Unworn avicularia are rare : the commonly worn avicularian aperture has an elongate-oval outline. Ovicells apparently endozooecial. In ovicelled zooecia the space between the enlarged distal oral spines is infilled with secondary tissue which may project for- wards above the distal margin of the orifice forming a prominent distal oral shield. This structure is apparently less pointed than that developed in ovicelled zooecia of P. somptingensis and tends to be more solidly buttressed than in that species. MEASUREMENTS. Zooecia Lz = i-oo to 1-20 mm. lz = 0-50 to 0-57 mm. hr = 0-18 mm. Ir = o-2i mm. Avicularia Lz =0-12 mm. lz = 0-09 mm. REMARKS. All available specimens recorded by Lang as P. marsupitorum or as P. roedeanensis have been re-examined. Much additional material, largely from the zone of G. [A .] quadrata, has also been assigned to P. marsupitorum as here revised. Compared with those of P. brydonei, the distal oral spines of the holotype of P. marsupitorum are more enlarged ; they show no tendency to bifurcate as in P. gregoryi or in P. somptingensis. P. roedeanensis is synonymous with P. marsupit- orumt, Lang distinguished the species on possible differences in zoarial growth habit only. The dimensions of the zooecia of P. roedeanensis fall within the range of those of P. marsupitorum and the two are similar in all other features. In 0.39363 several zooecia possess apparently endozooecial ovicells which are marked by prominent distal oral shields of the type described ; the orifices of these ovicelled zooecia are typically oblong. 0.39369 has well worn avicularia of a typically elongate-oval shape. One avicularium is comparatively unworn, with its stout transverse bar preserved and its aperture raised on a robust stalk, the walls of which appear to be thickened by the accretion of secondary tissue. In contrast, the occasionally preserved unworn avicularia of 0.39400 apparently lack a transverse bar and their apertures are constricted distally. This form of avicularian aperture seems to be more generally typical of P. marsupitorum. Unworn enlarged distal oral spines occur only occa- sionally. They tend to be triangular in shape, the apex of the triangle pointing towards the centre of the orifice. The shape of the enlarged distal oral spines may vary considerably according to the degree of wear. STRATIGRAPHICAL DISTRIBUTION. Senonian, zone of Marsupites to zone of G. [A.] quadrata, but not yet recorded from the subzone of E. scutata var. cincta in the zone of 0. pilula. SPECIMENS. 0.28867. Holotype see above. D.28866. Paratype. Zoarial fragment encrusting a piece of echinoid test. Horizon, locality and collection as for the holotype. 0.28868. Holotype of P. roedeanensis Lang. Zoarial fragment now unattached. Horizon, locality and collection as for the holotype. 174 CRETACEOUS CRIBRIMORPH POLYZOA (PELM ATOPORIN AE) 0.28282, 0.28287, 0.28869-70. Four zoarial fragments. Horizon, locality and collection as for the holotype. 0.29867. Zoarial fragment. Senonian, zone of 0. pilula, subzone of E. scutata var. depressula. Pit i of Gaster, south of College Farm, North Lancing, Sussex. 0.29866. Zoarial fragment. Horizon and collection as for 0.29867. Cliffs between last groyne east of Rottingdean Gap and Saltdean, Sussex. ? 0.28283. Very worn zoarial fragment. Horizon, locality and collection as for 0.29866. 0.29868-69. Two zoarial fragments labelled by Lang " P. roedeanensis ". Horizon and collection as for 0.29867. Cliffs east of Chimney Shaft, Roedean, east of Brighton, Sussex. 0.39363, 0.39408. Two zoarial fragments, the former with well-preserved ovicells. Senonian, zone of G, [A.] quadrata. Pit 15 of Gaster, large pit about one- third of a mile south-south-east of Salvington Windmill and north of Hill Cottages, Salvington, Sussex. 0.39369, 0.39371, 0.39373, 0.39376, 0.39383. Five zoarial fragments. Senonian, zone of G. [A.] quadrata. Pit 20 of Gaster, lower pit on Patching Hill, just above the 200 ft. contour, north of St. John's Church, Patching, Sussex. 0.39386-88. Three zoarial fragments. Senonian, zone of G. [A.] quadrata. Pit by track, near 200 ft. contour, south-east of Walderton, west side of Walderton Down, West Sussex. 0.39393, 0.39403, 0.39433-34. Four zoarial fragments. Senonian, zone of G. [A.] quadrata. Pit 26 of Gaster, South Woodleighs Pit, east of gravel pit, north-east of Woodleigh Lodge, about half a mile west of Pit 24 of Gaster, Warningcamp, north-east of Arundel, Sussex. 0.39398-99. Two zoarial fragments. Senonian, zone of G. [A.] quadrata. Pit 18 of Gaster, Old Lime Kiln, north-west corner of Munery's Copse, west of Pit 17 of Gaster, east end of Clapham Wood, Sussex. 0.39400. Zoarial fragment. Senonian, zone of G. [A.] quadrata. Pit 19 of Gaster, on western boundary of Church Copse, west of St. Mary's Church, Clapham, Sussex. 0.40707. Very large zoarial fragment encrusting a piece of echinoid test. Senonian, zone and subzone of Marsupites. Section 75 of Gaster, cliffs, east of Brighton, Sussex. 0.40708-10. Three zoarial fragments now unattached. Senonian, zone of 0. pilula, subzone of E. scutata var. depressula. Section 85 of Gaster. Roedean Cliffs, east of Brighton, Sussex. 0.40711-17. Seven zoarial fragments encrusting pieces of echinoid test. Horizon, locality and collection as for 0.40707. 0.40973. Pelmatopora cf. marsupitorum. Zoarial fragment encrusting a piece of echinoid test. Senonian, zone of 0. pilula, subzone of E. scutata var. depressula. Section 113 of Gaster, cliffs, Rottingdean to Lower Bannings, east of Saltdean Cottages, Sussex. CRETACEOUS CRIBRIMORPH POLYZOA (PELM ATOPORIN AE) 175 0.41036. Zoarial fragment encrusting large cyclostomatous polyzoan. Horizon, locality and collection as for 0.40973. 0.41037. Very large zoarial fragment encrusting part of an echinoid test. Horizon, locality and collection as for 0.40973. 0.41038-40. Three zoarial fragments encrusting pieces of echinoid test. Horizon, locality and collection as for 0.40973. 0.41042. Zoarial fragment encrusting a piece of echinoid test. Horizon, locality and collection as for 0.40708. 0.41047-49. Three zoarial fragments encrusting pieces of echinoid test. Horizon, locality and collection as for 0.29867. 0.41050-55. Six zoarial fragments, now unattached. Horizon, locality and collection as for 0.29867. 0.41056-57 Two zoarial fragments encrusting pieces of echinoid test Horizon, locality and collection as for 0.40973. 20. Pelmatopora gregoryi (Brydone) (PL 13 ; PI. 14, figs. 1-4 ; Text-figs. 84-94) 1852 non Semiescharipora simplex d'Orbigny, pi. 718, figs. 1-4 ; 1853, p. 481 ; 1854, p. 1097 [vide Lang]. Pi 900 Cribrilina sp. : Rowe, p. 341 [partim special undescribed form], [vide Lang]. 1906 Cribrilina gregoryi Brydone, pp. 290, 300, text-fig. 13 [partim specimens from zone of G. [A.] quadrata only, caet. excl.]. 1910 Cribrilina gregoryi Brydone : Brydone, p. 77. Pigio Cribrilina sp. : White, p. 56 [vide Lang]. Pigio Cribrilina simplex (d'Orbigny) : White, p. 55 [vide Lang]. Pign Cribrilina gregoryi Brydone : Griffith & Brydone, p. 4. Pigi2 Cribrilina gregoryi Brydone : Brydone, pp. 20, 53, 62, 70, 89-95. Pi9i2 Cribrilina gregoryi Brydone : White, pp. 35, 43. 1913 Cribrilina gregoryi Brydone : Brydone, p. 436, pi. 14, figs, i, 2 [partim non fig. 3]. Pi9i3 non Cribrilina gregoryi Brydone : White, p. 24 [vide Lang]. Pi9i3 Cribrilina gregoryi Brydone : White, pp. 27, 30, 32, 38 [partim vide Lang]. 1913 Cribrilina gregoryi Brydone : Lang, p. 171 [partim specimens other than 0.23963 from zone of G. [AJ] quadrata only : caet. excl.}. igi6a Pelmatopora gregoryi (Brydone) Lang, pp. 103, 106. igi6a Pelmatopora bidens Lang, pp. 103, 106. 19160 Pelmatopora lancingensis Lang, pp. 103, 106. I9i6a Pelmatopora promontoriorum Lang, pp. 103, 106. igi6a Pelmatopora collium Lang, pp. 103, 106. igi6a Pelmatopora saltdeanensis Lang, pp. 103, 106. 19160; Pelmatopora ranunculoides Lang, pp. 103, 106. igi6a Pelmatopora lacuum Lang, pp. 103, 106. igi6a Pelmatopora gyrinoides Lang, pp. 103, 106. 1917 Cribrilina gregoryi Brydone : Brydone, pp. 50, 52, 495 [partim]. Pelmatopora gregoryi (Brydone) : Lang, pp. 215, 221. Pelmatopora bidens Lang : Lang, pp. 214, 221, text-figs. 61, 62. Pelmatopora lancingensis Lang : Lang, pp. 214, 221, text-figs. 63, 64. Pelmatopora promontoriorum Lang : Lang, pp. 214, 221, text-fig. 67. 19190^ Pelmatopora collium Lang : Lang, pp. 214, 221, text-fig. 68. 19190! Pelmatopora saltdeanensis Lang : Lang, pp. 214, 221, 224, 226, text-figs. 65, 66. 176 CRETACEOUS CRIBRIMORPH POLYZOA (PELM ATOPORIN AE) 1919^ Pelmatopora ranunculoides Lang : Lang, pp. 214, 221, text-figs. 69, 70. 1919^ Pelmatopora lacuum Lang : Lang, pp. 214, 221, text-fig. 71. 1919^ Pelmatopora gyrinoides Lang : Lang, p. 214, text-fig. 72. 1921 Pelmatopora gregoryi (Brydone) : Lang, p. xci. 1921 Pelmatopora bidens Lang : Lang, pp. xci, xcii. 1921 Pelmatopora lancingensis Lang : Lang, pp. xci, xcii. 1921 Pelmatopora promontoriorum Lang : Lang, pp. xci, xcii. 1921 Pelmatopora collium Lang : Lang, p. xcii. 1921 Pelmatopora saltdeanensis Lang : Lang, p. xcii. 1921 Pelmatopora ranunculoides Lang : Lang, pp. xcii, xciii. 1921 Pelmatopora lacuum Lang : Lang, p. xcii. 1921 Pelmatopora gyrinoides Lang : Lang, p. xcii. 1922 Pelmatopora gregoryi (Brydone) : Lang, p. 304 [partim non D. 8009, 0.28537, 0.21169]. 1922 Pelmatopora bidens Lang : Lang, p. 311, pi. 6, fig. 8, text-figs. 73/, 97. 1922 Pelmatopora lancingensis Lang : Lang, p. 314, pi. 6, fig. 9 ; text-figs. 73^, 98. 1922 Pelmatopora saltdeanensis Lang : Lang, p. 316, text-fig. 99. 1922 Pelmatopora collium Lang : Lang, p. 319, text-fig. 100. 1922 Pelmatopora promontoriorum Lang : Lang, p. 320, pi. 6, fig. 10. 1922 Pelmatopora ranunculoides Lang : Lang, p. 321, pi. 6, fig. n, text-fig. 101. 1922 Pelmatopora lacuum Lang : Lang, p. 324. 1922 Pelmatopora gyrinoides Lang : Lang, p. 324, pi. 6, fig. 12 ; text-fig. 102. 1924 Pelmatopora bidens Lang : Gaster, second of three tables opp. p. no. 1924 Pelmatopora lancingensis Lang : Gaster, second of three tables opp. p. no. 1924 Pelmatopora collium Lang : Gaster, second of three tables opp. p. no. 1924 Pelmatopora promontoriorum Lang : Gaster, second of three tables opp. p. no. 1924 Pelmatopora ranunculoides Lang : Gaster, second of three tables opp. p. no. 1924 Pelmatopora lacuum Lang : Gaster, second of three tables opp. p. 110. ?ig24 Cribrilina gregoryi Brydone : White, pp. 55, 62. ?I929 Cribrilina gregoryi Brydone : Brydone, pp. 9, 12, 13. 1929 Pelmatopora gregoryi (Brydone) : Lang, p. 437. 1930 Pelmatopora gyrinoides Lang : Gaster, table opp. p. 340. 1930 Pelmatopora ranunculoides Lang : Gaster, table opp. p. 340. 1930 Pelmatopora bidens Lang : Gaster, table opp. p. 340. 1930 Pelmatopora lancingensis Lang : Gaster, table opp. p. 340. 1930 Pelmatopora saltdeanensis Lang : Gaster, table opp. p. 340. 1930 Pelmatopora collium Lang : Gaster, table opp. p. 340. 1930 Pelmatopora promontoriorum Lang : Gaster, table opp. p. 340. LECTOTYPE. (Chosen by Brydone, 1913 : 436.) S.M., 6.36120. The specimen figured by Brydone (1906 : 300, text-fig. 13). Senonian, zone of G. [A.] quadrata. Pit 1092 of Brydone, large pit in Stakes' Lane, Upham, Hampshire. R. M. Brydone Collection. EMENDED DIAGNOSIS. Pelmatopora with a pair of distally elongated, pointed, somewhat slender, enlarged distal oral spines which tend to bifurcate, the " outer horn " of the bifurcation curving away laterally and proximally ; interzooecial secondary tissue abundant, often tending to stand out as a ridge above the flat frontal shield. DESCRIPTION. Zoarium unilaminar, encrusting or may now be unattached, occasionally (in parts at least) erect or cylindrical. Adult zooecia oval to elliptical with somewhat parallel sides. Orifice wider than high, rounded distally and CRETACEOUS CRIBRIMORPH POLYZOA (PELM ATOPORIN AE) 177 laterally, with a straight proximal margin, its outline indented by the pair of enlarged distal oral spines. Only the distal pair of 4 oral spines are visible in the adult zooecia. The distal oral spines are enlarged, elongated, generally pointed and somewhat slender, lengthened in an outwardly curving fashion, or tending to bifurcate, the " outer horn " of the bifurcation curving towards the lateral or proximal margins of the orifice, and the " inner horn" only slightly developed. Other unmodified oral spines, if present, are always entirely concealed by the accumulation of secondary tissue round the margin of the orifice. Frontal shield of variable length, flat. Costae 11-20 (often 13-16), well denned, each with twopelmata and a. pelmatidium. Lateral costal fusions occur at the levels of the pelmata, produc- ing two paired rows of intercostal spaces. The outermost intercostal spaces vary in shape from slot-like to oval. Median area of fusion very narrow. Apertural bar wide and low, often sloping down to the proximal margin of the orifice, with con- spicuous pelmata on its proximal edge. Gymnocyst concealed by abundant inter- zooecial secondary tissue which fills the interzooecial valleys, often standing up as ridges above the general level of the commonly flat frontal shields. Irregular lacunae are variably developed in the interzooecial tissue. Avicularia prominent, distally pointed and directed, usually regularly paired, one near each proximal-lateral corner of the orifice. The avicularian aperture is almost circular proximally, narrowing distally to a triangular rostrum, and usually without a transverse bar ; the aperture is often raised on a stout stalk (Text-fig. 94). Occa- sionally sporadic avicularia of the same type also occur. Ovicells endozooecial. In ovicelled zooecia the space between the enlarged distal oral spines is infilled with secondary tissue producing a prominent distal oral shield, which is apparently less pointed than that developed in P. somptingensis. Young zooecia small, but with a relatively large orifice which is wider than high, with two pairs of oral spine-bases which are slightly enlarged but otherwise unmodi- fied. Apertural bar more rounded and narrower than in the adult zooecia, with two very prominent pelmata and with a slight proximal bend in the mid-line. Costae 10-13, each with a pelma and, in some, an inconspicuous pelmatidium nearer to the mid-line. Frontal shield more arched than in the adult zooecia. Small, sporadic avicularia may be present in the circum-ancestrular area in which secondary inter- zooecial tissue is lacking. Secondary tissue may, however, encroach on to the young zooecia from the adult stages of the same zoarium. MEASUREMENTS. Adult zooecia Lz = 0-75 to 1-20 mm. Iz = 0-40 to 0-50 mm. hr = 0-15 to 0-18 mm. Ir = o-2i mm. Young zooecia Lz = About 0-50 mm. Iz = About 0-33 mm. hr = 0-12 to 0-15 mm. Ir = 0-13 to 0-15 mm. [continued on p. 180. GEOL. 6, I. 12 178 CRETACEOUS CRIBRIMORPH POLYZOA (PELM ATOPORIN AE) O % 5mm. 87 Scale as for Fig. 84. FIGS. 84-87. Pelmatopora gregoryi (Brydone). (84) S.M. 6.36120. Lectotype. Adult zooecium with lengthened, enlarged distal oral spines and three avicularia surrounded by plentiful interzooecial secondary tissue with lacunae. (85) S.M. B. 36120. Lectotype. Ancestrula with one small, rounded lateral avicu- larium. (86) 0.39414. Part of encrusting zoarium with plentiful interzooecial secondary tissue which is smooth with shallow lacunae. The avicularia and most of the enlarged distal oral spines are worn. (87) 0.39414. Young zooecium of the circum-ancestrular area. Two small, worn avicularia are present near the proximal-lateral corners of the orifice. CRETACEOUS CRIBRIMORPH POLYZOA (PELM ATOPORIN AE) 179 O-Smm. 89 O O 5mm. I 88 Omm. 91 o 90 92 FIGS. 88-92. Pelmatopora gregoryi (Brydone). (88) Orifices of six adult zooecia showing variation in form of enlarged distal oral spines. The variation is due largely to different degrees of wear : (a) and (c) 0.28947, holotype of P. lancingensis Lang ; (b), (d) and (e) 0.28820, paratype of P. promon- toriorum Lang ; (/) D. 28934, holotype of P. bidens Lang. (89) D. 39046. Orifice of adult ovicelled zooecium with markedly thickened and projecting distal oral shield. (90) (a) D. 39301. Abnormal adult zooecium produced by coalescence of buds of two adjacent rows of zooecia. The orifice of the proximally adjacent zooecium and seven worn avicularia are also shown ; (b) 0.39301. Young zooecium from circum- ancestrular area. (91) D. 39301. Dorsal surface of normal adult zooecium with irregularly spaced small, hollow spines. (92) D. 39301. Enlarged dorsal spines developed along the line of a fracture in the basal zooecial wall. i8o CRETACEOUS CRIBRIMORPH POLYZOA (PELM ATOPORINAE) $.t f/umi^^^^ \ d l-Omm. I O;2mm. 93 94 FIGS. 93-94. Pelmatopora gregoryi (Brydone). (93) 0.39382. Aborted adult zooecium. a, avicularia ; d, worn, enlarged distal oral spine ; /, distorted frontal shield ; g, very prominent gymnocyst ; o, heavily calcined infilling of orifice ; s.t, distal extension of tongue of inter zooecial secondary tissue covering distal oral spine. (94) D. 288 1 6. Paratype of P. lancingensis Lang. Unworn avicularium. Ancestrula of lectotype Lz = 0-45 mm. lz = 0-30 mm. hr = 0-12 mm. Ir = 0-13 mm. Avicularia Lz = 0-12 to 0-15 mm. lz = 0-06 to 0-07 mm. REMARKS. The lectotype of Pelmatopora gregoryi (Brydone), S.M., 6.36120, is a very well preserved, unilaminar, encrusting zoarium with young zooecia. The adult zooecia possess enlarged distal oral spines of the type described. The range in number of costae is 12-15, and the outermost intercostal spaces slot-like. The avicularia are prominent, regularly paired, distally pointed and directed ; the pointed rostrum may be separated from the proximal part of the aperture by a slight transverse bar which is frequently distally curved more often there is no bar between the rostrum and the proximal part of the avicularian aperture. A few zooecia are ovicelled ; in these the distal oral shield produces a markedly oblong, transversely elongate orifice. The dimensions of the lectotype are : Adult zooecia Lz = 0-87 to 1-06 mm. lz = 0-45 to 0-50 mm. hr = 0-15 to 0-18 mm. Ir = 0-21 mm. CRETACEOUS CRIBRIMORPH POLYZOA (PELM ATOPORIN AE) 181 Young zooecia Lz = 0-48 to 0-50 mm. Iz = 0-32 to 0-34 mm. hr = 0-12 to 0-14 mm. Ir = 0-13 mm. Avicualaria Lz =0-13 mm. Iz = 0-06 to 0-07 mm. Pelmatopora bidens, P. lancingensis, P. promontoriorum, P. collium, P. saltdeanensis , P. ranunculoides , P. lacuum and P. gyrinoides, all species established by Lang, are here grouped together as synonymous with P. gregoryi. Lang originally interpreted the lectotype of P. gregoryi (Brydone) from Brydone's 1906 and 1913 descriptions and figures. Unfortunately these do not show the form of the enlarged distal oral spines. Examination of the actual specimen shows that they are not, as Lang (1922 : 305) has stated, " very much flattened distally and distinctly bilobed ", but are of the distally elongate curved form described above. This feature, and the range in number of the costae, the form of the avicularia, and the nature and amount of secondary tissue, are all similar to those of P. bidens Lang, which is thus synonymous with P. gregoryi. In addition the other seven species of Pelmatopora mentioned above are all synonymous with P. bidens and are thus all junior synonyms of P. gregoryi. P. saltdeanensis Lang is morphologically similar to P. promontoriorum Lang and was maintained as separate solely on supposed differences in zoarial growth habit. Similarly, Lang separated P. lacuum from P. ranunculoides. P. gyrinoides was established by Lang as a separate encrusting species only on the evidence of a single, somewhat worn zooecium : it might equally well be a young zooecium of P. ranunculoides. The latter species is morphologically similar to P. promontoriorum : the general range in number of costae is very similar (11-16 for ranunculoides and 12-19 f r promontoriorum), the zooecia of the latter are generally more slender than those of the former species, but this may be a reflection of dif- ferences in growth habit (see remarks on the Recent species Steganoporella buskii Harmer, p. 22). In turn, Pelmatopora promontoriorum is synonymous with P. bidens : they have the same general range in number of costae (11-19 an( i 12-20 respectively) and are similar in other features. P. collium was established by Lang on the basis of its apparently more plentiful, ridge-like interzooecial secondary tissue and on its supposedly fewer costae, but both of these features may be very variable even in a single zoarium. Lang divided the remaining species, P. lancingensis, from P. bidens primarily on the nature of the enlarged distal oral spines. But he stated that in P. bidens these structures vary " much and, apparently, irregularly, in individual development " from small and peg-like to large and more elongate. In his description of P. lancingensis, he referred to the enlarged distal oral spines as " varying somewhat and, apparently, irregularly in amount of development, but generally large, elon- gate . . ". The number of costae in both species is very similar. It was suggested by Lang (1922 : 315) that the avicularia of P. lancingensis have " somewhat blunt apertures ", whilst those of P. bidens he described (1922 : 312) as having apertures 182 CRETACEOUS CRIBRIMORPH POLYZOA (PELM ATOPORIN AE) " divided by a constriction into a proximal more-or-less circular portion and a rostrum, which is more-or-less triangular, sometimes rather blunt, and sometimes rather acutely pointed ". Here Lang was evidently comparing worn and unworn avicularia. The unworn avicularia of both species are distinctly pointed and of very similar form. Apparent variation in the form of the enlarged distal oral spines is due almost entirely to different degrees of wear ; as with the avicularia, the enlarged distal oral spines of both species, when unworn, are very similar in form. The two species are therefore regarded as synonymous. In these terms, Pelmatopora gregoryi is seen to be a species with a relatively wide range of morphological variation which includes the eight species discussed above, many of which have identical horizons and localities. Many specimens from the C. T. A. Gaster Collection, particularly from the zone of G. [A.] quadrata, have been assigned to Pelmatopora gregoryi as revised here. D.394o6 possesses some ovicelled zooecia with well-developed distal oral shields (Text-fig. 89). 0.39414 and 0.39301 are well-preserved encrusting zoarial fragments with young zooecia (Text-figs. 87, gob). An abnormal growth-form of zooecium occurs in 0.39301 (Text-fig. 900), it is possibly produced by the coalescence of the buds of two adjacent rows of zooecia. The dorsal surface of each zooecium of 0.39301 is covered by a variable number of small, hollow bosses. These may become lengthened into small, hollow spines possibly affording extra means of attachment to damaged parts of the zoarium (Text-figs. 91, 92). Some very unusual aborted zooecia are present in 0.39382 : in the figured example (Text-fig. 93), the avicularia appear to be duplicated, the orifice is almost completely sealed by secondary calcareous tissue, and the frontal shield is much distorted, with the gymnocyst showing very prominently. A worn proximally placed avicularium is also present. STRATIGRAPHICAL DISTRIBUTION. Senonian, zones of Marsupites to G. [A.] quadrata. SPECIMENS. 0.28934, 0.28828-35, 0.28933. Holotype and nine paratypes of P. bidens Lang. Senonian, zone of 0. pilula, subzone of E. scutata var. depressula. Pit 2 of Gaster, by reservoir, near Hill Barn, North Lancing, north-east of Worthing, Sussex. 0.28987. Paratype of P. bidens Lang. Senonian, zone of G. [A.} quadrata. Pit 10 of Gaster, western pit, in lane east of Charman Dean, north of Worthing, Sussex. 0.28796, 0.29873-78. Seven paratypes of P. bidens Lang. Senonian, zone of G. [A.] quadrata. Pit 9 of Gaster, eastern pit, lane east of Charman Dean, north of Worthing, Sussex. 0.28796 T. H. Withers Collec- tion. 0.28968-70. Three paratypes of P. bidens Lang. Senonian, zone of G. [A.~\ quadrata. Pit 7 of Gaster, pit in Upton Lane (Lambleys Lane), Sompting, north-east of Worthing, Sussex. 0.28804-05. Two paratypes of P. bidens Lang. Senonian, zone of 0. pilula, subzone of E. scutata var. depressula. Pit on East Hill, Rottingdean, east of Brighton, Sussex. CRETACEOUS CRIBRIMORPH POLYZOA (PELM ATOPORIN AE) 183 D. 21168. Paratype of P. bidens Lang. Senonian, zone of 0. pilula, subzone of E. scutata var. depressula. Pit north-west of Chilton Candover, west of Alton, Hampshire. L. Treacher Collection. 0.28953-58. Six paratypes of P. bidens Lang. Senonian, zone of O. pilula, subzone of E. scutata var. depressula. Pit 4 of Gaster, west of Boundstone Lane, south of Lancing Ring, north-east of Worthing, Sussex. 0.28963-64. Two paratypes of P. bidens Lang. Horizon as for 0.28953-58. Pit 5 of Gaster, Dankton Lane, north-east of Sompting Church, north- east of Worthing, Sussex. 0.7315. Large zoarial fragment labelled by Lang " P. bidens ". Senonian, zone of G. [A.] quadrata. Arreton Down, south of Newport, Isle of Wight. Miss M. Salter Collection. 0.29097. Three fragments of the same zoarium labelled by Lang " P bidens ". Senonian, zone of G. [A.] quadrata. Portsdown, Hampshire. W. Gamble Collection. 0.23992-24001. Ten zoarial fragments labelled by Lang " P. bidens ". Senonian, zone of G. [A.] quadrata. Newhaven, Sussex. F. Mockler Collection. 0.29865. Zoarial fragment labelled by Lang " P. bidens ". Senonian, zone of 0. pilula, subzone of E. scutata var. depressula. Large pit on Warning- camp Hill, north-east of Arundel, Sussex. 0.28947, 0.28946, 0.28948-50. Holotype and four paratypes of P. lancingensis Lang. Senonian, zone of 0. pilula, upper part of subzone of E. scutata var. depressula. Pit 3 of Gaster, east of Boundstone Lane, south of Lancing Ring, north-east of Worthing, Sussex. 0.28285-86. Two paratypes of P. lancingensis Lang. Senonian, zone of 0. pilula, subzone of E. scutata var. depressula. Cliffs, east side of Rottingdean Gap, near and above the last groyne, east of Brighton, Sussex. 0.28962. Paratype of P. lancingensis Lang. Horizon, locality and collection as for 0.28963-64. 0.28808-19, 0.28923-29. Nineteen paratypes of P. lancingensis Lang. Horizon, locality and collection as for 0.28934. D-4337- Zoarial fragment labelled by Lang " P. lancingensis ". Senonian, zone of G. [A.] quadrata. East Harnham, south of Salisbury, Wiltshire. W. Gamble Collection. 0.29874-75. Two zoarial fragments labelled by Lang " P. lancingensis ". Horizon, locality and collection as for 0.28953. 0.29055. Zoarial fragment with ovicelled zooecia, labelled by Lang " P. lancingensis". Senonian, zone of G. [A.] quadrata. Locality and collection as for 0.28796. 0.29871-73. Three zoarial fragments labelled " P. lancingensis ". Horizon, locality and collection as for 0.28947. 0.28842, 0.28841, 0.28843-44. Holotype and three paratypes of P. saltdeanensis Lang. Senonian, zone of 0. pilula, subzone of E. scutata var. depressula. Cliffs, between last groyne east of Rottingdean Gap and Saltdean, east of Brighton, Sussex. 184 CRETACEOUS CRIBRIMORPH POLYZOA (PELM ATOPORIN AE) 0.28538. Paratype of P. saltdeanensis Lang. Senonian, zone of G. [A.] quadrata. Southern England. F. H. Butler Collection. D. 21171. Zoarial fragment labelled by Lang " P. saltdeanensis ". Senonian, zone of G. [A.] quadrata. Compton, south-west of Winchester, Hampshire. L. Treacher Collection. 0.28824, 0.28825-27. Holotype and three paratypes of P. collium Lang. Horizon, locality and collection as for 0.28934. 0.28823. Paratype of P. collium Lang. Horizon, locality and collection as for 0.28842. 0.28284. Zoarial fragment labelled by Lang " P. collium ". Horizon, locality and collection as for 0.28842. 0.28930, 0.28836-40, 0.28849-52, 0.28871-73, 0.28931-32. Holotype and four- teen paratypes of P. promontoriorum Lang. Horizon, locality and collection as for 0.28934. 0.28959-61. Three paratypes of P. promontoriorum Lang. Horizon, locality and collection as for 0.28953. 0.28951-52. Two paratypes of P. promontoriorum Lang. Horizon, locality and collection as for 0.28947. 0.28806-07, 0.28874, 0.28877. Four paratypes of P. promontoriorum Lang. Horizon, locality and collection as for 0.28842. 0.28876. Paratype of P. promontoriorum Lang. Senonian, zone of 0. pilula, subzone of E. scutata var. cincta. Cliffs, east side of Telscombe Cliff Staircase, east of Brighton, Sussex. 0.28820-22. Three paratypes of P. promontoriorum Lang. Senonian, zone of 0. pilula, subzone of E. scutata var. cincta. Cliffs, east of Old Nore Point, west of Newhaven, Sussex. 0.28967. Paratype of P. promontoriorum Lang. Horizon, locality and collec- tion as for 0.28968. 0.28972. Paratype of P. promontoriorum Lang. Senonian, zone of G. [A.] quadrata. Pit 8 of Gaster, between Upton Lane (Lambleys Lane) and east of Charman Dean, north of Broadwater, Worthing, Sussex. 0.28856, 0.28857-59, 0.28845-48. Holotype, three paratypes and four zoarial fragments of P. ranunculoides Lang. Horizon, locality and collection as for 0.28842. 0.28864. Paratype of P. ranunculoides Lang. Horizon, locality and collection as for 0.28934. D.2886o. Paratype of P. ranunculoides Lang. Senonian, zone of 0. pilula, subzone of E. scutata var. cincta. Upper part of pit on East Hill, Rottingdean, east of Brighton, Sussex. 0.28861. Paratype of P. ranunculoides Lang. Senonian, zone of Marsupites [subzone unspecified]. Brighton, Sussex. 0.28875. Zoarial fragment labelled by Lang " P. ranunculoides ". Senonian, zone of 0. pilula, subzone of E. scutata var. depressula. Cliffs, west side of Saltdean Bottom, east of Brighton, Sussex. CRETACEOUS CRIBRIMORPH POLYZOA (PELM ATOPORIN AE) 185 D.28279. D.28280. D.I0995- D.28270. 0.9425. 0.19564. Zoarial fragment labelled by Lang " P. ranunculoides ". Senonian, zone of G. [A.] quadrata. Cliffs, between Rottingdean and Saltdean, east of Brighton, Sussex. Zoarial fragment labelled by Lang " P. ranunculoides ". Senonian, zone of G. [A.] quadrata. Saltdean, east of Brighton, Sussex. Two fragments of the same zoarium labelled by Lang " P. ranuncu- loides ". Rottingdean, east of Brighton, Sussex. H. D. Schloss Collection. 0.28862, 0.28863, 0.28938-43, 0.28935-37, 0.28853-55. Holotype and seven paratypes of P. lacuum Lang, and six zoarial fragments labelled by Lang " P. lacuum ". Horizon, locality and collection as for 0.28934. Holotype of P. gyrinoides Lang. Senonian, zone of G. [A.] quadrata, Saltdean, west of Newhaven, Sussex. D.39340-4I, 0.39344, 0.39348, 0.39351-52, 0.39357, 0.39359-60, 0.39366, 0.39368, 0.40057. Twelve zoarial fragments. Senonian, zone of G. [A.] quadrata. Pit 15 of Gaster, large pit about one-third of a mile south-south-east of Salvington Windmill, north of Hill Cottages, Salvington, Sussex. Zoarial fragment. Senonian, zone of G. [A.] quadrata. Locality unknown. Caroline Birley Collection. Zoarial fragment specimen presented by H. O. White, said to be identical with that described by him as a Cribrilina, resembling the sole of a hob-nailed boot (White, 1910 : 56). Senonian, zone of G. [A.] quadrata. Southampton Waterworks Pit, Otterbourne, south of Winchester, Hampshire. H. O. White Collection. 0.39379, 0.39382. Two zoarial fragments. Senonian, zone of G. [A.] quadrata. Pit 20 of Gaster, lower pit on Patching Hill, north of St. John's Church, just above the 200 ft. contour, Patching, Sussex. Zoarial fragment. Senonian, zone of G. [A.~] quadrata. Pit by track, near 200 ft. contour, south-east of Walderton, west side of Walderton Down, West Sussex. 0.39401, 0.40058. Two zoarial fragments. Horizon, locality and collection as for 0.28796. 0.39405, 0.40059-63. Six zoarial fragments. Senonian, zone of G. [A.] quadrata. South Woodleighs Pit, east of gravel pit, north-east of Woodleighs Lodge, about half a mile west of Pit 24 of Gaster, Warningcamp, north-east of Arundel, Sussex. Zoarial fragment, some zooecia ovicelled. Senonian, zone of G. [A.] quadrata. Labelled as " Material from Pits 17, 18, 19, 24 and 32 " of Gaster all in the zone of G. [A.] quadrata. 0.39412, 0.40064. Two zoarial fragments. Senonian, zone of G. [A.] quadrata. Labelled as " Material from Pits 8, n, 15, 16, 17 and 23 " of Gaster all in the zone of G. [A .] quadrata. 0.39414-15, 0.40065-66. Four zoarial fragments. Senonian, Pzone of G. [A.] quadrata. Locality uncertain. 0.39389. 0.39406. i86 CRETACEOUS CRI BRIMORPH POLYZOA (PELM ATOPORIN AE) 0.39301. Zoarial fragment with some aborted zooecia. Senonian, very prob- ably zone of G. [A.] quadrata. Specimen marked " W.p." ? White- parish, eight miles south-east of Salisbury, Wiltshire. H. P. Black- more Collection. D.4o68i. Zoarial fragment, now unattached. Senonian, zone of 0. pilula, sub- zone of E. scutata var. cincta. Locality and collection as for 0.28947. 0.40682. Zoarial fragment, now unattached. Horizon, locality and collection as for 0.28934. 0.40683-87. Five zoarial fragments, now unattached, the latter with ovicelled zooecia. Horizon, locality and collection as for 0.28972. 0.40688-95. Eight zoarial fragments, now unattached. Horizon, locality and collection as for 0.40682. 0.40696. Zoarial fragment, now unattached. Horizon, locality and collection as for 0.40688. 0.40697. Zoarial fragment encrusting a piece of echinoid test. Senonian, zone of 0. pilula, subzone of E. scutata var. depressula. Section 113 of Gaster, cliff, Rottingdean to Lower Bannings, east of Saltdean Cottages, Sussex. 0.40698-99. Two zoarial fragments, now unattached. Senonian, zone and subzone of Marsupites. Section 75 of Gaster, cliff and foreshore east of Brighton at Black Rock, Sussex. 0.40700. Zoarial fragment encrusting a piece of echinoid test. Senonian, zone of 0. pilula, subzone of E. scutata var. cincta. Section 114 of Gaster, cliff, Lower Bannings to Old Nore Point, near Brighton, Sussex. 0.40701. Zoarial fragment, now unattached. Horizon, locality and collection as for 0.40700. 0.40702. Zoarial fragment now unattached. Horizon, locality and collection as for 0.40697. 0.40703, 0.40704-05. Zoarial fragment encrusting a piece of echinoid test and two zoarial fragments now unattached. Horizon, locality and collection as for 0.40682. 0.40706. Zoarial fragment, now unattached. Senonian, zone of 0. pilula, sub- zone of E. scutata var. cincta. Pit 87 of Gaster, near cart-track to Newlands Barn, north end of East Hill, Rottingdean, Sussex. 0.40797-802. Six zoarial fragments, now unattached. Senonian, zone of G. [A.] quadrata. Pit 10 of Gaster, pit adjoining Charman Dean Lane, on east side, and west of Pit 9 of Gaster, north of Broadwater and Worthing, Sussex. 0.40803-54. Fifty-two zoarial fragments, now unattached. Senonian, zone of G. [A .] quadrata. Pit 12 of Gaster, large pit north of Pumping Station, top of Waterworks Lane, north-east of " The Warren ", north of Broadwater and Worthing, Sussex. 0.40855. Zoarial fragment, now unattached, partly embedded in small block of chalk. Senonian, zone of G. [A.] quadrata. Pit south of Beech Copse, Michelgrove, Sussex. CRETACEOUS CRIBRIMORPH POLYZOA (PELM ATOPORIN AE) 187 D.40856. Horizon, locality and collection Zoarial fragment, now unattached. as for 0.28968. 0.40857-59, 0.40930. Four zoarial fragments, now unattached. Senonian, zone of G. [A.] quadrata. Large pit about one-third of a mile south-south- east of Salvington Windmill, and north of Hill Cottages, Salvington, Sussex. 0.40946. Zoarial fragment encrusting a piece of echinoid test. Horizon, locality and collection as for 0.40706. 0.40947. Zoarial fragment encrusting three pieces of echinoid test. Horizon, locality and collection as for 0.40697. 0.40948. Pelmatopora cf. gregoryi. Zoarial fragment encrusting a piece of echinoid test. Horizon, locality and collection as for 0.40697. 0.40949. Small zoarial fragment encrusting part of a cheilostome polyzoan. Horizon, locality and collection as for 0.28934. 0.40950-51. Pelmatopora cf. gregoryi. Two zoarial fragments, now unattached. Horizon, locality and collection as for 0.28934. 0.40952-53. Pelmatopora cf. gregoryi. Two zoarial fragments, now unattached. Horizon, locality and collection as for 0.40697. 0.40955-67. Thirteen zoarial fragments, now unattached. Horizon, locality and collection as for 0.28934. 0.40968-71. Four zoarial fragments, now unattached. Horizon, locality and collection as for 0.28953. 0.40972. Zoarial fragment, now unattached. Senonian, zone of 0. pilula, subzone of E. scutata var. cincta. Pit 25 of Caster, small roadside pit, just over half a mile south of Burpham, one-third of a mile north of South Woodleighs Pit (26 of Gaster), west-north-west of Warningcamp Hill, north-east of Arundel, Sussex. 0.40974. Incomplete erect, cylindrical zoarium. Horizon, locality and collec- tion as for 0.28934. 0.40975. Zoarial fragment, now unattached. Senonian, zone of 0. pilula, subzone of E. scutata var. cincta. Pit 5 of Gaster, locality and collection as for 0.28963, see above. 0.40976. Zoarial fragment, now unattached. Horizon, locality and collection as for 0.28953. 0.40977-81. Five zoarial fragments, now unattached. Horizon, locality and collection as for 0.28947. 0.40982-90. Nine zoarial fragments, now unattached. Horizon, locality and collection as for 0.28934. 0.40991-92, 0.40993. Two zoarial fragments encrusting pieces of echinoid test, and a zoarial fragment, now unattached. Horizon, locality and collection as for 0.28953. 0.40994-41018. Twenty-five zoarial fragments, now unattached. Horizon, locality and collection as for 0.28934. 0.41019. Zoarial fragment, now unattached, some zooecia with sealed orifices. Horizon, locality and collection as for 0.28934. i88 CRETACEOUS CRIBRIMORPH POLYZOA (PELM ATOPORIN AE) 0.41020-29. Ten zoarial fragments, now unattached. Horizon, locality and collection as for 0.28934. 0.41030-35. Six zoarial fragments, now unattached. Horizon, locality and collection as for 0.28953. 0.41041. Zoarial fragment with some ovicelled zooecia, fragment now un- attached. Horizon, locality and collection as for 0.28934. 0.41043. Pdmatopora cf. gregoryi. Worn, large zoarial fragment encrusting a piece of echinoid test. Senonian, zone of 0. pilula, subzone of E. scutata var. cincta. Section Z of Gaster, Swansbourn Lake Section, Arundel Park, Arun Gap, Sussex. 0.41044. Zoarial fragment, now unattached, very well preserved. Senonian, zone of 0. pilula, subzone of E. scutata var. cincta. Locality and collection as for 0.28963. 0.41045-46. Two zoarial fragments encrusting the same piece of echinoid test. Horizon, locality and collection as for 0.40700. 0.41058. Very well preserved, erect, cylindrical zoarial fragment. Horizon, locality and collection as for 0.28934. 0.41059. Well-preserved, large, zoarial fragment, now unattached. Horizon, locality and collection as for 0.28953. 0.41060-61. Two zoarial fragments encrusting pieces of echinoid test. Horizon, locality and collection as for 0.40697. 0.41062. Well-preserved zoarial fragment, now unattached. Senonian, zone of 0. pilula, subzone of E. scutata var. cincta. Section 142 of Gaster, cliff, Old Nore Point to Inn on west side of entrance to Newhaven Harbour, Sussex. 0.41063. Zoarial fragment encrusting a piece of echinoid test. Horizon, locality and collection as for 0.40697. OTHER MATERIAL S.M., 6.36120. Lectotype see above. 1906 1913 1919^ 1921 1921 1922 1922 1924 1930 21. Pelmatopora somptingensis Lang (PI. 14, figs. 5, 6 ; PI. 15, figs, i, 2, 4 ; Text-figs. 95-99) non Cribrilina gregoryi Brydone, pp. 290, 300, text-fig. 13. Cribrilina gregoryi Brydone : Lang, p. 171 [partim 0.23963 only]. Pelmatopora somptingensis Lang, pp. 103, 106. Pelmatopora danktonensis Lang, pp. 103, 106. Pelmatopora somptingensis Lang Pelmatopora danktonensis Lang : Pelmatopora somptingensis Lang Pelmatopora danktonensis Lang : Pelmatopora somptingensis Lang Lang, pp. 214, 221, 224, text-figs. 57-58. Lang, pp. 215, 221. Lang, p. xci. Lang, p. xcii. Lang, p. 300, text-figs. 736, 94. Pelmatopora danktonensis Lang : Lang, p. 309, text-figs. 730, 96. Pelmatopora somptingensis Lang Pelmatopora danktonensis Lang : Gaster, second of three tables opp. p. no. Gaster, table opp. p. 340. CRETACEOUS CRIBRIMORPH POLYZOA (PELM ATOPORIN AE) 189 HOLOTYPE. 0.28762. Zoarial fragment encrusting a piece of echinoid test. Senonian, zone of G. [A.] quadrata. Sompting, Sussex. T. H. Withers Collection. EMENDED DIAGNOSIS. Pelmatopom with a pair of laterally flattened, distally expanded, enlarged distal oral spines which have a marked tendency to bifurcate. DESCRIPTION. Zoarium unilaminar, encrusting, or now unattached. Adult zooecia elliptical or with almost parallel sides. Orifice wider than high, distally and laterally rounded, with a straight proximal margin, the outline much indented by the pair of enlarged distal oral spines. Oral spines 4, only the distal pair visible ; they are much enlarged, laterally flattened, expanded distally, and have a marked tendency to bifurcate the " outer horn " of the bifurcation often considerably produced towards the proximal-lateral margins of the orifice. The unmodified lateral oral spines are always concealed by secondary tissue round the margin of the orifice. Frontal shield of variable length, apparently flat. Costae 14-22 (often 16 or 17), well spaced and well defined, each with a larger outer and a smaller inner pelma, and often with a pelmatidium close to the mid-line. Lateral costal fusions occur at the levels of the pelmata, producing two paired rows of intercostal spaces. Apertural bar wide, low, sloping down distally to the orifice and with obscure pelmata. Gymnocyst concealed by plentiful interzooecial secondary tissue which fills the inter- zooecial valleys. Slight, shallow, irregularly elongate depressions occur in the surface of the interzooecial tissue. Avicularia large, prominent, distally pointed and directed, regularly paired, one near each proximal-lateral corner of the orifice. The form of the avicularian aperture is variable ; it may be slit-like, as in 0.39361, widely oval but pointed distally, oval proximally and slit-like distally, as in 0.39343, or very occasionally, with a transverse bar dividing the aperture into an approximately semicircular proximal portion and a triangular rostrum. The various avicularian apertures are often raised on robust stalks of variable length (Text-fig. 98). Ovicells apparently endozooecial. In ovicelled zooecia, the space between the enlarged distal oral spines is infilled with secondary calcareous tissue producing a prominent, somewhat pointed distal oral shield. Young zooecia smaller than the adult and less complex. Very young zooecia close to the ancestrula have typically well-arched frontal shields with somewhat flattened median areas. The enlarged distal oral spines are more peg-like rather than ex- panded as in the adult zooecia. Costae 10-12, even in the smallest zooecia, each with a pelma about half-way along its length. It is difficult to determine whether pelmatidia are present possibly they occur very close to the mid-line. Apertural bar relatively very wide. The gymnocyst is possibly revealed in small, deep lacunae in the plentiful interzooecial secondary tissue. Avicularia are apparently already paired in the very young stages of zoarial growth, one on either side of each zooecium, but they are not definitely placed near the proximal-lateral corners of each orifice. Less young zooecia are larger than those immediately surrounding the ancestrula, but otherwise generally similar, the avicularia tend to be more definitely paired near the proximal-lateral corners of the orifice, and the enlarged distal oral spines are larger with a definite tendency to expand at their distal ends. igo CRETACEOUS CRIBRIMORPH POLYZOA (PELM ATOPORIN AE) jOmm. 97 0-5 FIGS. 95-97. Pelmatopora somptingensis Lang. (95) 0.28747. Paratype. (a) Young zooecium and four worn avicularia. (b) Adult zooecium and four worn avicularia ; the enlarged distal oral spines are very worn. (96) 0.28762. Holotype. Adult zooecium with well-preserved distal oral spines and one worn and three unworn avicularia. The two proximal avicularia belong to adjacent zooecia. (97) Orifices of seven adult zooecia of several zoaria. The variation in form of the enlarged distal oral spines is due largely to different degrees of wear, (a 1 ' 2 ) 0.28762, holotype, front and oblique side views ; (b, f) D. 39346 ; (c, g) D. 39343 ; (d) 0.28762, holotype ; ( f) D - 28770, para- type. (99) 0.28770. Paratype. (a) Front view and (b) side view of parts of two adult, ovicelled zooecia with shelf-like distal oral shields produced by the infilling of the space between the distal oral spines with secondary calcareous tissue. 192 CRETACEOUS CRIBRIMORPH POLYZOA (PELM ATOPORINAE) MEASUREMENTS. Adult zooecia Lz = i-oo to 1-15 mm. Iz = 0-45 to 0-55 mm. hr = 0-18 to 0-21 mm. Ir = 0-21 to 0-24 mm. Avicularia Lz = 0-15 to 0-20 mm. Iz = 0-07 to 0-09 mm. Young zooecia (Outer edge of circum-ancestrular area) Lz = 0-65 to 0-78 mm. Iz = 0-39 to 0-45 mm. (Very close to the ancestrula) Lz = 0-50 to 0-54 mm. Iz = 0-33 to 0-35 mm. REMARKS. The holotype and all available specimens identified by Lang as P. somptingensis have been re-examined. P. danktonensis Lang is synonymous with P. somptingensis Lang. The holotype of P. danktonensis, 0.23963, has all the features typical of the worn examples of P. somptingensis. The range in number of costae in 0.23963 is 13-19 ; the enlarged distal oral spines, where preserved, are lengthened distally and are relatively broad, the position and form of the avicularia compares closely with those in P. somptingensis, and the stratigraphical distribution is well within the range of P. somptingensis. In P. somptingensis the avicularian aperture varies in form as described above. It is significant that the avicularia, where unworn, are raised on robust stalks so that the apertures slope upwards distally and are raised above the general level of the zoarium. They are thus particularly exposed to wear, and may often be reduced to the apparently oval form which the avicularia of most slightly abraded specimens appear to have, and which is almost certainly produced by abrasion wearing down the hollow, oval avicularian stalks (e.g., the worn avicularia shown in Text-fig. 95, 6). The enlarged distal oral spines of P. somptingensis may show a considerable variety of shape and size, largely dependent on the amount of abrasion they have undergone. Text-fig, gja-g illustrates a series of orifices from several zoaria : the variations in form are due almost entirely to different degrees of wear, but the enlarged distal oral spines all tend to be distally extended and bifurcated, contrasting with the more narrowly elongate and more pointed enlarged distal oral spines of P. gregoryi, and with the smaller, peg-like enlarged distal oral spines of P. marsupi- torum. The description, given above, of very young zooecia and zooecia at the periphery of the circum-ancestrular area is based primarily on 0.28747. Although Lang (1922 : 301) has described its ancestrula, it is not possible to determine its form definitely. The specimen is well preserved, particularly in the circum-ancestrular area, but the smallest visible zooecium is considerably damaged and further obscured by two somewhat larger zooecia which stand up above the general level of the zoarium. CRETACEOUS CRIBRIMORPH POLYZOA (PELM ATOPORIN AE) 193 0.29064 is an extremely large, somewhat worn, encrusting zoarium of P. somptin- gensis with at least one abnormal zooecium produced, apparently, by the coalescence of the buds of two adjacent rows of zooecia. It is similar in general form to that figured from 0.39301 a specimen of P. gregoryi. A large number of specimens have been assigned to P. somptingensis. The species is particularly abundant in the material collected by Gaster from the zone of G. [A.] quadrata. In paratype 0.28770, and in 0.39343, ovicelled zooecia with prominent distal oral shields are present. The variations shown by 0.39343 in the number of costae in individual zooecia, in the shape of the zooecia, and in the form of the enlarged distal oral spines, are fairly typical of the species as a whole. Well-preserved oral spines and avicularia occur particularly in the following specimens : 0.39331, 0.39335, D.39338, 0.39346, 0.39349, 0.39350, 0.39361, 0.39372, 0.39377, 0.39407, 0.39409, and 0.39413. The enlarged distal oral spines of 0.39377 have an extremely wide bifurcated form which approaches that typical of the distal oral spines of P. palmata. STRATIGRAPHICAL DISTRIBUTION. Senonian, zone of 0. pilula, subzone of E. scutata var. depressula (upper part) into the zone of G. [A.] quadrata (especially abundant in the latter zone). SPECIMENS. 0.28762. Holotype see above. 0.28101-09, 0.28747-61, 0.28763-75. Thirty-seven paratypes. Zoarial frag- ments. Senonian, zone of G. [A.] quadrata. Pit 7 of Gaster, Upton Lane (Lambley's Lane), north-west of Sompting, Sussex. [The same locality, horizon and collection as the holotype.] 0.28776-86, 0.28788-94, 0.28797, 0.28979-85. Twenty-five paratypes. Zoarial fragments. Senonian, zone of G. [A.] quadrata. Pit 9 of Gaster, eastern pit in lane on eastern side of Charman Dean, north of Broad- water, Sussex. T. H. Withers Collection [except 0.28979-85, C. T. A. Gaster Collection]. 0.28798-801, 0.28988-92. Nine paratypes. Zoarial fragments. Senonian, zone of G. [A.] quadrata. Pit 10 of Gaster, western pit in lane on eastern side of Charman Dean, north of Broadwater, Sussex. 0.28798-801, T. H. Withers Collection ; 0.28988-92, C. T. A. Gaster Collection. 0.4338, 0.29062. Two zoarial fragments. Senonian, zone of G. [A.] quadrata. East Harham, south of Salisbury. W. Gamble Collection. 0.29056-58. Three zoarial fragments. Senonian, zone of G. [A.] quadrata. Pit 8 of Gaster, about half-way between Upton Lane (Lambley's Lane), Sompting, and the lane east of Charman Dean, north of Broadwater, Sussex. O-3933 1 - Zoarial fragment. Senonian, zone of G. [A.] quadrata. Pit 12 of Gaster, large pit north of Pumping Station, top of Waterworks Lane, north-east of " The Warren ", north of Broadwater and Worthing, Sussex. D.39332-37, 0.39465. Seven zoarial fragments. Horizon, locality and collection as for 0.28798. GEOL. 6, I. 13 194 CRETACEOUS CRIBRIMORPH POLYZOA ( PELM ATOPORIN AE) D-39338, 0.39342-43, 0.39345-47, 0.39349-50, 0.39353-54, 0.39358, 0.39361-62, 0.39364-65, 0.39367, 0.39409, 0.39466, 0.40054-56. Twenty-one zoarial fragments. Senonian, zone of G. [A.] quadrata. Pit 15 of Gaster, large pit about one-third of a mile south-east of Salvington Windmill, and north of Hill Cottages, Salvington, Sussex. 0.23963. Holotype of P. danktonensis Lang. Senonian, zone of 0. pilula, subzone of E. scutata var. depressula. Pit 5 of Gaster, pit in Dankton Lane, north of Sompting Church, north-east of Worthing, Sussex. W. D. Lang Collection. 0.29862. Zoarial fragment labelled by Lang " P. danktonensis " . Senonian, zone of 0, pilula, subzone of E. scutata var. cincta. Cliffs, west of Broadwater and Castle Hill, Newhaven, Sussex. 0.29877-78, 0.29864. Three zoarial fragments, the last labelled by Lang " P. danktonensis ". Senonian, zone of 0. pilula, subzone of E. scutata var. depressula (upper part). Pit 2 of Gaster, pit by reservoir, near Hill Barn, North Lancing, Sussex. 0.29863. Zoarial fragment labelled by Lang " P. danktonensis ". Senonian, zone of 0. pilula, subzone of E, scutata var. depressula. Pit 4 of Gaster, pit west of Boundstone Lane, south of Lancing Ring, north- east of Worthing, Sussex. 0.39372, 0.39374-75, 0.39377, 0.39380-810, b, 0.39384-85, 0.39467-68. Frag- ments of eleven zoaria. Senonian, zone of G. [A.] quadrata. Pit 20 of Gaster, lower pit on Patching Hill, north of St. John's Church, Patching, Sussex. 0.39391, 0.39469. Two zoarial fragments encrusting pieces of echinoid test. Horizon, locality and collection as for D. 28101. 0.39394, 0.39470-72. Four zoarial fragments. Senonian, zone of G. [A.] quadrata. Pit 44 of Gaster, by Mile Oak Road, about one-third of a mile north- east of Windmill Inn, Southwick, one furlong north of Upper Shoreham Road, Sussex. 0.39395-96, 0.40129, 0.40131. Four zoarial fragments. Horizon, locality and collection as for 0.29056. 0.39397, 0.39473-75. Four zoarial fragments. Senonian, zone of G. [A.] quadrata. Pit 18 of Gaster, Old Lime Kiln, north-west corner of Munery's Copse, west of Pit 17 of Gaster, and east end of Clapham Wood, Sussex. 0.39402, 0.39476-78, 0.40067-73, 0.40087-97, 0.40109-10, 0.40111-24, 0.40132. Thirty-nine zoarial fragments. Horizon, locality and collection as for 0.28776. 0.39404, 0.39479, 0.40050-53. Six zoarial fragments. Senonian, zone of G. [A.] quadrata. Pit 26 of Gaster, South Woodleighs Pit, east of gravel pit, north-east of Woodleighs Lodge, about half a mile west of pit 24 of Gaster, Warningcamp, north-east of Arundel, Sussex. 0.39407. Zoarial fragment. Senonian, zone of G. [A.] quadrata. From material labelled " Pits 17, 18, 19, 24 and 32 " of Gaster [all in the zone of G. [A.] quadrata]. CRETACEOUS CRIBRIMORPH POLYZOA ( PELM ATOPORIN A E) 195 D.394H. D-394I3- 0.40074-78, 0.40106-07. 0.40098-103, 0.40108. D-39435-49- 0.29064. D-39454-63- 0.39464. 0.29876. 0.40718-19. Zoarial fragment with some ovicelled zooecia. Senonian, zone of G. [A.} quadrata. Pit 35 of Gaster, small pit, north of Rake Mead Plantation, Church Hill Shaw, about half a mile north-west of Roger's Farm, and west of South Park, just above 400 ft. contour, Findon, Sussex. Zoarial fragment. Senonian, zone of G. [A.} quadrata. From material labelled " Pits 8, n, 15, 16, 17, and 23 " of Gaster. [All in the zone of G. [A.] quadrata.] 0.40104, 0.40081-86, 0.40079-80. Fourteen zoarial fragments. Horizon locality and collection as for 0.28101. Two zoarial fragments. Horizon, locality and collection as for 0.28101. 0.40105, 0.40125-28, 0.40130, 0.39450-53. Sixteen zoarial frag- ments. Horizon, locality and collection as for 0.28798. 0.39450- 53, T. H. Withers Collection. Zoarial fragment. Senonian, zone of G. [A.] quadrata. Pit 23 of Gaster, near Angmering Park Cottages, Angmering, Sussex. Fifteen zoarial fragments. Horizon and locality as for D. 28101. T. H. Withers Collection. Zoarial fragment. Senonian, zone uncertain, very probably zone of G. [A.] quadrata. South of England. F. H. Butler Collection. Ten zoarial fragments. Horizon, locality and collection as for 0.29877. Zoarial fragment. Horizon, locality and collection as for D. 28101. Zoarial fragment. Senonian, zone of 0. pilula, subzone of E. scutata var. cincta. Pit by roadside between Burpham and Arundel, and west-north-west of Warningcamp Hill, Sussex. Two zoarial fragments encrusting pieces of echinoid test. Senonian, zone of 0. pilula, subzone of E. scutata var. cincta. Locality as for 0.29877. Zoarial fragment, now unattached. Horizon and locality as for 0.28101. Zoarial fragment, now unattached. Horizon and locality as for 0.28776. Nine zoarial fragments, now unattached. Horizon, locality and collection as for 0.28798. Twenty-nine zoarial fragments, now unattached. Horizon, locality and collection as for 0.29056. Three zoarial fragments now unattached. Horizon, locality and collection as for 0.28798. Eight zoarial fragments, now unattached. Horizon, locality and collection as for 0.39331. Pelmatopora cf. somptingensis. Zoarial fragment, now unattached. Senonian, zone of 0. pilula, subzone of E. scutata var. cincta. Pit 25 of Gaster, small roadside pit, just over half a mile south of Burpham, one-third of a mile north of Pit 26 of Gaster, west-north-west of Warningcamp Hill, north-east of Arundel, Sussex. ig6 CRETACEOUS CRIBRIMORPH POLYZOA (PELM ATOPORIN AE) 22. Pelmatopora palmata Lang (PL 15, figs. 3, 5, 6 ; Text-figs. 100-102) igi6a Pelmatopora palmata Lang, pp. 103, 107. igi6a Pelmatopora damicornis Lang, pp. 103, 107. 191601 Pelmatopora (Cribrilina) gregoryi (Brydone) : Lang, p. 106 [partim D.Soog, 0.28537, D. 21 169 only]. 1919^ Pelmatopora palmata Lang : Lang, pp. 199, 214, 221, text-figs. 12-14, 59. 60. igigd Pelmatopora damicornis Lang : Lang, pp. 215, 221. 1921 Pelmatopora palmata Lang : Lang, p. xci. 1921 Pelmatopora damicornis Lang : Lang, p. xci. 1922 Pelmatopora palmata Lang : Lang, p. 306, pi. 6, fig. 7 ; text-figs. 73^, 96. 1922 Pelmatopora damicornis Lang : Lang, p. 307. 1922 Pelmatopora gregoryi (Brydone) : Lang, p. 304 [partim 0.8009, 0.28537, 0.21169 only]. 1924 Pelmatopora palmata Lang : Gaster, second of three tables opp. p. no. 1930 Pelmatopora palmata Lang : Gaster, table opp. p. 340. HOLOTYPE. D.Soio. Zoarial fragment, now unattached, Senonian, zone of G. [A.] quadrata. Winchester, Hampshire. R. M. Brydone Collection. EMENDED DIAGNOSIS. Pelmatopora with a pair of enlarged distal oral spines which are very broad distally and distinctly bilobed. DESCRIPTION. Zoarium uni- or bilaminar, encrusting or now unattached. Zooecia elliptical, the sides tending to be parallel. Orifice wider than high, distally and laterally rounded, with a straight proximal margin, its outline very much indented by the pair of enlarged distal oral spines. Oral spines 4 only the distal pair visible ; these are much enlarged, distally expanded and distinctly bilobed. The unmodified pair of lateral oral spines is always concealed by secondary tissue accumulated round the margin of the orifice. Frontal shield of variable length, apparently fairly flat. Costae 16-20 (often 1 8 or 19), well defined, each with a larger outer and a smaller inner pelma, and usually with a pelmatidium near the mid-line. Lateral costal fusions arise at the levels of the pelmata producing two paired rows of intercostal spaces. Apertural bar wide, low, with obscure pelmata ; the apertural bar slopes down slightly towards the proximal edge of the orifice. Gymnocyst entirely concealed by interzooecial secondary tissue which fills the interzooecial valleys and which contains irregularly elongate shallow depressions. Avicularia prominent, large, distally pointed and directed, regularly paired, one near each proximal-lateral corner of the orifice. Well-preserved avicularia lack transverse bars, the aperture is semicircular proximally with a distally pointed rostrum, the apertures of many avicularia are raised on stout stalks above the general level of the zoarium. Ovicells not seen. MEASUREMENTS. Zooecia Lz = i-oo to 1-25 mm. Iz = 0-42 to 0-50 mm. hr = 0-18 mm. Ir = 0-21 mm. Avicularia Lz =0-15 mm. Iz = 0-06 mm. CRETACEOUS CRIBRIMORPH POLYZOA (PELM ATOPORIN AE) 197 0,5mm. Oi2mm. 100 102 O;5mm 101 FIGS. 100-102. Pelmatopora palmata Lang. (100) D.Soio. Holotype. Adult zooecium and four worn avicularia ; those near the proximal end belong to adjacent zooecia. The distal oral spines are typically flat and bilobed, that on the right is worn obliquely. (101) D.Soio. Holotype. Orifices of two adult zooecia. (a) markedly flat, bilobed distal oral spines, that on the right is worn ; (b) both distal oral spines are worn obliquely. (102) D.Soio. Holotype. Avicularia. (a) Unworn, (b) worn the oval form is a cross-section of the avicularian stalk. 198 CRETACEOUS CRIBRIMORPH POLYZOA ( PELM ATOPORI N AE) REMARKS. Lang (1922 : 305) interpreted P. gregoryi (Brydone) from Brydone's 1906 description and figure. Unfortunately these were not sufficiently clear to show the nature of the enlarged distal oral spines, and Lang supposed P. gregoryi to be similar to P. damicornis in these respects. He maintained the three species (P. gregoryi, P. damicornis and P. palmata} as separate solely on supposed differences in zoarial growth habit. However, it has been shown that the enlarged distal oral spines of the lectotype of P. gregoryi, S.M., 6.36120, as well as other zooecial charac- ters, are different from those of P. palmata. The latter is thus retained as a separate species, but is regarded as synonymous with P. damicornis. The supposed differences in zoarial growth habit of P. palmata and P. damicornis are very uncertain, and the two species are otherwise morphologically alike. D.Soog, 0.28537 and 0.21169, labelled by Lang " Pelmatopora [Cribrilina] gregoryi (Brydone) ", are also referred to P. palmata Lang. 0.8009 an d 0.28537 are somewhat worn, but appear to have distally expanded, bilobed distal oral spines, and are thus placed in P. palmata with a query. 0.21169 is better preserved and is placed in P. palmata with certainty. 0.20204, holotype of P. damicornis Lang, is well preserved and may be definitely assigned to P. palmata. It may be significant that there is relatively little material which can definitely be placed in P. palmata. This is possibly explained by difficulties imposed by poor preservation, particularly by wear of the enlarged distal oral spines. It has, how- ever, been noted that worn bilobed oral spines differ in form from worn elongate oral spines such as occur in P. gregoryi. Where wear has reduced oral spines it is thus possible to differentiate between bilobed and elongate types, but the identification must also rest largely on other zooecial characters, such as zooecial size, range in number of costae, type and amount of interzooecial tissue and form and distribution of avicularia. 0.39355 and 0.39356 have especially well-preserved enlarged distal oral spines typical of P. palmata. STRATIGRAPHICAL DISTRIBUTION. Senonian, zone of 0. pilula, subzone of E. scutata var. cincta to zone of G. [A.] quadrata. SPECIMENS. D.Soio. Holotype see above. [The specimen is labelled " Idio- type of P. gregoryi (Brydone) ".] 0.28971. Paratype. Zoarial fragment. Senonian, zone of G. [A.} quadrata. Pit 8 of Gaster, between Upton Lane (Lambley's Lane), Sompting, and lane east of Charman Dean, north of Broadwater, Worthing, Sussex. 0.20204. Holotype of P. damicornis Lang. Zoarial fragment. Senonian, zone of G. [A .] quadrata. Seaford, Sussex. Collection unspecified. PD.Soog. Large fragment of a worn zoarium. Labelled by Lang " Pelmatopora gregoryi (Brydone). Idiotype ". Senonian, zone of G. [A.} quadrata. Sussex Coast. R. M. Brydone Collection. PD.28537. Three fragments of the same zoarium. Labelled as for 0.8009. Senonian, horizon unspecified, probably zone of G. [A.] quadrata. Southern England. F. K. Butler Collection. 0.21169. Zoarial fragment. Labelled as for 0.8009. Senonian, zone of G. [A.] CRETACEOUS CRIBRIMORPH POLYZOA (PELM ATOPO RIN AE) 199 quadrata. Southampton Waterworks Pit, Otterbourne, south of Winchester, Hampshire. L. Treacher Collection. 0.28865. Zoarial fragment. Senonian, zone of 0. pilula, subzone of E. scutata var. cincta. Pit on East Hill, Rottingdean, east of Brighton, Sussex. D.39339, 0.39355-56. Three zoarial fragments. Senonian, zone of G. [A.] quadrata. Pit 15 of Gaster, large pit about one-third of a mile south-south-east of Salvington Windmill, and north of Hill Cottages, Salvington, Sussex. 0.39370, 0.39378. Two zoarial fragments. Senonian, zone of G, [A.] quadrata. Pit 20 of Gaster, lower pit on Patching Hill, north of St. John's Church, just above the 200 ft. contour, Patching, Sussex. 0.39410. Zoarial fragment. Senonian, zone of G. [A.] quadrata. Pit 35 of Gaster, small pit north of Rake Mead Plantation, Church Hill Shaw, about half a mile north-west of Rogers Farm, and west of South Park, just above the 400 ft. contour, Findon, Sussex. PELMATOPORA sp. (PL 15, fig. 7) SPECIMEN. 0.39330. Zoarial fragment encrusting a piece of echinoid test. Senonian, zone of B. mucronata. Pit 105 of Rowe. White Pit Lane, Newport, Isle of Wight. DESCRIPTION. Zoarium encrusting, unilaminar. Zooecia elongate-elliptical with somewhat parallel sides. Orifice wider than high, distally and laterally rounded, with a straight proximal margin, its outline indented by two worn, enlarged distal oral spines. Only the distal pair of oral spines is visible, and only their distinctly rounded bases are preserved ; one enlarged oral spine is apparently hollow. Un- modified lateral oral spine-bases, if present, are concealed by secondary tissue. Frontal shield of variable length. Costae 20-24 (often 22), well denned, each with a fairly prominent pelma near its outer end, a second smaller pelma about half-way along its length, and a pelmatidium, often obscure, near the mid-line. Lateral costal fusions arise at the level of the pelmata producing two paired rows of intercostal spaces ; an additional irregularly developed row of small intercostal spaces may occur very close to the mid-line. The outermost intercostal spaces are slot-like. Apertural bar wide, flat, sloping down towards the proximal margin of the orifice. Gymnocyst entirely concealed by interzooecial secondary tissue, which fills the inter- zooecial valleys and which contains irregular, elongate, shallow lacunae. Avicularia either oval or elongate and distally pointed. In the specimen, all avicularia are worn. There is, however, a strong tendency for the avicularia to be arranged in pairs, one near each proximal-lateral corner of the orifice. Ovicells not seen. MEASUREMENTS. Zooecia Lz = 1-24 to 1-50 mm. Iz = 0-42 to 0-50 mm. hr = 0-15 to 0-18 mm. lr = 0-18 to o-2i mm. Avicularia Not measurable. 200 CRETACEOUS CRIBRIMORPH POLYZOA (PELM ATOPORI N AE) REMARKS. Lang has stated that Pelmatopora does not range above the zone of G. [A.] quadmta. However, 0.39330 was collected from Pit 105 of Rowe, which was placed by him (1908 : 280) in the zone of B. mucronata " beyond doubt ". Recent collecting neither confirms nor disproves Rowe's suggested horizon for his Pit 105. Some features of 0.39330 are unlike any seen in the other known species of Pelmatopora ; the large size of the zooecia and the large number of costae are particularly unusual. One zooecium with 28 costae is distorted proximally and is regarded as abnormal, the usual range in the specimen being 20-24. The specimen obviously belongs to the group of Pelmatopora species which possess enlarged distal oral spines, and it is very probable that its enlarged oral spines are not of the expanded bilobed type but rather of the elongate, outwardly curving form, with rounded bases, such as are developed in P. gregoryi. Although the specimen is unlike any known species of Pelmatopora, it is not advisable to erect a new species on a single somewhat worn specimen, and diagnosis must depend on better preserved material. The specimen is important as the only definite Pelmatopora from the zone of B. mucronata. Although Voigt (19256 ; 1930) has assigned species from the zone of B. mucro- nata and higher horizons to Pelmatopora, these may not be correctly placed in that genus. An exceptional occurrence of Pelmatopora in the Danian is noted in the remarks on P. daniensis Voigt (p. 202). SPECIES OF UNCERTAIN SYSTEMATIC POSITION PREVIOUSLY ASSIGNED TO PELMATOPORA (i) Pelmatopora incerta Voigt 19256 Pelmatopora incerta Voigt, pp. 99, 100, pi. 3, figs. 9, 10 ; text-fig, i. 1930 Pelmatopora incerta Voigt : Voigt, pp. 515, 561, pi. 31, fig. 15 [part of the same zoaiium figured by Voigt, 19256, pi. 3, fig. 9]. J 939 Pelmatopora incerta Voigt : Voigt, p. 93, text-fig. 40 [copy of Voigt, 19256, text-fig, i]. DESCRIPTION. [Based on Voigt's descriptions and figures.] Zoarium unilaminar, encrusting. Zooecia about two-thirds as wide as long. Orifice about as long as wide, distally and laterally rounded, with a straight proximal margin, and with proximal-lateral " slits ". Oral spine-bases 4, frontal shield flatly arched. Costae about 20, closely spaced, " fused " only in the mid-line, each with a number of pelmatidia (the outermost and the innermost pelmatidia appear to be better developed than the intervening ones). Individual costae taper towards their inner ends and have slightly curved margins (? = the slightly crenulate outlines shown in Voigt's text-figure). Lateral costal fusions possibly present. The costae meet and fuse in the mid-line, producing a slight median ridge, or, as in at least one zooecium figured by Voigt, there is a flat median area. Gymnocyst well exposed, especially proximally to the frontal shield. Interzooecial secondary tissue apparently absent. Avicularia apparently rare, elongate, oval (their form is not apparent from the photographs). Ovicells not seen. REMARKS. Voigt has suggested that the species belongs to the group of " primi- tive ", less complex Pelmatopora species in which the costae are fused only in the CRETACEOUS CRT BRIMORPH POLYZOA (PELM ATOPORI N AE) 201 mid-line. Although this is apparently so in several of the zooecia figured by Voigt, each costa also has a row of pelmata or pelmatidia a condition found in the later, more complex species of Pelmatopora. Also, in the earlier forms of Pelmatopora, the costae are characterized by single, large pelmata developed near the mid-line of the frontal shield, or surrounding the median area of fusion when this is present. In incerta the larger pelmata or pelmatidia are distinctly at the extreme outer ends of the costae. The avicularia, described by Voigt as rare and elongate oval, are not discernible in the photographs. The stylized text-figure shows a single avicularium which is directed proximally and constricted laterally so that it is partly divided into a smaller semicircular portion and a distal area which is elongate-oval. This type of avicularium is unknown in other species of Pelmatopora. In the absence of actual material it is undesirable to attempt to decide the definite systematic position of a species known only from inadequate photographs and descriptions. However, incerta is very probably not a Pelmatopora. STRATIGRAPHICAL DISTRIBUTION. " Ob. Senongeschiebe ", Kothen. (2) Pelmatopara grandiporosa Voigt 1930 Pelmatopora grandiporosa Voigt, pp. 514, 561, pi. 31, figs. 13, 14. DESCRIPTION. [Based on Voigt's description and figures.] Zoarium unilaminar, encrusting. Zooecia about twice as long as wide. Orifice large, distally and laterally rounded, with a straight proximal margin. Number and form of oral spines un- known. Frontal shield apparently fairly flat, but curving down steeply at the margins to meet the gymnocyst. Costae about 10, very wide, very irregularly arranged, each with a large, oval pelma at the outer end. Interzooecial secondary tissue probably abundant. Avicularia not distinct in the photographs, but, according to Voigt, many small avicularia occur between the zooecia. REMARKS. From the photographs it is not possible to place this species in Pelmatopora. Voigt has suggested that the irregular arrangement of the few, very thick costae distinguishes the species from all known species of Pelmatopora, but this irregular arrangement of the costae, their coarseness, and the numerous interzooecial avicularia which Voigt mentioned, all contrast with the generally settled more complex pattern of Pelmatopora at the horizon involved. The placing of the species as a Pelmatopora is thus very uncertain, and, in the absence of actual material, it may not be described with certainty beyond " cribrimorph of the Pelmatoporidae ". STRATIGRAPHICAL DISTRIBUTION. Granulatensenon. Gt. Biilten. (3) Pelmatopora sp. 1930 Pelmatopora sp., Voigt, pp. 514, 561, pi. 31, fig. 12. REMARKS. Voigt described the zoarium as " free ", bilaminar, with zooecia of Lz = 075 to 0-80 mm., and with frontal shield with 10-13 costae, he could not identify it with any of Lang's species of Pelmatopora. The photograph of the specimen is small, but apparently shows at least one lateral costal fusion arising between the inner ends of the costae near a narrow median area. 202 CRETACEOUS CRIBRIMORPH POLYZOA ( PELM ATOPORIN AE) From the description and photograph alone it seems very uncertain that the specimen should be placed in Pelmatopora. STRATIGRAPHICAL DISTRIBUTION. " Granulatensenon ". Gt. Biilten. (4) Pelmatopora daniensis (Voigt) 19256 Pelmatopora daniensis Voigt, pp. 99, 100, pi. 3, figs. 4-6 ; text-fig. 2. 1930 Pelmatopora daniensis Voigt : Voigt, pp. 514, 561, pi. 31, fig. u. DESCRIPTION. (Based on Voigt's figures.) Zoarium apparently unilaminar, erect. Zooecia elongate-oval. Orifice wider than high, evenly rounded distally and laterally, proximal margin straight. Oral spine-bases 4, slightly enlarged, unmodified. Frontal-shield fairly well arched. Costae 20-24, each with 4 or 5 lateral costal fusions and pelmatidia ; outermost intercostal spaces distinct. Apertural bar narrow, form obscure. Gymnocyst hardly visible ; no interzooecial secondary tissue. Avicularia proximally directed, large, elongate-oval, somewhat pointed, a prominent transverse bar divides a small semicircular proximal portion from a longer, bluntly triangular rostrum. Avicularia one-quarter to one-third as long as the zooecia they accompany, irregularly distributed, apparently comparatively rare. Ovicells not seen. MEASUREMENTS. (According to Voigt, 19256, p. 101.) Zooecia Lz = 0-75 to 1-05 mm. Iz = 0-36 to 0-44 mm. Avicularia Lz = 0-21 to 0-24 mm. Iz = 0-08 to 0-12 mm. REMARKS. The shape of the orifice, the nature of the frontal shield, and particu- larly the form of the avicularia, distinguish this species from other species of Pelmatopora, but the characters are reminiscent in some ways of Castanopora. It is difficult to be certain that the specimens which Voigt (1925 : 99, 100, pi. 3, figs. 4-6) assigned to Pelmatopora daniensis should be placed definitely in that genus. However, Mr. Ole Berthelsen has very kindly shown me a single specimen from the Upper Danian of Herfelge, Seeland, which differs in some respects from Voigt's description and figures, but which is undoubtedly a Pelmatopora. The occurrence of this genus at this horizon is exceptional. Voigt himself compared his species (19256 : 101) with Reptescharella radiata d'Orbigny (1852, pi. 716, figs. 4-6), commenting " Eine gewisse Ahnlichkeit mit unserer Form zeigt Reptescharella radiata d'Orb., ist jedoch von ihr durch das inkrustierende Zoarium und durch weniger zahlreiche (16-18) aus etwa je 7-8 Poren gebildete Punktreihen verschieden ". Reptescharella radiata d'Orbigny was assigned by Lang (1922 : 187) to Rhiniopora. As Voigt stated, it is an encrusting form with fewer costae and slightly fewer intercostal spaces than daniensis. It is also possible that Reptescharella radiata lacks avicularia. The horizon of d'Orbigny's material is Campanian and Santonian of Meudon and CRETACEOUS CRIBRIMORPH POLYZOA (PELM ATOPORIN AE) 203 Saintes, France, whilst Voigt 's specimen is of Danian age from Cothen. On morpho- logical and stratigraphical features the two are maintained as separate. STRATIGRAPHICAL DISTRIBUTION. Danian. Genus CASTANOPORA Lang 1851 Cellepora (? Dermatopora) : von Hagenow, p. 99, pi. 10, fig. 19. 1851 Escharipora d'Orbigny, pis. 603, 684-687, 700, 703 [partim]. ?i852 Reptescharella d'Orbigny, pis. 604, 715-716 [partim}. 1852 Reptescharipora d'Orbigny, pis. 719, 720 [partim]. 1852 Escharipora : d'Orbigny, p. 221 [partim]. ?i853 Reptescharella : d'Orbigny, p. 464 [partim]. ?i854 Reptescharella : d'Orbigny, p. 1097 [partim]. 1854 Escharipora : d'Orbigny, p. 1097 [partim]. ?i854 Reptescharipora : d'Orbingy, p. 1098 [partim]. 1865 Escharipora : Ubaghs, p. 51. 1887 Cribrilina : Marsson, p. 96 [partim]. 1894 Membranipora : Gregory, p. 62. 1896 Membranipora : Gregory, p. 212. ? 1 9006 Reptescharipora : Canu, p. 457 [partim]. ? 19006 Cribrilina : Canu, p. 445 [partim]. 1906 Cribrilina : Brydone, pp. 296-298 [partim]. 1907 Cribrilina : Levinsen, pp. 155-156. 1913 Cribrilina : Brydone, pp. 436-438 [partim]. 19160 Rhiniopora Lang, pp. 93, 96-97. I9i6a Castanopora Lang, pp. 93-96. 1917 Rhiniopora : Lang, p. 172. I9I9C Castanopora : Lang, p. 105, footnote. 1922 Rhiniopora : Lang, p. 180. 1922 Castanopora : Lang, p. 202. 1923 Rhiniopora : Waters, pp. 548, 551. 1923 Castanopora : Waters, pp. 548, 551, 558-560. 1925 Cribrilina : Levinsen, p. 375 [partim]. ?I925 Barroisina : Levinsen, p. 384 [partim]. 1925^ Cribrilina : Voigt, p. 176 [partim C. asperula only]. 1927 Cribrilina : Voigt, p. 102 [partim]. ?I927 Barroisina : Voigt, p. 102 [partim]. 1927 Rhiniopora : Canu & Bassler, p. 37. 1927 Castanopora : Canu & Bassler, p. 25. 1929 Castanopora : Lang, pp. 438, 439. 1929 Rhiniopora : Lang, pp. 438, 439. 1930 Rhiniopora : Voigt, pp. 510, 511, 551, 561. 1930 Castanopora : Voigt, pp. 512, 513, 551, 561. J 935 Castanopora : Bassler, pp. 31, 65. J 935 Rhiniopora : Bassler, pp. 31, 190. J 953 Castanopora : Bassler, p. Gig2. X 953 Rhiniopora : Bassler, p. Gi93. I 953 Rhiniopora : lilies, p. 76. 1958 Rhiniopora: Butler & Cheetham, p. 1154. TYPE SPECIES. (By original designation.) Castanopora castanea Lang, igi6a : 95. Senonian, " zone of B. mucronata " , probably boreal Maastrichtian, Riigen. EMENDED DIAGNOSIS. Pelmatoporinae with numerous costae and numerous 204 CRETACEOUS CRIBRIMORPH POLYZOA (PELM ATOPORIN AE) pelmata or pelmatidia and lateral costal fusions ; no secondary orifice ; no tertiary front wall, avicularia large, variously directed, of one, two or three kinds, or occa- sionally none. REMARKS. Lang established the genera Castanopora and Rhiniopora, which I consider synonymous, to distinguish between the larger forms of Castanoporinae [here synonymous with the Pelmatoporinae] which lack secondary orifices and tertiary front walls. Castanopora was briefly diagnosed (Lang, igi6a : 93) as having " avicularia of two kinds, (i) directed distally and (2) directed proximally (the latter kind may be very rare or absent) ", while Rhiniopora was distinguished by its avicularia which " (if present) [are] of one kind only, proximally directed ". In his subsequent expansion of these definitions (1922 : 181, 203) Lang diagnosed the two genera as follows : Rhiniopora " Large Castanoporinae with numerous costae ; with no secondary [= tertiary] front- wall and no secondary aperture ; aviculoecia dimorphic, monomorphic, or none ; when dimorphic, some aviculoecia have long rostra, others pointed (but comparatively short) rostra, the former variously directed, the latter (? always) proximally directed ; when monomorphic, the aviculoecia are always of the latter type ". Castanopora " Large Castano- porinae with numerous costae, no tertiary front-wall and no secondary aperture ; paired, distally directed aviculoecia, having apertures with elongate pointed rostra, are present, and some species have proximally-directed aviculoecia also, with short rostra ". Lang thus distinguished between Rhiniopora and Castanopora solely on the form, orientation and kinds of avicularia present. He summarized his general conclusions (1922 : 156) and stated " In both genera the early species possess both long and short aviculoecia, but in Rhiniopora they are all variously and on the whole proxi- mally directed, while in Castanopora two of the longer aviculoecia, situated more-or- less symmetrically one on each side of each aperture, are distally directed. Rhinio- pora soon loses the longer aviculoecia and gradually tends to lose the shorter ones as well, while Castanopora retains the distally-directed ones and likewise gradually loses the aviculoecia with shorter apertures ". Waters (1923 : 548) commented on the close similarity of some Cretaceous cribri- morphs with Recent European cribriline genera and stated " in fact, it almost seems as if some of the Cretaceous forms might be considered varieties of our recent species, though rather larger ; and for the zoologist, the genera Castanopora and Rhiniopora, separated on slight grounds, are the most interesting (even if the names are dropped) as being represented in the living fauna ". Later (p. 551) Waters states " the avicularia are given an important place and, like the other characters, must be carefully studied, but we may well remember that in recent Cheilostomatous forms there are not only genera, but species, which sometimes have avicularia, sometimes none. Sometimes, when Lang speaks of dimorphic avicularia, there seems no difference except size . . . Judging from recent forms it would seem natural to say that avicularian characters have been used for the fossil genera where they have not more than specific value, even if that, and in recent species there is very great variation ". Re-examination of all the available material assigned by Lang to Rhiniopora CRETACEOUS CRIBRIMORPH POLYZOA (PELM ATOPORIN AE) 205 and Castanopora makes it difficult to confirm his separation of the genera. Varia- tions in the form, position and orientation of the avicularia are insufficient for such a purpose. But these variations, in conjunction with other characters, are here used to distinguish species. Also, several of the original species which Lang placed in Rhiniopora appear to be synonymous, and the same applies to several species originally placed in Castanopora. In the one species which has three kinds of avicularia there are a constantly paired,, distally directed and pointed form and two unpaired proximally directed forms, the one sporadic and the other constantly placed just distal to each orifice. In species with two types of avicularia both types are not present in all zooecia ; the most frequently occurring form is usually paired, distally directed and pointed, or occa- sionally spatulate, the less frequent form is unpaired, rounded, probably due to wear, or pointed, proximally directed and sporadic. Species with only one kind of avicularium also occur avicularia of this type are frequently paired, pointed and either all distally or all proximally directed ; or occasionally single, almost rounded and sporadic. Very occasionally avicularia may be absent. I retain the name Castanopora, rather than Rhiniopora, for the revised genus, and thus the type-species is Castanopora castanea Lang. STRATIGRAPHICAL DISTRIBUTION. Senonian zone of Marsupites to Danian. Canu & Bassler (1933 : 53, 54) assigned two species from the Vincentown Limesand to Rhiniopora, thus extending the upward range of the genus into the Palaeocene. 1 KEY TO THE SPECIES OF CASTANOPORA (I) Zoarium encrusting or erect, uni- or bilaminar. (A) Castanopora with three types of avicularia . . . i. C. artnata sp. nov. (B) Castanopora with two types of avicularia. (1) 28-34 costae ; avicularia distally directed, unpaired, very large, rounded, widely spatulate ; a more frequent, proximally directed, small, rounded form also present . . . . . 2. C. labiata (Levinsen) (2) 16-23 costae. (a) 4 (less often 3) lateral costal fusions on each costa ; avicularia distally directed, frequently paired, very elongate, sharply pointed ; a proximally directed, shorter, pointed form also present 3. C. retrorsa Lang (b) 4-8 (often 6-7 lateral costal fusions on each costa). (i) 4 oral spines only ; orifice wider than high ; avicularia distally directed ; frequently paired, elongate, pointed ; an occasional probably proximally directed, rounded sporadic form also present 4. C. castanea Lang (ii) 4 (occasionally 5) oral spines ; orifice slightly wider than high or as wide as high ; avicularia distally directed, elongate, pointed, constantly paired near orifice ; a less frequent, proximally directed, elongate pointed, sporadic form also present 5. C. dibleyi (Brydone) (iii) 5 or 6 oral spines ; avicularia possibly proximally directed, paired near orifice ; an occasional, proximally directed, elongate, pointed, sporadic form also present . . . 6. C. guascoi (Ubaghs) 1 The age of the Vincentown Limesand has been established as Palaeocene by (Loeblich & Tappan, 206 CRETACEOUS CRIBRIMORPH POLYZOA (PELM ATOPORI N AE) (C) Castanopora with one type of avicularium. (1) Zooecia small, Lz = 0-26 to 0-34 mm., Iz = 0-17 to 0-27 mm., hr = 0-04 to 0-07 mm., Ir = 0-06 to 0-09 mm. . 7. C. spooneri (Butler & Cheetham) (2) Zooecia larger, Lz more than 0-75 mm., Iz more than 0-36 mm., hr more than 0-15 mm., Ir more than 0-15 mm. (a) Orifice wider than high. (i) 5-6 oral spines ; 26-30 costae, each with about 9 lateral costal fusions ; avicularia distally directed, paired near orifice, elongate, pointed ..... 8. C. multicostata (Voigt) (ii) 6 oral spines only ; costae with 8 lateral costal fusions ; 25-30 costae ; avicularia rounded, fairly frequent, sporadic 9. C.jurassica (Gregory) (6) Orifice higher than wide or height approximately the same as width. (i) Avicularia all distally directed, elongate, pointed ; 24-27 costae, each with 6-8 (often 7) lateral costal fusions ; 5 (sometimes 4) oral spines . . . . . 10. C. glandulosa Lang (ii) Avicularia all proximally directed. (a) Avicularia with sharply pointed, elongate rostra ii. C. aviculosa (Lang) (fi) Avicularia rounded, small or relatively large, occasional, sporadic, never paired ; 14-30 (often about 20) costae ; 4-8 (often 5-7) lateral costal fusions ; 4-5 oral spines 12. C. magnified (d'Orbigny) (D) Castanopora with avicularia ; 13-15 costae, each with 6-7 lateral costal fusions ; gymnocyst widely exposed . . . . 13. C. faujasi (Hagenow) (II) Zoarium cylindro-quadrate, erect ; zooecia of the four adjacent rows alternate ; 20-25 costae . . . . . . . . . 14. C. voigti sp. nov. Cellepora perforata Quenstedt and Reptescharella radiata d'Orbigny were both referred to Rhiniopora by Lang (1922 : 183, 187). But as their systematic position is very uncertain, they have been omitted from the above key. A discussion of the status of these species is on p. 237. Rhiniopora hispida Lang is also omitted from the above key ; the holotype, the only specimen, is very badly damaged and worn, making generic and specific diagnosis impossible. The species is discussed on p. 237. Reptescharipora ornata d'Orbigny, referred to Castanopora by Lang (1922 : 213), is also omitted from the above key. The holotype is so poorly preserved that it is not possible to place the species with any certainty at all. The species is discussed on p. 238. i. Castanopora armata 1 sp. nov. (PL 16, fig. i ; Text-fig. 103) HOLOTYPE. 0.31717, an encrusting zoarial fragment of about ten zooecia. Maastrichtian, zone of Belemnella lanceolata (0. lunata Chalk). Southern Bluff, Trimingham, Norfolk. T. H. Withers Collection. DIAGNOSIS. Castanopora with orifice as wide as high ; oral spine-bases 4 ; costae 18-22, each with 4-6 (often 5) lateral costal fusions and pelmatidia ; avicularia of three kinds : one form constantly paired on either side of the orifice, distally directed and elongate ; a second form very prominent, proximally directed, sporadic and 1 Lat., armare, " to arm ", referring to the numerous avicularia. CRETACEOUS CRIBRIMORPH POLYZOA (PELM ATOPORIN AE) 207 variable in position ; a third form also proximally directed, but constantly placed just distally to the orifice. DESCRIPTION. Zoariwm encrusting, unilaminar. Zooecia slightly elongate-oval to broadly oval, very closely placed. Orifice about as wide as high, evenly rounded distally and laterally and without proximal-lateral constrictions, the proximal margin straight. Oral spine-bases 4, in two pairs placed distally and laterally respectively, all of about the same thickness. Frontal shield almost flat, its margins I OjSmm. FIG. 103. Castanopora armata sp. nov. 0.31717. Holotype. Adult zooecium with five avicularia and part of orifice of proximally adjacent zooecium ; a, avicularium of form a ; b, avicularium of form b ; c avicularium of form c. descending sharply at the inner ends of the somewhat slot-like outer intercostal spaces. Costae 18-22, each with 4-6 (usually 5) lateral costal fusions and an equiva- lent number of pelmatidia. Apertural bar only slightly raised, triangular, the apex directed proximally with a very slight median ridge. Gymnocyst almost concealed by the closeness of the zooecia and the development of the avicularia : no interzooecial secondary tissue present. Avicularia of three kinds : (a) a distally directed form, constantly paired one on each side of the orifice, each with a straight or slightly proximally curved transverse bar, separating a large, semicircular proximal portion from an elongate, spatulate rostrum, the distal end of which is narrower and almost parallel-sided these avicularia may be directed distally or may tend to embrace the lateral-distal margins of the orifice and point obiquely inwards ; (b) proximally directed, sporadic, variable 208 CRETACEOUS CRIBRIMORPH POLYZOA (PELM ATOPORIN AE) in position, and raised on a very stout stalk with a slightly curved transverse bar dividing a lunate or semicircular proximal portion from a pointed rostrum with inwardly curving margins ; (c) proximally directed, very similar to (b] but regularly placed just distally to each orifice. Several broken avicularia of this last type look superficially like broken ovicells. They may be recognized in the broken state by the fact that they do not obscure or interrupt the development of the distal pair of oral spines. Ovicells not seen. MEASUREMENTS. Zooecia Lz = 0-72 to 0-75 mm. Iz 0-45 to 0-56 mm. hr = 0-14 to 0-16 mm. lr = 0-16 to 0-17 mm. Avicularia: Type (a) Lz =0-24 mm. Iz = 0-095 mm. Type (b) Lz =0-24 mm. Iz = 0-12 mm. Type (c) Not measurable. REMARKS. 0.31717 differs from other species in possessing three types of avicularia. The most unusual type present is the regularly placed, proximally directed avicularium lying immediately distally to each orifice. The occurrence of frequent, proximally directed avicularia, taking into account both types, is unusual at this high stratigraphic level. Lang in fact suggested that the various species of Castanopora tend, in successively higher horizons, to have fewer and fewer proximally directed avicularia. STRATIGRAPHICAL DISTRIBUTION. Maastrichtian, zone of Belemnella lanceolata (Ostrea lunata Chalk). SPECIMEN. Holotype see above. 2. Castanopora labiata (Levinsen) 1907 Cribrilina labiata Levinsen, pp. 155, 156, 158, pi. opp. p. 160, figs, i, la-f. 191 6a Rhiniopora labiata (Levinsen) Lang, p. 96. 1922 Rhiniopora labiata (Levinsen) : Lang, p. 186. 1925 Cribrilina valida Levinsen, p. 376, pi. 5, figs. 58^-^ (copy of Levinsen's 1907 figures). 1927 Cribrilina valida Levinsen : Voigt, p. 102. 1930 Cribrilina valida Levinsen : Voigt, p. 551. LECTOTYPE. (Chosen by Lang, 19160 : 96) Specimen figured by Levinsen, 1907, pi. opp. p. 160, fig. i. Lower Maastrichtian, zone of Belemnella lanceolata. M0en and Aalborg, Denmark. EMENDED DIAGNOSIS. Castanopora with 28-34 costae ; avicularia of two kinds : one form distally directed, very large, vicarious, rare, spatulate, with a straight transverse bar, the other form more frequent, proximally and obliquely directed, small, oval and slightly pointed proximally, with small lateral constrictions. DESCRIPTION. (Based on Levinsen's description and figure.) Zoarium apparently erect, unilaminar. Zooecia large, broadly oval. Orifice evenly rounded distally and CRETACEOUS CRIBRIMORPH POLYZOA (PELM ATOPORIN AE) 209 laterally, the sides tending to converge at the straight proximal margin, height of orifice about one-quarter the length of the zooecium. Oral spines unknown. Frontal shield flat. Costae 28-34, each with at least 4 (possibly 5 or 6) lateral costal fusions. Pelmatidia presumably present, number unknown. Apertural bar fairly wide, slightly curved proximally, with a slight median furrow. Gymnocyst probably concealed by interzooecial secondary tissue with triangular lacunae. Avicularia rare, of two forms : (a) distally directed, large, vicarious, sporadic, broadly spatulate, divided by a transverse bar into a small, semicircular proximal portion and a very large, distally rounded rostrum ; and (b) more frequent, proximally directed, unpaired, small [about one half the size of form (a)], rounded or slightly pointed proximally, with slight lateral constrictions dividing a semicircular proximal portion from a larger oval-triangular rostrum. Ovicells not seen. REMARKS. Levinsen's MSS. and figures were published posthumously in 1925 and edited by Nielsen & Mortensen, who stated (p. 285) that " the first seven plates represent the figures found together with the manuscript ". On pi. 5, fig. 58a-d, appears a copy of Levinsen's 1907 figures of Cribrilina labiata. Here (1925), however, the species is called Cribrilina valida sp. nov. and it is des- cribed as such on p. 376 and 377. It is probable that Levinsen himself, having omitted a description of Cribrilina labiata in 1907, regarded the name as invalid, and fully described the form as Cribrilina valida intending to re-use the original 1907 figure. But the name labiata is valid, and valida is a synonym. Levinsen's description (1925) supersedes that of Lang (1922 : 186) which was based only on Levinsen's 1907 figure. Levinsen described the zoarial habit, but gave no measurements. He stated that there were " no marks of spines " this may imply that the margins of the orifices were worn obliterating the oral spines. Lang (1922 : 186) referred the species to Rhiniopora. He regarded the marked dimorphism of the avicularia as a primitive feature suggesting affinities with his genus Castanopora, which here includes Rhiniopora. The horizon of the species was given by Levinsen (1925) as Senonian, zone of Belemnitella mucronata. STRATIGRAPHICAL DISTRIBUTION. Lower Maastrichtian, zone of Belemnella lanceolata. SPECIMENS. None in the collection. 3. Castanopora retrorsa Lang (PI. 16, fig. 2 ; Text-fig. 104) 1909 Cribrilina dibleyi Brydone : White, pp. 34, 39 [fide Lang] (non Cribrilina dibleyi Brydone, 1906, p. 297, text-fig. 8). igi6a Castanopora retrorsa Lang, pp. 94, 95. 1922 Castanopora retrorsa Lang : Lang, p. 206, pi. 4, fig. 9 ; text-fig. 65. HOLOTYPE. D.2H70. Zoarial fragment encrusting a piece of echinoid test. Senonian, zone of Marsupites, subzone of Uintacrinus, Uintacrinus Band. North- west of Newland's Barn, Odiham, Hampshire. L. Treacher Collection. EMENDED DIAGNOSIS. Castanopora with orifice wider than high ; oral spine-bases at least 4 ; costae 21-23, each with 4 (occasionally 3) lateral costal fusions and pelma- GEOL. 6, I. 14 aio CRETACEOUS CRI BRIMORPH POLYZOA (PELM ATOPORIN AE) tidia ; avicularia of two kinds : a distally directed, frequently paired form, very long and sharply pointed, and a proximally directed, shorter, pointed form. DESCRIPTION. Zoarium encrusting, unilaminar. Zooecia relatively large, closely placed, elongate oval. Orifice wider than high, evenly rounded distally and laterally, the sides tending to diverge at the straight proximal margin. Oral spine-bases at least 4. Frontal shield evenly and well arched, possibly flattening slightly in the median area of fusion. Costae 21-23, fairly coarse, each with 4 (occasionally 3) lateral costal fusions and an equivalent number of pelmatidia. The outer intercostal oy. 0:5 hOmm. FIG. 104. Castanopora retrorsa Lang, 0.21170. Holotype. Parts of two adult zooecia (frontal shields not shown) five avicularia and two broken and worn ovicells (ov.}. a, avicularia of form a ; b, avicularia of form b. spaces are long and slot-like. Apertural bar with a small, but distinct, median vertical projection formed by the slightly upturned distal ends of its component costae. Gymnocyst concealed by the closeness of the zooecia and the development of avicularia and ovicells. Avicularia of two kinds : either (a) distally directed, usually paired one on each side of the orifice or sometimes unpaired near the orifice, divided by a transverse bar, which is distally concave, into a narrow, elongate, acute rostrum and a short, some- what rounded, proximal portion ; or (b) shorter, proximally directed, usually paired, one on each side of the orifice, or sometimes unpaired near the orifice, divided by a straight transverse bar into a somewhat triangular, pointed rostrum and a semi- circular proximal portion : these avicularia may sometimes be directed proximally CRETACEOUS CRI BRIMO RPH POLYZOA (PELM ATOPORIN AE) 211 outwards. Ovicells hyperstomial, large, prominent, high, globular or slightly narrowed, smooth, resting on the frontal shield of the distally adjacent zooecium. The distal pair of oral spines may flank the opening of the ovicell. MEASUREMENTS. Zooecia Lz = 0-84 to 1-06 mm. lz = 0-50 to 0-59 mm. hr 0-15 to 0-18 mm. lr = 0-18 to 0-21 mm. Avicularia : Type (a) Lz = 0-39 to 0-42 mm. lz = 0-12 mm. Type (b) Lz = 0-21 mm. lz = 0-09 mm. REMARKS. Lang (1922 : 208) regarded C. retrorsa as the most primitive species of Castanopora. Stratigraphically it is the earliest, well separated from the main group in the upper part of the zone of B. mucronata and in the 0. lunata Chalk. The very narrow, distally directed avicularia are particularly distinctive, as are the frequent proximally directed forms. Lang (1922, text-fig. 65) indicated four avicularia a distally directed pair near the orifice, and a proximally directed pair near the proximal end of the zooecium, which are shown arising from the proximal- lateral areas of the gymnocyst. I have not seen in D. 2 1170 any zooecium which has four definitely associated avicularia : there is either a distally directed pair near the orifice or these are replaced by a proximally directed pair, or one or other of the avicularian forms may occur singly near the orifice. The widespread development of ovicells in 0.21170 tends to obscure the oral spine- bases, which are, however, probably always 4 in number. Lang regarded C. retrorsa as a form radical to the other species of Castanopora. Certainly the frequent apparent " replacement " of one form of avicularia by another seems to be a more primitive character. Some of the later species may possess proximally directed avicularia, but they always possess distally directed avicularia of fairly constant shape and position. STRATI GRAPHICAL DISTRIBUTION. Senonian, zone of Marsupites, subzone of Uintacrinus, Uintacrinus Band. SPECIMEN. Holotype see above. 4. Castanopora castanea Lang (PI. 16, figs. 3-5 ; Text-fig. 105) igi6a Castanopora castanea Lang, p. 95. I9i6a Castanopora nucifera Lang, p. 95. igi6a Castanopora juglans Lang, p. 95. 1922 Castanopora nucifera Lang : Lang, p. 214, pi. 4, fig. n ; text-fig. 67. 1922 Castanopora juglans Lang : Lang, p. 215, pi. 5, fig. i ; text-fig. 68. 1922 Castanopora castanea Lang : Lang, p. 217, pi. 5, fig. 2 ; text-fig. 69. 1923 Castanopora castanea Lang : Waters, pp. 548, 558, 560. 1923 Castanopora juglans Lang : Waters, pp. 558, 560. 1929 Castanopora castanea Lang : Lang, p. 438, text-fig. 39 (24). 212 CRETACEOUS CRIBRIMORPH POLYZOA (PELM ATOPORIN AE) 1930 Castanopora castanea Lang : Voigt, pp. 513, 561, pi. 30, fig. 17. I 935 Castanopora castanea Lang : Bassler, p. 65. *953 Castanopora castanea Lang : Bassler, p. Giga, text-fig. 144, 21. 0V I O: 5mm. FIG. 105. Castanopora castanea Lang, 0.16654. Holotype. Adult ovicelled zooecia, showing five distally directed, generally worn avicularia (a'} and one sporadic, large, rounded avicularium (a), fs, broken edge of frontal shield of adjacent zooecium ; o, worn orifices of adjacent zooecia ; ov, broken and worn ovicells ; x, break in the surface not an avicularium. HOLOTYPE. 0.16654. Zoarial fragment encrusting a piece of echinoid test. Horizon given as Senonian, zone of B. mucronata probably boreal Maastrichtian. Rtigen. Agnes Laur Collection. EMENDED DIAGNOSIS. Castanopora with orifice wider than high ; 4 oral spine- bases ; 16-23 costae, each with 4-8 (often 6-7) lateral costal fusions and pelmatidia ; avicularia of two kinds a common, frequently paired, distally directed and pointed form with elongate, triangular rostrum, and an occasional, sporadic form which is large, rounded and probably proximally directed. DESCRIPTION. Zoarium encrusting, unilaminar. Adult zooecia closely placed, relatively large, broadly-oval to somewhat elongate-oval. Orifice generally some- CRETACEOUS CRIBRIMORPH POLYZOA ( PELM ATOPORIN AE) 213 what wider than high, not very large, evenly rounded distally and laterally and without proximal-lateral constrictions, the proximal margin straight, usually shorter than the greatest width of the orifice. Oral spine-bases 4, of medium size, the lateral pair only slightly thicker than the distal pair. Frontal shield very flatly arched or slightly but evenly arched, its margin descending sharply at the inner ends of the outermost intercostal spaces which are more slot-like than rounded. Costae 16-23, each with 4-8 (often 6-7) lateral costal fusions and an equivalent number of pelma- tidia. Apertural bar of variable shape ; either of medium thickness, straight and not very prominent, or fairly wide, triangular, thickened, and slightly expanded proximally in the mid-line : a very slight median ridge may be present, or the median part of the apertural bar may distinctly protrude. None of the apertural bars appears to be furrowed in the mid-line. Gymnocyst almost totally concealed due to the closeness of the zooecia and the development of the avicularia : no interzooecial secondary tissue present. Avicularia of two kinds : (a) distally directed, elongate, with a long, triangular, pointed rostrum, divided by a straight or slightly proximally curved transverse bar from the small, semicircular proximal portion. This type is most frequently developed, commonly paired, one on either side of each orifice and placed near the distal-lateral margins, or more occasionally occurring singly on one side or the other of the orifice, (b) A second type occurs very occasionally : it is proximally directed, large, rounded, sporadic, and found more commonly in the earlier stages of zoarial growth. OviceUs hyperstomial, smooth, globular, of medium size but prominent. The opening of the ovicell may be flanked by the distal pair of oral spines. Young zooecia possess 4 oral spine-bases, the frontal shield is more evenly and markedly arched than that of the adult zooecia but still possesses a relatively flat median area of fusion. Costae 14 or 15, each with ?4 lateral costal fusions and Pan equivalent number of pelmatidia. Apertural bar much less prominent than in the adult zooecia. Definitely paired, distally directed avicularia are scarce. One large, rounded, proximally directed avicularium of the second type described above occurs between two zooecia of the second ring round the ancestrula in specimen N.C.M.76- 937 (27/1). MEASUREMENTS. Adult zooecia Lz = 0-78 to i-oo mm. lz = 0-50 to 0-75 mm. hr 0-12 to 0-15 mm. Ir = 0-15 to 0-18 mm. Avicularia : Type (a) Lz 0-27 to 0-39 mm. lz = 0-12 mm. Type (6) Lz = 0-21 mm. lz 0-18 mm. Young zooecium Lz = 0-57 mm. lz = 0-39 mm. hr = 0-15 mm. hr 0-15 mm. 214 CRETACEOUS CRIBRIMORPH POLYZOA (PELM ATOPORIN AE) REMARKS. Castanopora juglans Lang and C. nucifera Lang are here regarded as synonymous with C. castanea Lang. All the available specimens previously assigned to C. castanea, C. juglans and C. nucifera have been re-examined. Three specimens had been assigned to C. castanea, and C. nucifera was represented only by the holotype (0.15600). Though the latter has a more delicate structure than the specimens of C. castanea and has a slightly arched frontal shield, these differences are probably due to somewhat different growth conditions. But in both species the size and shape of the zooecia are closely similar ; there are 4 oral spine-bases ; the orifice tends to be wider than high ; there are 16-23 costae, and often 6 or 7 lateral costal fusions on each costa (in 0.15600 there may be 8 lateral costal fusions present between some costae) ; the distally directed avicularia are similar in position and type ; and both species also have very occasional, rounded, sporadic, proximally directed avicularia. The horizon of both species is Senonian, zone of B. mucronata. C. juglans is represented in the collection by the holotype (0.15608) and one other specimen (0.30110). According to Lang (1922 : 216) " C. juglans differs from C. nucifera . . . only in the shape of the aperture [orifice] and in the width of the apertural bar. It is of interest as being, in both respects, a connecting link between C. nucifera and C. castanea ". The shape of the orifice of the specimens assigned to C. juglans differs from that of C. castanea only very slightly and the same relationship between height and width is maintained. Beyond using the values of hr and Ir, which appear to be relatively constant for a given species, it is very difficult to apply a fine division of shapes of orifices as a diagnostic feature. In C. castanea, C. juglans and C. nucifera, hr is almost always less than Ir but the shape of the orifice may vary slightly even within a single zoarium. I do not regard slight widening or thickening of the apertural bar as of diagnostic value. A marked median ridge or process is a definite feature which can be used, in conjunction with other zooecial characters, for specific diagnosis, but slight variations in the width or thickness of the apertural bar occur frequently in different zooecia of the same zoarium. In the material examined and here assigned to C. castanea, such variations within single zoarial fragments were frequently found. Lang himself regarded C. juglans as a linkage form between C. castanea and C. nucifera : the three belong to a single species. The holotype of C. castanea is well preserved : in one part two zooecia coalesce and share a single orifice. Voigt (1930 : 513, pi. 30, fig. 17) briefly noted and figured a specimen which he assigned to C. castanea Lang. The horizon is again Upper B. mucronata Zone of Riigen. The measurements given and the range in number of costae agree with the material which has here been revised. Specimens N. C.M. 76. 937(27/1-4) are parts of a previously undescribed zoarium also placed in C. castanea ; much of the early growth stages of the zoarium is fairly well preserved and the description and measurements of the young zooecia of the species are based on parts of this zoarium. STRATIGRAPHICAL DISTRIBUTION. Senonian, upper part of zone of B. mucronata, and Maastrichtian, zone of Belemnella lanceloata (0. lunata Chalk), and boreal Maastrichtian of Riigen. CRETACEOUS CRI BRIMORPH POLYZOA (PELM ATOPORIN AE) 215 SPECIMENS. 0.16654. Holotype see above. 0.14990. Zoarial fragment encrusting a piece of echinoid test. Specimen badly damaged and worn, labelled " C. castanea Lang ", but the identification is here questioned. Horizon given as Senonian, zone of B. mucronata, Rtigen, but probably boreal Maastrichtian. Agnes Laur Collection. 0.15347. Zoarial fragment encrusting a piece of echinoid test. Labelled " Seno- nian, zone of B. mucronata, Riigen ", probably Maastrichtian. Agnes Laur Collecton. 0.15600. Zoarial fragment encrusting a piece of echinoid test. Holotype of C. nucifera Lang. Maastrichtian, zone of Belemnella lanceolata (0. lunata Chalk). Trimingham, Norfolk. A. C. Savin Collection. 0.15608. Zoarial fragment encrusting a piece of echinoid test. Holotype of C. juglans Lang. Horizon, locality and collection as for 0.15600. 0.30110. Zoarial fragment labelled " C. juglans Lang " encrusting a fragment of an Ostrea lunata. Horizon, locality and collection as for 0.15600. OTHER MATERIAL. N.C.M. 76. 937(27/1-4). Parts of an extensive zoarium with young zooecia, encrusting four fragments of the same echinoid test. Senonian, zone of B. mucronata. Weybourne Mill, Weybourne, Norfolk. R. M. Brydone Collection. 5. Castanopora dibleyi (Brydone) (PL 16, figs. 6-8 ; PI. 17, figs, i, 2 ; Text-figs. 106, 107) 1906 Cribrilina dibleyi Brydone, p. 297, text-fig. 8. 1909 non Cribrilina dibleyi Brydone : White, pp. 34, 39. 1913 Cribrilina dibleyi Brydone : Brydone, p. 437, pi. 14, fig. 9. I9i6a Castanopora dibleyi (Brydone) Lang, pp. 94, 95. 1921 Castanopora dibleyi (Brydone) : Lang, p. xci. 1922 Castanopora dibleyi (Brydone) : Lang, p. 209, pi. 14, fig. 10 ; text-fig. 66a, b. 1923 Castanopora dibleyi (Brydone) : Waters, pp. 548, 559, 560. 1929 Castanopora dibleyi (Brydone) : Lang, p. 438, text-figs. 39 (22, 23). 1930 Castanopora dibleyi (Brydone) : Voigt, pp. 512, 543, 561, pi. 30, fig. 18. ?I93O Castanopora sp. Voigt, pp. 512, 561, pi. 30, fig. 20. LECTOTYPE. (Chosen by Lang, 1922 : 210.) S.M., 6.36115. A very large fragment of zoarium, with some young zooecia, encrusting a piece of echinoid test. Two zooecia of this specimen were figured by Brydone (1906 : 297, text-fig 8) as Cribrilina dibleyi, and chosen by Lang as lectotype of Castanopora dibleyi. Maas- trichtian, zone of Belemnella lanceolata (0. lunata Chalk). Trimingham, Norfolk. R. M. Brydone Collection. EMENDED DIAGNOSIS. Castanopora with orifice as wide as, or slightly wider than, high ; oral spine-bases usually 4 (occasionally 5) ; costae 16-20, each with 5, 6 or 7 lateral costal fusions and pelmatidia ; avicularia of two kinds : a constantly paired, distally directed, elongate, pointed form near the orifice, and a proximally directed, less frequent, sporadic, pointed form. DESCRIPTION. Zoarium encrusting, unilaminar. Adult zooecia relatively small, broadly oval, some almost circular in outline ; very closely placed. Orifice slightly 216 CRETACEOUS CRIBRIMORPH POLYZOA (PELM ATOPORI N AE) wider than high or of equal height and width, straight sided but rounded distally, stiaight posteriorly ; there are no proximal-lateral constrictions. Oral spine-bases commonly 4, the lateral pair usually thicker than the distal pair, a fifth small, slender, median, distal oral spine may be present. Frontal shield broad, often almost circular in outline, very flatly arched, not sharply descending at the margin. Costae 16-20, each with 5, 6 or 7 lateral costal fusions and an equivalent number of pelma- tidia, each of which may be surrounded by a small rim producing a minute boss-like process opposite each lateral costal fusion : this is well seen in the lectotype. Apertural bar not prominent, somewhat swollen at either end ; a very slight median ridge may be present. Gymnocyst only very occasionally exposed where the close- ness of the zooecia and the development of avicularia have not obscured it. Avicularia of two kinds : (a) a constantly paired form placed one on either side of and close to the orifice, distally directed, elongate and pointed, divided by a slightly curved transverse bar into a semicircular proximal portion and a very elongate, narrow, triangular or spatulate rostrum ; (b) a proximally directed, in- frequent, sporadic form, similar to type (a) but probably slightly shorter. Ovicells hyperstomial, prominent, smooth, globular, slightly laterally compressed near the front, often with a broad median ridge. The lateral pair of oral spines may flank the entrance to the ovicell. Young zooecia smaller and relatively less broad than the adult zooecia. Orifices as wide as, or slightly wider than, high. Oral spine-bases 4 or 5, the latter number apparently occurring more frequently in the younger zooecia. Frontal shield more roundly arched than in the adult. Costae 11-15, each with 4 or 5 lateral costal fusions. The apertural bar of the ancestrula of 0.8003 has a slight median, proximal bend, but the zooecia in the first ring have straight apertural bars. Gymnocyst not visible in the circum-ancestrular area. Avicularia not paired on the ancestrula. The typically paired form which is distally directed on either side of the orifice occurs in the first ring of zooecia. The rostra of these avicularia tend to be directed outwards (in the adult the paired avicularia near the orifice are more parallel to its mid-line). Between two zooecia of the first ring round the ancestrula of 0.8003 is a proximally directed, slightly pointed, avicularium, which is larger than the avicularia of type (a) in the same ring of zooecia. Proximally directed avicularia possibly occur more frequently in the circum-ancestrular area than in the adult parts of the zoarium, but, as in S.M., 6.36267, they may be quite abundant locally in ovicelled parts of the adult zoarium. MEASUREMENTS. Adult zooecia Lz = 0-66 to i-oo mm. lz = 0-54 to 0-67 mm. hr = 0-12 to 0-19 mm. Ir = 0-12 to 0-19 mm. Young zooecia (of S.M., 6.36267) Lz = 0-50 to 0-55 mm. lz = 0-32 to 0-40 mm. hr = o-io to o-ii mm. Ir = 0-12 to 0-13 mm. ~ , = 0-085 mm. Type (a)< . ' = 0-050 mm. CRETACEOUS CRIBRIMORPH POLYZOA ( PELM ATOPORIN AE) 217 Ancestrula (of 0.8003) Lz = 0-42 mm. Iz = 0-24 mm. hr = 0-095 mm. lr = 0-090 mm. Avicularia (in adult part of zoarium) : T , . /Lz = 0-21 to 0-43 mm. ^ ' \\z = 0-065 to 0-14 mm. ~ ,,. f Lz = 0-27 to 0-30 mm. Type (b)< . 1 \\z = o-io to 0-19 mm. (Associated with the ancestrula of 0.8003) , TL (a)< . ' \\z (Associated with the first ring of zooecia of 0.8003) ~ , > f Lz = 0-125 mm - Type (a) < . 1 \\z = o-ooo mm. ~ ,,. fLz = 0-180 mm. Type AW . '\lz = 0-155 mm. REMARKS. All the available specimens of C. dibleyi (Brydone) in the British Museum (Natural History) have been re-examined, as well as those figured by Brydone (1906 : 297, text-fig. 8 the lectotype S.M., 6.36115 ; 1913 : 437, pi. 14, fig. 9 S.M., 6.36267). D.8oo3 and S.M., 6.36267 are of particular interest : the former is labelled as a metatype and has a well-preserved ancestrula and circum-ancestrular area ; the latter also possesses young zooecia close to the ancestrula. The description of the young zooecia is based largely on these specimens. In D.8oo4 well-preserved proximally directed avicularia are present in addition to some very young zooecia. 0.15599 a l so nas a preserved an- cestrula and numerous broken ovicells. 0.20609 is a very worn zoarial fragment encrusting a piece of Inoceramus shell fairly young zooecia are present, but the preservation is poor and the identification as Castanopora dibleyi is here queried. All the specimens are from the Maastrichtian, zone of Belemnella lanceolata (0. lunata Chalk) of Trimingham, Norfolk, except for 0.20609 which is from the Senonian, zone of B. mucronata, also from Norfolk. Apart from C. retrorsa apparently no other species of Castanopora occur below the zone of B. mucronata. Voigt (1930 : 512, pi. 30, fig. 18) briefly described a specimen as C. dibleyi (Brydone). The measurements and the number of costae agree with those given above. The reference to " comparatively short and blunt " avicularia apparently refers to worn examples. The figure shows no elongate pointed avicularia, those shown all appearing to be somewhat worn. It is probable that the specimen referred to Castanopora sp. by Voigt (1930 : 512, 561, pi. 30, fig. 20) is also C. dibleyi (Brydone) . STRATIGRAPHICAL DISTRIBUTION. Maastrichtian, zone of Belemnella lanceolata (0. lunata Chalk) and Senonian, zone of B. mucronata in England, and boreal Maastrichtian of Riigen. 2i8 CRETACEOUS CRIBRIMORPH POLYZOA (PELM ATOPORIN AE) 107 FIGS. 106-107. Castanopora dibleyi (Brydone). (106) 0.8003 metatype and 0.8004. Orifices and avicularia of three adult zooecia (frontal shields not shown). Avicularia of two kinds : a, paired, distally pointed and directed ; b, occasional, sporadic, interzooecial. (107) S.M., B. 36267. Figured Brydone (1913, pi. 14, fig. 9) as Cribrilina dibleyi. Orifice of adult ovicelled zooecium with four avicularia. Proximally directed avicu- laria of type b occur more frequently than is usual in other specimens of Castanopora dibleyi examined here. Possibly type b avicularia develop particularly in association with ovicelled zooecia, especially where development of the ovicell has apparently disturbed the normal development of the distally directed avicularia of type a. CRETACEOUS CRIBRIMORPH POLYZOA ( PELM ATOPORIN AE) 219 SPECIMENS. 0.8003. Zoarial fragment with ancestrula, encrusting a piece of echinoid test. Labelled " metatype specimen ". Horizon, locality and collection as for the lectotype. 0.8004. Zoarial fragment encrusting a piece of echinoid test. Horizon, locality and collection as for the lectotype. 0.15599. Zoarial fragment encrusting a piece of echinoid test. Horizon and locality as for the lectotype. A. C. Savin Collection. 0.20609. Part of a worn zoarium encrusting a fragment of Inoceramus shell. Labelled by Lang " C. dibleyi (Brydone) ", but the determination is doubtful. Senonian, zone of B. mucronata. Norwich, Norfolk. T. G. Bayfield Collection. OTHER MATERIAL. S.M., 6.36115. Lectotype see above. S.M., 6.36267. Zoarial fragment with ovicelled and very young zooecia encrusting a piece of echinoid test. [Part of this specimen was figured by Brydone (1913 : 437, pi. 14, fig. 9) as Cribrilina dibleyi]. Horizon, locality and collection as for the lectotype. 6. Castanopora guascoi (Ubaghs) 1865 Escharipora guascoi Ubaghs, p. 51, pi. 2, fig. $a-c. 1913 Cribrilina guascoi (Ubaghs) Brydone, p. 437. igi6a Castanopora guascoi (Ubaghs) Lang, pp. 95, 96. 1922 Castanopora guascoi (Ubaghs) : Lang, p. 221. 1930 Castanopora guascoi (Ubaghs) : Voigt, pp. 512, 561, pi. 31, fig. i. LECTOTYPE. (Chosen by Lang, 1922 : 221.) The specimen figured by Ubaghs, 1865, pi. 2, fig. 3&. Maastrichtian, Valkenburg (Fauquemont) , east of Maastricht, Limbourg, Holland. EMENDED DIAGNOSIS. Castanopora with orifice wider than high ; oral spine-bases probably 5 or 6 ; costae 18-20 ; gymnocyst well exposed ; avicularia of two kinds, a distal-lateral pair, apparently proximally directed, near each orifice, and an occasional, unpaired, sporadic, proximally directed form. DESCRIPTION. (Based on Ubaghs' and Voigt's figures.) Zoarium encrusting or erect, uni- or bilaminar. Zooecia relatively broad, elliptical. Orifice wider than high, evenly rounded distally and laterally, the sides tending to converge at the straight proximal border. Oral spine-bases fairly large, of uncertain number, definitely more than 4, probably 5 or 6. Frontal shield flat, descending sharply at the outer ends of the costae. Costae 18-20. Number of lateral costal fusions and Pelmatidia unknown, but probably few. Apertural bar fairly prominent, swollen at each end, somewhat rounded, not very thick, straight, with no marked median- proximal widening. Gymnocyst well exposed, much more so than in other species of Castanopora, visible laterally and proximally to each frontal shield ; no inter- zooecial secondary tissue. Avicularia of two kinds : (a) a distal-lateral pair near each orifice, each with a straight transverse bar, orientation uncertain, possibly proximally directed ; (b) an occasional, sporadic form, proximally directed, elongate and pointed, divided by a straight transverse bar into a small semicircular proximal portion and an elongate, triangular rostrum. Ovicells not seen. MEASUREMENTS. (According to Voigt, 1930 : 512.) Zooecia Lz = About i-o mm. Iz = 0-60 mm. REMARKS. The emended diagnosis and description of C. guascoi are based on a consideration of Ubaghs' original description and figure and Voigt's description and figure of a specimen from Maastricht. Voigt (1930 : 512) mentioned the zoarial habit, size of zooecia, and number of costae, and his figure (pi. 31, fig. i) also shows sporadic avicularia and more than four oral spine-bases. The nature of the paired avicularia is not determinable from the photograph. Ubaghs (1865 : 51) in his original description referred to a " distal bulge hiding the ovicell ", suggesting that the ovicell, as with other species of Castanopora, is hyperstomial. He also mentioned that " above the orifice, almost at the foot of the following cell [zooecium] there is found, on either side of the aforementioned orifice, a depression in which there lies an angular, non-marginate, lateral pore " [translation]. This could refer to worn, paired avicularia, and similar worn avicularia appear to be present in the specimen figured by Voigt. Ubaghs compared his original specimen with Escharipora pretiosa d'Orbigny [=E. magniftca d'Orbigny] which Lang (1922 : 212) also referred to Castanopora. Ubaghs stated that E. guascoi " has several similarities with E. pretiosa d'Orbigny, but may be distinguished from it by the lateral pores, which in d'Orbigny's species are elongate, slit-like and marginate. Also the cells [zooecia] of d'Orbigny's species are more elongate and show more rows of pores [intercostal spaces] piercing the cell surface [frontal shield] . . . Apart from this, our species (E. guascoi) shows, between the rows of cells, " blister-like ", elongate slits, which are rounded above [distally] and " turned down " below [proximally] . I am of the opinion that these should be regarded as avicularia ..." [translation]. In his figure of E. guascoi Ubaghs showed this second type of proximally directed sporadic avicularium ; a similar avicularium is shown in the photograph of Voigt's specimen from Maastricht. Until more specimens are available the description of Castanopora guascoi must rest on the interpretation of Ubaghs' and Voigt's figures. One of the most important features the nature of the paired avicularia near the orifice is still not determin- able ; apart from this most of the other diagnostic characters are reasonably clear and the described specimens are retained as a separate species of Castanopora. STRATIGRAPHICAL DISTRIBUTION. Maastrichtian. SPECIMENS. None in the collection. 7. Castanopora spooneri (Butler & Cheetham) 1958 Rhiniopora spooneri Butler & Cheetham, p. 1154, text-figs, i, 2. HOLOTYPE. Louisiana State University Geology Museum 1390. "... from a chalk bed exposed at Rayburn's dome, Bienville Parish, Louisiana . . . equivalent to the Upper Cretaceous Saratoga Chalk of Arkansas . . . ". CRETACEOUS CRIBRIMORPH POLYZOA (PELM ATOPORIN AE) 221 PARATYPE. L.S.U. Geology Museum 1391. Horizon and locality as for the holotype. EMENDED DIAGNOSIS [Based on Butler & Cheetham's diagnosis and detailed description and figures (1958 : 1154-1156).] Castanopora with small zooecia ; orifice of equal height and width or wider than high ; oral spine-bases 5 ; frontal shield with 14-20, usually 16-18 costae, each with 4-6 inconspicuous pelmatidia with 4 or 5 lateral costal fusions ; apertural bar curved, with a small median process ; gymnocyst concealed by the closely spaced zooecia ; avicularia interzooecial, of one kind only, distally pointed and directed without transverse bars or condyles ; ovi- cells hyperstomial, prominent, large, globular or somewhat elongate with a median, longitudinal ridge. MEASUREMENTS. (According to Butler & Cheetham, 1958 : 1156.) Zooecia Lz = 0-26 to 0-34 mm. lz = 0-17 to 0-27 mm. hr = 0-04 to 0-07 mm. lr = 0-06 to 0-09 mm. Avicularia Lz = o-n to 0-15 mm. lz = o-ii to 0-15 mm. REMARKS. The holotype and paratype specimens of Rhiniopora [Castanopora} spooneri encrust the inner surfaces of valves of Ostrea vesicularis and Inoceramus. The most distinctive features of the species are the small dimensions of the adult zooecia and the character and size of the avicularia. These features, combined with the range in number of the costae, pelmatidia and lateral costal fusions, clearly distinguish the species. STRATIGRAPHICAL DISTRIBUTION. Upper Cretaceous, equivalent of the Saratoga Chalk of Arkansas, U.S.A. The Saratoga Chalk was placed in the lower part of the Maastrichtian by Stephenson et. al. (1942, Chart 9, opp. p. 448). SPECIMENS. None in the collection. 8. Castanopora multicostata Voigt 1930 Castanopora multicostata Voigt, pp. 512, 561, pi. 30, fig. 19. LECTOTYPE. Specimen figured by Voigt, 1930, pi. 30, fig. 19. Horizon given as " Senonian, upper part of zone of B. mucronata. Riigen " probably boreal Maastrichtian. DIAGNOSIS. Castanopora with orifice generally wider than high ; oral spines 5-6 ; 26-30 costae, each with about 9 lateral costal fusions ; avicularia of possibly only one type, distally directed, paired near the orifice, pointed, elongate. DESCRIPTION. Voigt described the species as follows : " Zoarium encrusting. Zooecia about 0-9 mm. long and 0-55 to 0-60 mm. wide, elliptical. Gymnocyst very slightly developed. Frontal shield formed of about 30 very closely placed costae, 222 CRETACEOUS CRIBRIMORPH POLYZOA (PELM ATOPORI N AE) between which there are, on average, 9 lateral costal fusions . Orifice 0-15 mm. high, 0-15 to 0-20 mm. wide, with 5-6 oral spines (=' normal ' orifice of Lang). " Avicularia mainly paired, beside orifice, between 0-25 and 0-45 mm. long, distally directed, elongate, pointed " [translation]. To these characters it is possible to add the following from Voigt's figure : Zoarium unilaminar. Zooecia not so closely placed as in other species of Castanopora. Orifice generally wider than high, relatively small, evenly rounded distally and laterally, proximal margin straight. The lateral pair of oral spine-bases tend to be larger than the others. Frontal shield flatly arched ; costae 26-30. Apertural bar fairly thick and prominent, slightly swollen at each end, bluntly triangular, with the apex proximally directed. Gymnocyst exposed laterally and proximally to each frontal shield. Avicularia apparently of one type only, divided by a straight transverse bar into a small semicircular proximal portion and a narrowly elongate, acute, triangular rostrum ; placed near the distal-lateral margins of the orifice. Ovicells not described or figured. MEASUREMENTS (vide Voigt). Zooecia Lz = About 0-90 mm. lz = 0-55 to 0-60 mm. hr = 0-15 mm. Ir = 0-15 to 0-20 mm. Avicularia Lz = 0-25 to 0-45 mm. lz not given. REMARKS. In his observations on C. multicostata Voigt stated (1930 : 513), " The figure (pi. 30, fig. 19) is interesting in that two ' lobes ' of the same colony coalesce and that in the critical zone (where the two growing branches of the zoarium meet) the zooecia appear to be deformed in several ways. In parts, several zooecia have coalesced and others have been constricted and have not developed an orifice, so that they appear as ' rosettes '. This situation is, of course, only possible because of the intercommunication of the individuals. From several Castanopora species from the Riigen chalk, described by Lang, this species is distinguished by its large number of costae, and, at the same time, the small size of the zooecia. The nearest species appears to be Castanopora magnifica (d'Orb.) which is 1-14 to 1-26 mm. long and which possesses 12 oral spines as far as can be seen from d'Orbigny's drawing. Apart from this, the French species is bilamellar " [translation]. The large number of costae and lateral costal fusions and the occurrence of 5 or 6 oral spines are distinctive features of C. multicostata Voigt. The generally small size of the zooecia, and of the orifices, may also be diagnostic. Only a relatively small area of zoarium is shown in Voigt's figure, and no sporadic, more rounded and proximally directed avicularia, such as usually occur in other species of Castanopora from Riigen, can be seen. STRATI GRAPHICAL DISTRIBUTION. Given as " Senonian, upper part of zone B. mucronata ", but probably boreal Maastrichtian. SPECIMENS. None in the collection. CRETACEOUS CRIBRIMORPH POLYZOA (PELM ATOPORIN AE) 223 9. Castanopora jurassica (Gregory) (PI. 17, figs. 3-5 ; Text-figs. 108, 109) 1894 Membranipora jurassica Gregory, p. 62, text-fig, i. 1896 Membranipora jurassica Gregory : Gregory, p. 212, text-fig. 21. 1897 Membranipora jurassica Gregory : Woodward, pp. 63, 64, text-fig. 107. 1907 Membranipora jurassica Gregory : Bather, pp. 120, 122, text-fig. 65. 191 6a Rhiniopora jurassica (Gregory) Lang, p. 96. 19160 Rhiniopora scabra Lang, pp. 96, 97. 1922 Rhiniopora scabra Lang : Lang, p. 196, pi. 4, fig. 7 ; text-fig. 62. 1922 Rhiniopora jurassica (Gregory) : Lang, p. 197. 1930 Rhiniopora scabra Lang : Voigt, p. 551. HOLOTYPE. D.I 80, large fragment of worn and damaged zoarium partly em- bedded in matrix. Very probably Maastrichtian. Maastricht. Old Collection. EMENDED DIAGNOSIS. Castanopora with orifice wider than high ; zooecia up to 1-45 mm. long ; oral spine-bases 6 ; costae 25-30, each with 8 lateral costal fusions and pelmatidia ; avicularia sporadic, frequent. DESCRIPTION. Zoarium encrusting, unilaminar. Zooecia oval, large. Orifice wider than high, evenly rounded distally, with straight sides converging somewhat at the straight proximal margin. Oral spine-bases 6, occurring in two groups of three on the distal lateral margins of the orifice or as a distal and two lateral-distal pairs, the most proximal pair largest. Frontal shield flat, descending quite sharply at the inner ends of the outermost intercostal spaces, which are more often slot-like than rounded. Costae 25-30, each with 8 lateral costal fusions and pelmatidia. Apertural bar prominent, not very wide, straight, with a small, median ridge on the frontal shield. Gymnocyst exposed proximally, and to a less extent laterally, to the frontal shield : no interzooecial secondary tissue. Avicularia fairly frequent, sporadic, probably proximally directed, unpaired, placed near the distal-lateral margins of the orifice, relatively large, oval or slightly pointed proximally. Ovicells probably hyperstomial, apparently globular, prominent, and overlapping on to the distally adjacent zooecium : seen only in the broken state. MEASUREMENTS. Zooecia Lz = 1-18 to 1-45 mm. Iz = 0-66 to 0-81 mm. hr = 0-21 mm. Ir = 0-24 to 0-33 mm. Avicularia Lz = 0-27 to 0-36 mm. Iz = o-2i mm. REMARKS. Gregory (1894 : 62) incorrectly assigned D.iSo to the genus Mem- branipora and to the Jurassic (to the Calcaire a polypiers, Bathonian, of Ranville, Normandy, France). Lang (1916^ : 96 and 1922 : 197) recognized its cribrimorph structure and its very probable Maastrichtian age and referred it to his genus Rhiniopora. Both Rhiniopora jurassica (Gregory) and R. scabra Lang are synonymous and belong to Castanopora. It is unfortunate that the misleading specific name jurassica 224 CRETACEOUS CRIBRIMORPH POLYZOA (PELM ATOPORIN AE ) has to be retained for a Cretaceous species but, as it has priority of publication, no other course is open. In the holotype (0.14207) of Rhiniopora scabra Lang only one complete zooecium is preserved. The dimensions of this and surrounding broken zooecia are the same as those of the two available specimens (D.iSo and 0.3313) of Castanopora jurassica l-Omm. Omm. 108 109 FIGS. 108, 109. Castanopora jurassica (Gregory). (108) D.I 80. Holotype. Adult zooecium and parts of five adjacent, worn zooecia and worn, slightly pointed, probably proximally directed avicularium. (109) 0.14207. Holotype of Rhiniopora scabra Lang. Adult zooecium and parts of six adjacent worn zooecia. (Gregory), and the number of costae in the complete zooecium of 0.14207 is 25, each with 8 lateral costal fusions and pelmatidia, compared with 25-30 costae each with 8 lateral costal fusions and pelmatidia in D.iSo and 0.3313. The measurements given by Lang for R. scabra and R. jurassica were overestimated, and, in the latter species, avicularia are fairly frequent rather than " few ". Lang stated ' the preservation, both of the type specimen [D.iSo] and of 0.3313 is but poor ; the detailed characters, therefore, are uncertain ". However, careful examination of CRETACEOUS CRIBRIMORPH POLYZOA (PELM ATOPORIN AE) 225 the more complete zooecia in these specimens reveals most of the diagnostic charac- ters. STRATIGRAPHICAL DISTRIBUTION. Maastrichtian. SPECIMENS. D.iSo. Holotype see above. 0.3313. Large fragment of worn and damaged zoarium partly embedded in matrix. Maastrichtian. Maastricht, Holland. Old Collection. 0.14207. Holotype of Rhiniopora scabra Lang. Worn zoarial fragment. Horizon given as " Senonian, zone of B. mucronata, Riigen ", but probably boreal Maastrichtian. Agnes Laur Collection. 10. Castanopora glandulosa Lang (PI. 18, fig. i ; Text-fig, no) igida Castanopora glandulosa Lang, pp. 95, 96. 1922 Castanopora glandulosa Lang : Lang, p. 219, pi. 5, fig. 3 ; text-fig. 70, 1923 Castanopora glandulosa Lang : Waters, pp. 548, 558, 560. 1930 Castanopora glandulosa Lang : Voigt, p. 551. HOLOTYPE. 0.15009, zoarial fragment. Horizon given as " Senonian, zone of B. mucronata, Rugen " probably boreal Maastrichtian. Agnes Laur Collection. EMENDED DIAGNOSIS. Castanopora with very flatly arched frontal shield ; orifice generally of equal height and width ; oral spine-bases 5 (occasionally 4) ; costae 24-27, each with 6-8 (often 7) lateral costal fusions and pelmatidia ; avicularia frequently paired, probably all distally directed, elongate and pointed. DESCRIPTION. Zoarium encrusting or erect, unilaminar. Zooecia elongate-oval. Orifice generally as wide as high, relatively large, evenly rounded distally and laterally and without proximal-lateral constrictions, the proximal margin straight. Oral spine-bases 5 (occasionally 4), all relatively small, but the lateral pair tend to be larger, a fifth distal median oral spine is sometimes present. Frontal shield evenly, but flatly, arched. Costae 24-27, each with 6-8 (often 7) lateral costal fusions and an equivalent number of pelmatidia. Apertural bar flat, relatively wide with a slight thickening at the ends, triangular, the apex pointing proximally ; no median ridge or furrow. Gymnocyst only slightly exposed, mainly proximally to the frontal shield, but largely concealed owing to the closeness of the zooecia : no interzooecial secondary tissue present. Avicularia of one kind : frequently, but not always, paired, one on each side of the orifice near the distal-lateral margins. There are apparently no proximally directed avicularia. In the one specimen available, all the avicularia are broken, but they were very probably of the same type as in C. castanea. It is possible to see the broken proximal ends of some avicularia ; one of these possesses constrictions marking the position of a broken transverse bar. All the evidence suggests that all the avicularia are distally directed. Ovicells not seen. MEASUREMENTS. Zooecia Lz = 0-93 to 1-12 mm. lz = 0-50 to 0-64 mm. hr 0-18 mm. lr = 0-18 mm. Avicularia Not measurable. GEOL. 6, I. 15 226 CRETACEOUS CRIBRIMORPH POLYZOA (PELM ATOPORIN AE) REMARKS. Only the holotype, a zoarial fragment, is available. In his diagnosis of this species Lang (1922 : 219) suggested that occasionally proximally directed avicularia may be present : I cannot see any indications of these. The zooecial length was slightly overestimated as 1-25 to 1-50 mm., although the generally larger size of this species is still apparent from the measurements given above. The range O5mm. FIG. no. Castanopora glandulosa Lang, 0.15009. Holotype. Distal half of adult zooecium with five oral spines and paired, distally pointed and directed avicularia : that on the left is worn, that on the right is broken at its distal end. in number of costae (24-27) is generally above that of other species. The zoarium may have been encrusting. Lang stated that the number of oral spines is 4, and in the ensuing description he referred to 5 : both numbers occur as described, but the latter arrangement is more frequent. STRATIGRAPHICAL DISTRIBUTION. Probably boreal Maastrichtian. SPECIMEN. 0.15009. Holotype see above. ii. Castanopora aviculosa (Lang) (PL 19, fig. 3 : Text-fig, in). igiba Rhiniopora aviculosa Lang, p. 96. 1922 Rhiniopora aviculosa Lang : Lang, p. 184, text-fig. 58. 1929 Rhiniopora aviculosa Lang : Lang, p. 438, text-fig. 39 (19). 1930 Rhiniopora aviculosa Lang : Voigt, p. 551. HOLOTYPE. In the Collection of Mons. F. Canu. Photograph in the British Museum (Natural History). Maastrichtian ; Maastricht, Limbourg, Holland. EMENDED DIAGNOSIS. Castanopora with 24-26 costae ; avicularia proximally directed, paired, placed distal-laterally, elongate with sharply pointed rostra. CRETACEOUS CRIBRIMORPH POLYZOA (PELM ATOPORIN AE) 227 DESCRIPTION. Zoarium unilaminar, encrusting or erect. Zooecia broadly oval. Orifice evenly rounded distally and laterally, proximal margin straight, with distinct, pointed, proximal-lateral constrictions. Oral spine-bases of uncertain number, but at least 4, somewhat enlarged. Frontal shield flatly arched, variable in length. Costae 24-26, each generally with 6, occasionally 7 lateral costal fusions. Outermost intercostal spaces slot-like and narrow. Apertural bar not very wide, form obscure, but probably triangular. Gymnocyst not clearly visible, largely obscured by the avicularia ; the zooecia are, however, well spaced : little or no interzooecial secondary tissue. Avicularia of one form : all proximally directed, paired near the distal-lateral margins of the orifice ; other occasional, similar, sporadic forms may occur : a FIG. in. Castanopora aviculosa Lang, in PI. 17, fig. 6. Drawing from the photograph reproduced Scale approximate. transverse bar divides a small, semicircular, proximal portion from a large, elongate, sharply pointed, triangular rostrum. Ovicells not seen. MEASUREMENTS. (According to Lang, 1922 : 184.) Zooecia Lz = 1-25 to 1-50 mm. (No other measurements available.) REMARKS. Lang's figure and description of Rhiniopora aviculosa (1922 : 184, text-fig. 58), based on photographs of the holotype, are misleading. These photo- graphs are not sufficiently clear to show the exact number of oral spine-bases. In MS. notes on the photographs Lang refers to 6 oral spines as present but remarks " sometimes five ". He referred also to dimorphic avicularia " consisting of those with a very long and sharp rostrum, and those whose rostrum is comparatively short and not so sharp ; the former are numerous, sporadically distributed, variously, but generally proximally, directed ; the latter are more numerous, sporadically distributed, and probably always proximally directed ". All the definitely pointed, elongate avicularia visible in the photographs are proximally directed ; the broken and worn bases of this type are the " comparatively short and not so sharp " avicu- 228 CRETACEOUS CRIBRIMORPH POLYZOA (PELM ATOPORIN AE) laria of Lang. The avicularia are distinctly paired, with only occasional, sporadic forms. Nowhere are condyles visible in the broken avicularian apertures. A transverse bar is visible in one complete, pointed avicularium, and the lateral constrictions visible in other elongate avicularia are the broken remains of such transverse bars. Rhiniopora aviculosa Lang is here regarded as a species of Castanopora character- ized by proximally directed and pointed avicularia throughout the zoarium. STRATIGRAPHICAL DISTRIBUTION. Maastrichtian. SPECIMENS. None in the collections only photographs of part of the holotype zoarium. 12. Castanopora magnifica (d'Orbigny) (PI. 18, figs. 2-7 ; PL 19, figs, i, 2, 4-6 ; PL 20, fig. i ; Text-figs. 112-116) 1851 Escharipora magnifica d'Orbigny, pi. 686, figs. 1-5. 1852 Escharipora pretiosa d'Orbigny, pp. 227, 235 ; 1854, p. 1097. 1860 Escharipora pretiosa d'Orbigny : Coquand, p. 181. 1865 Escharipora pretiosa d'Orbigny : Ubaghs, p. 51. 1887 Cribilina asperula Marsson, pp. 97, 109, pi. 10, fig. 8. 1890 Cribrilina asperula Marsson : Osswald, p. 108. 1895 Cribillina [sic] asperula Marsson : Deecke, p. 79. 1895 Cribrillina [sic] asperula Marsson : Deecke, p. 87. 19006 Cribrilina asperula Marsson : Canu, p. 445. 19006 Cribrilina magnifica (d'Orbigny) : Canu, p. 447. 1913 Cribrilina cacus Brydone, p. 437, pi. 14, figs. 6-8. 191 6a Castanopora magnifica (d'Orbigny) Lang, pp. 94, 95. 1916*1 Rhiniopora aspera Lang, pp. 96, 97. 191 6a Rhiniopora asperula (Marsson) Lang, pp. 96, 97. I9i6# Rhiniopora cacus (Brydone) Lang, pp. 96, 97. igioa Rhiniopora horrida Lang, pp. 96, 97. 1917 Rhiniopora aspera Lang : Lang, p. 172. 1922 Rhiniopora aspera Lang : Lang, p. 118, pi. 4, fig. 4 ; text-fig. 59. 1922 Rhiniopora asperula (Marsson) : Lang, p. 190, pi. 4, fig. 5 ; text-fig. 60. 1922 Rhiniopora cacus (Brydone) : Lang, p. 193. 1922 Rhiniopora horrida Lang : Lang, p. 194, pi. 4, fig. 6 ; text-fig. 61. 1922 Castanopora magnifica (d'Orbigny) : Lang, p. 212. 1925 Cribrilina asperula Marsson : Levinsen, p. 376. 1925^ Cribrilina asperula Marsson : Voigt, p. 176. 1929 Rhiniopora aspera Lang : Brydone, p. 13. 1929 Rhiniopora asperula (Marsson) : Lang, p. 438, text-fig. 39 (20). 1929 Rhiniopora horrida Lang : Lang, p. 438, text-fig. 39 (21). 1930 Rhiniopora cacus (Brydone) : Voigt, pp. 511, 543, 561, pi. 31, fig. 3. 1930 Rhiniopora aspera Lang : Voigt, p. 511. 1930 Rhiniopora asperula (Marsson) : Voigt, pp. 511, 543, 561. 1930 Rhiniop^ra horrida Lang : Voigt, pp. 511, 561, pi. 31, fig. 5. J 935 Rhiniopora aspera Lang : Bassler, p. 190. ?I94O Cribrilina magnifica (d'Orbigny) : Gillard, p. 15. J 953 Rhiniopora aspera Lang : Bassler, p. 0193, text-fig. 144, 25. I 953 Rhiniopora aspera Lang : lilies, pp. 76, 91, 94. 1953 Rhiniopora asperula (Marsson) : lilies, p. 97. 1953 Rhiniopora cacus (Brydone) : lilies, pp. 76-101, pi. 15, figs. 1-6, pi. 16, figs. 1-2. CRETACEOUS CRIBRIMORPH POLYZOA (PELM ATOPORIN AE) 229 LECTOTYPE. (Chosen by Lang, 1922 : 212.) The specimen figured by d'Orbigny, 1851, pi. 686, fig. 2. Maastrichtian of Sainte-Colombe (Manche), and Royan (Charente Inferieure). d'Orbigny Collection. EMENDED DIAGNOSIS. Castanopora with relatively large orifice ; oral spine-bases 4 or 5 ; costae 14-30 (often about 20) , each with 4-8 (often 5-7) lateral costal fusions and pelmatidia ; avicularia oblique, proximally directed, occasional, sporadic, somewhat variable in size, rounded. DESCRIPTION. Zoarium encrusting or erect, unilaminar. Zooecia oval, large. Orifice may be wider than high, or of equal height and width, relatively large, evenly rounded distally, sides approximately straight and slightly converging proximally, proximal margin straight, slight proximal-lateral constrictions may be present. Oral spine-bases generally 4, less frequently 5, the lateral pair more thickened than the distal pair, a fifth, slender, median, distal oral spine may be present. Where only 4 oral spines are present there is seldom enough space between the distal pair for another single oral spine to develop. Frontal shield generally flatly arched. Costae of very variable number (from 14 to 30 according to lilies, 1953). In the specimens examined the range was found to be from 14 to 24, taking account of adult individuals only. Each costa generally bears from 4 to 8 (commonly 5-7) lateral costal fusions and pelmatidia, but there are fewer on the shorter costae close to the apertural bar. Outermost intercostal spaces more rounded than slot-like. Apertural bar prominent, not very wide, but thickened, especially near the outer ends ; a median ridge is present on the apertural bar and it tends to be prolonged on the frontal shield as an irregular, slight, median ridge producing a narrow median area of fusion. Gymnocyst more prominently exposed proximally to the frontal shield than on its lateral margins, not concealed by interzooecial secondary tissue. Communication pores are seen as two or three shallow, circular depressions in the lateral walls of some zooecia, and as single, larger depressions in the proximal and distal wails, the centre of each depression being perforated by a small, round pore. Avicularia of one kind : of variable size and occurrence, approximately twice as long as wide, prominent, fairly frequent, proximally directed, oblique, divided by a transverse bar into a somewhat smaller proximal portion and a larger, rounded or slightly pointed rostrum. Their appearance alters considerably with the degree of wear. Ovicells rare, hyperstomial, prominent, large, globular, overlapping on to the proximal part of the frontal shield of the distally adjacent zooecium. Each bears two ridges, which converge distally at the mid-line from the proximal-lateral corners. The lateral pair of oral spines may flank the opening of the ovicell. MEASUREMENTS. Zooecia Lz = 0-75 to 1-48 mm. Iz = 0-45 to 1-20 mm. hr = 0-15 to 0-33 mm. lr = 0-15 to 0-30 mm. Avicularia Lz = 0-17 to 0-25 mm. Iz = 0-09 to 0-18 mm. The highest values of length and breadth given by lilies (1953) are Lz = 1-80 mm. 230 CRETACEOUS CRIBRIMORPH POLYZOA (PELM ATOPORIN AE) O-5mm. I 0-5 1 Omm. 12 14 Scale as for Fig. 112 15 116 CRETACEOUS CRIBRIMORPH POLYZOA (PELM ATOPORIN AE) 231 and Iz =1-7 mm. These unusually high values possibly include measurement of abnormally long and wide zooecia which occur occasionally in this species. REMARKS. Voigt (1930 : 511) regarded a free specimen, which he assigned to Marsson's species asperula, as synonymous with Rhiniopora aspera Lang. Marsson (1887 : 97) originally included both free and encrusting forms in his species Cribrilina asperula. Lang (1922 : 192) suggested that Marsson's encrusting specimens were Rhiniopora aspera which was distinguished by Lang from R. asperula by its supposedly different growth habit, its slightly greater number of costae, and the occurrence in R. aspera of " generally five but occasionally only four " oral spine-bases compared with " 4 considerably thickened " oral spine-bases in R. asperula. In the present re- examination of the specimens named R. aspera by Lang, it was found that 4 oral spine-bases, rather than 5, are more frequently present. The range in number of costae was given by Lang as 18-20 for R. aspera and 20-24 for R. asperula. Only one specimen (0.14176) labelled by Lang " R. asperula (Marsson) " is available : 4 oral spine-bases are present and the range in number of costae is 19-22. In the re-examined specimens labelled " R. aspera " the range in number of costae is 14-20. Thus the differences between the species are very slight and it is difficult to separate them. Recently (1953), a statistical variation-study of 40 zoaria of a species placed in Rhiniopora [R. cacus (Brydone)], from the Maastrichtian of Hemmoor, Germany, has been carried out by lilies. This careful analysis of characters which can be studied quantitatively (those which can be measured or counted) has shown in particular that the number of costae in each frontal shield varies widely, both between individuals of the same colony and individuals of separate zoaria. If anything, the length and breadth measurements of zooecia show the least variation. lilies (1953 : 99) summarized her work as follows : "40 colonies of the bryozoan Rhiniopora cacus (Brydone) from the chalk of the Maastrichtian of Hemmoor (Niederelbe) were investigated by variation-statistical methods. " In the first section, the variation of quantitative characters within a single FIGS. 112116. Castanopora magnified, (d'Orbigny). (112) 0.31630. A very well-preserved single adult zooecium. Distal and lateral communication pores are well displayed. (113) D. 15620. Holotype of Rhiniopora aspera Lang. Distal end of adult zooecium with five oral spines and large oval avicularium with narrow transverse bar. (114) 0.14176. Labelled by Lang " Rhiniopora asperula (Marsson) ". Adult zooe- cium and parts of three distally adjacent zooecia and one worn, oval avicularium. The gymnocyst is typically widely exposed. (115) N.C.M.76.Q37 (25/1). Distal end of adult zooecium with five oral spines and worn oval avicularium. (116) D. 15591^. One of five fragments of the same zoarium labelled by Lang " Rhiniopora cacus (Brydone) ". Adult zooecium, parts of four adjacent zooecia and two worn, interzooecial avicularia. 232 CRETACEOUS CRIBRIMORPH POLYZOA (PELM ATOPORIN AE) colony are examined. From this, it can be shown that a number of characters in the central area of the zoarium vary differently from the characters in the younger (outer) zones. Whereas length-breadth measurements increase in value and lateral costal fusions, costae etc. increase in number in the first four growth-rings, they remain more or less constant in the outer rings. " The comparison of several zoaria in the second section based on the outer rings only, gave wider limits to the variations than has previously been acknow- ledged. The number of costae varies greatly, so that their taxonomic importance must now be regarded as less than that of the length and breadth measurements which are seen to be of the greatest value " [translation]. In a preceding section on the limits of variation of the species, lilies listed the extremes of length-breadth measurements of zooecia and the following characters : Lateral costal fusions . 4-8, mainly 5-7. Form of orifice . . Normal, subcircular or super-normal 1 (the last form being found in all colonies). Oral spines . . . Some colonies always with 5, others with 4-5. Apertural bar . . Possesses lateral " swellings " of varying strength in different colonies. Gymnocyst . . . Varies in breadth. Avicularia . . . Vary from 5 to 66 per 100 zooecia. Median area of fusion . May be " rib-like ", flattened, or not particularly distinct. Length-breadth ratio . Varies considerably . . . indicating irregular growth. Ovicells .... Rare, those found, all developed to the same degree. 1 Lang, 1921, p. xlvii, and p. 34 here. Except for the statements on avicularia and ovicells this revision is confirmed by an examination of the material available in the British Museum (Natural History) and other collections mentioned. lilies (p. 97) referred to Voigt's (1930) suggestion of re-combining Rhiniopora asp era Lang with R. asperula (Marsson). In her opinion " such a synonymy is only justified if an encrusting form of asperula is also found with, apart from the same measurements, less than twenty costae and with thin oral spines. The statisti- cal investigation of variation in R. cacus (Brydone) has shown, however, that the variation of definitive characters is far greater than was previously recognised in the literature, so that it may be presumed that in a similar investigation of R. aspera and R. asperula the present limits are like- wise found to be too narrow and a merging of aspera and even cacus to asperula may be necessary " [translation]. It is apparent that for R. cacus the results gained from more usual combined qualitative and quantitative investigations are very similar to those achieved by a statistical study of those characters which may be measured or counted. In the material examined here lilies' revision of the characters of R. cacus is confirmed, and this species is regarded as synonymous with Rhiniopora aspera Lang, in its turn a growth form of Rhiniopora asperula (Marsson). R. horrida is, as stated by Lang (1922 : 194), like R. cacus, except for its growth habit, and is also, therefore, included in the synonymy. CRETACEOUS CRIBRIMORPH POLYZOA (PELM ATOPORIN AE) 233 But R. asperula is itself a junior synonym of Castanopora magnified (d'Orbigny). Mons. E. Buge has kindly provided a photograph (PL 20, fig. i) [by Mons. P. Memin of the Serv. Photo. Geol., E.N.S.] of the holotype (?) of d'Orbigny's species as well as the following details : " Costules : 24-26, 4 epines orales, aviculaires oraux a bee dirige vers la partie proximale de la zoecie ". The characters given, as well as those shown in the photograph, clearly justify the synonymy of the species. Apparent growth habit is not here regarded as of diagnostic value. Accepting this, the ranges in number of costae, lateral costal fusions and the pelmatidia and oral spines of these species (i.e. Castanopora magnified, Rhiniopora asperula, R. aspera, R. cacus, R. horrida) all overlap, or are similar, and are contained within the limits established by lilies on statistical evidence for R. cacus. Qualitative characters, such as degree of arching of the frontal shield, shape and arrangement of avicularia, and width of exposed gymnocyst, all appear to vary within the same relatively wide limits, both in zooecia of the same colony and between zooecia of separate colonies. The following specimens (labelled by Lang as Rhiniopora aspera) have been re-examined ; they include the holotype and 5 paratypes of this species and are here assigned to Castanopora magnifica (d'Orbigny). In 0.15620 the better preserved zooecia were measured, Lz ranges from 078 to 0-90 mm., Iz from 0-45 to 0-50 mm. ; the range in number of costae varies from 14 to 16 and the number of lateral costal fusions varies from 4 to 6, oral spine-bases generally number 4, infrequently 5 may be present. In 0.14153, 0.14210, 0.15383, 0.16675 and 0.16677 all from Riigen the range in number of costae is 15-20. 0.14210 and 0.16677 have well exposed gymnocysts. In these specimens only 4 oral spine-bases are developed on each zooecium ; compared with those of 0.15620 these are all slightly thickened. 0.15302 and 0.15324, also from Riigen, are very badly damaged and worn. 0.31630 is a well-preserved zooecium not included in Lang's 1922 Catalogue. Seventeen costae are present, each with 5 lateral costal fusions and pelmatidia ; there are 4 oral spine-bases. The lateral, proximal and distal walls are completely exposed displaying communication pores. The dimensions of the zooecium are : Lz = 1-15 mm., Iz = 0-66 mm., hr = 0-24 mm., Ir = 0-21 mm. The holotype of Rhiniopora horrida Lang, 0.14171, possesses only four whole zooecia, each with four oral spine-bases, the lateral pair in each case being thicker than the distal pair, a condition common in the other specimens here referred to Castanopora magnified (d'Orbigny). All the oral spine-bases in 0.14171 tend to be slender, and the zooecia are generally less robust than in the encrusting forms, probably reflecting the growth habit (cf. p. 22 for remarks on the growth habit of Steganoporella buski Harmer). The range in number of costae in 0.14171 is 19-21 with 5-6 lateral costal fusions on each costa. 0.15020 is much broken and very worn. The zooecia are over i-oo mm. long. It is not possible to determine the specific characters, and its placing, by Lang, in this species is very doubtful. 0.15591 a-e, labelled by Lang as R. cacus (Brydone), is an imperfectly preserved, fragmented zoarium encrusting five pieces of echinoid test. In fragment b three abnormal zooecia are present, two being very wide and one unusually long. The measurement of zooecia such as these may account for the somewhat high values 234 CRETACEOUS CRIBRIMORPH POLYZOA (PELM ATOPORIN AE) recorded by lilies for R. cacus. Several zooecia in fragment a possess broken ovicells. Poorly preserved avicularia are present in 0.15591, 0.14167 and 0.16676 the last two are specimens from Riigen also labelled by Lang as R. cacus. Four specimens from the Norwich Castle Museum collections N.C.M.2I94 (3), 76.937 (25/1), 76.937 (26/1) and 112.22 (i/i) belong to Castanopora magnified (d'Orbigny). The range in number of costae is 16-21, with 4, occasionally 5, oral spine-bases and from 4 to 6 lateral costal fusions and pelmatidia on each costa. N.C.M.76.937 (26/1) has less thickened oral spine-bases than is usual. A very well preserved zoarial fragment, 0.40673, encrusting a piece of echinoid test, from a recently exposed outcrop of the 0. lunata Chalk at Mundesley, Norfolk, is also assigned to Castanopora magnifica (d'Orbigny). In addition, the three zoarial fragments figured by Brydone (1913 : 437, pi. 14, figs. 6-8) as Cribrilina cacus have been re-examined. S.M., 6.36264, that shown in fig. 6, was placed by Lang (1922 : 188) in Rhiniopora aspera. S.M., 6.36265 (fig. 7 of Brydone) was chosen by Lang (p. 193) as lectotype of Rhiniopora cacus (Brydone), to which species Lang also assigned S.M., 6.36266 (fig. 8 of Brydone). These specimens all belong to Castanopora magnifica (d'Orbigny) ; their dimensions and other details are as follows : Zooecia Lz = 1-18 to 1-45 mm. lz = 0-68 to 1-20 mm. hr = 0-25 to 0-31 mm. lr == 0-22 to 0-30 mm. Costae 20-24. Lateral costal fusions 5-8. Oral spine-bases 4 or 5. Avicularia Lz = 0-17 to 0*25 mm. lz = o-io to 0-18 mm. It is evident that the specimens are generally larger than most of the material which is here assigned to C. magnifica (d'Orbigny) ; they all, however, fall well within the limits of variation established by lilies (1953) and confirmed here by qualitative as well as quantitative study. STRATIGRAPHICAL DISTRIBUTION. Senonian, zone of Belemnitella mucronata, and Maastrichtian, zone of Belemnella lanceolata (Ostrea lunata Chalk). SPECIMENS. 0.15620. Zoarial fragment. Holotype of Rhiniopora aspera Lang. Maastrichtian, zone of Belemnella lanceolata (Ostrea lunata Chalk). Trimingham, Norfolk. A. C. Savin Collection. 0.14153, 0.14210, 0.15383, 0.16675, 0.16677. Five paratypes of Rhiniopora aspera Lang. Zoarial fragments encrusting pieces of echinoid test. Horizon given as " Senonian, zone of B. mucronata ", but probably boreal Maastrichtian. Riigen. Agnes Laur Collection. 0.14171. Holotype of Rhiniopora horrida Lang. Small zoarial fragment. Horizon locality and collection as for 0.14153. CRETACEOUS CRIBRIMORPH POLYZOA (PELM ATOPORIN AE) 235 0.14176. Zoarial fragment labelled by Lang " Rhiniopora asperula (Marsson) ". Horizon, locality and collection as for 0.14153. 0.15020. Very worn and damaged zoarial fragment labelled by Lang " Rhiniopora horrida ". Horizon, locality and collection as for 0.14153. 0.15302, 0.15324. Broken and worn fragments of two zoaria labelled " Rhiniopora aspera Lang ". Horizon, locality and collection as for 0.14153. D.i559i#-. Five fragments of the same zoarium encrusting pieces of echinoid test. Horizon, locality and collection as for 0.15620. The specimen was labelled by Lang " Rhiniopora cacus (Brydone) ". 0.14167, 0.16676. Two small zoarial fragments labelled by Lang " Rhiniopora cacus (Brydone) ". Horizon, locality and collection as for 0.14153. 0.31630. A well-preserved single zooecium. Senonian, zone of B. mucronata. Norwich, Norfolk. T. H. Withers Collection. 0.31707. Small zoarial fragment encrusting a piece of echinoid test. Senonian, zone of B. mucronata. Pit a quarter mile south-south-west of Coltishall, Norfolk. T. H. Withers CoUection. 0.40673. Zoarial fragment encrusting a piece of echinoid test. Maastrichtian, zone of Belemnella lanceolata (Ostrea lunata Chalk). Exposed on fore- shore, 1954, 100 yards south of the Kiln Camping Site, Mundesley, Norfolk. D. R. Hewlett CoUection. OTHER MATERIAL. N.C.M.76 . 937 (25 /i) . Incomplete zoarium encrusting a whole test of Cardiaster ananchytis Leske. Senonian, zone of B. mucronata. Catton, near Norwich, Norfolk. R. M. Brydone Collection. N.C.M. 2194(3). Incomplete zoarium encrusting a whole echinoid test labelled " Epiaster gibba S. Woodward ". Senonian, zone of B. mucronata. Collection unknown. N.C.M. 76. 937(26/1). Zoarial fragment encrusting a whole test of Cardiaster anan- chytis Leske. Senonian, zone of B. mucronata. Harford, near Norwich, Norfolk. R. M. Brydone Collection. N.C.M. 112. 22(1/1). Incomplete zoarium encrusting a whole echinoid test labelled " Galerites vulgaris Lam.". Senonian, zone of B. mucronata. Thorpe- next-Norwich, Norfolk. Collection unknown. S.M., 6.36264-66. Three well-preserved zoarial fragments encrusting pieces of echinoid test. Maastrichtian, zone of Belemnella lanceolata (Ostrea lunata Chalk). Trimingham, Norfolk. R. M. Brydone Collection. S.M., 6.36264 part of this specimen was figured by Brydone (1913 : 437, pi. 14, fig. 6) as Cribrilina cacus. Lang (1922 : 188) tentatively assigned the specimen to Rhiniopora aspera. S.M., 6.36265 part of this specimen was figured by Brydone (1913 : 437, pi. 14, fig. 7) as Cribrilina cacus. Lang (1922 : 193) chose it as lectotype of Rhiniopora cacus (Brydone). S.M., 6.36266 part of this specimen was figured by Brydone (1913 : 437, pi. 14, fig. 8) as Cribrilina cacus. Lang (1922 : 193) assigned it to Rhiniopora cacus. 236 CRETACEOUS CRIBRIMORPH POLYZOA ( PELM ATOPORIN AE) 13. Castanopora faujasi (von Hagenow) 1851 Cellepora (? Dermatopora) faujasi von Hagenow, p. 99, pi. 10, fig. iga, b [the question- mark is omitted on p. 99]. 1930 Rhiniopora faujasi (von Hagenow) Voigt, p. 511, pi. 31, fig. 2. EMENDED DIAGNOSIS. Castanopora with orifice wider than high ; Lz about i-oo mm., Iz about 0-60 mm. ; costae 13-15, each with 6-7 lateral costal fusions ; gymnocyst widely exposed ; apparently no avicularia. REMARKS. Von Hagenow's figure of this species (1851, pi. 10, fig. 196) shows only broken zooecia lacking frontal shields. But the shape of the broken apertures strongly suggests a cribrimorph, with well-spaced zooecia which had wide orifices. Von Hagenow described the zoarium as a series of " quincuncially arranged cells with transversely oval, almost round, apertures, each with a semicircular emargina- tion " [translation]. This " emargination " is undoubtedly the orifice lacking its proximal border, and it is thus an apparent continuity with the worn aperture of the zooecium. Voigt (1930 : 511) assigned a specimen to the species ; complete frontal shields are present and it is clearly a Castanopora. Apart from the characters mentioned in the above diagnosis it is not possible to interpret other details from the figure or from Voigt's note on the specimen. STRATIGRAPHICAL DISTRIBUTION. Horizon given as " Senonian, upper part of zone of B. mucronata ", but very probably Maastrichtian (Maastricht, Holland). SPECIMENS. None in the collection. 14. Castanopora voigti 1 sp. nov. 1930 Rhiniopora cf. hispida Lang : Voigt, pp. 511, 561, pi. 31, fig. 6. HOLOTYPE. The specimen figured by Voigt, 1930, pi. 31, fig. 6. Horizon given as " Senonian, upper part of zone of B. mucronata, M0en ", but since shown to be Maastrichtian, zone of Belemnella lanceolata (see below). DIAGNOSIS. Castanopora with erect, cylindro-quadrate zoarium ; zooecia of the 4 adjacent rows alternate ; orifice higher than wide ; costae 20-25. DESCRIPTION. (Based on Voigt's figure.) Zoarium erect, cylindro-quadrate, composed of 4 adjacent rows of alternating zooecia. Zooecia oval or rectangular. Orifice higher than wide, evenly rounded distally and laterally, proximal margin straight. Oral spine-bases of uncertain number, at least two pairs present. Frontal shield oval, very flatly arched, descending sharply near the outer ends of the costae. Costae 20-25, each with 4, possibly at least 5 lateral costal fusions. Apertural bar not very wide, slightly curved proximally. Gymnocyst well exposed, especially proximally to the frontal shield. Avicularia and ovicells not shown in the figure. MEASUREMENTS. (According to Voigt.) Zooecia Lz = 0-75 to 0-80 up to i-oo mm. REMARKS. Voigt (1930 : 511, pi. 31, fig. 6) briefly described a specimen from the same horizon as the holotype of Rhiniopora hispida Lang, but he only compared it 1 After Prof. Ehrhard Voigt. CRETACEOUS CRI BRIMORPH POLYZOA (PELM ATOPORIN AE) 237 with that species in view of the uncertainty of the characters given by Lang. R. hispida was founded on an extremely worn and badly damaged specimen (0.14996), in which all the frontal shields are missing except for a fragment of one. The characters given by Lang are largely hypothetical as he himself indicated by placing most of them in square brackets, a usage which he reserved for conjectural and uncertain statements. The name Rhiniopora hispida must therefore be discarded since the species cannot be satisfactorily denned. C. voigti is distinguished from all other known species of Castanopora by its cylindro-quadrate zoarium. Further material may show the presence of avicularia and the number of oral spine-bases. Voigt (in a letter dated i6th June, 1952) has indicated that the chalk of M0en, the locality of the holotype, is of Maastrichtian age belonging to the zone of Belem- nella lanceolata. Lang (1921 : Ixxxiv) had regarded the M0en chalk as Danian, and Voigt (1930 : 511) had originally placed it as Senonian, uppermost part of the zone of Belemnitella mucronata. STRATIGRAPHICAL DISTRIBUTION. Maastrichtian, zone of Belemnella lanceolata. SPECIMENS. None in the collection. SPECIES OF UNCERTAIN SYSTEMATIC POSITION PREVIOUSLY ASSIGNED TO RHINIOPORA AND CASTANOPORA (1) Cellepora perforata Quenstedt 1879 Cellepora perforata Quenstedt, p. 312, pi. 154, fig. 37. REMARKS. Lang (1922 : 183) referred this species to Rhiniopora, but from Quenstedt's original description and figure it is possible to deduce only that the specimen was an encrusting cribrimorph with hyperstomial ovicells. It cannot be assigned with any certainty at all to Castanopora or any other genus, even though its horizon is recorded as Maastrichtian of Maastricht. (2) Reptescharella radiata d'Orbigny 1852 Reptescharella radiata d'Orbigny, pi. 716, figs. 4-6. 1853 Reptescharella radiata d'Orbigny : d'Orbigny, p. 468. REMARKS. Lang placed this species in Rhiniopora. In the original description of Reptescharella radiata d'Orbigny (1853 : 468) referred to the encrusting habit of the species and to the presence of 16 costae, and the orifice was described as " ovale, transverse " suggesting that Ir exceeds hr in value. Further interpretation of the species must rest on d'Orbigny's figures (1852, pi. 716, figs. 4-6), which, however, are highly stylized ; no avicularia are shown, and the zooecia are closely placed with 16-18 costae each with 5-7 lateral costal fusions. The orifices are about twice as wide as high. Without information on the nature of the oral spines, the avicularia and other details, it is not possible to state with certainty that the species belongs to Castano- pora. The recorded horizon, Campanian and Santonian, is lower than for most species of Castanopora. 238 CRETACEOUS CRIBRIMORPH POLYZOA (PELM ATOPORIN AE) (3) Rhiniopora hispida Lang 191 6a Rhiniopora hispida Lang, pp. 96, 97. This species has been discussed on p. 236 under the remarks on Castanopora voigti sp. nov. (4) Reptescharipora ornata d'Orbigny 1852 Reptescharipora ornata d'Orbigny, pi. 720, figs. 68. 1853 Reptescharipora ornata d'Orbigny : d'Orbigny, p. 494. 1854 Reptescharipora ornata d'Orbigny : d'Orbigny, p. 1098. HOLOTYPE. d'Orbigny Collection, No. 8012, Laboratoire de Paleontologie, Museum National d'Histoire naturelle, Paris. Senonian. Vendome, (Loir et Cher), France. REMARKS. Lang (1916^ : 94 ; 1922 : 213) placed this species in Castanopora. Dr. E. Buge has kindly provided me with a photograph (by Mons. P. Memin of the Serv. Photo. Geol. E.N.S.) of the holotype and details of its preservation. In a letter (8th December, 1954) he stated, " Costules nombreuses, mais presque indis- cernables sur le specimen. Epines non distinctes (probablement detruites). Avicu- laires oraux (?) erodes, non definissables ". The recorded horizon, Senonian [Santonian] of Vendome, Loir et Cher, is again lower than for most species of Castanopora and it is most uncertain that the species belongs to that genus. Genus UBAGHSIA Jullien 1826 Celepora : Goldfuss, pp. 26, 248 [partim]. 1828 Cellepora Morren, p. 34 [partim]. 1832 Cellepora Dumont, p. 360 [partim]. 1834 Cellepora von Kloden, pp. 264, 341 [partim]. 1836 Discopora : Edwards, p. 248 [partim]. 1840 non Eschardoides : Roemer, p. 14. 1846 Cellepora : Geinitz, p. 609 [partim]. 1848 Cellepora : Bronn, p. 253 [partim]. 1848 Discopora : Bronn, pp. 255, 431 [partim]. 1849 Discopora : Bronn, p. 130 [partim]. 1849 Cellepora : Geinitz, p. 248 [partim]. 1850 Escharina : d'Orbigny, p. 262 [partim]. ?i85i Cellepora (Discopora) : von Hagenow, p. 96 [partim]. 1851 Cellepora (Dermatopora} : von Hagenow, p. 98 [partim]. 1851 Cellepora (Dermatopora} : Bronn & Roemer, p. 102 [partim]. ?i852 Reptescharella d'Orbigny, pis. 604, 715-716 [partim]. ?i852 Semiescharipora d'Orbigny, pis. 717-719 [partim]. ?i852 Reptecharipora d'Orbigny, pis. 719-720 [partim]. ?i853 Reptescharella : d'Orbigny, p. 464 [partim]. ?i853 Semiescharipora : d'Orbigny, p. 479 [partim]. ?i853 Reptescharipora : d'Orbigny, p. 489 [partim]. ?i854 Semiescharipora : d'Orbigny, p. 1097 [partim]. ?i854 Reptescharipora : d'Orbigny, p. 1098 [partim]. ?i857 Reptescharella : Pictet, p. no [partim]. ?i857 Semiescharipora: Pictet, p. 112 [partim]. CRETACEOUS CRIBRIMORPH POLYZOA (PELM ATOPORIN AE) 239 ?i86o Semiescharipora : Coquand, p. 183. 1862 Cellepora : Goldfuss, p. 24 [partim]. 1865 Steginopora : Ubaghs, p. 55. 1879 Cellepora : Quenstedt, p. 303 [partim]. 1879 Semiescharipora : Ubaghs, p. 217 [partim]. ?i879 Lepralia : Ubaghs, p. 221 [partim]. 1 88 1 Semiescharipora: Mourlon, p. 116 [partim]. ?i88i Lepralia : Mourlon, p. 119 [partim]. 1885 Semiescharipora : Vine, pp. 116, 156 [partim]. 1885 Cellepora : Vine, p. 161 [partim]. 1885 Cellepora (Dermatopora) : Vine, p. 164 [partim]. ?i885 Cellepora (Discopora) : Vine, p. 164 [partim]. 1886 Steginopora : Jullien, pp. 612, 614 [partim non S. irregularis d'Orbigny, Inon S. aculeata d'Orbigny, non S. pulchella d'Orbigny, ?ow S. ornata d'Orbigny]. 1886 Ubaghsia Jullien, pp. 610, 616 [partim U. reticulata only]. 1887 Cribrilina : Marsson, pp. 96, 109 [partim]. 1889 Semiesharipora : Ubaghs, p. 52. 19006 Cribrilina : Canu, p. 445 [partim]. 19006 Cribrilina (Costula) : Canu, p. 450. 19006 Steginopora (Ubaghsia) : Canu, p. 455 [partim S. (Ubaghsia) reticulata only]. 19006 Semiescharipora : Canu, p. 457 [partim]. 19006 Reptescharipora : Canu, p. 457 [partim]. 1910 Cribrilina : Canu, p. 63 [partim]. igi6a Ubaghsia : Lang, 93, 99. 19160 Batrachopora Lang, pp. 101, no [partim ?B. ovalis (d'Orbigny), ??. convexa (d'Orbigny), ?[.] signata (von Hagenow), non B. royanensis Lang]. ?i9i6a Cellepora (Discopora) : Lang, p. in. 191 gc Batrachopora : Lang, p. 105. 1919*2 Batrachopora : Lang, pp. 192, 197, 199, 203, 208, 217, 223 [partim IB. ovalis (d'Orbigny), ?B. convexa (d'Orbigny), ?[-B.] signata (von Hagenow), non B. royan- ensis Lang]. ligigd Cellepora (Discopora) : Lang, p. 205. 1920 Steginopora : Canu & Bassler, p. 282, fig. 81 S. 1921 Batrachopora : Lang, pp. Ivii, xc, xci [partim]. 1921 Ubaghsia : Lang, pp. Ixvi, xc, xci, xciii. 1922 Ubaghsia : Lang, p. 225. 1922 Batrachopora : Lang, p-357 [partim IB. ovalis (d'Orbigny), ?J5. convexa, (d'Orbigny), ?[B.] signata (von Hagenow), non B. royanensis Lang]. 1925 Cribrilina : Levinsen, p. 375 [partim C. brachiata only]. 19256 non Batrachopora : Voigt, pp. 99, 103. I925C ? Batrachopora : Voigt, p. 175. 1927 Cribrilina : Voigt, p. 102 [partim]. 1927 Ubaghsia : Canu & Bassler, p. 41. 1927 Batrachopora : Canu & Bassler, p. 55. 1929 Steginopora : Canu & Bassler, p. 243 [partim 5. ocellata only]. 1929 Ubaghsia : Canu & Bassler, p. 244. 1929 Batrachopora : Lang, p. 439. 1929 Ubaghsia : Lang, p. 439. 1930 Ubaghsia : Voigt, pp. 513, 515, 538, 561. 1930 Batrachopora : Voigt, pp. 515, 561 [partim non B. ultima Voigt]. J 935 Batrachopora : Bassler, pp. 31, 55. J 935 Ubaghsia : Bassler, pp. 31, 222. 1939 non Batrachopora : Voigt, p. 93. ?i94O Cribrilina : Gillard, p. 15 [partim]. 240 CRETACEOUS CRIBRIMORPH POLYZOA (PELM ATOPORIN AE) 1949 non Batrachopora [Escharoides] : Voigt, pp. 41, 43. 1953 Batrachopora : Bassler, p. Gig-z. *953 Ubaghsia : Bassler, p. 0193. TYPE SPECIES. Steginopora reticulata Ubaghs, 1865 : 55. Maastrichtian. Ober Bryozoenschichte (horizon / of Ubaghs). Valkenburg (Fauquemont), east of Maastricht, or Geulem, north-east of Maastricht, Holland. EMENDED DIAGNOSIS. Pelmatoporinae with relatively large zooecia ; branched or unbranched distal oral spines ; proximal and distal oral shields present, the latter may be less developed ; the former composed of paired, large, proximal-lateral oral avicularia, raised on stout stalks, united above the secondary orifice and often fused on their distal sides with the distal-lateral oral spines, the distal oral shield less prominent, formed by the enlarged, sometimes branched, often fused, distal oral spines and the upgrowth of secondary calcareous tissue on the rim of the secondary orifice ; apertural bar not involved in the proximal oral shield ; each costa with two or more pelmata ; secondary tissue forming a tertiary front wall, those of adjacent zooecia usually united (the tertiary front wall is frequently destroyed during fossilization) ; interzooecial avicularia may occur. REMARKS. Ubaghsia Jullien and Batrachopora Lang were regarded by Lang as distinct genera which he placed in separate subfamilies of the Pelmatoporidae, the former in the Castanoporinae (1922 : 154) and the latter in the Pelmatoporinae (1922 : 235). The two subfamilies are here merged : see remarks on the subfamily Pelmatoporinae. Neither pelmata nor pelmatidia were indicated in the original figures or descrip- tions of Ubaghsia given by Ubaghs (1865) and Jullien (1886), but other characters, which were clearly shown, are very closely comparable with those of Batrachopora Lang. The diagnoses of Ubaghsia and Batrachopora given by Lang (191601 : 93, 101) and later slightly modified (1922 : 225, 358) show that he distinguished between the genera on the basis that the former possessed pelmatidia and branched distal oral spines, while the latter had pelmata and unbranched distal oral spines. The distinction between pelmata and pelmatidia is not a valid one, nor should the branching of oral spines be considered of generic importance. Further, it is very doubtful whether Ubaghsia reticulata has branched spines (cf. Jullien, 1886, pi. 18, fig. 4 ; and Voigt, 1930, pi. 31, fig. 19). Thus Ubaghsia and Batrachopora are synonymous, as Voigt (1930 : 515) has already suggested might be the case. In the present revision, all the available material, previously assigned to Ubaghsia and Batrachopora, has been re-examined, and two new species of Ubaghsia are described. Where specimens have been available, the species have been distinguished on general zooecial and avicularian characters rather than on the form of the oral shields which are mainly of generic significance. The form of the proximal oral shield is very often much modified by wear, but the original presence or absence of this large secondary structure can usually be determined even in well-worn specimens. Lang (1922 : 358), in his remarks on Batrachopora, was concerned principally with the evolutionary relationships of the species which he recognized as belonging to CRETACEOUS CRIBRIMORPH POLYZOA (PELMATOPORIN AE) 241 the genus. Several of these species, and others later assigned to Batrachopora by Voigt, are of very uncertain systematic position (see p. 264) ; they are not accepted here as species of Ubaghsia. Jullien (1886 : 614, pis. 17-20) described and figured several species which he assigned to Steginopora d'Orbigny, and erected the genus Ubaghsia to include Steginopora reticulata Ubaghs and a new species, Ubaghsia arcifera. Lang (19160 : 99, 100 ; 1922 : 225) regarded all these species as belonging to Ubaghsia, with the exception of U. arcifera which he placed in Phrynopora (Lang, 19160; : 97, 98 ; 1922 : 201). If the species of uncertain systematic position, previously assigned to Batrachopora, are excluded from Ubaghsia, and if Jullien's species are taken into account, much of Lang's suggested evolution of the genera must also be questioned. It is possible that Ubaghsia Jullien is synonymous with Disteginopora d'Orbigny and Steginopora d'Orbigny, which apparently differ from one another only in their zoarial growth-habit. The tertiary front wall of Ubaghsia ocellata and U. demorgani appears to be somewhat similar to that found in Steginopora ornata d'Orbigny and Disteginopora horrida d'Orbigny. However, it is difficult to interpret species from d'Orbigny's stylized figures and inadequate descriptions. Until the holotypes, or new topotype material, of d'Orbigny's species can be examined it is better to retain Ubaghsia Jullien as a separate genus. STRATIGRAPHICAL DISTRIBUTION. Senonian, zones of M. cor-anguinum, G, [A.] quadrata, B. mucronata and Maastrichtian. KEY TO THE SPECIES OF UBAGHSIA JULLIEN (I) Ubaghsia with orifice much smaller than the frontal shield. (A) Oral spines unbranched. (1) Avicularia of one kind only a large oral pair. (a) 8-1 o costae, each with 3 lateral costal fusions, Lz = 0-70 to 0-80 mm., Iz = 0-50 to 0-57 mm., oral avicularia fused above secondary orifice to give a complete proximal oral shield. . i. 17. ranunculus (Lang) (b) 18-22 costae ; proximal oral shield apparently incomplete ; frontal shield distinctly pointed proximally . . 2. 17. aurita (Lang) (2) Avicularia of two kinds : (a) a large oral pair, (b) an interzooecial or vicarious, paired or unpaired, small form. (a) Shape of orifice variable : wider than high or of equal height and width. (i) Zooecia larger, 9-10 costae, each with 2 lateral costal fusions ; interzooecial avicularia small, rounded, unpaired . 3. 17. gasteri sp. nov. (ii) Zooecia shorter, 7-10 costae, each with 2, more often 3, lateral costal fusions ; interzooecial avicularia larger, pointed . 4. 17. langi sp. nov. (b) Orifice always wider than high. (i) 7 costae, each with 2, occasionally 3, lateral costal fusions ; zooecia over i-oo mm. long . . . . . 5. 17. crassa (Lang) (ii) 10-14 costae, each with 3 or 4 lateral costal fusions. (a) Zooecia over i-oo mm. long . . . . 6. 17. coaxans (Lang) (P) Zooecia about o 73 mm. long . . 7. 17. perforata (Marsson) (B) Oral spines branched. (i) Distal oral spines bifurcate only ; tertiary front wall with regular lacunae and a longitudinal, narrow, median depression proximal to each orifice 8. 17. ocellata (Jullien) GEOL. 6. i. 16 242 CRETACEOUS CRIBRIMORPH POLYZOA (PELM ATOPORIN AE) (2) Distal oral spines each with 3-6 branches. (a) Orifice often as wide as high ; tertiary front wall thick and very irregular 9. U. meudonensis (Jullien) (b) Orifice wider than high ; transversely elongate-oval or oblong ; tertiary front wall thin, with regularly arranged lacunae and a longitudinal, narrow, median depression proximal to each secondary orifice 10. 17. detnorgani (Jullien) (II) Ubaghsia with orifice nearly as large as, or larger than the frontal shield. (A) Orifice wider than high (hr o 20 to o 25 mm., Ir = o 26 to o 35 mm.) ; distal oral spines unbranched, often fused together at base .11. 17. reticulata (Ubaghs) (B) Orifice very large, of equal height and width (hr = 0-40 to 0-42 mm., Ir = 0-40 to 0-45 mm.) . . . . . . .12. U. ornata (Goldfuss) The following species, previously assigned to Batrachopora Lang, are of uncertain systematic position, and are therefore omitted from the above key. They are discussed on pp. 264-266. (1) Cellepora (Discopora) signata von Hagenow. (2) Semiescharipom ovalis d'Orbigny. (3) Reptescharipora convexa d'Orbigny. (4) Batrachopora royanensis Lang. (5) Batrachopora ultima Voigt. (6) Escharoides peltata Roemer. i. Ubaghsia ranunculus (Lang) (PI. 20, fig. 2 ; Text-fig. 117) igi6a Batrachopora ranunculus Lang, pp. no, in. 1919^ Batrachopora ranunculus Lang : Lang, pp. 203, 206, 208, 219, 221, text-figs. 33-35, 81. 1921 Batrachopora ranunculus Lang : Lang, pp. Ivii, xci. 1922 Batrachopora ranunculus Lang : Lang, p. 362, pi. 8, fig. i ; text-fig. 114. 1935 Batrachopora ranunculus Lang : Bassler, p. 55. 1953 Batrachopora ranunculus Lang : Bassler, p. 0192, text-fig. 144, 14. HOLOTYPE. 0.23388. Small zoarial fragment encrusting part of a Cidaris plate. Labelled " Batrachopora ranunculus Lang. Upper Senonian, Riigen " probably boreal Maastrichtian. Agnes Laur Collection. EMENDED DIAGNOSIS. Ubaghsia with zooecia 0-70 to 0-85 mm. long, 0-50 to 0-57 mm. wide ; secondary orifice wider than high (hr = 0-13 to 0-15 mm., Ir = 0-20 mm.), much smaller than the frontal shield ; costae 8-10, each with 3 lateral costal fusions and pelmata ; avicularia of one kind only, a relatively large lateral oral pair fused above the secondary orifice to form a prominent proximal shield. DESCRIPTION. Zoarium encrusting, unilaminar. Zooecia broadly oval. Second- ary orifice wider than high, much smaller than the frontal shield, distally rounded, sides and proximal margin straight ; distal oral shield indistinct ; proximal oral shield prominent, formed by the paired, large, lateral oral avicularia which are raised on stout stalks and connected above the orifice by a bar of calcareous tissue. Oral spines probably 4, the distal pair are somewhat enlarged, but not lengthened, and are immersed in the secondary tissue accumulated on the distal rim of the orifice. The distal-lateral pair of oral spines are very probably fused on to the distal sides of the lateral oral avicularia and thus form part of the proximal oral CRETACEOUS CRIBRIMORPH POLYZOA (PELM ATOPORIN AE) 243 shield. Frontal shield flat, except at the margins, broadly oval. Costae 8-10, fairly narrow, slightly tapering inwards. Near the outer end of each costa is a pelma, proximally to this the costa slopes down steeply to meet the gymnocyst ; inwards from this pelma each costa is level and carries two smaller pelmata. Other pelmata or pelmatidia have not been seen. Somewhat arcuate lateral costal fusions arise at the levels of the pelmata producing fairly regular, somewhat elongate intercostal spaces. Apertural bar not markedly thickened, but generally wider than the largest costae, flat and straight, with at least two large primary pelmata near either end. Omm. FIG. 117. Ubaghsia ranunculus (Lang), 0.23388. Holotype. complete proximal oral shield. Adult zooecium with Gymnocyst smooth, well-exposed proximally to the frontal shield, but often obscured laterally by interzooecial secondary tissue which is fairly abundant, in places filling the interzooecial valleys and containing irregularly oval lacunae. Tertiary front wall not seen, very probably never formed. Avicularia apparently of one kind only, a large, prominent, lateral oral pair occurring one on either side of, and very close to, the proximal-lateral margins of the secondary orifice. They are raised on stout, much thickened stalks and are joined above the orifice by a bar of calcareous tissue forming a complete proximal oral shield. Interzooecial avicularia not seen, very probably absent. Ovicells not seen. MEASUREMENTS. Zooecia Lz = 0-70 to 0-85 mm. Iz = 0-50 to 0-57 mm. hr = 0-13 to 0-15 mm. Ir = 0-20 mm. 244 CRETACEOUS CRIBRIMORPH POLYZOA (PELM ATOPORIN AE) REMARKS. Only one specimen, 0.23388, is available. Lang (1922 : 364) has stated that " occasional, sporadically-distributed aviculoecia [avicularia] appear in the interoecial [interzooecial] secondary tissue ", but they have not been seen. He probably interpreted oval lacunae as avicularia. Nor have " quaternary pelma- tidia " been observed. Lang suggested that this species might have been derived from a form resembling Ubaghsia perforata (Marsson), but this is very uncertain. STRATIGRAPHICAL DISTRIBUTION. Probably Maastrichtian. SPECIMEN. 0.23388. Holotype see above. 2. Ubaghsia aurita (Lang) (PI. 20, fig. 3 ) I9i6a Batrachopora aurita Lang, p. in. 1919*2 Batrachopora aurita Lang : Lang, pp. 205, 206. 1922 Batrachopora aurita Lang : Lang, p. 376, text-fig. 119. EMENDED DIAGNOSIS. Ubaghsia with zooecia more than twice as long as wide [according to Lang, Lz = about i-io mm., Iz = about 0-49 mm.] ; secondary orifice wider than high or of equal height and width, much smaller than the frontal shield ; oral spines probably 4 ; frontal shield distinctly pointed proximally ; costae very numerous, 18-22 ; avicularia apparently of one kind only, a large lateral oral pair. DESCRIPTION. [Based on a photograph of the holotype.] Zoarium unilaminar, encrusting [according to Lang], Zooecia fairly closely placed, noticeably elongate. Secondary orifice wider than high, or of equal height and width, rounded distally with straight sides which tend to converge somewhat proximally, and a straight proximal margin. Oral spines probably 4. It is possible to distinguish, from the photograph, a distal pair of thickened, but not lengthened, oral spines ; distal- lateral oral spines, if present, are probably fused on to the distal sides of the lateral oral avicularia, forming, with these, the proximal oral shield. Distal oral shield indistinct. Frontal shield tapered proximally. Costae very numerous, 18-22, closely placed. Number of pelmata and lateral costal fusions not determinable. Apertural bar apparently fairly wide, straight, with at least two large pelmata, one at each end. Gymnocyst exposed proximally to the frontal shield, apparently not obscured by interzooecial secondary tissue. Avicularia apparently of one kind only, a prominent, large, lateral oral pair. It cannot be determined, from the photograph, whether or not the lateral oral avicularia unite above the orifice to produce a complete proximal oral shield. Ovicells not seen. MEASUREMENTS. [According to Lang, 1922 : 376.] Zooecia Lz About i-io mm. Iz = About 0-49 mm. REMARKS. On the evidence obtainable from the photograph of the specimen (in Mons. F. Canu's Collection) Lang placed it as a species of Batrachopora [ Ubaghsia.]. This is apparently correct, judging from the general form of the secondary orifice and its proximal shield. The figure given by Lang (1922 : 375, text-fig. 119) is, however, largely hypothetical. The photograph is not sufficiently clear to show the CRETACEOUS CRIBRIMORPH POLYZOA (PELM ATOPORIN AE) 245 precise shape of the oral avicularia, and certainly not clear enough to allow any accurate assessment of the number of pelmata or lateral costal fusions. If the specimen is correctly placed as a species of Ubaghsia it is clearly distinguish- able from other species of the genus by its unusually high number of costae, 18-22, and its single kind of avicularia. STRATIGRAPHICAL DISTRIBUTION. Maastrichtian. SPECIMEN. Only a photograph of the holotype in the F. Canu Collection. Royan, south of Rochefort, Charente-Inferieure, France. 3. Ubaghsia gasteri 1 sp. nov. (PI. 20, figs. 4, 7 ; Text-figs. 118-120) HOLOTYPE. 0.40546. Unattached zoarial fragment. Senonian, lower part of zone of G. [A.] quadrata. Pit 21 of Gaster, northernmost of two pits on Patching Hill, Patching, Sussex. PARATYPES. 0.40547. Unattached zoarial fragment. Horizon, locality and collection as for the holotype. 0.40548. Unattached zoarial fragment. Senonian, lower part of zone of G. [A.] quadrata. Pit 150; of Gaster, small pit by roadside, south-east of Salvington Wind- mill, north-west of large pit (No. 15 of Gaster), and south of Pit 14 of Gaster, Salvington, Sussex. DIAGNOSIS. Ubaghsia with closely placed zooecia (Lz 0-80 to 0-03 mm.,. lz = 0-50 to 0-63 mm.) ; secondary orifice relatively large (hr = 0-19 to o 25 mm., Ir = 0-20 to 0-25 mm.), of variable shape, usually a little wider than high or of equal height and width, but occasionally a little higher than wide, smaller than the frontal shield ; distal oral shield present, proximal oral shield prominent ; oral spines 4 ; frontal shield flat, not descending steeply to meet the gymnocyst ; costae 9 or 10 (very occasionally more), each with two lateral costal fusions and pelmata ; interzooecial secondary tissue abundant ; avicularia of two kinds : (a) a large, prominent, proximal-lateral oral pair, (b) an occasional small, rounded, interzooecial form. DESCRIPTION. Zoarium probably encrusting (but all specimens fragmentary and now unattached), unilaminar. Zooecia broadly oval, closely placed. Secondary orifice large, but much smaller than the frontal shield, usually a little wider than high, or of equal height and width, but occasionally slightly higher than wide. The shape of the orifice varies from almost square to rounded distally, with straight sides and a straight proximal margin. Proximal-lateral constrictions are visible in some orifices, particularly those with worn rims. Distal oral shield formed by the distal oral spines and secondary tissue ; proximal oral shield very prominent, formed mainly by the proximal-lateral oral avicularia with the distal-lateral pan 1 of oral spines apparently fused on to the distal sides of the avicularia. Oral spines 4, enlarged, thickened, partly embedded in secondary tissue, hollow and cylindrical, arranged as a distal and a distal-lateral pair the latter may be fused on to the distal sides of the lateral oral avicularia. Frontal shield flat : the edges may be partly 1 After C. T. A. Gaster. 246 CRETACEOUS CRIBRIMORPH POLYZOA (PELMATOPORIN AE) o L 120 0-5 i 119 FIGS. 118-120. Ubaghsia gasteri sp. nov. (118) 0.40548. Paratype. Adult zooecium with worn, but very prominent, proxi- mal-lateral oral avicularia fused to distal-lateral pair of oral spines. A small oval avicularium of type b occurs near the right edge of the frontal shield. (119) D. 40546. Holotype. (a) Worn orifice of adult zooecium with proximal- lateral constrictions in the primary orifice, (b) Orifice of adult zooecium showing the square form produced by proximal oral shield, (c, d, e) Proximal, inner and outer views respectively of one side of a broken proximal oral shield showing the proximal- lateral oral avicularia fused with the distal-lateral oral spines. (120) 0.40546. Holotype. Orifice of adult zooecium with worn proximal-lateral oral avicularia and worn oral spines. CRETACEOUS CRIBRIMORPH POLYZOA (PELM ATOPORIN AE) 247 concealed by expansions of the interzooecial secondary tissue. Costae 9 or 10, very occasionally 13, tapering inwards, wide at their outer ends, where they descend slightly to meet the gymnocyst. Each costa carries a large, prominently rimmed pelma near its outer end and one, occasionally two, other pelmata nearer to the inner end. Lateral costal fusions arise at the levels of the pelmata, producing irregular intercostal spaces. Apertural bar straight, thickened, particularly at each end, and bearing two large pelmata and a pair of smaller pelmata between them nearer to the mid-line, which may be slightly furrowed. Gymnocyst almost entirely concealed by the close placing of the zooecia, which may result in the frontal shields of adjacent zooecia appearing contiguous, and by abundant interzooecial secondary tissue which generally fills the interzooecial valleys and in places expands on to the frontal shields. The interzooecial secondary tissue is marked by slight, irregular ridges surrounding shallow lacunae. Avicularia of two kinds : (a) a very prominent proximal-lateral form, well raised on stout stalks with secondarily thickened walls, paired, one on each side of, and very close to, the orifice, (&) an occasional, interzooecial form which is very small, and distally pointed and directed. Avicularia of type (a) probably did not unite above the secondary orifice to form a complete proximal oral shield. Each of the lateral oral avicularia may be fused on its clistal side to one of the distal-lateral pair of oral spines. Ovicells not seen. MEASUREMENTS. Zooecia Lz 0-80 to 0-93 mm. Iz = 0-50 to 0-63 mm. hr 0-19 to 0-25 mm. Ir = 0-20 to 0-25 mm. Avicularia Not measurable. REMARKS. U. gasteri is distinguished from other species of Ubaghsia by the close placing of its zooecia, the four thickened, often visibly separate, oral spines and the form of the frontal shield which does not descend steeply at the edges. The zoarial fragments were probably encrusting, but the specimens are broken and no longer attached. Two worn avicularia of type (6) are present in 0.40548. STRATIGRAPHICAL DISTRIBUTION. Senonian, zone of G. [A.] quadrata. SPECIMENS. 0.40546, holotype and 0.40547-48, two paratypes see above. 4. Ubaghsia langi 1 sp. nov. (PI. 21, figs. 4, 5 ; Text-figs. 121-123) HOLOTYPE. N. .1^.247.956 (4/1). Incomplete zoarium encrusting a test of Conulus albogalerus. Senonian, zone of M. cor-anguinum. Northfleet, Kent. A. W. Rowe Collection. DIAGNOSIS. Ubaghsia with closely placed zooecia (Lz = 0-73 to 0-80 mm., Iz = 0-50 to 0-60 mm.) ; secondary orifice fairly large, wider than high or of equal height and width, smaller than the frontal shield ; oral spines 4, much thickened and enlarged ; frontal shield flat, very steeply descending at the outer edges ; costae 1 After W. D. Lang. 248 CRETACEOUS CRIBRIMORPH POLYZOA (PELM ATOPORI N AE) o I O5 121 122 I O mm. _J FIGS. 121-123. Ubaghsia langi sp. nov. N.C.M.247.956 (4/1). (121) Holotype. Adult zooecium and part of a proximally adjacent zooecium : a, proximal-lateral oral avicularia forming proximal oral shield ; ia, interzooecial avicularia ; 05, distal oral spines. (122) Young zooecium ; the rim of the secondary orifice is damaged. (123) Three interzooecial avicularia. CRETACEOUS CRIBRIMORPH POLYZOA (PELM ATOPORIN AE) 249 7-10 ; lateral costal fusions 2 or 3 ; avicularia of two kinds : (a) a prominent, large, proximal-lateral oral pair, very close to the orifice, raised on stout stalks and united above the orifice to produce a strong proximal shield, (b) a prominent, frequent, distally pointed and directed, interzooecial form. DESCRIPTION. Zoarium unilaminar, encrusting. Adult zooecia broadly oval, closely spaced. Secondary orifice wider than high, its form obscured by the proximal and distal oral shields. The rim of the secondary orifice is much thickened by secondary tissue which incorporates the much enlarged oral spines. The orifice is rounded distally with straight sides and a straight proximal margin. Oral spines in two pairs, much enlarged and thickened. Distal oral shield formed by the pair of distal oral spines and secondary tissue. Proximal oral shield very prominent, produced by the upgrowth and median fusion above the orifice of the very large lateral oral avicularia, often fused with the distal-lateral pair of oral spines. Occa- sionally the proximal shield may be enlarged by the additional incorporation of an enlarged interzooecial avicularium (ia. in Text-fig. 121). Frontal shield flat within the outermost lateral costal fusions, but outwards from them the costae descend very steeply to meet the obscured gymnocyst. Costae 7-10, stout, each with a very prominent pelma nearer the outer end, and, towards the inner end, one, or often two, smaller pelmata. Lateral costal fusions arise at the levels of the pelmata producing very irregular intercostal spaces in the wide median area. Apertural bar prominent, straight, with a pelma near each of the outer ends and another pelma near the mid-line. Gymnocyst obscured by fairly abundant interzooecial secondary tissue which almost fills the interzooecial valleys and contains irregular shallow lacunae. The secondary tissue forms a tertiary front wall which connects the proximal and distal oral shields of the zooecia, and often encroaches on to the edges of the frontal shields or stands up above their general level as a ridge. Avicularia of two kinds : (a) a very large, thickened, heavily calcified lateral oral pair, raised on stout stalks, very close to, and one on either side of, the orifice. These unite above the orifice to produce the very prominent proximal oral shield ; (b) an interzooecial form, fairly prominent, frequent, unpaired, distally pointed and directed, lacking a transverse bar, but laterally constricted, producing a semicircular proximal portion and a triangular rostrum. Secondary thickening of avicularia of type (b) is variable. Ovicells not seen. Young zooecia small. Orifice of equal height and width. Oral spines 4, thickened, the distal pair not so enlarged as the distal-lateral pair. Frontal shield very well arched but flat on top. Costae 9 or 10, not so closely placed as in the adult zooecia, each with a very large, prominent, pelma, and, inwards from this, one, occasionally two, pelmatidia. The pelmata form a conspicuous ring round the flat median area. Outwards from them the costae descend very steeply to meet the gymnocyst. Lateral costal fusions occur at the levels of the pelmata and pelmatidia, producing very irregular intercostal spaces. Apertural bar thickened, prominent, relatively straight, with two pelmata near the mid-line. Gymnocyst smooth ; widely exposed, especially proximally to the frontal shield. There is some interzooecial secondary tissue but this does not fill, or extend from, the interzooecial valleys as in the adult stages. Avicularia of two kinds : (a] a lateral oral pair, raised on stout stalks, and 250 CRETACEOUS CRIBRIMORPH POLYZOA (PELM ATOPORIN AE) apparently not uniting to form a complete proximal oral shield ; (b) an occasional, sporadic, unpaired, rounded, small, interzooecial form. MEASUREMENTS. Adult zooecia Lz = 0-73 to 0-80 mm. lz = 0-50 to 0-60 mm. hr 0-20 mm. lr = 0-20 to 0-23 mm. Avicularia of type (a) Lz = 0-20 mm. lz = o-n mm. Young zooecia Lz = 0-53 to 0-62 mm. lz = 0-30 to 0-32 mm. hr 0-12 mm. lr = 0-12 mm. REMARKS. Ubaghsia langi is distinguished from U. gasteri particularly by its more numerous, larger, distally pointed, interzooecial avicularia, and by its smaller size and generally fewer costae. The holotype encrusts a test of Conulus albogalerus from the Senonian, zone of M. cor-anguinum. On the base of the same echinoid is a well-preserved zoarial fragment of Lagynopora horsleyensis Lang, N. 6^.247.956 (4/2), a species recorded previously from the higher M. cor-anguinum Chalk. Ubaghsia langi is, as yet, the earliest known Ubaghsia. It does not have the features which Lang (1922 : 395) regarded as " primitive " for the genus, i.e., a large number of costae and a small size compared with the Maastrichtian species. STRATIGRAPHICAL DISTRIBUTION. Senonian, higher part of zone of M. cor- anguinum. MATERIAL. N. ^.247.956 (4/1). Holotype see above. 5. Ubaghsia crassa (Lang) (PL 20, fig. 5 ; PL 21, fig. 7 ; Text-fig. 124) igi6a Batrachopora crassa Lang, pp. no, in. 1919^ Batrachopora crassa Lang : Lang, pp. 206, 208, 217, 219, 221, text-fig. 83. 1922 Batrachopora crassa Lang : Lang, p. 365, pi. 8, fig. 3 ; text-fig. 116. 19256 Batrachopora crassa Lang : Voigt, p. 104. 1930 Batrachopora crassa Lang : Voigt, p. 551. HOLOTYPE. 0.16674. Poorly preserved zoarial fragment encrusting a cheilo- stome polyzoan ; only one worn zooecium is complete, in all others the frontal shield is destroyed. Labelled by Lang " Batrachopora crassa. Senonian, zone of B. mucronata, Riigen " probably Maastrichtian. Agnes Laur Collection. EMENDED DIAGNOSIS. Ubaghsia with fairly closely placed large zooecia (Lz = i-oo to i -12 mm., lz = 0-66 to 0-82 mm.) ; secondary orifice relatively large, wider than high (hr = 0-22 to 0-26 mm., lr = 0-28 to 0-30 mm.), smaller than the frontal shield ; oral spines at least 4 ; frontal shield flat, descending at the outer edges ; costae 7, each with 2 (very occasionally 3) lateral costal fusions and pelmata ; interzooecial secondary tissue fairly abundant ; avicularia of two kinds : (a) a large lateral oral pair, (b) an occasional, small, sporadic, interzooecial form. CRETACEOUS CRIBRIMORPH POLYZOA (PELM ATOPORIN AE) 251 DESCRIPTION. Zoarium encrusting, unilaminar. Zooecia broadly oval, less closely placed than in U. gasteri. Secondary orifice large, but smaller than the frontal shield, wider than high, shape variable from square or oblong to rounded distally with straight sides and a straight proximal margin. Oral spines probably at least 4, thickened but not lengthened, a distal pair visible in the rim of secondary tissue and a distal-lateral pair apparently fused on to the distal sides of the lateral oral avicularia. Distal oral shield indistinct. Proximal oral shield formed by the distal-lateral oral Omm. FIG. 124. Ubaghsia crassa (Lang), D. 16674. Holotype. Very worn adult zooecium the only complete zooecium in the holotype zoarial fragment. spines fused with the lateral oral avicularia which probably united above the orifice. Frontal shield occasionally somewhat arched, but commonly flat over most of its width, descending steeply at the outer edges. Costae of unusually constant number, 7, each with 2 (very occasionally 3) stout lateral costal fusions arising at the levels of large, prominent pelmata. A distinct ridge surrounds the pelmata and is apparently continuous on the upper surface of each costa between the pelmata. Pelmatidia may occur irregularly very close to the mid-line. Apertural bar broad, straight, with the outer ends bent distally, widening near the mid-line, with a straight median furrow and bearing two very large, elongate pelmata. Gymnocyst smooth, partly concealed by fairly abundant, irregularly 252 CRETACEOUS CRIBRIMORPH POLYZOA (PELM ATOPORIN AE) distributed interzooecial secondary tissue, which may in places expand on to the edges of the frontal shields. Irregular, shallow lacunae occur in the interzooecial tissue. Avicularia of two kinds : (a) a very prominent, large lateral oral pair, well raised on stout stalks, with secondarily thickened walls, occurring very close to, and one on either side of, the orifice ; (b) an occasional, small, sporadic, interzooecial form. Avicularia of type (a) probably united above the orifice to produce a complete proximal oral shield. Ovicells not seen. MEASUREMENTS. Zooecia Lz = i-oo to 1-12 mm. lz 0-66 to 0-82 mm. hr = 0-22 to 0-26 mm. Ir = 0-28 to 0-30 mm. Avicularia Not measurable. REMARKS. Lang (1922 : 368) based his description of Batrachopora crassa on the holotype, 0.16674, the only specimen available. Unfortunately, it is badly damaged and worn, the details of the pelmata, oral spines and avicularia being particularly uncertain. The dimensions of its only complete zooecium are : Lz = i-io mm., lz = 0-75 mm., hr = 0-22 mm., Ir = 0-30 mm. There are 7 costae, each with at least two pelmata and lateral costal fusions. These characters compare very closely with those found in N. ^.76.937 (30), which is a better preserved zoarial fragment encrusting a piece of echinoid test. He suggested that interzooecial secondary tissue is scanty and the gymnocyst widely exposed. This opinion was based on the very worn holotype where most of the frontal shields and much of the interzooecial tissue have been destroyed. N.C.M.76.937 (30), however, has fairly plentiful interzooecial secondary tissue. Avicularia are of two kinds, the oral pair being large and prominent, not, as Lang has stated, " apparently confined to a comparatively small, somewhat raised, apertural [oral] pair ". N.C.M.76.937 (30) from the B. mucronata Chalk of Catton, Norfolk, extends the downward range of Ubaghsia crassa from the Riigen horizon. STRATIGRAPHICAL DISTRIBUTION. Probably Maastrichtian, and Senonian, zone of B. mucronata. SPECIMEN. 0.16674. Holotype see above. OTHER MATERIAL. N.C.M.76.937 (30). Zoarial fragment encrusting a piece of echinoid test. Senonian, zone of B. mucronata. Catton, near Norwich, Norfolk. R. M. Brydone Collection. 6. Ubaghsia coax an s (Lang) (PL 20, fig. 6 ; PI. 21, fig. 6 ; Text-fig. 125) igi6a Batrachopora coaxans Lang, p. in. 1919^ Batrachopora coaxans Lang : Lang, pp. 206, 208, 221, text-fig. 84. 1922 Batrachopora coaxans Lang : Lang, p. 377, pi. 8, fig. 5 ; text-fig. 120. 1930 Batrachopora coaxans Lang : Voigt, p. 551. CRETACEOUS CRIBRIMORPH POLYZOA (PELM ATOPORIN AE) 253 HOLOTYPE. 0.14209. Fragment of zoarium, now unattached, with two com- plete zooecia. Labelled by Lang " Batrachopora coaxans. Upper Senonian, Riigen " probably Maastrichtian. Agnes Laur Collection. EMENDED DIAGNOSIS. Ubaghsia with zooecia 1-07 to 1-15 mm. long, 0-78 to 0-83 mm. wide, secondary orifice wider than high (hr = 0-25 to 0-26 mm., Ir = 0-31 to 0-35 mm.) ; costae 11-14, eacn w ^h 3 or 4 lateral costal fusions and pelmata ; avicularia apparently of two kinds : (a) a large lateral oral pair, (b) a somewhat smaller, occasional, unpaired interzooecial form. o O-5 FIG. 125. Ubaghsia coaxans (Lang), D. 14209. Holotype. Adult zooecium with broken proximal oral shield. DESCRIPTION. Zoarium unilaminar, now unattached but probably encrusting. Zooecia very broadly oval. Secondary orifice wider than high, much smaller than the frontal shield, rounded distally, sides and proximal margin straight. Distal oral shield indistinct. Proximal oral shield formed by the paired, large lateral oral avicularia which possibly united above the orifice. Oral spines probably at least 4 ; a distal pair of thickened and slightly enlarged, but not markedly lengthened, oral spines is almost completely immersed in the secondary tissue of the rim of the orifice, and a distal lateral pair probably fused on to the distal sides of the lateral oral avicularia, thus forming part of the proximal oral shield. Frontal shield wide, flat except at the margins. Costae 11-14, narrow. Near the outer end of each costa is a relatively small pelma, outwards from this each costa slopes down more steeply to meet the gymnocyst ; inwards from this pelma each costa is level and 254 CRETACEOUS CRIBRIMORPH POLYZOA (PELM ATOPORIN AE) carries another two, more commonly three, smaller pelmata. Lateral costal fusions 3 or 4 (corresponding in number to the pelmata), narrow, those at the level of the outermost pelmata arcuate. Intercostal spaces regularly arranged. Apertural bar wide, flat, straight, with 3 or 4 small pelmata. Gymnocyst smooth, well exposed, particularly proximally to the frontal shield, not obscured by interzooecial secondary tissue which is absent or only slightly developed. Avicularia apparently of two kinds : (a) a large, prominent, lateral, oral pair with much thickened walls, (b) a somewhat smaller, occasional, unpaired, sporadic, rounded interzooecial form. Avicularia of type (a) were raised to some extent on thickened, stout stalks, and possibly fused above the orifice, but in the available material they are all worn down to the level of the secondary orifice. Ovicells not seen. MEASUREMENTS. Zooecia Lz = 1-07 to 1-15 mm. lz 0-78 to 0-83 mm. hr = 0-25 to 0-26 mm. lr = 0-31 to 0-35 mm. REMARKS. Ubaghsia coaxans is clearly distinguished by its numerous costae, pelmata and lateral costal fusions, and its dimensions. It is not possible to decide, on the available evidence, whether or not the oral avicularia united above the orifice. STRATIGRAPHICAL DISTRIBUTION. Specimens labelled " Upper Senonian, Riigen ", but probably boreal Maastrichtian. SPECIMENS. 0.14209. Holotype see above. 0.15041. Paratype. Zoarial fragment, now unattached. Labelled by Lang " Batrachopora coaxans ". Horizon, locality and collection as for the holotype. 7. Ubaghsia perforata (Marsson) 1887 Cribrilina perforata Marsson, pp. 98, 109, pi. 10, fig. n. 1895 Cribillina [sic] perforata Marsson : Deecke, p. 80. 19006 Cribrilina perforata Marsson : Canu, p. 445. 19160 Batrachopora perforata (Marsson) Lang, pp. no, in. 1919^ Batrachopora perforata (Marsson) : Lang, pp. 206, 219, 221. 1921 Batrachopora perforata (Marsson) : Lang, p. xci. 1922 Batrachopora perforata (Marsson) : Lang, p. 362. 1925 Cribrilina brachiata Levinsen, p. 377, pi. 8, fig. 24. 1927 Cribrilina brachiata Levinsen : Voigt, p. 102. 1930 non Stichocados ordinatus Lang : Voigt, p. 510, pi. 30, fig. 14. LECTOTYPE. (Chosen by Lang, 1922 : 362.) The specimen figured by Marsson, 1887, pi. 10, fig. ii. " Schreibkreide of Riigen " (? boreal Maastrichtian). EMENDED DIAGNOSIS. Ubaghsia with encrusting or unattached zoarium ; second- ary orifice wider than high, much smaller than the frontal shield ; costae 10-13, each with at least 3 lateral costal fusions ; avicularia apparently of two kinds : (a) a prominent lateral oral pair (b) ? occasional interzooecial forms ; [length of zooecia given by Lang (1922 : 362) as about 0-73 mm.]. CRETACEOUS CRIBRIMORPH POLYZOA (PELM ATOPORIN AE) 255 REMARKS. Although Levinsen (1925 : 377, pi. 8, fig. 24) introduced Cribrilina brachiata as a new species, he himself suggested by its synonymy that it might be the same as C. perforate/, Marsson. I accept their synonymy, and although Levinsen's figure is obscure, the diagnosis of Ubaghsia perforata may be expanded as above to include Levinsen's species. I do not accept Voigt's (1930 : 510) placing of the species as synonymous with Stichocados ordinatus Lang. Levinsen's specimen was encrusting ; Marsson's material was unattached. Lang (1922 : 362) regarded the species as " primitive in most of its features ". STRATIGRAPHICAL DISTRIBUTION. Maastrichtian, possibly extending downwards into the Senonian, upper part of the zone of B. mucronata. SPECIMENS. None in the collection. 8. Ubaghsia ocellata (Jullien) (PI. 22, figS. I, 2) 1886 Steginopora ocellata Jullien, p. 614, pi. 19, figs. 1-3. 19006 Steginopora ocellata Jullien : Canu, pp. 453, 454, text-fig. 66 [a reduced copy of Jullien, 1886, pi. 19, figs. 1-3]. I9i6a Ubaghsia ocellata (Jullien) Lang, p. 99. 1920 Steginopora ocellata Jullien : Canu & Bassler, p. 282, text-fig. 8iS [a reduced copy of Jullien, 1886, pi. 19, fig. i]. 1921 Ubaghsia ocellata (Jullien) : Lang, p. xciii. 1922 Ubaghsia ocellata (Jullien) : Lang, p. 226. 1929 Steginopora ocellata Jullien : Canu & Bassler, p. 243. LECTOTYPE. (Chosen by Lang, 1922 : 226.) The specimen figured by Jullien, 1886, pi. 19, fig. i. " Etage senonien. Port Brehay ", north-east of Gourbesville, north-west of Carentan, Manche, France. [Horizon probably middle or lower parts of zone of B. mucronata.] EMENDED DIAGNOSIS. (Based on Jullien's figures and description of the species.) Ubaghsia with unilaminar, apparently unattached zoarium ; distal oral spines bifurcate ; orifice large, transversely elongate, almost oblong to rounded oblong, with straight proximal margin, much smaller than the convex frontal shield ; number of costae, lateral costal fusions, and pelmata uncertain ; avicularia of two kinds : (a) a large prominent, well-raised, lateral oral pair, (6) a single, occasionally paired, small, vicarious form, directed variously but always outwards from the zooecium it accompanies, distally pointed and divided by a straight transverse bar into a triangular rostrum and a smaller semicircular proximal portion ; tertiary front wall complete, with a median depression containing two or three lacunae, and two or three more lacunae symmetrically placed near the margin : other lacunae, of about the size of the orifice, occur interzooecially. REMARKS. Lang (1922 : 226) stated " having simpler apertural [oral] spines than Ubaghsia demorgani and M. [sic] meudonensis, M. [sic] ocellata is probably more primitive than these ; its relationship to M. [sic] reticulata is doubtful ". However, Ubaghsia ocellata may be readily distinguished from U. reticulata, which has un- branched distal oral spines and a very irregular tertiary front wall. U. meudonensis and U. demorgani have more complex oral spines, each being branched from three to 256 CRETACEOUS CRIBRIMORPH POLYZOA (PELM ATOPORIN AE) six times ; this feature particularly distinguishes these two species from U. ocellata. The tertiary front walls of the latter and of U. demorgani are, however, very similar. STRATIGRAPHICAL DISTRIBUTION. Senonian, ? lower or middle part of zone of B. mucronata. SPECIMENS. None in the collection. 9. Ubaghsia meudonensis (Jullien) (PI. 22, figs. 3, 4) 1886 Steginopora meudonensis Jullien, p. 614, pi. 17, figs. 1-5 ; pi. 18, figs. 1-3. igi6a Ubaghsia meudonensis (Jullien) Lang, pp. 99, 100. 1921 Ubaghsia meudonensis (Jullien) : Lang, p. xci. 1922 Ubaghsia meudonensis (Jullien) : Lang, p. 228. LECTOTYPE. (Chosen by Lang, 1922 : 228). The specimen figured by Jullien, 1886, pi. 17, fig. 3. " Etage senonien." Les Moulineaux, near Meudon, south-west of Paris. Zone of B. mucronata. EMENDED DIAGNOSIS. (Based on Jullien's figures and description of the species.) Ubaghsia with unilaminar, encrusting zoarium ; distal oral spines with from two to six branches ; orifice large, as wide as high, rounded distally, sides and proximal margin straight, smaller than the frontal shield ; number of costae, lateral costal fusions and pelmata unknown ; avicularia of two kinds : (a) a large, prominent, well-raised, lateral oral pair, (6) a smaller, interzooecial form, usually paired but occasionally single or absent, often raised on a stout stalk, variously directed, with a small, lunate, proximal portion divided by a curved transverse bar from a triangu- lar rostrum ; tertiary front wall apparently much thicker than in U. ocellata and U. demorgani, containing irregular large and small lacunae and well-marked secondary orifices. REMARKS. U. meudonensis possesses a more robust tertiary front wall than U. demorgani, but differences in this character alone may be insufficient to keep the two species distinct. However, until specimens are available for study these two species are maintained as separate. See also remarks on U. ocellata, (p. 255). STRATIGRAPHICAL DISTRIBUTION. Senonian, zone of B. mucronata. SPECIMENS. None in the collection. 10. Ubaghsia demorgani (Jullien) (PL 22, figs. 5, 6) 1886 Steginopora demorgani Jullien, p. 615, pi. 19, figs. 4, 5 ; pi. 20, fig. i. 19160 Ubaghsia demorgani (Jullien) Lang, p. 99, 100. 1921 Ubaghsia demorgani (Jullien) : Lang, p. xci. 1922 Ubaghsia demorgani (Jullien) : Lang, p. 227. LECTOTYPE. (Chosen by Lang, 1922 : 227.) The specimen figured by Jullien, 1886, pi. 19, fig. 4. " Etage senonien, craie de Meudon (Les Moulineaux)." Meudon, south-west of Paris. Zone of B. mucronata. CRETACEOUS CRIBRIMORPH POLYZOA (PELM ATOPORIN AE) 257 EMENDED DIAGNOSIS. (Based on Jullien's figures and description of the species.) Ubaghsia with bilaminar zoarium ; distal oral spines with three or four branches ; orifice large, transversely elongate-oval or almost oblong, or rounded distally with straight sides and a straight proximal margin, much smaller than the convex frontal shield ; number of costae, lateral costal fusions, and pelmata not known ; avicularia of two kinds : (a) a large, prominent, well-raised, lateral oral pair, (b) a small, vicarious form, commonly paired but occasionally single or absent, directed variously, but always outwards from the zooecium it accompanies, distally pointed and divided by a straight transverse bar into a triangular rostrum and a smaller, semi- circular proximal portion ; tertiary front wall complete, with the orifice markedly transversely elongate, and the lacunae and median depression similar to those of U. ocellata in number and arrangement, though the interzooecial lacunae are ap- parently much smaller than those of that species. REMARKS. See remarks on U. ocellata (p. 255) and U. meudonensis, p. 256). STRATIGRAPHICAL DISTRIBUTION. Senonian, zone of B. mucronata. SPECIMENS. None in the collection. ii. Ubaghsia reticulata (Ubaghs) (PI. 21, figs. 1-3 ; PI. 22, figs. 7, 8 ; Text-figs. 126-128) 1865 Steginopora reticulata Ubaghs, p. 55, pi. 2, fig. ja-d. 1886 Ubaghsia reticulata (Ubaghs) Jullien, pp. 610, 612, 616, pi. 18, figs. 4, 5. 19160 Ubaghsia reticulata (Ubaghs) : Lang, p. 99. igi6a Batrachopora hyla Lang, pp. in, 112. 1919^ Batrachopora hyla Lang : Lang, pp. 205, 208, 219, 221, text-fig. 82. 1921 Ubaghsia reticulata (Ubaghs) : Lang, pp. Ixvi, xc. 1921 Batrachopora hyla Lang : Lang, p. xc. 1922 Ubaghsia reticulata (Ubaghs) : Lang, p. 227. 1922 Batrachopora hyla Lang : Lang, p. 364, pi. 8, fig. 2 ; text-fig. 115. 1922 Batrachopora ornata (Goldfuss) : Lang, p. 370 [partim pi. 8, fig. 4, specimen 0.1391 only]. 1929 Steginopora reticulata Ubaghs : Canu & Bassler, p. 244. 1930 Ubaghsia reticulata (Ubaghs) : Voigt, p. 513 [partim], pi. 31, fig. 19 only, non fig. 20. 1930 Batrachopora ornata (Goldfuss) : Voigt, p. 515, pi. 31, fig. 18. 1930 Batrachopora hyla Lang : Voigt, p. 515. J935 Steginopora reticulata Ubaghs : Bassler, p. 222. J 953 Steginopora reticulata Ubaghs : Bassler, p. 0193. J 953 Ubaghsia reticulata (Ubaghs) : Bassler, p. 0193, text-fig. 144, 30. LECTOTYPE. (Chosen by Lang, 1922 : 227.) The specimen figured by Ubaghs, 1865, pi. 2, fig. jc. Maastrichtian. Ober Bryozoenschichte (horizon /of Ubaghs). Valkenburg (Fauquement), east of Maastricht, or Geulem, north-east of Maastricht, Holland. EMENDED DIAGNOSIS. Ubaghsia with unbranched distal oral spines ; zooecia 0-80 to 0-85 mm. long 0-60 to 0-72 mm. wide ; secondary orifice wider than high (hr = 0-20 to 0-25 mm., Ir = 0-26 to 0-35 mm.) ; costae 4-7 (often 5 or 6) each with 3 (occasionally 2) lateral costal fusions and pelmata ; avicularia of two kinds : (a) a large lateral oral pair, (b) small, rounded, occasionally paired, interzooecial forms. GEOL. 6, I. 17 258 CRETACEOUS CRI BRIMORPH POLYZOA (PELM ATO PORI N AE) O5mm. 126 127 128 CRETACEOUS CRIBRIMORPH POLYZOA (PELM ATOPO RIN AE) 259 DESCRIPTION. Zoarium unilaminar, probably encrusting. Zooecia broadly oval, smaller than in U. ornata. Secondary orifice very large, wider than high, almost as large as the frontal shield, rounded distally and laterally with a straight proximal margin. The orifice is surrounded by complete distal and proximal oral shields. The distal oral shield is formed by the amalgamation of the pair of distal oral spines which are enlarged and joined by secondary tissue. The proximal oral shield is composed of the very large, paired oral avicularia, which fuse above the apertural bar and orifice, and which incorporate on their distal sides the distal-lateral oral spines. Oral spines originally 4, rapidly enlarged but unbranched, united by secondary tissue to form parts of the distal and proximal oral shields. Frontal shield generally flat, broadly oval. Costae 4-7 (often 5-6), broad, irregular, tapering inwards ; near the outer end of each costa is a large pelma, outwards from which the ends of the costae bend down abruptly to meet the gymnocyst, while inwards there is one other pelma of large size and commonly, nearer the mid-line a third pelma. No other definite pelmata or pelmatidia have been seen. Lateral costal fusions occur opposite the pelmata, so that there are normally at least three pairs on each costa producing irregular, somewhat lacunate, intercostal spaces. Apertural bar not prominently thickened, straight, with at least two, often three, pairs of pelmata. Gymnocyst smooth, particularly exposed proximally to some frontal shields. Avicularia of two kinds : (a) a very large lateral oral pair raised on much thickened stalks, one on either side, of, and close to, the lateral margins of the orifice, (b) a small, rounded, interzooecial form which is apparently sometimes paired, one near each end of the apertural bar and a little proximal to it. Avicularia of type (a) make up an essential part of the proximal oral shield ; the unmodified form of these avicularia has not been seen. Tertiary front wall ultimately developed. The distal and proximal oral shields, above the secondary orifices, increase in size by the virtual sealing of the space directly above the orifice by a secondary plug of tissue. In addition, the huge, complete oral shields of adjacent zooecia join up by further accumulation of secondary calcareous tissue to form a very irregular cover pierced by deep lacunae and raised above the levels of the underlying frontal shields on the very stout stalks of the oral avicularia and on the ramifications of the distal oral shields. Ovicells not seen. FIGS. 126-128. Ubaghsia reticulata (Ubaghs), 0.1391. Labelled by Lang " Batrachopora ornata (Goldfuss) ". (126) Adult zooecium and part of proximally adjacent zooecium. The tertiary front wall has been destroyed by wear. (127) Adult zooecium with complete proximal oral shield supporting a fragment of tertiary front wall. (128) Proximal oral shields, (a) Front view of orifice with broken proximal oral shield ; fd, fused distal oral spines ; ia, interzooecial avicularia ; la, lateral oral avicu- laria. (b, c) Side and top views respectively of orifice of adult zooecium with complete proximal oral shield ; ab, apertural bar ; cp, central plug of secondary tissue ; fd, fused distal oral spines ; la, lateral oral avicularia. 260 CRETACEOUS CRIBRIMORPH POLYZOA ( PELM ATOPORIN AE) MEASUREMENTS. Zooecia Lz = 0-80 to 0-85 mm. Iz = 0-60 to 0-72 mm. hr 0-20 to 0-25 mm. Ir = 0-26 to 0-35 mm. Avicularia Not measurable. REMARKS. Voigt (1930 : 513) recognized that Ubaghsia reticulata (Ubaghs) and Batrachopora hyla Lang are synonymous. He stated " Batrachopora hyla Lang is merely a Ubaghsia reticulata in which the lamina peristomica [tertiary front wall] is missing " [translation]. Discussing other species of Batrachopora, he also remarked (1930 : 515) that " this [i.e., loss of the tertiary front wall in fossilization] is also true for other species, for example, in the case of the closely related Batrachopora ornata (Goldfuss), or even for the whole genus. But until there is more definite proof of this I retain the other species in Batrachopora " [translation]. Voigt's suggestions are here regarded as valid and the two genera are merged, for the frontal shields of Batrachopora and Ubaghsia are completely similar in structure, while the tertiary front wall was obviously loosely attached and easily lost in fossilization. Comparison of Jullien's figures (1886, pi. 18, figs. 4, 5) of Ubaghsia reticulata with 0.1391, in which part of the tertiary front wall is preserved, make the synonymy particularly convincing. See also remarks under Ubaghsia ornata (Goldfuss), (p. 263). STRATIGRAPHICAL DISTRIBUTION. Maastrichtian. SPECIMENS. D.n852. Holotype of Batrachopora hyla Lang. Small fragment of zoarium, now unattached. Maastrichtian, Maastricht, Holland, van Breda Collection. 0.1391. Zoarial fragment labelled by Lang " Batrachopora ornata (Goldfuss) ". Part of the tertiary front wall is preserved. Maastrichtian, Maas- tricht, Holland. G. R. Vine Collection. 0.40674-78. Five zoarial fragments labelled by Lang " Batrachopora hyla ". Horizon, locality and collection as for 0.11852. 12. Ubaghsia ornata (Goldfuss) (PI. 23, figs. 1-4 ; Text-fig. 129) 1826 Cellepora ornata Goldfuss, pp. 26, 248, pi. 9, fig. la, b. 1828 Cellepora ornata Goldfuss : Morren, p. 34. 1832 Cellepora ornata Goldfuss : Dumont, p. 360. 1834 Cellepora ornata Goldfuss : von Kloden, pp. 266, 341, pi. 5, fig. 3. 1836 Discopora ornata (Goldfuss) Edwards, p. 253. 1846 Cellepora ornata Goldfuss : Geinitz, p. 612. 1848 Cellepora ornata Goldfuss : Bronn, p. 255. 1848 Discopora ornata (Goldfuss) : Bronn, p. 432. 1849 Discopora ornata (Goldfuss) : Bronn, p. 130. 1849 Cellepora ornata Goldfuss : Geinitz, p. 252. 1850 Escharina ornata (Goldfuss) d'Orbigny, p. 262. 1851 Cellepora (Dermatopora) ornata Goldfuss : von Hagenow, p. 98, pi. 10, fig. 16. 1851 Cellepora (Dermatopora) ornata Goldfuss : Bronn and Romer, p. 103 ; 1852, pi. 29 2 , fig. ii [copy of von Hagenow, 1851, pi. 10, fig. 16]. CRETACEOUS CRIBRIMORPH POLYZOA (PELM ATOPORIN AE) 261 1853 Semiescharipora ornata (Goldfuss) d'Orbigny, p. 480. 1857 Semiescharipora ornata (Goldfuss) : Pictet, p. 112. 1862 Cellepora ornata Goldfuss : Goldfuss, p. 24, pi. 9, fig. i, b. 1879 Cellepora ornata Goldfuss : Quenstedt, p. 313, pi. 154, fig. 42. 1879 Semiescharipora ornata (Goldfuss) : Ubaghs, p. 217. 1 88 1 Semiescharipora ornata (Goldfuss) : Mourlon, p. 116. 1885 Cellepora ornata Goldfuss : Vine, p. 161. 1885 Cellepora (Dermatopora) ornata Goldfuss : Vine, p. 164. 1889 Semiescharipora ornata (Goldfuss) : Ubaghs, p. 52. 19006 Cribrilina (Costula) ornata (Goldfuss) Canu, p. 450. I9i6a Batrachopora ornata (Goldfuss) Lang, pp. in, 112. 19160 Cellepora ornata Goldfuss : Lang, p. 169. 1919^ Batrachopora ornata (Goldfuss) : Lang, pp. 205, 206, 217, 219, 221. 1921 Batrachopora ornata (Goldfuss) : Lang, p. xc. 1922 Batrachopora ornata (Goldfuss) : Lang, p. 370 [partim], text-fig. 117 [non pi. 8, fig. 4 = Ubaghsia reticulata (Ubaghs)]. 1930 non Batrachopora ornata (Goldfuss) : Voigt, pp. 515, 543, 561, pi. 31, fig. 18. 1930 Ubaghsia reticulata (Ubaghs) : Voigt, p. 513 [partim], pi. 31, fig. 20, only non fig. 19. LECTOTYPE. (Chosen by Lang, 1922 : 372). The specimen figured by Goldfuss, 1826, pi. 9, fig. 16. Maastrichtian, St. Petersburg, near Maastricht, Holland. EMENDED DIAGNOSIS. Ubaghsia with unbranched distal oral spines ; zooecia large (Lz = i-oo to 1-25 mm., Iz = 0-70 to 0-90 mm.) ; secondary orifice usually of equal height and width, as large as or larger than, the frontal shield ; costae massive, 3-7 (commonly 5), each with two lateral costal fusions and two very large pelmata ; avicularia of two kinds : (a) a very large lateral oral pair, (b) commonly paired, small, distally pointed interzooecial avicularia directed obliquely outwards from the zooecium they accompany. DESCRIPTION. Zoarium unilaminar, probably encrusting. Zooecia broadly oval, very large. Secondary orifice very large, generally of equal height and width, as large as, or larger than, the frontal shield, rounded distally and laterally with a relatively straight proximal margin, or circular. The orifice is surrounded by complete distal and proximal oral shields. Distal oral shield probably formed by the amalgamation of the distal and distal-lateral pairs of oral spines. All the available specimens are generally worn, with only occasional zooecia with undamaged distal and proximal oral shields. Apparently the distal-lateral oral spines do not fuse on to the distal sides of the large oral avicularia as in Ubaghsia reticulata. Proximal oral shield formed by the very large, paired, lateral oral avicularia, which are raised on very thick stalks. The oral avicularia are distally pointed, proximally rounded and directed distally and obliquely inwards. They very probably fuse above the secondary orifice by the addition, mainly on their upper, inner sides, of secondary calcareous tissue. Oral spines 4, enlarged, unbranched, and immersed in much secondary tissue forming the distal oral shield. Frontal shield generally flat, transversely oval or longitudinally oval. Costae 3-7 (commonly 5), often very coarse and wide : the occurrence of only 3 very large costae in an adult zooecium of normal size is exceptional (D.8529). Each costa bears two very large pelmata at the levels of the lateral costal fusions, which are of variable thickness producing irregular intercostal spaces. Outwards from the very large proximal pelma each 262 CRETACEOUS CRIBRIMORPH POLYZOA (PELM ATOPORIN AE) costa bends downwards abruptly to meet the gymnocyst which is apparently smooth but seldom visible. The apertural bar is about as wide as the costae, straight or slightly concave, and carrying two large pelmata which may be confluent in one large depression. Avicularia of two kinds : (a) a very large lateral oral pair, one on either side of, and close to, the lateral margins of the orifice, (6) a small, commonly paired inter- zooecial form. Avicularia of type (a) are proximally rounded and distally pointed, directed distally and obliquely inwards, raised on much thickened stalks, and prob- ably connected by a bar-like accumulation of secondary tissue between them. ? i i O5mm. I FIG. 129. Ubaghsia ornata (Goldfuss). 0.19356. Labelled by Lang " Batrachopora ornata (Goldfuss) ". Adult zooecium with typically very large orifice and two pointed interzooecial avicularia. The proximal oral shield and tertiary front wall destroyed by wear. Avicularia of type (b) are much smaller, commonly paired, one near each end of the apertural bar and a little proximally to it ; they are pointed, rounded proximally and directed distally and obliquely outwards from the zooecium they accompany. These small interzooecial avicularia are often worn and partly obscured by secondary tissue expanding from the proximal oral shield. Tertiary front wall probably present and formed as in Ubaghsia reticulata, but eroded in the specimens available. Ovicells not seen. MEASUREMENTS. Zooecia Lz = i-oo to 1-25 mm. lz = 0-70 to 0-90 mm. hr = 0-40 to 0-42 mm. Ir = 0-40 to 0-45 mm. Lateral oral avicularia Lz = 0-16 mm. lz = o-io mm. Interzooecial avicularia Not measurable. CRETACEOUS CRIBRIMORPH POLYZOA ( PELM ATOPORI N AE) 263 REMARKS. Lang (1922 : 372) emphasized the importance of the distal and proxi- mal oral shields as distinguishing features of the species, and compared the distal shields with those of Ichnopora denticulata. He figured (1922, pi. 8, fig. 4), as representative of Ubaghsia ornata, four zooecia of 0.1391, which is a fairly well- preserved zoarial fragment retaining part of its tertiary front wall. This specimen clearly belongs to Ubaghsia reticulata (Ubaghs), for its measurements and other characters agree with those of that species and differ consistently from those of the other specimens (0.8529, 0.19356-57) which Lang also placed in ornata. I agree that the last three specimens should be retained in Ubaghsia ornata. Ubaghsia ornata (Goldfuss) is distinguished from U. reticulata (Ubaghs) by its fewer costae, its pelmata (which are equal in number to the lateral costal fusions), its larger zooecia, and its larger and differently shaped orifice. In addition, the lateral oral and interzooecial avicularia of U. ornata differ from those of U. reticulata. The species can be distinguished without placing too much reliance on the characters of the distal and proximal oral shields ; not only are these structures easily eroded, but they may also vary considerably in form and size, depending on the amount of secondary tissue accumulated round them. The tertiary front wall is extremely variable and irregular, and is seldom preserved at all in the material available ; it is of diagnostic value generically but does not aid in separation of the species. 0.28526 is doubtfully assigned to U. ornata. The measurements and other characters of three of the complete adult zooecia in the specimen (e.g., Lz, Iz and the number of lateral costal fusions) are more in accord with those of U. ornata than with those of U. reticulata. But the dimensions of the orifice (hr = 0-30 mm., lr = 0-35 mm.) are generally smaller than those of U. ornata and it is somewhat wider than high. Ubaghsia ornata (Goldfuss) and U. reticulata (Ubaghs) are closely related but distinguishable species. As yet they have been recorded only from the Maastrichtian of Maastricht. Lang (1922 : 365) has suggested that they were derived respectively from U. crassa and U. ranunculus, two species described by him from the Riigen Chalk. Apart from the possibility that the Riigen horizon of these specimens is equivalent to the littoral Maastrichtian of the type area, the geographical relationship of the two areas makes such a relationship very unlikely. If Lang's suggested lineages for Ubaghsia ornata and U. reticulata are not accepted, it does not mean that the " alternative hypothesis " mentioned by him (1922 : 366), that U. ornata is derived from U. reticulata, must be adopted. There is no evidence to decide whether U. ornata developed from U. reticulata or vice versa. STRATIGRAPHICAL DISTRIBUTION. Maastrichtian. SPECIMENS. 0.8529. A large zoarial fragment, now unattached, labelled by Lang " Batrachopora ornata (Goldfuss) ". Maastrichtian. Fauque- ment, east of Maastricht, Holland. W. Gamble Collection. 0.19356-57. Two zoarial fragments, now unattached, labelled by Lang " Batracho- pora ornata (Goldfuss) ". Maastrichtian. Maastricht, Holland. G. R. Vine Collection. 264 CRETACEOUS CRIBRIMORPH POLYZOA (PELM ATOPORIN AE) ?D. 28526. A fragmentary zoarium, labelled by Lang " Batrachopora ornata (Goldfuss) ". Horizon, locality and collection unknown, but very probably Maastrichtian of Maastricht, Holland. [The specimen is here only doubtfully assigned to Ubaghsia ornata (Goldfuss).] SPECIES OF UNCERTAIN SYSTEMATIC POSITION PREVIOUSLY ASSIGNED TO BATRACHOPORA (1) Cellepora (Discopora) signata von Hagenow 1851 Cellepora (Discopora) signata von Hagenow, p. 96, pi. 10, fig. ija, b. REMARKS. Although Lang (1922 : 361) chose the specimen figured by von Hagenow as lectotype, he also remarked " from the evidence available, it is impossible to diagnose this species or more than tentatively to refer it to Batrachopora ". There is no evidence to suggest it might be a Batrachopora ; the genus and species are indeterminate. (2) Semiescharipora ovalis d'Orbigny 1852 Semiescharipora ovalis d'Orbigny, pi. 719, figs. 13-16. 1853 Semiescharipora ovalis d'Orbigny : d'Orbigny, p. 488. 1854 Semiescharipora ovalis d'Orbigny : d'Orbigny, p. 1098. i. REMARKS. Lang (19160 : no, in) placed Semiescharipora ovalis d'Orbigny in Batrachopora and later (1922 : 367) selected the specimen figured by d'Orbigny (1852, pi. 719, fig. 14) as lectotype. Again there is no definite evidence to suggest that the material figured by d'Orbigny or described by him (1853 : 488) belongs to Batrachopora. Canu (19006 : 457) has listed the species as worn and doubtful. Ah" that may be deduced with certainty from the figure and description is that Semies- charipora ovalis d'Orbigny is a cribrimorph polyzoan from the Maastrichtian of Royan. It has a well-developed frontal shield with fairly numerous costae and lateral costal fusions, and paired, large, lateral oral avicularia. (3) Reptescharipora convexa d'Orbigny 1852 Reptescharipora convexa d'Orbigny, pi. 720, figs. 1-3. 1853 Reptescharipora convexa d'Orbigny : d'Orbigny, p. 492. 1854 Reptescharipora convexa d'Orbigny, : d'Orbigny, p. 1098. REMARKS. Lang (191601 : in, 112) regarded Reptescharipora convexa d'Orbigny as a species of Batrachopora and later (1922 : 368) selected the specimen figured by d'Orbigny (1852, pi. 720, fig. 2) as lectotype. There is, if anything, even less evidence for regarding Reptescharipora convexa as a Batrachopora than in the case of Semiescharipora ovalis d'Orbigny. It is a cribri- morph polyzoan, from the Senonian of Meudon, with apparently about 10 costae and about 5 lateral coatal fusions. The paired lateral oral avicularia are not large. Canu (19006 : 449) referred the species to Cribrilina. He gave the dimensions of the species as Lz = i-oo to 1-14 mm., Iz = 0-57 to 0-71 mm., hr = 0-17 to 0-22 mm., Ir = 0-28 mm., and mentioned the occasional presence of two marginal [oral] spines. CRETACEOUS CRIBRIMORPH POLYZOA (PELM ATOPORIN A E) 265 (4) Batrachopora royanensis Lang 19160 Batrachopora royanensis Lang, pp. no, in. 1919^ Batrachopora royanensis Lang : Lang, pp. 205, 206, 221. 1922 Batrachopora royanensis Lang : Lang p. 374, text-fig. 118. REMARKS. Lang (1916^) based his diagnosis of this species on a photograph of the holotype, which is in the F. Canu Collection. It can be seen from the photo- graph that the orifices of the zooecia are much smaller than the frontal shields, wider than high, rounded distally with straight sides, which begin to converge proximally, and with a straight proximal margin. There are apparently no lateral oral avicularia. Apparently 12-14 costae are present, each with at least two lateral costal fusions and pelmata and pelmatidia. The number of oral spines is indetermin- ate. Interzooecial avicularia of two kinds appear to be present : (a) a small, rounded, paired form just distal to each orifice, (b) a larger, laterally constricted, occasional, sporadic form of uncertain shape and orientation. Ovicells cannot be seen. There is no indication that the zoarium is necessarily " erect [and] bilaminar " as Lang (1922 : 374) has stated. There is not sufficient evidence to place the specimen with certainty in any cribrimorph genus. It is clear, however, that the specimen lacks the large, well- defined, lateral oral avicularia characteristic of Batrachopora, and that its frontal shield is different from those of species of Ubaghsia (which here includes Batracho- pora) . (5) Batrachopora ultima Voigt 19256 Batrachopora ultima Voigt, pp. 99, 103, pi. 3, figs. 7, 8 ; text-fig. 4. 1930 Batrachopora ultima Voigt : Voigt, pp. 515, 561, pi. 31, fig. 16 (copy of part of pi. 3, fig 8, 19256). 1939 Batrachopora ultima Voigt : Voigt, p. 93, text-fig. 4^. REMARKS. Voigt (19256 : 103) described the species as follows : " zoarium unilaminar, erect. Zooecia arranged in regular quincuncial lines, elongate-oval, sometimes twice as long as broad but usually somewhat shorter. The ' anterior wall ' is formed only from the frontal shield, which, on the average, consists of from 7-10 exceptionally broad costae which fuse laterally and at their inner ends along the mid-line. Thus the frontal shield is pierced generally by 4, or more rarely 5, regular, parallel, transverse, rows of pores [intercostal spaces], usually 3 or 4 to a row. The broad ' prolongations ' [outermost ends] of the costae alternate at the margin [of the frontal shield] with the narrower inter[-costal] spaces. Under the microscope, delicate ' vertically crossing ' lines may be seen on the costae. Pelmata were presumed in view of the ' sporadic punctures ' [Ppores or intercostal spaces] rather than observed ; the figure [Voigt, 19256, text-fig. 4] is to be considered in this light. 1 Orifice semicircular . . . surrounded usually by 5 [oral] spines. In all probability there is a small, elongate avicularium on either side of the orifice. I consider this to be the case because of the small protuberances on either side of the orifice, each of which seems to have possessed a pore. Several other species of Batrachopora support this, as they always have avicularia on either side of the orifice. But I have 1 My italics. 266 CRETACEOUS CRIBRIMORPH POLYZOA (PELM ATOPORIN AE) not observed the avicularia for certain because of the condition of preservation of the specimen. 1 " Batrachopora ultima is the youngest Batrachopora. B. crassa Lang is similar (also with about 7 costae) but it is distinctly larger (1-25 mm.). B. perforata (Marsson), from Riigen, which is distinguished by two large lateral avicularia, is more distantly related " [translation]. It is apparent that Voigt described B. ultima without fully determining the charac- ter of the frontal shield, particularly the presence or absence of definite pelmata. He also seemed uncertain of the nature of the oral avicularia, or even whether they were present or not. I do not accept B. ultima Voigt as a definite species of Ubaghsia, because of the uncertainty of the true character of the type material. There is one specimen, 0.31990, in the British Museum (Natural History), presented by Prof. E. Voigt, and labelled by him " Batrachopora ultima Voigt, Daniendrift, Blaue Berge, near Rosslau, Anhalt ". This specimen is a cribrimorph polyzoan with frequent, prominent, hyperstomial ovicells, and is quite unlike any species of Batrachopora [ Ubaghsia]. Lang's label with the specimen shows that he doubtfully retained it in Batrachopora. (6) Escharoides peltata Roemer 1840 Escharoides peltata Roemer, p. 14, pi. 5, fig. 7. REMARKS. Lang (1916 : 410 ; 1921 : 13) has already listed this as a species of doubtful systematic position. However, Voigt (1949 : 41, pi. 10, figs. 4, 5) recorded Batrachopora [Escharoides} peltata (Roemer) from the Senonian, zone of G. [A.] quadrata of Oberg and Misburg, Hanover, Germany. I do not agree with Voigt's placing of his specimens as a species of Batrachopora. Roemer's figure is difficult to interpret, and Voigt's very clear figures (1949, pi. 10, figs. 4, 5) show a species which may belong to Escharoides peltata Roemer, but definitely not to Batrachopora Lang. Genus ANDRIOPORA Lang 1921 Andriopora Lang, p. 89 for earlier references. The new species described below are assigned to Andriopora which has not been completely revised. The described material has been compared with all available specimens of Andriopora in the collections of the British Museum (Natural History). i. Andriopora minor 2 sp. nov. (PI. 23, fig. 6 ; Text-fig. 130) HOLOTYPE. 0.39417. Zoarial fragment encrusting the dorsal surface of a frag- ment of a unilaminar zoarium of Pelmatopora cf. palmata Lang. Senonian, zone of G. [A.] quadrata. Pit 17 of Gaster, large pit, in two sections, in Cote Bottom, Dumngton, Sussex. 1 My italics. 2 With reference to the small size of the zooecia. CRETACEOUS CRIBRIMORPH POLYZOA (PELM ATOPORI N AE) 267 DIAGNOSIS. Andriopora with small, elliptical, non-caudate zooecia ; orifice wider than high ; oral spine-bases 6 ; costae 15-20, each with about 4 lateral costal fusions ; apertural bar unmodified ; gymnocyst narrowly exposed round the frontal shield ; avicularia generally paired. DESCRIPTION. Zoarium encrusting, uniserial, tending to appear multi-serial through an irregular decrease in the angle of branching and through the tendency for different series of zooecia to overlap. Zooecia small, elliptical, non-caudate. Orifice wider than high, rounded distally and laterally or tending to be straight-sided, proximal margin straight. Oral spine-bases 6, very minute, hardly visible. Frontal O5mm. FIG. 130. Andriopora minor sp. nov. 0.39417. Holotype. Five zooecia ; one with single avicularium and one with paired avicularia. One zooecium with slightly damaged ovicell. shield well arched, slightly flattened on top. Costae 15-20, very narrow, with a variable number, often 4, very fine lateral costal fusions. There are no median pores or slits on the costae, nor do the costae tend to be up-turned at their inner ends. Median area of fusion narrow. Apertural bar unmodified, but tending to be some- what wider than the costae. Gymnocyst narrowly exposed laterally, and more widely exposed proximally to the frontal shield and round the avicularia. Avicularia large, prominent, paired, one just beyond each distal lateral margin of the orifice, or occurring singly on one side or the other, directed distally away from the mid-line of the orifice they accompany. The avicularian aperture is elongate- oval, or tending to be pointed distally, and is divided by a narrow transverse bar into a more-or-less triangular rostrum, and a wider, semicircular proximal portion. Ovicells hyperstomial, very prominent, large, globular, smooth, somewhat com- pressed laterally and standing up above the zooecium on which they are developed. 268 CRETACEOUS CRIBRIMORPH POLYZOA ( PE LM ATOPORI N AE) MEASUREMENTS. Zooecia Lz = 0-27 to 0-33 mm. Iz = 0-15 to 0-18 mm. hr = 0-035 mm. lr = 0-060 mm. Avicularia Lz = 0-06 mm. Iz = 0-03 mm. REMARKS. Andriopora minor is characterized by its small size and its closely placed non-caudate zooecia. The oral spine-bases are very minute and not at all thickened. STRATIGRAPHICAL DISTRIBUTION. Senonian, zone of G. [A.} quadrata. SPECIMENS. 0.39417. Holotype see above. 2. Andriopora major 1 sp. nov. (PI. 23, fig. 5 ; Text-figs. 131, 132) HOLOTYPE. 0.39418. Small zoarial fragment encrusting a piece of echinoid test. Senonian, zone of B. mucronata. Norwich, Norfolk. A. W. Rowe Collection. DIAGNOSIS. Andriopora with large, widely elliptical zooecia, each with a long narrow cauda ; orifice higher than wide, with proximal-lateral constrictions ; oral spine-bases 6, prominent, somewhat thickened ; costae 15-19, without lateral costal fusions ; apertural bar sharply bent proximally ; gymnocyst well exposed ; avicu- laria apparently absent. DESCRIPTION. Zoarium encrusting, uniserial, the angle of branching is apparently maintained, keeping the individual series of zooecia clearly separate. Zooecia broadly elliptical, with long, straight caudae. Orifice higher than wide, rounded distally and laterally with proximal-lateral constrictions, the proximal margin " U "- shaped. Oral spine bases 6, somewhat enlarged, tending to be arranged laterally in two groups of three. Frontal shield well arched. Costae 15-19 (occasionally 13), usually fairly wide. No lateral costal fusions. The inner ends of the costae are not up-turned near the mid-line, nor are any pores or costal slits visible. Median area of fusion fairly wide. Apertural bar with rounded outer ends, narrowed and bent proximally along the mid-line, otherwise not flattened in a vertical plane nor sub- stantially thickened. Gymnocyst widely exposed laterally and particularly proxi- mally to the frontal shield where it is prolonged into a straight, rapidly tapering, narrow cauda. The gymnocyst also appears on either side of the orifice and tapers rapidly distally giving a rounded distal margin to the zooecium from which the cauda of the distally adjacent zooecium often arises. Avicularia not seen. There is no evidence of broken avicularia or other hetero- zooecia, and avicularia are presumed absent in this species. Ovicells hyperstomial, globular, smooth, apparently somewhat compressed laterally. 1 With reference to the unusually large size of the zooecia. CRETACEOUS CRIBRIMORPH POLYZOA (PELM ATOPORIN AE) 269 MEASUREMENTS. Zooecia Lz = 0-72 mm. Iz = 0-42 mm. hr 0-15 to 0-18 mm. Ir = 0-12 mm. Lc = 0-33 to 0-50 mm. lc = 0-02 mm. REMARKS. The large size of the zooecia, the widely exposed gymnocyst, and the apparent absence of avicularia are particularly distinctive characters of Andriopora IO 2Omm. O6mm. 132 131 FIGS. 131, 132. Andriopora major sp. nov. 0.39418. Holotype. (131) Single adult zooecium ; the cauda worn away. (132) Part of zoarium showing mode of branching and long, straight, narrow caudae. major. The orifice is more complex than in A . minor and the oral spine-bases more distinct than in that species. The ovicells of A. major are described from one broken example present on an isolated zooecium. STRATIGRAPHICAL DISTRIBUTION. Senonian, zone of B. mucronata. SPECIMEN. 0.39418. Holotype see above. VIII. SYSTEMATIC BASIS, STRATIGRAPHY AND EVOLUTION OF THE GENERA AND SPECIES REVISED Recognition of distinct species in the Cretaceous cribrimorph Polyzoa is made difficult by the wide variation in morphology which may occur between adult zooecia 270 CRETACEOUS CRIBRIMORPH POLYZOA (PELM ATOPORI N AE) of the same and different zoaria of a single species, and between young and adult zooecia of a single zoarium. It is important to assess this range of variation, espe- cially as Cretaceous cribrimorph polyzoan colonies are often broken, so that the extremes of variation originally part of the same zoarium become separated and form apparently distinct species. This fragmentation also gives a false idea of the abundance of a particular species at any one horizon or locality. The present assessment of the species-unit in Cretaceous cribrimorph Polyzoa is an attempt to use all available zooecial characters rather than distinguishing species by the modifications which may be apparent in any one character. Divisions based solely on measurements of the length and width of zooecia, or on zoarial growth habit alone, have been avoided, and, generally, where Lang has distinguished species by these methods they have proved to be synonymous. In addition to comparative morphology Lang used stratigraphical and astogenetic " criteria of relationship " in his systematic assessment of species. Thus species which differ only very slightly in one or more characters were maintained as distinct if they occurred at well-separated horizons. Species may be maintained on this basis when little material is available for study. The principle has been followed to some extent in the present revision, with the reservation that the slight, but distinct, differences must be essentially structural rather than incidental differences in size or growth habit. The astogenetic basis on which Lang occasionally distinguished some species has not been followed. He generally used astogenetic differences as indications of the possible course of evolution. As several of the species established by Lang are here merged it has been necessary to revise the stratigraphical ranges of some species, and the large amount of new material examined has extended the known ranges of most species. The stratigraphical ranges of the species revised and described here are shown in the accompanying distribution table and discussed subsequently. The range of some species is shown in parts as a broken line indicating that the species has not yet been recorded from that horizon, but that it is thought to range through. Lang's very extensive studies (19160, b, igiga-d, 1921, 1922, 1925, 1929) of Cretaceous Polyzoa, and other groups, led him to adopt an orthogenetic view of evolution, formulated in what has since been termed the " Theory of Trends ". This concept required that, by means of an internal compulsive force, groups of related organisms may follow a predetermined and irreversible course of evolution to a pitch of disharmony with their environment, developing apparently functionless structures ; and that they may undergo periodic, parallel evolution or recapitulation independent of environmental effects. Lang applied this vitalist view of evolution to the Cretaceous cribrimorph Polyzoa (igigc : 105 ; 1919^ : 196 ; 1921 : xvii ; 1922). This application of the Theory of Trends produced much lively criticism which laid increasing emphasis on environmental adaptations as a more acceptable explana- tion of the apparent sequence of evolutionary changes (e.g., Bather, 1921 : 18 ; Brydone, 1929 : 6 ; Withers, 1935 : 8). In the genera revised here, and in other genera of Cretaceous cribrimorph Polyzoa, evolution in the detailed sequence of forms has taken place in a diverging plexus of CRETACEOUS CRIBRIMORPH POLYZOA (PELM ATOPORIN AE) 271 Stratigraphical Distribution of Genera and Species Revised SEXOSIAN .MAASN. Met. Mca ; M. Op. G[A]q. Bm. BL (01.) Aeolopora distincta Lang . . . A- nebulosa Lang .... Lafiynopora ptislulosa sp. nov. . L. /torsleyensis Lang L. praecursor Lang .... 'L. saltdeanensis Lang . . . L. birlingensis Lang .... L. amphora Lang .... L. (iiiipiiUa Lang .... Jj.furcifera (Brydone) L. ollula Lang .... L. lagena Lang .... L. urceolus Lang .... //. rnscultim (Lang). Ilejacanthoixtra sexspinosa Lang //. riginticoxtata Voigt LeptwJteiloptim inagna Lang //. temiilabrosa Lang .. . L. filliozati (Brydone) . . . L. nAnerata (Brydone) . PelmntojMra calceata Lang P. crcpidaria Lang .... P. solmris Lang .... P. gaxteri Lang .... P. chrysalis (d'Orbigny) . . . /'. larra Lang .... P. striata (d'Orbigny) P. fragilis (d'Orbigny) P. (Torbignyi Lang .... P. tfitadrata Lang .... P. fecampensis Lang . . . P. pero Lang ..... /'. snffulta (Brvdone) . . P. simpler- Lang .... P. plantar is Lang .... /'. ifiiadri-volucris Lang .... P. brydonei Lang .... P. coryli Lang . . . P. marsupilorum Lang . . . P. gregwyi (Brvdone) . . P. somplinyensis Lang P. palmata Lang . | _ r 1= 1 I ... ~ U r _ " _J _ . ^~~ *- - 1 1 | U - L - 1 1 1 1 ! - -1 1 1 1 1 | r Castanopora atmata sp. nov. . . . , C. labiata (Levinsen) . . . : C. retrorsa Lang . . . . C. castanea Lang . . . . C. dibleyi (Brydone) ('. guascoi (Ubaghs) C. spooneri (Butler & Cheetham) ( '. multicostata Voigt ... C.jurassica (Gregory) ... C. glandulosa Lang ... C. magnified (d'Orbigny) . . . ; C. faujasi (von Hagenow) (-. voigti sp. nov. Ubayhsia ranunculus (Lang) U. aurita (Lang) .... U. crassa Lang .... /'. coarans (Lang) .... U. perforata (Marsson) . . . U. ocellata (Jullien) U. meudonensis (Jullien) ... V. demortjani (Jullien) ... U. reticulata (Ubaghs) ... V. ornala (Gold fuss) . . . 272 CRETACEOUS CRIBRIMORPH POLYZOA (PELM ATOPORIN AE) variation, rather than along the confined and determinate, distinct lines of develop- ment which Lang has postulated. The present revision merges several of the species, and some genera, recognized by Lang so that his suggested detailed, and even more general, lines of evolution break down. This is particularly so in the case of Pelmatopora. AEOLOPORA Two species, A. distincta and A. nebulosa, are here regarded as comprising the genus. By an increase in zooecial size, a thickening of the apertural bar, a slight reduction in the number of costae and an apparent loss of avicularia A . nebulosa has evolved from A . distincta. The stratigraphical occurrence of both species is discussed on p. 64. LAGYNOPORA The stratigraphical ranges of the twelve species of Lagynopora recognized here are almost all brief. Only L. horsleyensis is recorded from the zone of M. cor- anguinum as well as from the zone of G. [A .] quadrata, and no specimens are as yet recorded from the intervening zones. L. pustulosa sp. nov. is"stratigraphically the highest species known from the Senonian. The evolutionary relationships of the twelve species are uncertain. Probably L. horsleyensis may be excluded from the main plexus of evolution of the genus as it is the only species with lateral costal fusions. Similarly the small zooecia and other distinctive characters of L. saltdeanensis and L. pustulosa suggest that the evolution of these two has been somewhat different from that of the remaining nine species of Lagynopora. These are generally related, but it is very uncertain that the individual lineage linkages shown by Lang (1921 : 54) are correct. HEX A CANTHOPORA Only two species are recognized here ; H . sexspinosa, from the zones of ?M. cor- anguinum to G. [A.~\ quadrata of the English Chalk, and H. viginticostata from the zones of G. [A.] quadrata and B. mucronata in Germany. H. sexspinosa is not yet recorded from the Echinocorys scutata var. cincta zubzone of the zone of 0. pilula. H. viginticostata may have evolved from H. sexspinosa by an increase in the number of costae, a marked widening of the median area of fusion, and by a reduction in the number and type of avicularia. LEPTOCHEILOPORA Only four species are recognized here. L. tenuilabrosa is the earliest, and L. fittiozati has the longest range in the Senonian and is represented by the greatest number of specimens. L. magna ranges from the Senonian, zone of B. mucronata, in England, to the Lower Maastrichtian, in Germany, but is not yet recorded from the Chalk with Ostrea lunata in England. L. vulnerata is known from only three specimens, one from the Senonian, zone of B. mucronata, and two from the Lower Maastrichtian, zone of Belemnella lanceolata, from the Chalk with Ostrea lunata. Leptocheilopora is unrecorded from the upper part of the zone of Marsupites. CRETACEOUS CRIBRIMORPH POLYZOA (PELM ATOPORIN AE) 273 The sequence L. tenuilabrosa-L. filliozati-L. vulnerata probably indicates the main course of evolution in the genus. There is a slight reduction in zooecial size and in the number of costae and a loss of avicularia. By contrast, there is an increase in the number of oral spines from four in L. tenuilabrosa and L. fdliozati to seven in L. vulnerata. The structure of the ovicell is simplified from the costate type in L. tenuilabrosa to more usual smooth ovicells in the remaining species. In L. magna, the youngest species of the genus, there is a pronounced increase in zooecial size and very marked proximal-lateral constrictions in the orifice. The four oral spine bases are very small, but, like the preceding species, there are no avicularia. L. magna possibly diverged from the main course of evolution in early B. mucronata times. PELMATOPORA Lang (1922 : 242) has stated that " though almost certainly arising in the Turonian (since Sandalopora, an obvious derivative, has occurred in the Turonian of France) the earliest known forms of Pelmatopora are found at the base of the Senonian, and immediately appear in great numbers both of species, and in some species, of individuals ". While it is true to say that several species of Pelmatopora make an abrupt appearance at the base of the Senonian it is an overstatement that they are present in great numbers. They occur frequently, but they are by no means so abundant as in the upper part of the Senonian, particularly in the zones of 0. pilula and G. [A.] quadrata. The twenty-two species of Pelmatopora recognized here fall stratigraphically into two well-defined groups. There is an early Senonian development in the zones of M . cortestudinarium and M. cor-anguinum of sixteen species, which, with the excep- tion of P. brydonei and P. quadrivolucris , all have unmodified oral spine-bases. A second, very abundant, group of six species characterizes the higher Senonian zones of Marsupites to G. [A.} quadrata. With the exception of P. simplex, these all have modified and enlarged distal oral spines. No species of Pelmatopora are yet recorded definitely from the Uintacrinus Subzone of the Marsupites Zone. Recently a definite Pelmatopora specimen has been recorded from the Danian of Herfolge, Denmark (see p. 202). The ranges of certain species of Pelmatopora are apparently limited within some zones of the Senonian. Thus P. pero and P. brydonei are recorded only from the upper part of the zone of M. cor-anguinum, while P. calceata, P. crepidaria, P. solearis, P. gasteri, P. fragilis, P. quadrata, P. suffulta, P. plantaris and P. quadri- volucris are most frequent in the lowest quarter of the same zone. P. chrysalis, P. larva, P. striata, P. d'orbignyi and P. fecampensis apparently characterize the middle part of the zone of M . cortestudinarium. P. simplex occurs frequently in the zone of 0. pilula. The remaining five species of Pelmatopora are very abundant from the upper part of the zone of Marsupites to the upper part of the zone of G. [A.] quadrata, but, unlike the earlier Senonian species, they do not appear to be limited to distinct horizons of these zones. The broad course of evolution in Pelmatopora may be summarized as a develop- ment from a Lower Senonian group of smaller, less complex, species with unmodified GEOL. 6, I. 1 8 274 CRETACEOUS CRIBRIMORPH POLYZOA (PELM ATOPORIN AE) oral spine bases to an Upper Senonian group of larger, more complex, species with modified, enlarged distal oral spines. Several of the species which Lang recognized in the higher group are synonymous. The almost total absence of Pelmatopora species in the Uintacrinus Subzone of the Marsupites Chalk, and in fact the general absence of Polyzoa and other fossils at this level in the Senonian, may correlate with contemporary deeper water conditions. Calcareous shells of other organisms, such as echinoids and lamellibranchs, are noticeably scarce in the Uintacrinus Chalk thus reducing the occurrence of substrates suitable for polyzoan growth. Where larger shelled organisms are more abundant there is a clearly marked increase in the polyzoan fauna. Such an effect would account for the apparent periodicity of evolution which Lang regarded as having occurred during the development of Pelmatopora. The suggested evolution from P. pero of the higher group of more complex Pelma- topora species (Lang, 1922 : 250) seems less likely than the course of evolution indicated here. P. quadrivolucris and P. brydonei, in contrast to other species of the Lower Senonian group, both possess distinctly enlarged oral spines and more complex frontal shields, therefore I regard them as fore-runners of the Upper Senonian group of Pelmatopora species in which the distal oral spines form a prominent distal oral shield. P. simplex, which lacks enlarged distal oral spines, is the only species of its kind above the zone of Marsupites. Within the Upper Senonian group of more complex species there was, apparently, a tendency to evolve increasingly larger, flatter and more bifurcated distal oral spines. P. palmata, in which this tendency is most marked, is closely related to the species-group of P. marsupitorum, P. gregoryi and P. somptingensis. CASTANOPORA Fourteen Cretaceous species of Castanopora are described here. Only one of these, C. retrorsa, represented by an isolated specimen from the Uintacrinus Subzone of the Marsupites Zone, occurs below the top part of the zone of B. mucronata. Ah 1 other species are of Maastrichtian age many coming from the boreal Maastrichtian of Riigen. C. castanea, C. dibleyi and C. magnifica have been recorded from the Senonian, zone of B. mucronata, but are more common in the Maastrichtian, in the zone of Belemnella lanceolata (Ostrea lunata Chalk) in England, and in that zone abroad. The appearance of several new species of Castanopora in the Ostrea lunata Chalk of Trimingham, Norfolk, is a significant indicator of the general faunal change, shown particularly by the foraminifera at this level, between the Senonian, and the Maastrichtian. Canu & Bassler (1933 : 53, 54) have assigned two species from the Vincentown Limesand to Rhiniopora thus extending the upward range of the genus into the Palaeocene. The main evolutionary spread of Castanopora took place at the close of the Senonian, so that Castanopora characterizes the Lower Maastrichtian. The species recognized exhibit considerable variation in the number and type of avicularia. CRETACEOUS CRIBRIMORPH POLYZOA (PELMATOPORINAE) 275 UBAGHSIA Twelve species of Ubaghsia are recognized here. Of these, only U. gasteri sp. nov. and U. langi sp. nov. occur below the zone of Belemnitella mucronata. There is a marked increase in the number of species in the Maastrichtian, most specimens coming either from the boreal Maastrichtian of Riigen, or from the littoral Maas- trichtian of Maastricht, Holland. The two new species, U. gasteri and U. langi, from the English Senonian (zones of G. [A.] quadrata and M. cor-anguinum respectively), extend the downward range of the genus. All the material previously described by Lang, and Jullien's original specimens, were from continental localities, either from the Senonian zone of Belemnitella mucronata of Meudon [U. meudonensis and U. demorgani] and Port Brehay [U. ocellata], or from the boreal Maastrichtian of Riigen [U. perforata, U. ranunculus, U. crassa and U. coaxans], from the littoral Maastrichtian of Maastricht [U. ornata and U. reticulata], and from Royan, France [U. aurita], The later species of Ubaghsia fall into two main groups. U. ranunculus, U. aurita, U. crassa, U. coaxans and (?) U. perforata all lacking the very heavy tertiary front wall which characterizes the other group of U. ocellata, U. meudonensis, U. demorgani, U. reticulata and U. ornata. There is some indication that the marked accumulation of calcium-carbonate, in the tertiary front walls of the second group, may be related to habitat. As with some Cretaceous cirripedes (Withers, 1935 : n, 13) there seems to be some correlation between a shallow water habitat and marked skeletal develop- ment of calcium-carbonate, since the species of the second group occur in littoral Maastrichtian sediments of the type locality, but other species from the boreal Chalk of Riigen are noticeably less robust. It is thus evident, from the material revised here alone, that the Cretaceous cribrimorph polyzoan faunas of the Chalk contain a number of species and genera with well-marked stratigraphical ranges. Some species apparently have a limited range within the existing recognized zones. Some division of the very thick zones of M. cor-anguinum and B. mucronata should be possible, on the basis of their contained cribrimorph polyzoan faunas, when further systematic revision of other genera is completed and when new material has been examined from collections made more recently. IX. REFERENCES BARNARD, T. & BANNER, F. T. 1953. 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Aeolopora 15, 23, 34, 29*. 30, 40, 52, 53, 54, 272 distincta 33*. 43, 44, 54, 55, 56*. 57*. 58*. 64, 272 ; PI. 2, figs. 1-7 -^nebulosa 15, 33*, 55, 62, 63*. 272 ; PL 2, figs. 8, 9 stellata 58, 59 Amphiblestrum 36 cervicorne 37* ancestrulae 45 Andriopora 23, 266 frequens 55 gallica 55 major 33*. 268, 269* ; PI. 23, fig. 5 minor 32, 33*, 266, 267*, 269 ; PL 23, fig. 6 Anornithopora 54 apertural bars 32 avicularia 41 Barroisina galeata 106 Batrachopora 52, 240, 241, 244, 264 coaxans 253 crassa 250, 252, 253, 266 - hyla 260 ornata 260 -peltata 266 perforata 266 ranunculus 242 royanensis 242, 265 ultima 242, 265, 266 Belemnella lanceolata, Zone of 12 Belemnitella mucronata, Zone of n BRYDONE, R. M. 19, 20 Canupora prima 66, 67 Carydiopora 54, 170 Castanopora 15, 24, 29*, 40, 41, 43, 52, 53, 202, 203, 274 armata 41, 205, 206, 207* ; PL 16, fig. i aviculosa 15, 206, 226, 227* ; PL 19, fig. 3 castanea 15, 33*, 39, 203, 205, 211, 212*. 274 ; PL 1 6, figs. 3-5 dibleyi 15, 39, 205, 215, 218*, 274 ; PL 16, figs. 6-8, PL 17, figs i, 2 faujasi 15, 206, 236 Castanopora glandulosa 15, 206, 225. 226* ; PL 1 8, fig. i guascoi 15, 205, 219 juglans 214 jurassica 15, 206, 223, 224* ; PL 17, figs. 3-5 labiata 15, 41, 42*, 205, 208 magnifica 15, 25, 33*, 206, 228, 230*, 274 ; PL 1 8, figs. 2-7, PL 19, figs, i, 2, 4-6 ; PL 20, fig. i multicostata 16, 206, 221 nucifera 214 retrorsa 205, 209, 210, 217, 274 ; PL 16, fig. 2 spooneri 16, 206, 220 voigti 16, 22, 206, 236 Cellepora perforata 206, 237 (Discopora) signata 242, 264 Cenomanian 8 Chaperia 36 cervicornis 37* galeata 37* quadrispinosa 36* Colletosia bellula 1 1 1 Corymbopora 23 costae 26 Cribrilina 264 alcicornis 36* annulata 27* balzaci 27* brachiata 255 cacus 234 fragilis 139, 144 furcifera 82 galanthis 163 gregoryi 163 innominata 27* insignis 155, 156 labiata 209 perforata 255 radiata 26 repleta 153, 154, 163 suffulta 154, 163 tumuliformis no, in valida 209 INDEX 283 DAVIS, A. G. 13 Decurtaria 54 Diacanthopora 30 Dishelopora 24, 30 Disteginopora 54, 241 horrida 241 Elect? a pilosa 23 Escharipora chrysalis 133 guascoi 220 magnified 220 mumia 137 pretiosa 220 striata 133, 137 Escharoides peltata 242, 266 Eucheilopora 55 Figularia in philomela in spatulata in frontal shield 25 wall 25 GASTER, C.T. A. 5, 19 Gephyrotes nitido-punctata 27* Gonioteuthis [Actinocamax] quadrata, Zone of ii Granulatensenon 19 gymnocyst 25 Haplocephalopora 42 HASTINGS, Anna B. 7 Hesperopora 54 heterozooecia other than avicularia 43 Hexacanthopora 16, 24, 25, 30, 31, 40, 52, 53, 65, 97, 272 brightonensis 99, 100 kintburiensis 99, 100 sexspinosa 16, 25, 32, 33*, 39, 43, 97, 98, 272 ; PL 5, figs. 3-6 viginticostata 16, 97, 102, 272 Hippiopora 34 Histricopora 30 Holaster planus, Zone of 9 subglobosus, Zone of 8 Hyphantoceras reussianum, Subzone of 9 Ichnopora 54 denticulata 263 Inoceramus labiatus, Zone of 8 intercostal spaces 31 mterzooecial secondary tissue 40 Lagynopora 16, 24, 25, 30, 31, 32, 35, 39, 40, 43, 52, 53, 65, 66, 97, 272 amphora 39, 66, 77* ; PL 3, fig. 9 ampulla 33*, 39, 66, 78, 79* ; PL 3, figs. 7, 8 birlingensis 39, 66, 74, 75* ; PL 3, fig. 6 furcifera 16, 39, 66, 81* ; PL 4, figs, i, 2 horsleyensis 16, 66, 68, 69*, 250, 272 ; PL 3, figs. 2, 3 lagena 16, 39, 65, 66, 86, 87* ; PL 4, figs. 4-6 ollula 39, 66, 82, 83, 84*, 95, 97 ; PL 4, fig- 3 praecursor 39, 66, 71* ; PL 3, fig. 5 -prima 16, 67, 96, 97 pustulosa 33*, 66, 67*, 272 ; PL 3, fig. i saltdeanensis 66, 73*. 76, 272 ; PL 3, fig. 4 urceolus 39, 66, 90, 91*, 92* ; PL 4, fig. 7, PL 5, fig. i vasculum 39, 66, 82, 83, 93, 94* ; PL 5, fig. 2 LANG, W. D. 5, 7 lateral costal fusions 30 Lepralia otto-mulleriana 26, 28*, 30 pediculus 66, 67, 95 Leptocheilopora 16, 25, 30, 31, 40, 43, 52, 53, 97, 102, 272 arcuata 114 filliozati 16, 32, 33*, 34, 35, 39, 103, 112, 113*, 115*, 272, 273; PL 7, figs. 3, 4, PL 8 gasteri 109 longuessensis 106, 118 magna 16, 25, 30, 35, 39, 103, 104*. 105*. 113, 115, 272, 273 ; PL 6, figs. 1-7 regularis 119 tenuilabrosa 35, 41, 43, 44, 103, 107, 108*, 109*. no*, in*, 115, 272, 273 J PL 6, figs. 8-1 1, PL 7, figs, i, 2 vulnerata 33*, 39, 97, 103, 115, 116, 117*. 272, 273 ; PL 9, figs, i, 2 Lithothamnienkalk of Haidhof 19 lumen pores 27 Maastrichtian 12 Mammillatensenon 19 Marsupites testudinarius, Zone and Subzone of 10 median area of fusion 31 Membranipora 223 crenulata 119 meudonensis 255 nitida 26, 31 284 INDEX Membranipora ocellata 255 reticulata 255 Micraster cor-anguinum, Zone of 9 cortestudinarium, Zone of 9 M0en Chalk 19 Monoceratopora 41 Murinopsia 54 Off aster pilula, Zone of 10 oral spines 35 shields 39 orifice, primary 34 secondary 35 Ostrea lunata, Chalk with 13 ovicells 43 Pachydera 54 Pancheilopora 55 pelmata 27 pelmatidia 27 Pelmatopora 17, 22, 25, 30, 32, 34, 35, 36, 39, 40, 41, 43, 52, 53, 119, 272, 273 bidens 181 brydonei 17, 21, 38, 123, 150, 164, 165*, 166, 273, 274 ; PI. 12, fig. 3 calceata 40, 41, 42*, 122, 123, 124*, 129, 273 ; PI. 9, fig. 3 chrysalis 17, 122, 132, 133*, 136, 137, 273 ; PI. 9, ng. 7 collium 181 coryli 38, 123, 168, 169* ; PI. 12, fig. 4 crepidaria 40, 122, 125, 126*, 273 ; PI. 9, fig- 4 damicornis 198 daniensis 17, 200, 202 danktonensis 192 d'orbignyi 17, 33, 122, 140, 141*, 142*. 273 ; PI. 10, fig. 3 fecampensis 17, 40, 44, 122, 145, 146*, 147*, 148*, 273 ; PI. 10, fig. 6 filliozati 139, 144 fragilis 17, 122; 138*, 273 ; PI. 10, figs, i, 2 gasteri 122, 130, 131*, 273 ; PI. 9, fig. 8 grandiporosa 201 - gregoryi 21, 38, 40, 42*, 44, 123, 146, 154, 166, 175, 178*, 179*, 180*, 192, 193, 198, 200, 274 ; PI. 13, PI. 14, figs. 1-4 gyrinoides 181 incerta 200 insignis 154, 155 interrupts, 136 lacuum 181 lancingensis 181 Pelmatopora larva 17, 22, 122, 134*, 142, 273 ; PI. 9, fig. 9 marsupitorum 17, 38, 42*. 44, 123, 171, 172*, 192, 274 ; PI. 12, figs. 2, 5 palmata 33*, 38, 123, 193, 196, 197*, 274 ; PI. 15, figs. 3, 5, 6 pauciclavia 139 pero 120, 123, 148, 149*, 167, 273, 274 ; PI. 10, fig. 7 plantaris 123, 159, 160*, 273 ; PI. n, fig- 4 promontoriorum 181 quadrata 17, 44, 122, 143, 144*, 273 ; PL 10, figs. 4, 5 quadrivolucris 38, 123, 161, 162*, 273, 274 ; PI. n, figs. 5, 6, PI. 12, fig. i ranunculoides 181 repleta 153, 154, 155 roedeanensis 173 saltdeanensis 181 simplex 123, 157, 158*, 161, 273, 274 ; PI. 11, figs. 2, 3 solearis 33*, 40, 122, 127*, 128*, 273 ; PI. 9, figs. 5, 6 somptingensis 21, 24, 31, 33*, 38, 41, 42*, 44, 123, 146, 188, 190*, 191*, 274 ; PI. 14, figs. 5, 6, PI. 15, figs, i, 2, 4 spp. 199, 201 ; PI. 15, fig. 7 striata 17, 122, 136, 273 ; PI. 9, fig. 10 suffulta 17, 123, 151, 152*, 163, 273 ; PI. 10, figs. 8, 9, PI. n, fig. i Pelmatoporidae 51 Pelmatoporinae 52 Phrynopora 54, 241 Pliophloea 30, 43 Pnictopora 22, 40 Polycephalopora 21 Prodromopora 52, 66, 76, 96 praecursor 66, 72 Reptescharella radiata 202, 206, 237 Reptescharipora convexa 242, 264 ornata 206, 238 Reptoporella 103, 119 regularis 103, 119 Rhabdopora 22 Rhiniopora 52, 202, 204, 237, 274 aspera 231, 232, 233, 234 asperula 231, 232, 233 aviculosa 227, 228 cacus 231, 232, 233, 234 hispida 206, 236, 237, 238 horrida 232, 233 INDEX 285 Rhiniopora jurassica 223, 224 scabra 223, 224 spooneri 221 " Rhynchonella " cuvieri, Zone of 8 Rocanean 19 Riigen Chalk 19 Sandalopora 22, 54, 273 Schloenbachia varians, Zone of 8 Scrupocellaria 36 frondis 37* securifera 37* Semiescharipora interrupta 133 ovalis 242, 264 Senonian 9 Steganoporella buski 22, 233 Steginopora 54, 241 ornata 241 reticulata 240 Stichocados 54 ordinatus 255 Terebratulina lata, Zone of 9 tertiary frontal wall 33 THOMAS, H. D. 7 Tricephalopora 30, 33, 35 Trochiliopora Bed 10 Turonian 8 Ubaghsia 18, 19*, 33, 35, 36, 39, 52, 53, 238, 275 arcifera 241 Ubaghsia aurita 18, 241, 244, 275 ; PI. 20, fig. 3 coaxans 18, 241, 252, 253*, 275 ; PI. 20, fig. 6, PI. 21, fig. 6 crassa 18, 241, 250, 251*, 263, 275 ; PI. 20, fig. 5, PI. 21, fig. 7 demorgani 18, 36, 241, 242, 255, 256, 275 ; PI. 22, figs. 5, 6 gasteri 241, 245, 246*, 250, 275 ; PI. 20, figs. 4, 7 langi 241, 247, 248*, 275 ; PI. 21, figs. 4, 5 meudonensis 18, 36, 242, 255, 256, 257, 275 ; PL 22, figs. 3, 4 ocellata, 18, 36, 241, 255, 256, 257, 275 ; PI. 22, figs, i, 2 ornata 18, 31, 33*, 242, 260, 262*. 275 ; PI. 23, figs. 1-4 perforata 18, 241, 244, 254, 275 ranunculus 18, 42, 241, 242, 243*, 263, 275 ; PI. 20, fig. 2 reticulata 18, 36, 240, 242, 255, 257, 258*, 262, 263, 275 : PI. 21, figs. 1-3, PI. 22, figs. 7, 8 Uintacrinus westphalicus , Subzone of 10 young zooecia 45 zoarial budding 23 growth habit 21 zooecial walls other than the frontal walls 24 size 24 shape 24 PLATE i Aeolopora distincta Lang FIG. i. Group of adult zooecia, some ovicelled (o), interzooecial avicularium present (a). Holotype. X3O. D. 28062. FIG. 2. Group of adult zooecia. Holotype of A . stellata Lang. X3O. 0.28911. FIG. 3. Group of adult zooecia showing particularly the form of the apertural bar and inter- zooecial avicularia (a). Holotype of A. stellata Lang. X3O. D. 28911. FIG. 4. Group of adult zooecia. x 30. 0.40654. FIG. 5. Group of adult zooecia with a cluster of heterozooecia (h). X 30. 0.40658. FIG. 6. Group of adult zooecia, some with six oral spine bases (o.s.). X3O. 0.40657. FIG. 7. Group of adult zooecia, some ovicelled, showing prominently the " rings " of boss- like pelmatidia (p). Paratype. x 30. 0.28061. FIG. 8. Adult zooecia, the ovicell with small lateral slits (1). x 100. 0.40599. FIG. 9. Adult zooecia, showing the median ridge on the ovicell in the centre, x 100. 0.40653. Bull. B.M. (N.H.) Geol. 6, 1 PLATE 1 AEOLOPORA PLATE 2 Aeolopora distincta Lang FIG. i. Part of a zoarium with the zooecia budded in long lines, x 30. 0.40653. FIG. 2. Group of adult zooecia, showing the tendency for the successively budded zooecia of one line to be ovicelled. X 30. 0.40651. FIG. 3. Ancestrula (A), young and adult zooecia. X 30. 0.40633. FIG. 4. Ancestrula and first ring of zooecia. X3O. 0.40588. FIG. 5. Adult zooecia and interzooecial avicularia (a). X3O. 0.40559. FIG. 6. Adult zooecia, showing particularly the form of the apertural bars and interzooecial avicularia (a). X3o. 0.40579. FIG. 7. Ancestrula and young zooecia. x 30. 0.40589. Aeolopora nebulosa Lang FIG. 8. Adult zooecia, showing thick apertural bars. X3O. 0.40661. FIG. 9. Ancestrula (A) and young zooecia with thick apertural bars. Holotype. X 30. 0.29061. Bull. B.M. (N.H.) Geol. 6, 1 PLATE 2 AEOLOPORA PLATE 3 Lagynopora pustulosa sp. nov. FIG. i . Young and adult zooecia, some with ovicells, showing prominent proximal oral shield (pos) and boss-like pelmatidia (p). Holotype. X32. 0.39419. Lagynopora horsleyensis Lang FIG. 2. Adult ovicelled zooecia with lateral costal fusions and interzooecial avicularia (a). A large distal communication pore (cp) is visible in some zooecia. Holotype. x 20. 0.28908. FIG. 3. Group of larger, adult ovicelled zooecia. X2O. N.C.M. 247.956 (4/2). Lagynopora saltdeanensis Lang FIG. 4. Poorly preserved group of adult ovicelled zooecia, some with proximal oral shield (pos) complete. Holotype. x 20. 0.28896. Lagynopora praecursor (Lang) FIG. 5. Adult part of the zoarium with two relatively complete ovicelled zooecia showing the enlarged proximal-lateral oral spines and large, oval, interzooecial avicularia (a). Holotype. X2o. 0.8351. Lagynopora birlingensis Lang FIG. 6. Group of adult ovicelled zooecia; proximal oral shield (pos). Holotype. x 20. 0.28254. Lagynopora ampulla Lang FIG. 7. Adult ovicelled zooecia; proximal oral shield (pos). Holotype. X2O. 0.28256. FIG. 8. Ovicelled zooecia and prominent distal communication pore (cp). Holotype. X20. 0.28256. Lagynopora amphora Lang FIG. 9. Adult zooecia with damaged ovicells. Holotype. x 20. 0.28255. Bull. B.M. (N.H.) Geol. 6, 1 PLATE 3 LAGYNOPORA PLATE 4 Lagynopora furcifera (Brydone) FIG. i. Part of the extensive zoarium with well-preserved adult ovicelled zooecia and several complete proximal oral shields (pos). Lectotype. x 20. S.M., 6.36165. FIG. 2. Young zooecia with six oral spine bases (os) and an oval, interzooecial avicularium (a). Lectotype. X2o. S.M., 6.36165. Lagynopora ollula Lang FIG. 3. Adult ovicelled zooecia ; proximal oral shield (pos), oval, interzooecial avicularia (a). Lectotype. X2o. S.M., 6.36166. Lagynopora lagena Lang FIG. 4. Ancestrula (A), young and adult zooecia. Holotype. x 20. 0.4042. FIG. 5. Ovicelled adult zooecia, some with complete proximal oral shields (pos). Paratype. X 20. 0.4028. FIG. 6. Adult zooecia, with broken proximal oral shields, showing the form of the apertural bar (ab). Paratype. x 20. 0.2633. Lagynopora urceolus Lang FIG. 7. Adult ovicelled zooecia with broken proximal oral shields, an incomplete one is marked (pos). Distal communication pores (cp) are visible at the edges of the zoarial fragment. Holotype. x 20. 0.28889. Bull. B.M. (N.H.) Geol.6, 1 PLATE 4 I AGYNOPORA GEOL. 6, 1. PLATE 5 Lagynopora urceolus Lang FIG. i. Extensive zoarium with adult ovicelled zooecia and prominent interzooecial avi- cularia (a), x 20. 0.41067. Lagynopora vasculum Lang FIG. 2. Obscured ancestrula (A], young, and adult ovicelled zooecia, some with well- preserved proximal oral shields (pos) and interzooecial avicularia (a). Lectotype. x 20. S.M., 6.36164. Hexacanthopora sexspinosa Lang FIG. 3. Well-preserved zoarium, with ancestrula (A) and broken, worn ovicells. The broken zooecia near the edge of the zoarial fragment reveal distal and lateral pore chambers (pc). Holotype. x 20. 0.21205. FIG. 4. Distal (dcp) and lateral (Icp) communication pores are visible. Paratype. x 20. D. 21206. FIG. 5. Poorly preserved adult zooecia ; the circum-ancestrular area destroyed. Large avicularia present (a). Holotype of H. brightonensis Lang, x 20. D. 28890. FIG. 6. Adult ovicelled zooecia with median processes (mp) on the apertural bars and large avicularia (a). Holotype of H. kintburiensis Lang, x 20. 0.21204. Bull. B.M. (N.H.J Geol. 6, 1 PLATE 5 LAGYNOPORA, HEXACANTHOPORA PLATE 6 Leptocheilopora magna Lang FIG. i. Ancestrula and young zooecia ; pelmatidia (p) visible on the costae of some zooecia. Holotype. X2o. 0.19623. FIG. 2. Adult zooecia, some with broken ovicells. x 20. 0.38919. FIG. 3. Adult zooecia, some with broken ovicells (o). x 20. 0.38918. FIG. 4. Ancestrula and young zooecia. x 20. 0.39424. FIG. 5. Adult zooecia with three complete ovicells. The minute oral spine bases (05) are visible and distal and lateral communication pores are exposed near the edge of the zoarial fragment. X2O. 0.39425. FIG. 6. Ancestrula (A) and young zooecia. The apertural bar of the zooecium on the left is particularly well preserved showing the small median ridge which is sometimes present, x 20. 0.39426. FIG. 7. ? Leptocheilopora magna Lang. Copy of part of a photograph in the British Museum (Natural History) of the holotype of L. longuessensis Lang. Leptocheilopora tenuilabrosa Lang FIG. 8. Adult zooecia with broken, costate ovicells (o). Holotype. x 20. 0.28892. FIG. 9. Adult zooecia. Holotype of L. gasteri Lang, x 20. 0.29901. FIG. 10. Two adult zooecia, one with complete costate ovicell. Holotype of L. gasteri Lang. X20. 0.29901. FIG. ii. Adult zooecia and broken costate ovicells (o). Paratype of L. tenuilabrosa Lang. X2O. D.2I2IO. Bull. B.M. (N.H.) Geol. 6, 1 PLATE 6 LEPTOCHEILOPORA PLATE 7 Leptocheilopora tenuilabrosa Lang FIG. i . Adult ovicelled zooecia with large, spatulate avicularium with costate frontal shield (a), x 20. Figured Brydone (1917, pi. 3, fig. 7) as Cribrilina tumuliformis. S.M., 6.36338. FIG. 2. Adult zooecia and large, vicarious, spatulate avicularium with costate frontal shield and minute apertural spine bases (a). X2O. Figured Brydone (1917, pi. 3, fig. 8) as Cribrilina tumuliformis. S.M., 6.36339. Leptocheilopora filliozati (Brydone) FIG. 3. Adult zooecia, some ovicelled ; distal communication pores (dcp) visible in some zooecia. Lectotype. x 20. S.M., 6.36167. FIG. 4. Adult zooecia with typical median ridges on each frontal shield. Holotype of L. arcuata Lang, x 20. 0.28294. Bull. B.M. (N.H.) Geol. 6, 1 PLATE 7 OPOR A PLATE 8 Leptocheilopora filliozati (Brydone) FIG. i . Well-preserved group of adult zooecia, one exceptionally long with 35 costae. x 20. 0.40940. FIG. 2. Group of adult zooecia. X2o. 0.39427. FIG. 3. Ancestrula (A), young and adult zooecia with marked median ridge on the frontal shield. X2O. Paratype of L. arcuata Lang. 0.4279. FIG. 4. The only specimen in the British Museum (Natural History) labelled by Lang " Leptocheilopora filliozati (Brydone) ". Two adult zooecia, the most distal with a distal communication pore, and two small zooecia to the right, x 20. 0.29900. FIG. 5. Very young zooecia with Pancestrula. Paratype of L. arcuata Lang. X2O. 0.28895. FIG. 6. Adult zooecia, some with slightly damaged ovicells. Paratype of L. arcuata Lang. X20. 0.28893. FIG. 7. Adult ovicelled zooecia with marked median ridges on frontal shields and very young zooecia (Y). X20. S.M., 6.36168. FIG. 8. Ancestrula (A), young and adult zooecia with well-displayed distal communication pores, x 20. 0.39430. FIG. 9. Edge of a damaged zoarial fragment with adult zooecia with distinct distal and lateral communication pores. X2O. 0.39429. Bull. B.M. (N.H.) Geol. 6, 1 PLATE 8 T FPTOrHFTT OPOR A PLATE 9 Leptocheilopora vulnerata (Brydone) FIG. i. Young and adult zooecia, those at the top with visible pelmata (p). Lectotype. X 20. S.M., 6.36271. FIG. 2. Extensive zoarium of young and adult, ovicelled zooecia. x 20. S.M., 6.36272. Pelmatopora calceata Lang FIG. 3. Adult zooecia with well-exposed gymnocyst, prominent, large pelmata and small, round, sporadic avicularia. Holotype. x 20. 0.4032. Pelmatopora crepidaria Lang Fig. 4. Adult zooecia with tubular avicularia (a). One zooecium with ? the remains of a broken calcareous lamina in the orifice (cl). Holotype. X2O. D. 21200. Pelmatopora solearis Lang FIG. 5. Group of adult zooecia. Holotype. x 20. D. 21211. FIG. 6. Group of young zooecia with well-exposed gymnocyst (g). Holotype. X2O. D.2I2II. Pelmatopora chrysalis (d'Orbigny) FIG. 7. Group of adult zooecia. Copy of a photograph in the British Museum (Natural History) of the middle specimen of three on a slide labelled " Escharipora striata d'Orbigny, Coniacian, Villedieu ". F. Canu Collection, Paris. Pelmatopora gasteri Lang FIG. 8. Adult zooecia with small orifices with distinct proximal-lateral constrictions. Holo- type. x 20. 0.28274. Pelmatopora larva Lang FIG. 9. Long adult zooecia with paired, distally pointed and directed avicularia (a). Holo- type. x 20. 0.28440. Pelmatopora striata (d'Orbigny) FIG. 10. Group of adult zooecia. Copy of a photograph in the British Museum (Natural History) of one of the outer specimens of three on a slide labelled " Escharipora striata d'Orbigny, Coniacian, Villedieu ". F. Canu Collection, Paris. Bull B.M. (N.H.) Geol 6, 1 PLATE 9 10 LEPTOCHEILOPORA. PELMATOPORA PLATE 10 Pelmatopora fragilis (d'Orbigny) FIG. i. Copy of a photograph in the British Museum (Natural History) of one of three specimens on a slide labelled " Cribrilina [Semiescharipora] fragilis d'Orbigny ". Senonian, Emscherian, Fecamp, Seine Inf6rieure, France. F. Canu Collection, Paris. FIG. 2. Adult zooecia with commonly paired avicularia. Holotype of Pelmatopora pauci- clavia Lang, x 20. 0.28273. Pelmatopora d'orbignyi Lang FIG. 3. Group of adult zooecia with prominent, paired avicularia (a) and abundant inter- zooecial secondary tissue with deep lacunae (/). Holotype. x 20. 0.28453. Pelmatopora quadrata Lang FIG. 4. Adult zooecia with commonly paired avicularia (a) and well immersed ovicells (o). Holotype. X2O. 0.28271. FIG. 5. Group of adult zooecia. Copy of a photograph in the British Museum (Natural History) of a specimen mounted nearest to the label on a slide labelled " Cribrilina [Semie- scharipora] fragilis d'Orbigny ". Senonian, Emscherian, Fe'camp, Seine Infe'rieure, France. F. Canu Collection, Paris. Lang (1922 : 273) made the specimen the holotype of Pelmatopora filliozati Lang. Pelmatopora fecampensis Lang FIG. 6. Adult zooecia with paired, distally pointed and directed avicularia (a). The orifice may be closed by a thin, calcareous lamina (cl) as in the zooecium on the left. Holotype. X2o. 0.28473. Pelmatopora pero Lang FIG. 7. Adult zooecia with prominent, distally pointed and directed avicularia (a). Holo- type. x 20. 0.23405. Pelmatopora suffulta (Brydone) FIG. 8. Edge of zoarial fragment with pointed, distally directed avicularia and adult ovicelled zooecia. Lectotype of P. repleta (Brydone). x 20. S.M., 6.36263. Figured Brydone (1913, pi. 14, fig. 5) as Cribrilina suffulta. FIG. 9. Adult zooecia with widely exposed gymnocysts (g). Lectotype of Pelmatopora suffulta (Brydone). x 20. S.M., 6.36262. Figured Brydone (1913, pi. 14, fig. 4) as Cribrilina suffulta and chosen as lectotype of Pelmatopora suffulta (Brydone) by Lang (1922 : 277). Bull. B.M. (N.H.) Geol. 6, 1 PLATE 10 PELMATOPORA PLATE ii y Pelmatopora suffulta (Brydone) FIG. i. Adult zooecia with pointed avicularia (a). Lectotype of P. repleta (Brydone). X20. S.M., 6.36263. Pelmatopora simplex Lang FIG. 2. Adult zooecia with deep interzooecial lacunae (/). Holotype. X2O. 0.28281. FIG. 3. Young zooecia. Holotype. x 20. 0.28281. Pelmatopora plantaris Lang FIG. 4. Adult zooecia, with sharply denned interzooecial lacunae (/), and young zooecia (Y). Holotype. x 20. 0.19620. Pelmatopora quadrivolucris Lang FIG. 5. Adult zooecia, each with two pairs of enlarged oral spines. Holotype of Cribrilina galanthis Brydone. x 20. S.M., 6.36261. FIG. 6. Adult zooecia, each with two pairs of enlarged oral spines. Holotype of Pelmato- pora quadrivolucris Lang. X2O. 0.28907. Bull. B.M. (N.H.) Geol. 6, I PLATE 11 PELMATOPORA PLATE 12 Pelmatopora quadrivolucris Lang FIG. i. Adult zooecia, each with two pairs of enlarged oral spines, x 20. S.M., 6.36363. Pelmatopora marsupitorum Lang FIG. 2. Adult zooecia, showing enlarged, peg-like, distal oral spines (d) and secondary thickening (st) obscuring the lateral oral spines. Holotype. x 20. D. 28867. FIG. 5. Adult zooecia, one with an ovicell (0). Holotype of P. roedeanensis Lang. X 20. D.28868. Pelmatopora brydonei Lang FIG. 3. Adult zooecia, showing enlarged distal oral spines and visible, unmodified, proximal- lateral oral spine bases. Holotype. x 20. 0.23396. Pelmatopora coryli (Lang) FIG. 4. Adult zooecia with enlarged distal oral spines. Holotype. x 20. 0.28998. Bull. B.M. (N.H.) Geol. 6, I PLATE 12 PELMATOPORA GEOL. 6, I. 20 PLATE 13 Pelmatopora gregoryi (Brydone) FIG. I. Adult zooecia with plentiful interzooecial secondary tissue. The orifices of ovi- celled zooecia (o) are oblong. Lectotype. x 20. S.M., 6.36120. FIG. 2. Adult zooecia, some ovicelled (o). Holotype of P. bidens Lang, x 20. 0.28934. FIG. 3. Adult zooecia with abundant interzooecial secondary tissue. Holotype of P. collium Lang, x 20. 0.28824. FIG. 4. Adult zooecia. Holotype of P. lancingensis Lang, x 20. 0.28947. FIG. 5. Probably a young zooecium. Holotype of P. gyrinoides Lang, x 20. 0.28270. FIG. 6. Adult zooecia. Holotype of P. saltdeanensis Lang, x 20. 0.28842. FIG. 7. Adult zooecia. Holotype of P. ranunculoides Lang, x 20. 0.28856. Bull B.M. (N.H.) Geol. 6, I PLATE 13 PELMATOPORA PLATE 14 Pelmatopora gregoryi (Brydone) FIG. i. Adult zooecia. Holotype of P. lacuum Lang, x 20. D. 28862. FIG. 2. Adult zooecia. Paratype of P. bidens Lang, x 20. D. 28828. FIG. 3. Adult zooecia. X2O. 0.39301. FIG. 4. Adult zooecia. Holotype of P. promontoriorum Lang, x 20. 0.28930. Pelmatopora somptingensis Lang FIG. 5. Adult zooecia, showing the great variation of length which may occur in the same part of a single zoarium. Very long and very short zooecia are adjacent, x 20. 0.39333. FIG. 6. Adult zooecia, showing very prominent, laterally flattened and distally expanded distal oral spines. Holotype. X2O. 0.28762. Bull. B.M. (N.H.) Geol. 6, I PLATE 14 PELMATOPORA PLATE 15 Pelmatopora somptingensis Lang FIG. i. Adult zooecia. Holotype of P. danklonensis Lang, x 20. 0.23963. FIG. 2. Adult zooecia, some ovicelled (o) producing a prominent distal oral shield, x 20. D-39343- FIG. 4. Dorsal surface of zoarium. x 20. 0.39358. Pelmatopora palmata Lang FIG. 3. Adult zooecia. Holotype of P. damicornis Lang, x 20. 0.20204. FIG. 5. Adult zooecia. Holotype of P. damicornis Lang, x 20. 0.20204. FIG. 6. Adult zooecia, with very prominent, bilobed, enlarged distal oral spines. Holotype of P. palmata Lang, x 20. D.Soio. Pelmatopora sp. FIG. 7. Specimen from the Senonian, zone of Belemnitella mucronata. Isle of Wight, x 20. D-39330 Bull. B.M. (N.H.) Geol 6, 1 PLATE 15 PELMATOPORA PLATE 16 Castanopora armata sp. nov. FIG. i. Adult zooecia and avicularia of types a, b and c. Holotype. X2o. 0.31717. Castanopora retrorsa Lang FIG. 2. Adult zooecia, some ovicelled, with numerous interzooecial avicularia (a). Holotype. X20. D.2II70. Castanopora castanea Lang FIG. 3. Well-preserved adult zooecia with paired, distally pointed and directed avicularia (a). The very wide zooecium (z) results from the coalescence of the buds of two adjacent rows of zooecia. Holotype. x 20. 0.16654. FIG. 4. Adult zooecia with paired, distally pointed and directed avicularia. Holotype of C. juglans Lang, x 20. 0.15608. FIG. 5. Adult zooecia with paired, distally pointed and directed avicularia (a). The zoo- ecium marked (R) has been damaged and completely regenerated. Holotype of C. nucifera Lang, x 20. 0.15600. Castanopora dibleyi (Brydone) FIG. 6. Adult zooecia, some with broken ovicells (o), and paired, distally pointed and directed avicularia (a). Lectotype. X2o. S.M., 6.36115. FIG. 7. Younger part of the zoarium. Lectotype. x 20. S.M., 6.36115. FIG. 8. Adult zooecia, some with undamaged ovicells. x 20. S.M., 6.36267. Bull. B.M. (N.H.) Geol. 6, 1 PLATE 16 CASTANOPORA PLATE 17 Castanopora dibleyi (Brydone) FIG. i. Ancestrula, young and earlier adult zooecia. Very long avicularia (a) occur in the adult stages, xao. S.M., 6.36267. FIG. 2. Ancestrula (A], young and adult zooecia with paired, distally pointed and directed avicularia. x 20. 0.8003. Castanopora jurassica (Gregory) FIG. 3. Very worn specimen. Adult zooecia with large, oval, interzooecial avicularia (a). X20. 0.3313. FIG. 4. Adult zooecia. Holotype of Rhiniopora scabra Lang, x 20. 0.14207. FIG. 5. Worn and damaged zoarial fragment partly embedded in matrix, but with one complete frontal shield, on what is probably a young zooecium, and large, oval, sporadic, interzooecial avicularia (a). Holotype of Castanopora jurassica (Gregory), x 20. D.iSo. Bull BM. (N.H.) Geol 5, 1 PLATE 17 CASTANOPORA PLATE 18 Castanopora glandulosa Lang FIG. i. Adult zooecia with paired avicularia (a). Holotype. x 20. 0.15009. Castanopora magnifica (d'Orbigny) FIG. 2. Adult zooecia with interzooecial avicularia. x 20. N.C.M.76.937 (26/1). FIG. 3. Adult zooecia with prominently thickened apertural bars. X2O. N.C.M.y6.937 (27/4). FIG. 4. Large, well-preserved adult zooecia. X2O. 0.40673. FIG. 5. Large zooecia, one with broken ovicell (o). X2O. S.M., 6.36266. Figured Brydone (1913, pi. 14, fig. 8) as Cribrilina cacus and assigned to Rhiniopora by Lang (1922 : 193). FIG. 6. Adult zooecia with interzooecial avicularia. Holotype of Rhiniopora aspera Lang. X2o. 0.15620. FIG. 7. Adult zooec'a. X20. 0.14176. Labelled by Lang "Rhiniopora asperula (Marsson) ". Bull B.M. (N.H.) Geol. 6, 1 PLATE 18 CASTANOPORA PLATE 19 Castanopora magnified (d'Orbigny) FIG. i. Well-preserved, large, adult zooecia, several totally regenerated (R) after damage to frontal shield, x 20. S.M., 6.36264. Figured Brydone (1913, pi. 14, fig. 6) as Cribrilina cacus and tentatively assigned to Rhiniopora aspera by Lang (1922 : 188). FIG. 2. Adult zooecia with oval, interzooecial avicularia. x 20. N.C.M.y6.937 (27/1). FIG. 4. Large, well-preserved, adult zooecia with four or five oral spine-bases, x 20. S.M., 3.36265. Figured Brydone (1913, pi. 14, fig. 7) as Cribrilina cacus and chosen by Lang (1922 : 193) as lectotype of Rhiniopora cacus (Brydone). FIG. 5. Adult zooecia. Holotype of Rhiniopora horrida Lang, x 20. 0.14171. FIG. 6. Adult zooecia with long, oval avicularium (a), x 20. N.C.M.76.937 (27/1). Castanopora aviculosa Lang FIG. 3. Adult zooecia with marked proximal-lateral constrictions in the orifices and frequent, variously directed, pointed avicularia. Copy of a photograph in the British Museum (Natural History) of a specimen in the F. Canu Collection, Paris. Bull. B.M. (N.H.) Geol. 6, 1 PLATE 19 CASTANOPORA PLATE 20 Castanopora magnified (d'Orbigny) FIG. i. Large adult zooecia, with large, oval, interzooecial avicularia. Copy of part of a photograph by P. M6min (Serv. Photo. G6ol. E.N.S.) of d'Orbigny Collection No. 7992, Paris. Holotype (?). X25. Ubaghsia ranunculus (Lang) FIG. 2. Adult zooecia, one with unbroken proximal oral shield (pos). Holotype. X2O. 0.23388. Ubaghsia aurita (Lang) FIG. 3. Group of adult zooecia. Copy of a photograph in the British Museum (Natural History) of the holotype in the F. Canu Collection, Paris. Ubaghsia gasteri sp. nov. FIG. 4. Adult zooecia. Paratype. x 20. 0.40548. FIG. 7. Adult zooecia, with large, paired lateral oral avicularia (a), forming part of the proximal oral shield, and occasional small, round, sporadic avicularia (b). Holotype. X2O. 0.40546. Ubaghsia crassa (Lang) FIG. 5. Group of adult zooecia. X2O. N.C.M.76.937 (30). Ubaghsia coaxans (Lang) FIG. 6. Two adult zooecia with broken and worn proximal oral shields. Holotype. x 20. 0.14209. Bull. B.M. (N.H.) Geol. 6, 1 PLATE 20 CASTANOPORA, UBAGHSIA GEOL. 6, I. 21 PLATE 21 Ubaghsia reticulata (Ubaghs) FIG. i. The frontal shields of the adult zooecia are in focus, a fragment of tertiary front wall (W] is blurred. X2O. 0.1391. Labelled by Lang " Batrachopora ornata (Goldfuss) ". FIG. 2. The fragment of tertiary front wall (W) is shown in focus above the zooecia. x 20. D.I39I. FIG. 3. Adult zooecia ; the orifices are almost as large as the frontal shields. Holotype of Batrachopora hyla Lang. X2O. 0.11852. Ubaghsia langi sp. nov. FIG. 4. Ancestrular area. Holotype. x 20. N.C.M.247-956 (4/1). FIG. 5. Group of adult zooecia. Holotype. x 20. N.C.M.247.956 (4/1). Ubaghsia coaxans (Lang) FIG. 6. Three damaged, worn adult zooecia. Paratype. x 20. 0.15041. Ubaghsia crassa (Lang) FIG. 7. Worn, adult zooecium. Holotype. x 20. 0.16674. Bull. B.M. (N.H.) Geol. 6, 1 PLATE 21 UBAGHSIA PLATE 22 Ubaghsia ocellata (Jullien) FIG. i. Adult part of zoarium showing bifurcated distal oral spines and, in the lower part of the figure, the complete tertiary front wall. Copy of part of figure by Jullien (1886, pi. 19, fig- I). FIG. 2. Vertical section through the unilaminar zoarium. Copy of figure by Jullien (1886, pi. 19, fig. 3). Ubaghsia meudonensis (Jullien) FIG. 3. Adult part of zoarium lacking tertiary front wall. Copy of part of figure by Jullien (1886, pi. 17, fig. i). FIG. 4. Three adult zooecia lacking tertiary front walls, showing an interzooecial avicularium between the two zooecia at the top. Copy of part of figure by Jullien (1886, pi. 17, fig. 4). Ubaghsia demorgani (Jullien) FIG. 5. Part of adult zoarium with complete tertiary front wall. Copy of part of figure by Jullien (1886, pi. 19, fig. 4). FIG. 6. Part of adult zoarium with tertiary front wall largely removed. Copy of part of figure by Jullien (1886, pi. 19, fig. 5). Ubaghsia reticulata (Ubaghs) FIG. 7. Part of adult zoarium lacking a tertiary front wall in lower part of the figure. Copy of part of figure by Jullien (1886, pi. 18, fig. 4). FIG. 8. Worn, adult zooecia with two interzooecial avicularia. Copy of part of figure by Jullien (1886, pi. 18, fig. 5). Bull. B.M. (N.H.) Geol 6, 1 PLATE 22 UBAGHSIA PLATE 23 Ubaghsia ornata (Goldfuss) FIG. i. Worn, adult zooecia with very large orifices. The zooecium (Z) on the left has only four costae. X 20. 0.19357. FIG. 2. Somewhat worn, adult zooecia with very large orifices and few costae. The zooe- cium (Z) has only three costae. x 20. 0.8529. FIG. 3. Ubaghsia ? ornata (Goldfuss). Worn adult zooecia. x 20. 0.28526. FIG. 4. Adult zooecia with orifices as large as the frontal shields, with paired, pointed, oral avicularia (a) and small rounded interzooecial avicularia (b). x 20. 0.19356. Andriopora major sp. nov. FIG. 5. Caudate, adult zooecia. Holotype. x 20. 0.39418. Andriopora minor sp. nov. FIG. 6. Adult zooecia, some ovicelled (o). Holotype. X4O. 0.39417. Bull. B.M. (N.H.) Geol. 6,1 PLATE 23 UBAGHSIA, ANDRIOPORA PRINTED IN GREAT BRITAIN BY A D L A R D AND SON LIMITED BARTHOLOMEW PRESS, DORKING ON PTERUCHUS, A MICROSPOROPHYLL OF THE CORYSTOSPERMACEAE J. A. TOWNROW BULLETIN OF THE BRITISH MUSEUM (NATURAL HISTORY) GEOLOGY Vol. 6 No. 2 LONDON: 1962 ON PTERUCHUS A MICRO SPOROPHYLL OF THE CORYSTOSPERMACEAE BY JOHN A. TOWNROW (University of Tasmania) Pp. 287-320 ; Pis. 24-26 ; ii Text-figures BULLETIN OF THE BRITISH MUSEUM (NATURAL HISTORY) GEOLOGY Vol. 6 No. 2 LONDON: 1962 THE BULLETIN OF THE BRITISH MUSEUM (NATURAL HISTORY), instituted in 1949, is issued in five series corresponding to the Departments of the Museum, and an Historical series. Parts will appear at irregular intervals as they become ready. Volumes will contain about three or four hundred pages, and will not necessarily be completed within one calendar year. This paper is Vol. 6, No. 2 of the Geological (Palaeontographical] series. Trustees of the British Museum, 1962 PRINTED BY ORDER OF THE TRUSTEES OF THE BRITISH MUSEUM Issued June 1962 Price Twenty shillings ON PTERUCHUS A MICRO SPOROPHYLL OF THE CORYSTOSPERMACEAE By J. A. TOWNROW SYNOPSIS Three species of Pteruchus are redescribed, P. africanus Thomas, the type species, P. dubius Thomas and P. simmondsi (Shirley) Thomas. The material comes from Burnera Waterfall, Upper Umkomaas, Natal, and is of Molteno (Middle Triassic) age. A number of species are merged with P. africanus. The specimen originally named Pteruchus edwardsi Thomas is transferred to Stachyopitys. The ascription of Pteruchus to the Dicroidium-Xylopteris group of leaves, and the morphology of Pteruchus, are discussed. Pteruchus is compared with a number of other pollen organs, but is distinct from all. INTRODUCTION Pteruchus was first described as a separate genus by Dr. H. Hamshaw Thomas (1933). He believed it to be the pollen organ of the extremely abundant Triassic forking leaves here called the Dicroidium-Xylopteris group. This term is meant to include the ten or so leaf-species placed in Dicroidium (Jakob & Jakob, 1950 ; Townrow, 1957) and the three species of Xylopteris (Jones & Jersey, 1947 under the name Stenopteris, and also p. 308) . New information is now brought forward which strongly supports some of Thomas' conclusions, particularly the ascription of Pteruchus to the Dicroidium-Xylopteris group ; but is against some other of his views, e.g. the limits of the several species of Pteruchus. It enables one to take up a definite stand on some points, in particular, on the morphology of Pteruchus which Dr. Hamshaw Thomas was obliged to leave uncertain. The material examined consists of Thomas' material, and further more abundant specimens from the same locality, that is, from the Burnera Waterfall, Upper Umkomaas, Natal. This locality falls within the Molteno, and is of Middle Triassic age (Townrow, 1957 : 30, 31). All type and figured specimens of Pteruchus are in the British Museum (Natural History) and are referred to by their British Museum registration numbers. Genus PTERUCHUS Thomas, 1933 : 232 EMENDED DIAGNOSIS. Microsporophyll borne singly, without subtending organ, on cutinized axis of about same size as rachis. Axis radially symmetrical, cuticle showing similar rectangular cells all over. Microsporophyll, unforked alternate pinnate. Rachis showing lateral wing, and occasional vegetative pinnules, cuticle dorsiventral. Pinnae expanding into rounded or elongate lobed sporangia! heads Heads more or less dome-shaped, non-sporangial surface often rugose. Venation pinnate, shown on sporangia! side of heads. This surface completely occupied by pollen sacs : non-sporangial surface covered with cuticle. Pollen sacs borne over GEOL. 6, 2. 22 2QO A MICROSPOROPHYLL OF THE COR YSTOSPERM ACE AE central part of head, but absent over thin margins and lobes and over continuation of pinna on to head. Pollen sacs numerous, more or less cigar-shaped, 075 mm. to 2-5 mm. long and 075 mm. to 1-5 mm. wide, unilocular, dehiscing by longitudinal slit, wall at maturity consisting of epidermis only, composed of narrow longitudinally elongated uniform cells, sometimes with slightly sinuous outlines. Cuticles of all parts delicate, about I /* thick, showing faint to pronounced, normally slightly, sinuous cell outlines, and rarely papillae ; cells more or less in rows over rachis and pinnae, without apparent orientation over heads. Stomata few, about 5 /mm. 2 over heads, exposed or sunken, normally flanked by two lateral and two terminal subsidiary cells, encircling cells normally distinguishable. A few usually tricellular pointed hairs present. Pollen bisaccate, sacci slightly to distinctly offset distally, overlapping or not, on to proximal face of body of grain, longer than wide, as long as or slightly shorter than body, normally more or less parallel sided and ornamented with modera- tely distinct reticulum, meshes 2 [i to 3-5 fi wide, walls of mesh about i fi thick. Body of grain about 50% longer than wide, ends obtuse or bluntly pointed, rarely round, wall between body and sacci normally distinct, body minutely reticulate or almost smooth. Distinct sulcus present, flanked by strip of thicker cutin, about as long as body, not occupying whole space between sacci on distal surface. Length : 50 /* (typical). Total width : 80 fi (typical) . Ratios (means) : Length of body /width of body, 1-27. Width of whole grain /length of body, 1-54. Length of body /width of saccus (to distal roots), 1-25. TYPE SPECIES. Pteruchus africanus Thomas. DESCRIPTION. There are two difficulties presented by the Waterfall material. The first is that the specimens split through the fossil, leaving about equal quantities of plant material on both part and counterpart, which are thus mirror-images. This is an important point for it means that the part and counterpart as they stand cannot be superimposed directly, but to see one surface of the organ the part and a transfer of the counterpart must be superimposed (Text-fig. 2A, B). The second is that when macerated, the material, especially if of thick substance, breaks up into small fragments only a millimetre or so square. This is probably because the cuticle is too delicate to hold the coaly substance together when it swells in acid. Hence cuticle data have to be put together from very small pieces, and few stomata, for example, are seen on any one specimen. The sporophylls are unforked and pinnate, the pinnae being offset towards the upper (adaxial) surface of the rachis (PI. 24, fig. 4 ; Text-figs. 2D, 411). In the small P. simmondsi, and the smaller specimens of P. africanus this is not obvious, although it can be deduced from the course of the cellular striae of the pinnae, which are interrupted by the lower surface of the rachis, but viewed from the upper surface, continue on to the rachis (Text-figs. 2D, 411). This feature, together with the pinnate habit, and the lateral wing on the rachis, imparts bilateral symmetry to the organ. Two specimens of P. africanus were still attached to short lengths of axis (PI. 25, (fig. 2 ; Text-fig. IB) : one specimen of P. dubius is probably similar (PI. 24, fig. 6) A MICROSPOROPHYLL OF THE COR Y STOSPERM ACE AE 291 B FIG. i. Pteruchus africanus, P. dubius A-D, P. africanus. A, sporophyll with some heads pointing towards the base of the organ, showing rugose non-sporangial surface of heads, a divided pinna, and, in heads with pollen sacs pointing downwards, undisturbed cell rows on the pinnae. .42684. X2-5. B, two sporophylls, one attached to a piece of the axis (running horizontally) and one detached. V.42688. x 2-5. c, sporophyll (P. peltatus) showing marginal attach- ment of pinna in uppermost and lowest right-hand heads. V.23386. x 2-5. D, sporophyll attached to a length of axis (running horizontally). .42685. x 2-5. E, P. dubius. Small complete sporophyll showing unforked habit and some divided pinnae. .42686. x 5. F, P. africanus. A pollen sac compressed laterally, showing dehiscence slit. The specimen is partly overlain by another pollen sac. x 25. GEOL. 6, 2. 22 292 A MICROSPOROPHYLL OF THE COR YSTOS PE RM ACE AE while one specimen of P. simmondsi had bits of cutinized plant matter, possibly of, the axis, sticking to the base of the rachis. The two specimens of P. africanus, and probably the specimen of P. dubius also, are attached singly, not in a cone or " flower ", and either at right angles to the axis, or else curving away from it at a wide angle. Other specimens of all three species showing the sporophyll base often (8 out of n) show a curvature, suggesting that the sporophyll normally came to lie at a wide angle to the axis. None of the attached specimens shows any subtending organ on the axis, nor any sign of one such as a scar. The central part of the axis is raised but the organ does not show strong relief. It does not show a wing (PI. 25, fig. 2). The cuticle is extremely thin, but shows somewhat obscure outlines of rectangular cells all over, and again, no sign of a wing (cf . p. 313) . It was therefore radially symmetrical (at least externally) . The fact that the organ is cutinized and of low relief suggests that it had not undergone much secondary thickening, and, a connected point, that lignified tissue was not massive. The rachis cuticle is different. It is dorsiventral, showing on the lower surface more or less uniform elongated cells and very few or even no stomata. Similar elongated cells, devoid of stomata, are present over the wing on both surfaces. On the upper surface there is an ill-defined stomatal band, in which the cells are more nearly square, and the stomata are set obliquely, or even at right angles to the rachis long axis (Text-figs. QB-D, IOB, c). This dorsiventrality is more marked in the larger specimens, though discernible in all. In all the species the rachis may be raised in irregular lumps, especially in the larger specimens (PI. 24, figs. 4, 6 ; Text-figs, ic, 411). The lumps leave no trace on the cuticle, and after treatment with acid, stand out as areas of darker matter. They must be wholly internal and are possibly nests of thickened cells. The pollen sacs almost certainly pointed towards the base of the organ. In some specimens they are so preserved (PI. 24, fig. 3 ; Text-fig. IA, c), and here the cell rows on the pinnae are not twisted. But in the more numerous specimens in which the heads are rotated in various ways the cell rows are twisted (Text-figs. 2D, 411). Vegetative pinnules are rare, they occur in only six of the fifty-one specimens available (P. africanus (4), P. simmondsi (i), P. dubius (i)) and, with two exceptions (.23360, .42683) these specimens showed only a single pinnule each. One pinnule of P. dubius (.42683) is set just above the point at which the first pinna (divided in this specimen) arises (Text-fig. 40). The others lie at varying levels between the sporophyll base and the first pinna. None subtend anything (PI. 26, fig. 6 ; PI. 25, fig. i ; Thomas, 1933, text-fig. 40). In one specimen of P. africanus (.23360), there are two pinnules near the sporophyll base, lying one about i mm. above the other (Text-fig. 36). I cannot find the two minute pinnules figured by Thomas (1933, text-fig. 36) in the specimen called P. papillatus, while in the specimen he states showed a basal pair (p. 236) only one is now seen, and there is no clear impres- sion of a second (PI. 26, fig. 6). The sporangial heads show the same basic plan, though they differ in proportions and detail (pp. 298, 300, 303). They are attached marginally, though, rather as in a pelargonium leaf, the attachment is mainly on the under (sporangial) side, and may A MICROSPOROPHYLL OF THE COR YSTOSPE RM ACE AE 293 FIG. 2. Pteruchus simmondsi, P. africanus A-C, P. simmondsi. A, B, part and transfer of the counterpart of a sporophyll showing swollen base (probably with fragments of axis attached) and, at top, a head compressed laterally, showing smooth non-sporangial surface. V. 42687. x 3-75. c, small sporophyll showing branching and with (almost certainly) only some of the pollen sacs originally present. V. 42691. x 3-75. D-G, P. africanus. D, sporangial head showing sporangial surface almost free of pollen sacs, vascular ridges with rows of elongated cells along their crests, area of pollen sac attachment and twisted cell rows on pinna, interpreted as a consequence of rotation of head into the bedding plane. Specimen seen from under (adaxial) surface. Note pinna interrupted by edge or rachis. .42682. x 7. E, sporangial head, seen from non-sporangial surface, showing marginal attachment of pinna and marginal lobes. Surface of head nearly smooth. V. 23384. x 7. F, G, same fragment, seen from sporangial (F) and non-sporangial (G) sides, showing form of pollen sacs, cell rows on them and their dehiscence slits. X3-5- 294 A MICROSPOROPHYLL OF THE COR YSTOSPE RM ACE AE be overlapped by the marginal lobes (PI. 25, fig. 3 ; PI. 26, fig. 12 ; Text-figs. 2D, 4A, G). Thomas suggested (1933 : 238) that the specimen named P. peltatus (.23386) was peltate. This I believe to have been an error. The specimen is refigured in Text-fig, ic ; two heads show their marginal attachment, and a transfer shows another was the same ; the others do not show their attachment at all. Pteruchus seems to have been shed as a complete organ, without disarticulating, shedding its pollen sacs, or even all its pollen. There are thus few heads showing their sporangial surface unobscured by pollen sacs. There are eight sporangial heads preserved in this way in P. africanus, some incomplete. The sporangial surface is raised in ridges, one ridge more or less opposite each marginal lobe, which coalesce near the point of attachment (PI. 26, figs. 9, 10 ; Text-figs. 2D, 30). In two heads, lines of elongated cells were plain, running along the top of these ridges (Text-figs. 2D, 3c) which therefore almost certainly mark the course of the veins. The veins are pinnate, based upon a first division of the main vein near its base into three nearly equal parts, fanning out from the point of attachment (PI. 26, fig. 10). Over most of the heads, the surface is rough, sometimes raised in little rings about i mm. in diameter, but usually showing no distinct pattern. It seems likely that these rings and the rough area in general, mark the insertion of the pollen sacs. It is not clear whether the pollen sacs had any definite arrangement. Usually none is apparent, but in one place (PI. 26, fig. 9) the rings seem to run in rows parallel with a vein. I can find no evidence that the pollen sacs were borne in groups. Over most of the lobes, around the margins, in areas extending as embay- ments between the vascular ridges and over the " midrib ", i.e. the continuation of the pinna on to the head, the surface is smooth and presumably devoid of pollen sacs (PI. 26, fig. 10 ; Text-figs. 2D, 30). Except for a rim, the sporangial surface is uncutinized (PI. 26, fig. 7) while the number of pollen sacs and the very close-set arrangement of the little rings (where visible) indicate that the pollen sacs were closely packed together, so that there was no epidermal tissue between them. In the other species the evidence is much less clear. One head of P. simmondsi is largely free of pollen sacs, and shows ridges with elongated cells over them, probably set in a pinnate pattern, as in P. africanus (Text-fig. 4H), and other heads show that the main vein at least was free of pollen sacs (PI. 26, fig. 12). I have not seen any heads of P. dubius with their sporangial surface unobscured, but several heads show that the main vein at least was free of pollen sacs, as were the marginal lobes (PL 25, fig. 3). Although the evidence is not complete, it is most likely that the heads in all three species were constructed on the same pinnate plan, as indicated by the veins. This is an important point, for it means that the heads were also bilaterally symmetrical and dorsiventral. The heads can thus be described as showing elongated sori over the veins, which become concrescent where the veins join up. I do not know why elongated cells along the vascular ridges are shown in two heads, but not in others. Perhaps the veins became displaced during fossilization. The non-sporangial surface of the heads is strongly wrinkled in P. africanus, slightly so in P. dubius and hardly at all in P. simmondsi. I believe that some of this wrinkling existed in life (pp. 298, 303), some, however, is almost certainly caused A MICROSPOROPHYLL OF THE CORYSTOSPERM A CE AE 295 by the compression of a thick organ. This wrinkling is apt to obscure the cell outlines of the cuticle of the head, especially over the centre of the head, the lobes and margins being, even in P. africamis, scarcely wrinkled at all (PI. 26, fig. 7). As far as can be made out, both cells and stomata lack any preferred orientation, a useful point distinguishing marginal lobe from pollen sac (p. 303 and Text-fig. IOA ; Thomas, 1933, text-fig. 48). The pollen sacs dehisced by a longitudinal slit often (but by no means always) directed towards the centre of the pollen sac group. It also often extends a little way on to the dorsal surface of the pollen sac, so that, in sacs seen dorsal surface uppermost (the majority) it may appear like an apical nick. This has been taken for a terminal pore (Thomas, 1933 : 234), but a transfer reveals its nature, which is confirmed from the cuticle, and also shows a slit down one face (Text-fig. 2F, G). Seen as transparencies, e.g. in transfer, the pollen sac waU is composed of one layer of cells, corresponding to those seen on the cuticle from the pollen sac, and there- fore epidermal (PI. 26, fig. u ; Text-fig. 60). The periclinal walls as seen in transfer are about 15 times as thick as the cell outlines seen on the cuticle. They may have been thickened. The cells are uniform over the whole pollen sac, except, possibly, next to the dehiscence slit. Here they may be narrower than elsewhere (Text-fig. 6x) . However, this appearance may be caused by folding, which is almost invariably seen at this point. It has been suggested that the pollen sacs were bilocular (Thomas, 1933 : 235), but there is convincing evidence that this is not so. Sections of pollen sacs from each species show only one loculus (PI. 26, fig. 5), while the wall shows no sign of any partition, unlike a dehisced Angiosperm anther in which the partition between thecea is often visible. I have macerated about 80 pollen sacs, and have never seen more than one pollen mass. On the other hand, it is rather easy to macerate parts of two closely adherent pollen sacs, in which case the appearance described by Thomas could very well arise. The cuticle of the three species is most variable in every character. In each it varies in thickness from about 1-5 fi down to so thin as to be almost impossible to prepare, probably less than 0-5 //. In addition the stomata, even on one specimen, vary in the extent to which they are sunken. In general the most exposed lie on the lower heads or rachis (Text-figs. SA-K). These two facts strongly suggest that the sporophylls were rather long lived, certainly not ephemeral, and that they varied in response to factors other than genetical, just like leaves for example. This view, however, is contrary to that of Thomas (1933 : 202). The cell outlines may be faint or plain to see, but in either case are usually decorated with small sinuosities, consisting of projections about i /* long from the actual outline (i.e. the part occupied in life by the middle lamella) on to the general cuticle surface. In a few specimens of P. africanus the cells also bear a papilla (Text-fig. 90 ; Thomas, 1933, text-fig. 37). The stomata are based upon the same plan in all three species ; that is to say the guard cell poles lie more or less on the general cuticle surface, though in P. simmondsi they are sometimes overlapped by the terminal subsidiary cells (Text-fig. SA), while the aperture is more or less sunken in a depression. The walls of the depression are formed by the lateral subsidiary 2Q6 A MICROSPOROPHYLL OF THE COR YSTOSPE RM ACE AE cells, which are normally two, but may be divided into three or four. Quite un- specialized encircling cells are usually discernible, but may be absent, especially over the rachis (Text-fig, gc, D). The hairs are rare in all three species, scarcely 12 occur in any one specimen but all species show them. On the cuticle the hair base appears as a thickened ring (Text-fig. 6c ; Thomas, 1933, text-fig. 35) the area enclosed by the ring is sometimes FIG. 3. Xylopteris elongata, Pteruchus africanus, Dicroidium feistmanteli A, X. elongata. A leaf base showing large divided basal pinnule set a short way up from extreme tip of leaf (cf. PI. 25 ; Text-fig. 50). x 8. B, c, P. africanus. B, sporophyll base (impression only) showing two alternate basal pinnules. V. 23360. x 8. c, sporangial head, showing sporangial surface free of pollen sacs. It shows main vein, vascular ridges, area of pollen sac attachment, smooth margins and marginal lobes. V. 42682. x 8. D, E, D. feistmanteli. Equivalent portions of same leaf (E a transfer), drawn from upper (adaxial) (D) and lower (E) surfaces, showing that the pinnae are offset towards upper rachis surface, and venation, x 8. A MICROSPOROPHYLL OF THE CORYSTOSPERM ACE AE 297 thinly cutinized, sometimes open. On a transfer of the counterpart of a specimen, the hairs themselves may be found. Though often obscure they seem normally to be pointed, and to have three obliquely divided cells, as in Text-fig. 6j. I cor- relate the hairs with the hair bases on the cuticle, because, though rare, each can be found with regularity, and there is no other structure that I can find to which the hair bases might belong. It proved difficult to obtain satisfactory pollen preparations of Pteruchus. Either the grains stuck together in a mass, obscuring the individuals, or else the pollen sacs were nearly empty, and some of the grains remaining were clearly strays. By breaking up the masses, and examining grains at their edges it was possible to obtain small samples (15 or 20 grains) from every specimen. The grains are variable (see diagnosis and specific descriptions pp. 298, 300, 303, PI. 26, figs. 1-4; Text-figs. IOD-G, n). One of the most prominent features is the sulcus (here the term is confined to the presumed germination furrow lying between the distal roots of the sacci, and not occupying the whole distal surface of the body of the grain, see Erdtmann, 1947). In many grains the lips touch along their whole length, but in others, otherwise similar, the sulcus gapes open. Pteruchus africanus Thomas (PI. 24, fig. 4, PI. 25, figs, i, 2, PI. 26, figs. 2, 4-11 ; Text-figs. 1-3, 6-10) 1933 Pteruchus africanus Thomas, p. 235, pi. 24, figs. 71, 72, text-figs. 34, 35. Fig. of holo- type pi. 24, fig. 71. 1933 Pteruchus papillatus Thomas, p. 237. pi. 24, fig. 77, text-figs. 36, 37. Pollen figd. pi. 24, fig- 77- *933 Pteruchus peltatus Thomas, p. 238, text-figs. 38, 39. J 933 Pteruchus hoegi Thomas, p. 239, pi. 24 fig. 75, text-figs. 40, 41. J933 Pteruchus stormbergensis Thomas, p. 241, text-fig. 43. 1933 Pteruchus sp. Type X, Thomas, p. 243, text-figs. 47, 48. Specimens doubtfully identified. 1876 Sphenolepis rhaetica Geinitz, p. 12, pi. 2, figs. 23, 24. 1888 Male flower of Baiera tenuifolia Johnston, pi. 27, figs. 20, E. 1890 Trichopitys johnstoni Feistmantel, p. 113, pi. 10, fig. 5. Johnston's specimen refigured. 1898 Stachyopitys annularioides Shirley, p. 13, pi. 18, fig. i. 1917 Stachyopitys annularioides Shirley : Walkom, p. 13, pi. 4, fig. 6. 1925 Male flower of Baiera tenuifolia Johnston : Walkom, p. 85, text-figs. 15, 16. Johnston's Tasmanian material refigured. !933 Pteruchus annularioides (Shirley) Thomas, p. 233. New name only. 1933 Pteruchus minor Thomas, p. 242, text-fig. 46. Small specimen regarded as indeterminable. J 933 Pteruchus sp. Type Y, Thomas, p. 243. No figure. 1947 Pteruchus annularioides (Shirley) Jones & Jersey, p. 55, text-fig. 38. 1947 Pteruchus sp. Jones & Jersey, p. 56. No figures. Specimen regarded as distinct : 1947 Pteruchus cf. africanus Thomas : Jones & Jersey, p. 55, text-fig. 51. HOLOTYPE. Brit. Mus. (N.H.) No. .23384. MATERIAL. H. Hamshaw Thomas Colin., Brit. Mus. (N.H) Nos. .23360, .23384- 88, .23390-94. J. A. Townrow Colin., Nos. .42682, '.42684-85, .42688-90, .42797. 2g8 A MICROSPOROPHYLL OF THE COR YSTOSPERM ACE AE EMENDED DIAGNOSIS. Microsporophyll about 2 cm. long, rachis about 1-5 mm. wide at base. About eight (6-9) long, normally unbranched pinnae present. Heads round to about four times as long as wide, width about 5 mm. ; non-sporangial surface strongly rugose, about 10 lobes per head, lobes small in proportion to size of head. Pollen sacs more than 30 per head, about 2-5 mm. long and 1-5 mm. wide. Cell outlines faint, i // wide or less, sinuosities small, sometimes absent, about i /* long, usually obtuse, not pointed. Stomata somewhat sunken, poles exposed, pit not overlapped by cutin flanges. Pollen with sacci scarcely extending on to proxi- mal surface of grain, usually shorter than body of grain, often slightly inflated. Body of grain sometimes bluntly pointed, reticulum on sacci normally conspicuous, meshes about 3 fi in diameter, walls about i ju, thick ; ornamentation on body faint or absent. Dimensions in /* (standard deviations bracketed) : Length of body 46-25 (6-45) ; width of body 32-2 (7-45) ; length of sacci 35-2 (12-6) ; width of sacci 36-2 (9-2) ; height of grain 20 (2-8) ; total width of grain 63 (6-3). DESCRIPTION AND REMARKS. The pinnae are almost always unforked, but in two specimens (.42684, .42707, Text-fig. IA) certain pinnae branch on leaving the rachis. When compressed laterally (Text-fig. IA) the heads appear dome-shaped and the non-sporangial surface is raised in irregular lumps. Probably, therefore, the wrinkling of the cuticle of the heads is not ah 1 connected with the compression of a thick organ, but is partly original. The pollen sacs, while varying consideraly in size and form, are normally not much inflated (PI. 24, fig. 4 ; Text-fig. 2F, G). Cell outlines are sometimes so faint that they are scarcely visible and, about one- third of the preparations lack them altogether. When present the sinuousities are small (i fi or less) and grade gradually into the residue of the cuticle so that it is difficult to decide exactly where they end. (Text-fig. 7A). Text-fig. SB, c show two stomata from the same specimen. One, Text-fig. 76, comes from an upper head, the other, Text-fig. 8c from a lower head. Each is typical of the degree of sinking seen on upper and lower heads respectively. Stomata from a lower head, but sunken like Text-fig. SB, or stomata from an upper head but nearly exposed like Text-fig. 8c number less than i in 6. Almost exposed stomata (Text-fig. 10) number about i in 5 on the marginal lobes of some lower heads. In most pollen grains the insertion of the sacci is similar to that shown in PI. 26, fig. 2, they do not extend on to the proximal surface of the body of the grain, but this character is a variable one, and some grains show overlap on to the proximal surface (Text-fig. IOF). As seen in tangential longitudinal view, the body of the grain is usually about as broad as high (PI. 26, fig. 2 ; Text-fig. IOF, G). The reti- culum on the sacci is normally prominent, but on the body, faint, and sometimes absent, at least from the proximal surface where this is seen in optical section. (Text-fig. IOF, G). All the various alternatives mentioned above can often be found within a preparation made from a single pollen sac, so that there is no question that the sundry variations in pollen form among the specimens determined as P. africanus indicate that more than one species of microsporophyll is present. All but three of the specimens given separate specific names by Dr. Hamshaw Thomas are here merged with P. africanus. They form a series which cannot be split. As regards gross form, Dr. Thomas' specimens vary, but when my material A MICROSPOROPHYLL OF THE COR YSTOSPERM ACE AE 299 H FIG. 4. Pteruchus simmondsi, P. dubius A, P. simmondsi. Part of a sporangial head showing marginal attachment of pinna. .42692. x 15. B, c, P. dubius. B, part of a head showing slightly rugose non-sporangial surface and form of pollen sacs. V.42683. x 10. c, lowest (divided) pinna of a sporophyll, showing a pinnule set just above insertion of pinna, drawn from under side of specimen. V.42683- Xio. D-H, P. simmondsi. D, E, same sporangial head before (D) and after (E) transfer, showing shape and spreading habit of pollen sacs. No marginal lobes seen. .42693. x 10. F, G, the part (F) and transfer of counterpart (G) of a sporangial head, showing nearly smooth non-sporangial surface of head (F) and three marginal lobes (G). A fourth marginal lobe broke off in preparation. V. 42687. x 10. H, sporangial head seen from sporangial surface ; whole specimen seen from upper surface. It shows marginal lobes, pollen sacs vascular ridges and pinnae from this side, not interrupted by edge of rachis (cf. Fig. 20). .42681. x 10. GEOL. 6, 2. 300 A MICROSPOROPHYLL OF THE CORYSTOSPERM ACE AE is added to his, the new specimens do not fall into his species, but fill in the gaps between them (and, indeed, extend the variation) so that the whole material forms one continuously varying series. Thomas noted the dorsiventrality of the rachis cuticle, but did not state in his cuticle figures which surface is drawn. Text-fig. 9A-D shows the cuticle from a single specimen (.42682), it comprises very nearly all the variation seen in Thomas' figures. As already noted, the pollen points away from the suggestion that more than one species is involved. I conclude there is only one species, which is compared with the other two here recognized on p. 307, Table I. The specimens named Pteruchus annularioides (pp. 297, 310) from Queensland are only doubtfully identified with P. africanus. The holotype is an impression only, and shows little detail (Jones & Jersey, 1947 : 55). From the existing descriptions and figures it is impossible to identify, or to reject, this species with regard to any of the better known species of Pteruchus. However, the figured specimens resemble small specimens of P. africanus, and agree in dimensions. It may be that these specimens, like the Waterfall material, are split in such a way that not all the pollen sacs are visible on any one specimen (Text-fig. 2c). Re examination of the holo- type might well show that P. annularioides and P. africanus are identical ; and if so Shirley's name will have priority. While this is uncertain, however, the name P. africanus is provisionally retained. The earlier records of Geinitz(i876)a and Feistmantel (1890) likewise cannot be identified, or excluded at present. When these specimens are re-examined the question of prior names will again arise. The records of Johnston (1888) and Walkom (1925) do not affect the nomenclature, since they did not give a particular name to the specimens now considered ; the leaf Czekanowskia (originally Baiera] tenuifolia (Johnston) Jones & Jersey (1947) is now believed to have nothing to do with Pteruchus (see p. 310). Pteruchus dubius Thomas (PI. 24, figs. 5, 6 ; PL 25, fig. 3 ; PI- 26, fig. i ; Text-figs. IE ; 46, c ; 76 ; 80 ; IOA-C ; IIA, B) J 933 Pteruchus dubius Thomas, p. 241, text-figs 44, 45. Single head and part of pinna. Holo- type, text-fig. 44. 1942 Pterorrachis barrealensis Frenguelli, p. 311, pi. 2. Large specimen, impression only. 1944 Zuberia zuberi Frenguelli, p. 16, pi. 2, text-fig. 12. Same specimen described. Text-fig. 12 reconstruction. 1947 Pteruchus cf. africanus Thomas : Jones & Jersey, p. 55, text-fig. 51. Impression only. HOLOTYPE. Brit. Mus. (N.H.) No. .23389. MATERIAL. J. A. Townrow Colin., Nos. .42683, .42686, .42695. EMENDED DIAGNOSIS. Microsporophyll about 4 cm. long, rachis about 2-5 mm. wide at the base. About four (3-6) long, slender, often branched pinnae present. Heads elongated, from three to five times long as broad, width about 4 mm., non- sporangial surface slightly rugose, head bearing about 15 marginal lobes. Lobes small in proportion to head. Pollen sacs about 100 per head, about 2 mm. long and 1-25 mm. wide. Cell outlines faint, i /i wide or less, sinuosities small, normally A MICROSPOROPHYLL OF THE COR YSTOSPERM ACE AE 301 present, I ju, to 1-5 fi long, normally slightly pointed. Stomata more or less exposed, lateral subsidiary cells often thickened over their whole cutinized surface. Pollen with sacci normally extending on to proximal surface of grain, as long as body of grain, usually parallel-sided. Reticulum on sacci normally conspicuous, meshes about 2 JLI in diameter, walls about i ju, thick, body smooth or very nearly so. Dimen- sions in fi (standard deviation bracketed) : Length of body 53-0 (7-35) ; width of body 43-3 (6-2) ; length of sacci 53-0 (7-05) ; width of sacci 33-1 (6-85) ; height of grain 50-0 (4-95) ; total width of grain 88-3 (15 '3). DESCRIPTION AND REMARKS. The material includes two complete sporophylls (.42683 .42686 ; PI. 24, fig. 5, Text-fig. IE). Both are unforked. This species, like the others is simple and not forked. About half the pinnae are divided. In some cases this can be seen (PL 24, fig. 6 ; Text-figs. IE, 4C and FrengueUi, 1942, pi. 2), in other cases there are more sporangial heads than pinna origins, so a division is deduced. Compressed laterally the heads are of thick substance (PL 24, fig. 5) and of slightly rugose surface, but much less so than in P. africanus. The pollen sacs are almost cylindrical, and on two small heads I counted over 100, so that this figure given in the diagnosis is probably on the conservative side ; they are so crowded, however, that counting is difficult. The cell outlines are apt to be faint, but they almost always show sinuosities. The sinuosities are larger than in the other two species (about 1-5 fi). The central part of the outlines is thin, and the sinuosities at their ends grade into the generality of the cuticle, but are distinct elsewhere, (Text-fig. 76). The stoma in Text-fig. 80 is from a head at the top of the specimen (.42683) where it is typical. A few, probably less than i in 10, are more sunken, but none so sunken as the stoma shown in Text-fig. SB. On the lower heads the stomata may be even more exposed (Text- fig. 10). In about half the stomata seen the lateral subsidiary cells are thickened uniformly. On staining this shows as a darker area but without staining it is not visible (Text-figs. So, 10 ; Thomas, 1933, text-fig. 45). The pollen is shown in PL 26, fig. i and Text-fig. IIA, B. The sacci overlap the proximal surface of the grain, so that they lie very nearly in the para position, while the body of the grain, seen in tangential longitudinal view, is higher than wide. The ornament on the sacci is usually prominent, but on the body none or almost none is visible, the proximal surface, when seen in optical section, showing at most a minutely scabrid surface. As in P. africanus all variants can be found in a pre- paration from one pollen sac. The holotype consists of a single head, and part of a pinna. It is split through, leaving about equal proportions of plant material on both part and counterpart. Each shows part of the head and some of the pollen sacs, both of which correspond in their form with the other material here identified with P. dubius. However, if the part and counterpart are superimposed as they stand, because of the way the specimen is split, the pollen sacs appear to have originated all round the head (Thomas, 1933 : 242, text-fig. 41). The pollen and cuticle are normal. For these reasons, I identify my material with Dr. Thomas' specimen. The single large specimen described and figured by FrengueUi (1942, 1944) is an impression only, and there is no counterpart. Judging from the figures the specimen 302 A MICROSPOROPHYLL OF THE COR YSTOSPERM ACE AE comprises the basal three-quarters, approximately, of the sporophyll, and there is no evidence whatever that it was forked. It is a larger specimen than any other so far discovered, but agrees with the present material in general appearance and in structure, but no cuticle or pollen is available. The specimen is therefore identi- fied with P. dubius, and is included above in the synonymy of that species. I agree with Frenguelli (1942) that the other two species placed in Pterormchis probably B FIG. 5. Dicroidium odontopteroides, Xylopteris elongata A, D. odontopteroides. Leaf, seen from under side, showing curving leaf base and rotated pinnae, x i. B, c, X. elongata. B, small leaf showing a small undivided basal pinnule (see also PI. 25). xi. c, lower portion of large leaf showing larger, divided, basal pinnule (see also Fig. 3 A), xi. belong to different plants. The ascription of P. dubius to the leaf called Zuberia zuberi is discussed below (p. 313). Frenguelli (1944, text-fig. 12) gives a reconstruction based on his specimen. My interpretation of the material is very different from his, and I regard his figure as misleading in most respects. The specimen of Pteruchus cf. africanus described by Jones & Jersey (1947) is an impression, and as they remark, scarcely identifiable. However, it has divided pinnae, considerably elongated heads and small pollen sacs, and is therefore more likely to be a specimen of D . dubius than P. africanus, with which they tentatively compared it. A MICROSPOROPHYLL OF THE CORYSTOSPERM ACE AE 303 Pteruchus simmondsi (Shirley) Thomas (PI. 24, figs. 1-3 ; PI. 26, figs. 3, 12 ; Text-figs. 2, 4, 6-8, u) 1898 Stocky opitys simmondsi Shirley, p. 13, pi. 18, fig. 2. Diagnosis and fig. of holotype, but without detail. From Denmark Hill, Ipswich, Queensland. Ipswich Series. 1917 Stachyopitys simmondsi Shirley : Walkom, p. 13. Shirley's material, no figure. T 933 Pteruchus simmondsi (Shirley) Thomas, p. 233. New name only. 1944 Stachyopitys anthoides Frenguelli, p. 365, pis. i, 2 ; text-fig, i. PI. I, fig. 3, distinct. Several specimens from Argentina. 1947 Pteruchus simmondsi (Shirley) : Jones & Jersey, p. 55, Shirley's material discussed. No figure. EMENDED DIAGNOSIS. Microsporophyll about 1-5 cm. long, rachis with bulbous base. Width just above base about 1-5 mm. About 8 (4-11) short unbranched pinnae. Heads round, width from lobe to lobe about 2-5 mm. ; non-sporangial sur- face almost or quite smooth, substance thin, 4 (3-5) lobes per head, lobes large in proportion to head. Pollen sacs, about 15 per head, about 1-5 mm. long and i mm. wide. Cell outlines usually distinct, about 1-5 /* wide, straight or with small obtuse sinuosities less than i /i long. Stomata sunken, poles sometimes covered by terminal subsidiary cells, pit sometimes overhung by cutin flanges on lateral subsidiary cells. Pollen with sacci extending on to proximal surface of grain, parallel-sided or tapering. Reticulum on sacci conspicuous, meshes about 5 fi in diameter, walls about i'5 /* thick ; ornament on body usually conspicuous. Dimensions in fi (standard deviations bracketed) : Length of body 58-0 (6-1) ; width of body 47-5 (4-25) ; length of sacci 55-5 (6-5) ; width of sacci 34-0 (4-05) ; height of grain 42-25 (4*35) '> total width of grain 84-5 (12-6). HOLOTYPE. Queensland Geological Survey Colin., No. F256. MATERIAL. J. A. Townrow Colin., Brit. Mus. (N.H.) Nos. .42681, .42687, .42691-94. DESCRIPTION AND REMARKS. The pinnae are short, compared with the size of the whole organ and no branching ones were seen ; they are alternate, but may be almost opposite (PI. 24, fig. 3, Text-fig. 2A-c). The bulbous base is seen in the holotype (PI. 24, fig. 2) and in two specimens from the Waterfall (Text-fig. 2A). The marginal lobes are seldom seen complete. They may look like pollen sacs, but can be distinguished on the cuticle (p. 295). It seems that, when ripe, the pollen sacs drew away from each other, so that both they and the marginal lobes came to lie almost back to back (Text-fig. 4F). Thus in a transfer there is very little tissue of the lobes which can stick on to the balsam. Some, however, are seen in Text-fig. 4F, and others laterally compressed in Text-fig. 2A. They are large in proportion to the head, so that the whole head, when flat, has an appearance some- what resembling a trefoil (PI. 26, fig. 12). The head compressed laterally shows that its substance was thin and the non-sporangial surface almost or quite smooth. The pollen sacs are short and much inflated, sometimes almost globose (Text-fig. 40). Although the cuticle is little if any thicker than in the other species, the cell outlines are both thicker and more distinct. The small sinuosities are sharply marked off from the rest of the cuticle, being less than i /* long but about 2 ju, wide 304 A MICROSPOROPHYLL OF THE COR YSTOSPE RM ACE AE FIG. 6. A, Phoenicopsis elongatus ; B-D, G, Pteruchus africanns ; E, F, Xylopteris elongata ; H, Czekanowskia tenuifolia ; j, K, P. simmondsi A, fragment from thinner cuticle (? lower) and a stoma. X4i6. B, cuticle from axis, showing more or less uniform cells all over, (j) marks position where two surfaces join. .42688. x 94. c, abnormally exposed stoma from a marginal lobe of head near base A MICROSPOROPHYLL OF THE CO R YSTOSPERM ACE AE 305 at the base the central part of the outline is wide, and with obscure edges (Text-fig. 70). The stomata are nearly always sunken, nearly exposed ones (such as in Text- fig. 70), probably number about i in 10. Text-figs. 8A, H show stomata with covered guard cell poles, and cutin flanges on the subsidiary cells. Both sorts together make up about 75% of all those seen. The pollen is shown in PI. 26, fig. 3 and Text-fig, nc, D. The sacci normally overlap on to the proximal surface of the grain, but do not always, and the body of the grain in tangential longitudinal view is commonly wider than high. On the body some ornament is usually visible, sometimes a reticulum, more often irregular lines of thicker cuticle. Thanks to the kindness of Dr. O. A. Jones, University of Queensland and of the Director, Queensland Geological Survey, to both of whom I am much indebted, I have been able to examine the holotype of P. simmondsi here refigured (PI. 25, fig. 2). The specimen is an impression only, but it is identified with P. simmondsi because it agrees in dimensions with the present material, and because it shows the bulbous base, delicate, short pinnae and inflated pollen sacs (probably dehisced in the holotype) characteristic of this species. The impressions of the cellular outlines are very faintly seen on some of the pollen sacs ; they agree in shape and dimensions with those seen on cuticle. There are two difficulties : the pollen sacs are few, but I suspect this is connected with the way the specimen has split (cf. Text-figs. 2A-c), and one pinna on the holotype may be divided. I cannot decide whether it is, or whether we are looking at part of the sporangial head. Frenguelli's (1944^) record consists of several well-preserved specimens. He does not give detail in his description, but the form and size of his specimens agree closely with mine, and so I identify his material with P. simmondsi ; which name therefore takes priority. The specimen figured in his pi. i, fig. 3 shows a number of pollen sacs attached to a somewhat elongated head ; it is therefore distinct from P. sim- mondsi. It may be a small specimen of P. africanus, but there is not enough in- formation for an identification. GENERAL DISCUSSION (i) The Species of Pteruchus The three species (P. africanus, P. dubius and P. simmondsi) are usually distin- guished readily (see Table I), but fragments may be difficult to classify, and in some species one or other character is poorly developed, and rather as in another species The specimen originally described as Pteruchus edwardsi Thomas is here transferred to Stachyopitys. of a sporophyll. .42689. x 975- D, cells from cuticle of pollen sac (cf. PI. 26). .42690. X 250. E, F, cuticle from opposite sides of axis, originally joined along their adjacent edges, showing more or less uniform cells all over and one stoma. From specimen figured PL 25. x 50. G, trichome base. .42689. X975- H, fragment from leaf surface with thicker cuticle (? upper) with a stoma. x 416. j, trichome from the transfer of a counterpart. .42687. x 310. K, cuticle from apex of a pollen sac showing dehiscence slit, and in places, the cell outlines. .42694. X94- 306 A MICROSPOROPHYLL OF THE COR YSTOSPERM ACE AE FIG. 7. A, Pteruchus africanus ; B, P. dubius ; c, Xylopteris elongata ; D, P. simmondsi ; E, Dicroidium odontopteroides ; F, D. feistmanteli Portions of cuticle from non-sporangial surface of sporangial heads, or lower surface of lamina of leaves, showing form of cell outlines. All XQ75- A MICROSPOROPHYLL OF THE COR YSTOS PERM ACE AE 307 Stachyopitys edwardsi (Thomas) nov. comb. 1933 Pteruchus edwardsi Thomas, p. 240, pi. 24, fig. 74, text-fig. 42. I have examined the holotype (the only specimen) which is preserved as a hollow cast. It does not show much detail and lacks cuticle or pollen. I agree with Dr. Thomas that the branching is spiral, and the heads peltate with a single ring of about 8 marginal sporangia. The specimen thus differs widely from Pteruchus as here defined. It bears some resemblance to Stachyopitys preslii Schenk (1867 : 185, pi. 64, figs. 9-12), the type species, and this genus is probably its best resting place at present (see also Seward, 1903 : 66, 67, pi. 9, fig. 2 and Gothan 1914 : 62, 63, pi. 29, fig. 4 pl- 33, ng. 3). TABLE I. Comparison of the Species of Pteruchus Species _ -A Character Length Pinnae Sporangial heads Pollen sacs Cell outlines Stomata Pollen : (a) Size Insertion of sacci (c) Ornament P. africanus 2-5 cm. approx. About 5 mm. long, rare- ly divided Elongated to round, of thick substance, strongly rugose, ca. 10 lobes per head More than 30 per head, about 2-5 mm. long, about twice as long as wide, slightly inflated Faint, about i // wide, straight or slightly sinuous, sinuosities obtuse Normally somewhat sunken, poles of guard cells exposed, pit not overhung Length ca. 46 fj, : Total width ca. 63 fi Not or scarcely overlap- ping on to proximal surface, body high as wide Obscure on body, mesh- es on sacci about 3 p diameter P. dubius 4 cm. approx. About i cm. long, often divided Elongated, of thick sub- stance, slightly rug- ose, ca. 15 lobes per head 100 or more per head, about 2-0 mm. long, about twice as long as wide, not, or scarcely inflated Faint, about i fi wide, normally sinuous, sin- uosities normally slightly pointed Normally exposed or slightly sunken Length ca. 53 ]u : Total width ca. 88 /u Overlapping on to prox- imal surface, body higher than wide Body smooth or nearly so, meshes on sacci about 2 n in diameter P. simmondsi 1-5 cm. approx. About 3 mm. long, not divided. Iso diametric, thin sub- stance, smooth or nearly so, 3-5 lobes per head. Approx. 20 per head, about 1-5 mm. long, less than twice as long as wide, mar- kedly inflated. Distinct, 1-2 fi wide, straight or slightly sinuous, sinuosities obtuse. Normally strongly sun- ken, poles of guard cells sometimes co- vered, pit sometimes overhung by cutin flanges. Length ca. 58 fj, : Total width 84-5 /LI. Overlapping on to proximal surface, body wider than high. Body with fairly dis- tinct reticulate orna- ment, meshes on sac- ci about $]u in dia- meter. 308 A MICROSPOROPHYLL OF THE COR YSTOSPERM ACE AE (2) The Ascription of Pteruchus to Leaves of the Dicroidlum-Xylopteris Group, (a) Ascription of the Genus Pteruchus Thomas (1933) suggested that Pteruchus was the pollen organ of the leaves here called the Dicroidium-Xylopteris group, on account of a general similarity in cuticle, and association at the Waterfall and at one or two other localities, e.g. Denmark Hill, Ipswich, Queensland. I most fully agree. A much stronger case can now be made out than that which Dr. Thomas was able to advance. The Dicroidium-Xylopteris group (see p. 288) consists of 12 or 14 extremely similar species of leaf. It is not clear whether they are best dealt with under two genera, as they are at present, or merged in one, Dicroidium having priority. The forking habit is common to all whilst their cuticles offer no basis for separation into different genera. It may be best to make some arbitary separation, perhaps on the number of veins at a given point in the leaf segment, but no workable distinction on such lines is yet apparent (see Jones & Jersey, 1947 : 30 for X. tripinnata and Townrow, 1957 : 43-45 for D. superbum}. Evidence for the reference of the genus Pteruchus to these leaves comes from agreement in anatomical structure, and from association. (1) Agreement in Structure Both leaves and microsporophylls are borne in the same way on axes that are similar, though of different sizes (p. 290, PI. 25, figs. 2, 5). The venation of the heads of P. africanus at least is built upon a first division, very near the point of attachment, into three more or less equal branch veins. This is just like the venation of Dicroi- dium odontopteroides , and sometimes of D. feistmanteli and D. coriacium (PI. 26, fig. 10 ; Text-fig. 30, E ; Townrow, 1957 : 34, 35, text-figs 4, 90). The cuticles of the rachises of both leaves and microsporophylls are very similar. Both show a lateral wing, both are dorsiventral by reason of the same cellular pattern, and the distribution of stomata is the same (Text-fig. gA-D ; Townrow, 1957 : 26, text-fig. 2) . As regards detailed cuticle structure, the stomata are built on exactly the same plan in both leaf and microsporophyll, being distinguishable only because the stomata of Pteruchus are usually smaller than on the leaves (Text-fig. 8) , while both also show occasional tricellular pointed hairs of identical form (Text-fig. 6j). Other points of agreement are in the construction of the sinuosities of the cell outlines (Text-fig. 7) and in the presence of papillae (rare in Pteruchus} (Text-fig. 90 ; Townrow, 1957, text-figs. 5, 6). (2) Evidence from Association The genus Pteruchus has now been found in twelve localities, one at the Waterfall, Natal, ten in the Ipswich Series, Queensland, and one, near Ischigualasto Argentina. The position, however, is not entirely straightforward. Some of the associated leaves at the Waterfall have not yet been identified ; in the Ipswich Series (Jones & Jersey, 1947) the specimens are nearly all impressions, and only two are figured, so that there is inevitably some doubt as to the identifications ; while at Ischigualasto the complete species list is not given. For the present purpose the Ischigualasto locality is ignored (but see p. 313), all records of Pteruchus are treated simply as A MICROSPOROPHYLL OF THE CO R YSTOSPE RM ACE AE 309 records of the genus (the species are discussed later, p. 312) and some of the most critical leaves are lumped into groups. So far as I can judge, none of these steps alters the conclusions which may be drawn. At the Waterfall, Pteruchus is quite a common fossil, represented in the Townrow Collection by 51 specimens (P. africanus 32, P. dubius 5, P. simmondsi 14). It FIG. 8. Pteruchus simmondsi, P. africanus, P. dubius, Dicroidium odontopteroides , D. feistmanteli , Xylopteris elongata A, E, P. simmondsi. Two stomata from same head on the same specimen showing (A) continuous cutin rim round stomatal pit, and covered guard cell poles, and (E) cutin flanges overhanging stomatal pit, and exposed guard cell poles. V. 42687. B, c, P. africanus. Stomata from an upper (B) and a lower (c) head, each sort characteristic of the heads from which they come. V. 42682. D, P. dubius. Stoma from a head near top of the sporophyll, of the sort most commonly met with in the species (cf. Fig. IOA). V. 4 268 3 . F, H, X. elongata. Comparable stomata to A and E, from under surface of same leaf. G, K, D. feistmanteli and D. odontopteroides. Stomata from the under surface of the leaves, each of the sort most commonly met with in their respective species. All x 650. 3 io A MICROSPOROPHYLL OF THE CO R YSTOSPERM ACE A E therefore seems very probable that the leaf of the same plant is still more abundant. Only those leaves represented by more than 20 specimens are considered. Though arbitrary, this limit does include all the common fossils. The residue consists of many more rare species usually represented by 10 or fewer specimens. Table II summarizes the facts of association of Pteruchus. It will be seen that (i) the three leaves Dicroidium odontopteroides, D. feistmanteli and XylopUfis elongata have higher scores than any other leaf, and this impression is heightened by the fact that in four out of the five localities in which D. feistmanteli and X. elongata do not occur, D. talbragarense and X. spinifolia are recorded. These leaves are exceedingly like D. feistmanteli and X. elongata and have at times been merged with them (Jones & Jersey, 1947 : 15, 28). (ii) The only other leaves which rival the above three, are Doratophyllum tenison-woodsi and Czekanowskia tenui folia both of which are known in gross form and cuticle, and can be discussed with some confidence, (iii) No further leaves, or group, comes near the Dicroidium-Xylopteris group, D. tenison-woodsi and C. tenuifolia in constancy of association. The other associates of Pteruchus can be excluded on their cuticles. Doratophyllum tenison-woodsi (Jones & Jersey, 1947 : 37, 38, pi. 10, fig. i) has straight cell outlines and stomata surrounded by a rather regular ring of 5 or 6 subsidiary cells whose inner edges overarch and form a rim above the stomatal pit. Czekanowskia TABLE II. Pteruchus and its Associates Localities { * Ipswich Series localities 1 Water- (Jones & Jersey, 1944, pp. 65-71) a fill -*- A otal of .ssocia- Total tions local- per ities species 1 1 (over 20 Rylance speci- 19 20 21 29 31 34 36 39 39A No. 3 s mens) Pit ( + + + + 4-4-4- + 4-4- 4- 4- 4-4-4-4-4-4- 4- ii 8 9 5 7 i i i i 3 ^ 4- 4-4-4- + - . 4- + + + 4- 4- 4- 4-4- .. 4- 4- -. 4- 4- 4- + 4- 4- 4- + 4- 4- -f . . + ) 4- 4-4- Species Dicroidium odontopteroides Dicroidium feistmanteli Xylopteris elongata Czekanowskia tenuifolia . Doratophyllum tenison-woodsi Phoenicopsis elongatus . ? Stachyotaxus sp. Linguifolium lilieanum . Lepidopteris stormbergensis Taeniopterids (i) . Pseudoctenis, Zamites and Ptero phyllum group (2) (1) Comprises the " broad leaved Taeniopterids " viz. : T. crassinervis, T. lata, T. immersa, T. wiana- mattae, T. dunstani and T. lentriculiforme (see Walkom, 1917 : 3440 ; duToit, 1927 : 350-354, 401-403 ; Jones & Jersey, 1947 : 45-58). (2) Comprises the leaves placed under Pseudoctenis, Zamites and Pterophvllum (in absence of inform- tion about the cuticle) by duToit, 1927 : 373-391 and Jones & Jersey, 1947 : 35-40. In the absence of cuticle data I regard the separation of the above groups into species as nearly impossible. A MICROSPOROPHYLL OF THE COR YSTOS PE RM ACE AE 311 tenuifolia (Jones & Jersey, 1947 : 59-61, pi. 6, fig. 2 and Text-fig. 6n) has at times been thought to be the leaf belonging with Pteruchus (p. 297), but its cuticle is different. It has straight cell outlines, and the stomal aperture is (at least normally) orientated parallel with the long axis of the leaf. In Pteruchus the stomata are (at least usually) orientated obliquely or at right angles to the long axis of the organ FIG. 9. Pteruchus africanus A, cuticle from rachis margin (the line along which cuticle of the two surfaces joined slightly folded and shown in heavy stipple), showing elongated cells over marginal wing and different cell pattern on the two rachis surfaces (lower surface to left). B, cuticle from rachis upper surface, near top of sporophyll. c, D, two fragments of cuticle, originally opposite, from lower (c) and upper (D) rachis surfaces, showing different cell pattern on the two surfaces. All V-42682. X250. 312 A MICROSPOROPHYLL OF THE CORYSTOS PERM ACE AE on the rachis and lack any preferred orientation on the heads. The stomata of C. tenuifolia are normally monocyclic, but those of Pteruchus dicyclic. In additon the C. tenuifolia from the Waterfall contains dense masses (? resin) in the leaf that are resistant to maceration, but nothing like this has been found in Pteruchus. Of the other associates, the Pseudodenis-Zamites-Pterophylhim and the taenio- pterid groups have a very thin cuticle (probably less than 0-5 ju,) and so are unlikely to belong with a microsporophyll which has a thicker cuticle. The stomatal structure of these leaves is obscure, but it is less like Pteruchus than that of the Dicroidium-Xylopteris group. Linguifolium lilieanum (Jones & Jersey, 1947 : 48, 49) has such a delicate cuticle that I could not prepare it. Lepidopteris stormber- gensis and Phoenicopsis elongatus each have stomata that are different from Pteruchus (Townrow, 1960 and Text-fig. 6A). The fossil called ? Stachyotaxus sp. (Krausel, 1950) looks most like a conifer, and though it has stomata rather like those of Pteruchus it is, I think, unlikely to have anything to do with Pteruchus. By the above arguments the leaves to which the three species of Pteruchus probably belonged are narrowed down to three, D. odontopteroides , D. feistmanteli and X. elongata. It is not yet possible to say with much conviction which species of Pteruchus belongs with which leaf ; the cuticles are too alike, and evidence from association is still slight. There are, however, small cuticle differences which suggest that D. odontopteroides and P. africanus (the commonest leaf and sporophyll), D. feistmanteli and P. dubius (the rarest) and X. elongata and P. simmondsi (intermediate as regards abundance) belong together. This suggestion is based on a comparison of cuticle of lamina and sporangial head. The cuticle of the rachises is nearly indistinguish- able in both leaves and sporophylls, it lacks the distinctive form of the cell outines and shows stomata often of somewhat anomalous form and degree of sinking. In D. odontopteroides the central part of the cell outline is thin, but distinct, and the small sinuosities tend to grade into the general cuticle so gradually that their exact outline is hard to see. In D. feistmanteli the central part of the outlines is thin but distinct and the sinuosities are large, and distinct for most of their margins. In X. elongata the central part of the outline is wide but with indistinct edges, while the small sinuosities are clearly marked off from the rest of the cuticle. The three species of Pteruchus show similar differences (Text-fig. 7). In D. odontopteroides the stomata are normally sunken, but the stomatal pit is not overhung and the guard-cell poles exposed : the same is true of P. africanus (p. 298, Text-fig. SB, c, K ; Townrow, 1957, text-fig. 6). In D. feistmanteli and P. dubius the stomata are, at most, only slightly sunken, while there is a general thicken- ing of the lateral subsidiary cells in about half the stomata seen (p. 297, Text-fig. SD, G ; Thomas, 1933, text-fig. 45 ; Townrow, 1957, text-fig. 9). In such specimens of X. elongata as I have examined and in those which have been adequately figured, the stomata are sunken and are either overhung by cutin flanges borne on the lateral subsidiary cells, or by a continuous cutinized margin of all the subsidiary cells, so that the guard cell poles (though partly cutinized) are covered. In P. simmondsi stomata with these features represent about three-quarters of all those seen (p. 305, Text-fig. SA, E, F, H ; Jones & Jersey, 1947, pi. 3, fig. i). A MICROSPOROPHYLL OF THE CORYSTOSPERM ACE AE 313 However, the differences discussed above are slight and subject to variation (see p. 295) ; they cannot sustain the weight of much argument. It seems likely that evidence from repeated association is necessary before reference of leaf to sporo- phyll at specific level can be made convincing. Frenguelli (1944) regarded the microsporophyll he called Pterorrachis barrealensis (here Pteruchus dubius, p. 300), as belonging with the leaf he calls Zuberia zuberi. The evidence is restricted to the association of a single sporophyll with the leaves. The leaf called Z. zuberi is composite. Frenguelli has ignored cuticle data, but some of his figures show the thick leaf substance which is characteristic of the genus Hoegia and distinguishes it at once from Dicroidium (Frenguelli, 1944, pi. 9, figs, i, 2 ; ? pi. 7, fig. 3) : other figures are indistinguishable from Dicroidium feistmanteli (pis. i, 4 & ?8, fig. 4). Others again are indeterminable on the information given. I accept the reference of Frenguelli's specimen to Dicroidium feistmanteli, but it is most unlikely that Hoegia has anything to do with Pteruchus or Dicroidium. It has a very thick leaf substance and a thick cuticle quite different from Pteruchus (Townrow, 1957 : 47-51). Frenguelli (19440) records that the fossil he named Stachyopitys anthoides (here P. simmondsi) was found in a locality in the Estratos de Potrerillos where X. elongata, Equisetites and Yabeiellia spp. were common ; but D. odontopteroides and D. feistmanteli are not mentioned. This may be additional evidence from association that P. simmondsi belongs with the leaf X. elongata, as is suggested on other grounds above (p. 312). (3) The Morphology of Pteruchus Thomas (1933 : 265 ; 1933^ : 31, 40) has suggested that Pteruchus was a sporophyll, but by using the terms " axis ", " bract " and " branch " (here rachis, pinnule and pinna) kept open the possibility that it was of stem-like nature, or a combination of leaf and stem. More evidence is now to hand, and I conclude that Pteruchus is best regarded purely as a sporophyll ; i.e. that it is of leaf-like nature, and not like any other category of organ. Pteruchus africanus is known to be borne directly on a stem in the manner of a leaf, and not in the axil of a leaf or bract (p. 292). All three species show characters that are normal in leaves but not normal in stems, namely (i) They are built upon a pinnate plan throughout (pp. 290, 294) ; (2) they are dorsiventral and bilaterally symmetrical (pp. 290, 294) ; (3) the pinnae are offset towards the upper surface of the rachis like many (probably most) com- pound leaves, and certainly like the leaves Dicroidium and Xylopteris (Text-fig. 30, E ; Townrow, 1957 : 28). In two features the microsporophylls resemble the leaves to which they are referred but differ from the axes of the same plants : (i) the rachis cuticle is dorsiventral in microsporophyll and leaf, but is similar all over the axes (Text-fig. 6s , E, F) ; (2) the rachises of leaf and microsporophyll have a lateral wing, absent from the axes (p. 292). The structures here called pinnules, but referred to as" bracts or bracteoles by Thomas were what caused him to suggest that Pteruchus might possibly be of stem- A MICROSPOROPHYLL OF THE COR YSTOSPERM ACE AE FIG. 10. Pteruchus dubius, P. africanus A-C, P. dubius. A, cuticle from non-sporangial surface of head showing pattern of cells and stomata. .42695. x 250. B, c, cuticle fragments originally opposite, from upper (B) and lower (c) surfaces of rachis, showing difference in cell pattern and usual orientation of stomata. .42695. x 250. D-G, P. africanus. D, E, two pollen grains in distal (D) and proximal (E) polar views, showing sulcus and variation in shape and ornament of body and sacci. From same sporophyll, but not same pollen sac. .42689. X 975- F G two pollen grains in tangential longitudinal view showing sulcus and variation of position of insertion of sacci. From the same pollen sac. .42688. x 525. A MICROSPOROPHYLL OF THE CORYSTOSPERM ACE AE 315 like nature. The question is whether these organs are more like pinnules of a pinnate leaf, or bracts on an inflorescence. The reasons why they seem to me to be like pinnules and not bracts are as follows : (i) They are only produced occasionally, as might be expected of lower pinnules ; but morphologically important organs like subtending bracts, or even bracteoles, should be constant. (2) No specimen has been seen which subtended a pinna, (or branch as it might be). (3) The pinnules set near the base of the microsporophyll have close agreement with a basal pinnule sometimes produced by leaves of the Dicroidium-Xylopteris group (Text-figs. 2A, B, D FIG. 1 1 . Pteruchus dubius, P. simmondsi A, B, P. dubius. c, D, P. simmondsi. Pollen grains in lateral (A, c) and proximal (B, D) polar views, showing body shape, insertion and ornament of sacci. A, B, holotype, v. 23389. c, D, .42694. All x 650. 5B, c). (4) The two alternately arranged pinnules near the sporophyll base in .23360 (Text-fig. 36) can easily be explained as reduced alternate pinnae ; to regard them as bracteoles involves a number of assumptions (e.g. that the organ here called a sporophyll is part of a larger organ that has never been seen complete) which run contrary to other evidence, and have nothing to support them. On the other hand, I can find no evidence that suggests that Pteruchus is a stem- like structure. Regarded as a sporophyll all the available evidence falls into a coherent picture ; but regarded as any other sort of organ a number of points cannot be made to fit in, and must be dismissed arbitrarily as of no importance (Thomas, 1933 : 200). Regarded as a sporophyll, the nature of the sporangial heads is easily explained. They are the distal portions of the pinnae, expanded into a. lamina, bearing sori along the veins, the sori lacking a definite boundary, and becoming concrescent towards 316 A MICROSPOROPHYLL OF THE COR YSTOSPERM ACE AE the centre of the head. They are thus analagous to the sori of e.g. Acrostichum aureum. This view avoids the more complicated explanations, involving the possible presence of a cupule (an organ never satisfactorily denned, and of uncertain mor- phology) into which Thomas (1933 : 265) was obliged to enter. At present I express no views upon possible homologies between the parts of Pteruchus and of Umkomasia and its allies, though, like Thomas, I believe they belonged to the same plants. (4) Comparisons and Taxonomic Position A full discussion of the taxonomic position of the Corystospermaceae must wait until their seed-bearing organs are reconsidered. At present Pteruchus is compared with various other pollen organs to clear the ground for such a wider discussion. Here the older and usually more inclusive terms Pteridospermae ( = Cycadofilicales) , Lyginopterideae, Medulloseae and Corystospermaceae are used in preference to any of the more recent alternatives (Pant, 1957). This is for two reasons. The first is that for the present purpose, the older terms are more useful. The second is that the fundamental point the morphology of the seed-bearing organs of the Corystosper- maceae is not yet satisfactorily decided. Thomas (1933 : 256) describes them as inflorescences, but points out several facts inconsistent with this view : until these organs are re-examined and their morphology decided, the Corystospermaceae cannot be classified otherwise than as a family incertae sedis. A difficult point in comparing Pteruchus is that there is no evidence suggesting which way evolution within the genus has gone. Taking different basic premises any of the species could be called the most primitive, and the others derived from it, or all could be considered equally advanced, derived independently from a common (hypothetical) ancestor. Accepting the suggested ascriptions to the leaves (pp. 312, 313) it is not clear which is the older (Jones, 1949 ; Jones & Jersey, 1947 : 73), hence this line of argument does not help. Thomas regarded the Corystospermaceae as belonging to the Pteridospermae. I agree entirely, if we define the Pteridospermae as " gymnospermous plants with leaves, pollen- and seed-bearing organs pinnate. Reproductive structures not aggregated in cones or flowers ". Pteruchus has been compared with Crossotheca (Kidston, 1923 ; Remy, 1956) by Thomas (1933 : 256). They are alike in two respects : both are pinnate and bear the pollen sacs on what is most reasonably regarded as a modified pinna or pinnule. Otherwise they are different ; differing in the manner of insertion of the pinna petiole, the way in which the pollen sacs are arranged, and in that Crossotheca (at least the better known species) has bilocular synangia. Crossotheca is regarded as belonging to a lyginopterid plant (Jongmans, 1950). There is some resemblance between Pteruchus and Potoniea (Halle, 1933 ; Remy, 1956) for both bear long, free, unilocular sporangia, dehiscing by a longitudinal slit, toward the centre of a cup-like pinnule with a lobed or dentate margin. Potoniea is attached basally, and the pollen differs. Thomas (1933 : 254) also compared Pteruchus with Dictyothalamus schrollianus W. & R. Remy, 1958). There are a number of most interesting similarities. D. A MICROSPOROPHYLL OF THE COR YSTOSPERM ACE AE 317 schrollianus is pinnate, and may be forked, and the rachis is lumpy, at any rate in some specimens, like Pteruchus. The pollen sacs are massed over one surface of the " head ", and the pinna appears to be inserted on, or mostly on, the sporangial side, and its continuation on to the " head " is free of pollen sacs. The pollen sacs probably lie in rows, as may be so in Pteruchus. The comparison cannot be pressed too far. The pollen of D. schrollianus is monosaccate, while the structure of the " head " and pollen sac is unknown. D. schrollianus is of unknown affinities. Its pollen is like that of Schuetzia anomala (Remy & Rettschlag, 1954 ; W. & R. Remy, 1958) but otherwise the two organs appear to be rather different. Two Rothliegend fossils, Pteridospermostrobus gimmianus Remy (1954) and Manebachia polysporangiata W. & R. Remy ( 19580) bear superficial resemblance to P. simmondsi and P. dubius, but differ in structure. Thuringia callipteroides Remy (1953) has bisaccate pollen like Pteruchus but is otherwise quite different. According to Potonie & Kremp (1956) the pollen of T. callipteroides is monosac- cate, however. Pteruchus shows no point of approach to any Medullosean pollen organ (Halle, I 933)> neither is it like any of the fructifications belonging to Glossopteris and Gangamopteris (Plumstead, 1959, discussion). It differs widely from those fossils found associated with Glossopteris (Thomas, 1958 ; Pant, 1958), except that it has bisaccate pollen. There are no Mesozoic fossils that can be closely compared with Pteruchus. Among the supposed pteridosperm derivatives Caytonanthus (Harris, 1950, discussion) is pinnate and has bisaccate pollen like Pteruchus. Caytonanthus bears a radially symmetrical group of (usually) four pollen sacs, pendulous from an unexpanded branchlet end of the sporophyll, which dehisces by the pollen sacs splitting apart from one another. These features are quite different from anything seen in Pteru- chus, and, in detail the pollen is different ; Caytonanthus pollen is about 15 /* wide, and has a scarcely visible sulcus, but Pteruchus pollen is about 70 /i wide, and shows a distinct sulcus. Antevsia the pollen organ of the Peltaspermaceae (Townrow, 1960) resembles Pteruchus only in being pinnate and in having pollen sacs that dehisce by a longi- tudinal slit. Otherwise it differs markedly. The pollen sacs are either borne margin- ally on a disc, or on the under surface, possibly opposite on marginal lobes, of a fertile branchlet of the sporophyll. The pollen sacs are massive, with stomata, and probably with vascular tissue. The pollen is monosulcate. Four other Triassic fossils have bisaccate pollen rather like Pteruchus. They are : Harrisiotheciummarsiloides (Harris, 1935 ; Lundblad, 1950) which branches in all three planes, and has a two-valved synangial pollen-bearing portion with immersed pollen sacs, one row in the tissue of each valve. It is thus widely different from Pteruchus. Pamelreuthia halberfelneri (Krausel, 1948) which is pinnate, but differs in having pollen sacs, probably one row, sunken in the tissue of the expanded pinna ends, so forming synangia. Ruhleostachys pseudoarticulatus Roselt (1956) which is an organ of entirely different structure from Pteruchus, probably very close to the conifers, and the conifer Voltzia (?) heterophylla (Wills, 1910 ; Couper, 1958), which is clearly unconnected with Pteruchus. 3i8 A MICROSPOROPHYLL OF THE COR YSTOSPERM ACE AE It has been suggested (Thomas, 1933 : 260) that Pteruchus is comparable with a catkin, e.g. of Populus, but since Pteruchus is a sporophyll this comparison cannot be maintained. In conclusion, the genus Pteruchus cannot be exactly classified. It resembles a number of fossils in being pinnate, or having bisaccate pollen, or pollen sacs that dehisce by a longitudinal slit ; but these are all characters which are shared by a wide range of plants otherwise dissimilar. The bisaccate pollens, for example, are very numerous and all rather similar (see Potonie, 1958). As far as evidence from the pollen organs goes, Pteruchus is remote from any of the " Mesozoic Pterido- sperms " (including, for convenience only, the Caytoniales) , indeed, as far as they are known, each of the " Mesozoic Pteridosperms " is remote from the others. The evidence (and it is far from complete) suggests that they are so different that they are best placed in different orders (but see Gothan & Weyland, 1954). Among the Palaeozoic pteridosperms comparison is possible, though never close, between Pteruchus and pollen organs in which the pollen sacs were borne on a laterally attached pinnule. This seems to have been a character of the Upper Carboniferous Lyginopterideae (if indeed Crossotheca did belong to a lyginopterid plant), and so suggests some connection with the Lyginopterideae. The differences between Pteruchus and any lyginopterid fossil indicate the connection is remote. I am indebted to the Keeper of Palaentology and to Mr. F. M. Wonnacott, British Museum (Natural History) for facilitating my examination of Dr. Hamshaw Thomas' material, as well as for much other help. I owe thanks to Dr. W. G. Chaloner University CoUege, London and Dr. Sergio Archangelsky, Institut Lillo, Tucuman, for help and useful criticism, while to my wife I owe much help in making the collection here described. To Professor T. M. Harris, F.R.S., Botany Department, The University, Reading, I am indebted for encouragement to start the present work and for unfailing help during its progress. REFERENCES COUPER, R. A. 1958. British Mesozoic microspores and pollen grains ; a systematic and strati- graphic study. Palaeontographioa, Stuttgart, 103B : 75-179, pis. 15-31. DUTOIT, A. L. 1927. The Fossil Flora of the Upper Karroo Beds. Ann. S. Afr. Mus., Cape Town, 22 : 289-420, pis. 16-22. ERDTMAN, G. 1947. An Introduction to Pollen Analysis, xv + 239 pp., text-figs. New York. FEISTMANTEL, O. 1890. Uhlonosne utvary v Tasmanii. Spis. poc. jub. spot. Nauk Praze, 3 : vii + 162 pp., 10 pis. FRENGUELLI, J. 1942. Contribuciones al conocimiento de la flora del Gondwana superior en la Argentina, VI. Pterorrachis n. gen. Not. Mus. La Plata, 7 : 303-313, pis. i, 2. - 1944. Contribuciones al conocimiento de la flora del Gondwana superior en la Argentina, XV. Stachyopitys anthoides n. sp. Not. Mus. La Plata, 9 : 365-392, pis. i, 2. i944. Las especies del genero Zuberia en la Argentina. Ann. Mus. La Plata (Paleobot., B), 1 : 1-30, pis. 1-13. GEINITZ, H. B. 1876. Ueber rhaetische Pflanzen-und Thierreste in den Argentinischen Pro- vinzen, La Rioja, San Juan und Mendoza. Palaeontographica, Stuttgart, suppl., 3, 3 : 1-14, pis. 2, 3. A MICROSPOROPHYLL OF THE CORYSTOSPERM ACE AE 319 GOTHAN, W. 1914. Die unterliassische (" rhatische ") Flora der Umgegend von Niirnberg. Abh. naturh. Ges. Niirnberg, 19 : 91-186, pis. 17-39- GOTHAN, W. & WEYLAND, H. 1954. Lehrbuch der Paldobotanik. 535 pp., 450 figs. Berlin. HALLE, T. G. 1933. The structure of certain fossil spore-bearing organs believed to belong to the Pteridosperms. K. svenska VetenskAkad. Handl., Stockholm (3) 12, 6 : 1-103, pis. i-i5- HARRIS, T. M. 1935. The Fossil Flora of Scoresby Sound, East Greenland. Part III, Cay toniales and Bennettitales. Medd. Gronland, Kj0benhavn, 85, 5 : 1-133, P ls - 1-19- 1950. The relationships of the Caytoniales. Phytomorph., Delhi, 1 : 29-39, figs, i, 2. JAKOB, K. & C. 1950. Preliminary account of the structure of the cuticles of Dicroidium (Thinnfeldia) from the Mesozoic of Australia. Proc. Nat. Inst. Sci. India, Delhi, 16 : 101- 126, figs. 1-27. JOHNSTON, R. 1888. The Geology of Tasmania, xxii + 408 pp., 57 pis. Hobart. JONES, O. A. 1944. Problems of Queensland Mesozoic Palaeobotany. Aust. J. Sci., Sydney, 11 : 192-193. JONES, O. A. & JERSEY, N. J. DE. 1947. The Flora of the Ipswich Coal Measures Morphology and Floral Succession. Univ. Qd. Papers Geol., Brisbane (n.s.) 3 : 1-88, pis. i-io. JONGMANS, W. J. 1950. The female fructification of Sphenopteris hoeninghausi and the supposed relationship of this species with Crossotheca. Palaeobotanist, Lucknow, 1 : 267-276, pis. 1-2 1. KIDSTON, R. 1923. Fossil Plants of the Carboniferous Rocks of Great Britain. Mem. Geol. Surv. Gt Brit., Palaeont., London, 2, 4 : 275-376, pis. 69-91. KRAUSEL, R. 1948. Koniferen und andere Gymnospermen aus der Trias von Lunz, Nieder- Osterreich. Palaeontographica, Stuttgart, 89B : 36-82, pis. 6-18. 1950. Stachyotaxus sahnii nov. spec., eine Konifer aus der Trias von Neuewelt bei Basel. Palaeobotanist, Lucknow, 1 : 285-288, pi. i. LUNDBLAD, B. 1950. Studies in the Rhaeto-Liassic Floras of Sweden, I. Pteridophyta, Pteri- dospermae and Cycadophyta from the mining district of N.W. Scania. K. svenska Vetensk- Akad. Handl., Stockholm (4) 1 : 1-82, pis. 1-13. PANT, D. D. 1957. The classification of Gymnospermous plants. Palaeobotanist, Lucknow, 6 : 65-70. 1958. The structure of some leaves and fructifications of the Glossopteris Flora of Tan- ganyika. Bull. Brit. Mus. (Nat. Hist.) Geol., London, 3 : 126-175, pl - 18-21. PLUMSTEAD, E. P. 1958. Further fructifications of the Glossopteridae and a provisonal classi- fication based on them. Trans. Geol. Soc. S. Afr., Johannesburg, 61 : 51-76, pis. 7-32. POTONIE, R. 1958. Synopsis der Gattungen der Sporae Dispersae, II. Beih. Geol. Jb., Hannover, 31 : 1-114, pis. I ~9- POTONIE, R. & KREMP, G. 1956. Die Sporae Dispersae des Ruhrkarbons, III. Palaeontographica, Stuttgart, 100B : 66-120. REMY, W. 1953. Beitrage zur Kenntnis der Rotliegendflora Thiiringens, I. S.B. Akad. Wiss. Berlin, 1953 : 1-24, pis. 1-5. 1954- Beitrage zur Kenntnis der Rotliegendflora Thiiringens, II. S.B. Akad. Wiss. Berlin, 1953, 3 : 1-20, pis. 1-4. 1956. Die Systematik der Pteridospermen unter Beriicksichtigung ihrer Pollen. Zeitschr. Geol., Berlin, 3 : 312-325, pis. 1-3. REMY, W. & R. 1958. Beitrage zur Kenntnis der Rotliegendflora Thiiringens, 111. S.B. Akad, Wiss. Berlin, 1958, 3 : 1-16, pis. 1-4. i958a. Die sporen von Dictyothalamus schrollianus Goppert. Abh. Akad. Wiss. Berlin, 1958, 5 : 3-6, pi. i. REMY, W. & RETTSCHLAG, R. 1956. Neue Untersuchungen uber die Pollen von Schuetzia anomala H. B. Geinitz. Zeitschr. Geol., Berlin, 3 : 582-589, pis. i, 2. ROSELT, G. 1956. Eine neue mannliche Gymnospermen fruktifikation aus dem untere Keuper von Thuringen und ihre Beziehung zu andere Gymnospermen. Wiss. Zeit. F. -Schiller Univ. Jena, 1 : 75-118, pis. 1-12. 320 A MICROSPOROPHYLL OF THE COR YSTOSPERM ACE AE SCHENK, A. 1867. Die fossile Flora der Grenzschichten des Keupers und Lias Frankens. xxiv + 232 pp., atlas 45 pis. Wiesbaden. SEWARD, A. C. 1903. Fossil Floras of Cape Colony. Ann. S. Afr. Mus., Capetown, 4 : 1-122, pis. 1-14. SHIRLEY, J. 1898. Additions to the Fossil Flora of Queensland, mainly trom the Ipswich Formation, Trias-Jura System. Qd Geol. Surv. Bull., Brisbane, 7 : 1-25, pis. 1-27. THOMAS, H. HAMSHAW. 1933. O n some Pteridospermous Plants from the Mesozoic Rocks of South Africa. Philos. Trans., London, 222B : 193-265, pis. 23, 24. ~ I 933- The old morphology and the new. Proc. Linn. Soc. Lond., 1932-1933 : 17-32. 1958. Lidgettonia a new type of fertile Glossopteris. Bull. Brit. Mus. (Nat. Hist.) Geol., London, 3 : 179-189, pis. 22, 23. TOWNROW, J. A. 1957. On. Dicroidium, probably a pteridospermous leaf, and other leaves now removed from this genus. Trans. Geol. Soc. S. Afr., Johannesburg, 60 : 21-56, pis. 2, 3. 1960. On the Peltaspermaceae ; a pteridospermous family of Lower Mesozoic age. Palaeontology, Oxford, 3 : 333-361, pi. 58. WALKOM, A. B. 1917. The Mesozoic Floras of Queensland. Part 1 concluded (d) Ginkgoales (e) Cycadophyta (f) Coniferales. Qd Geol. Surv. Publ., Brisbane, 259 : 1-30, pis. 1-9. 1925. Notes on some Tasmanian Mesozoic Plants. Part I. Proc. Roy. Soc. Tasmania, Hobart, 1924 : 73-89, figs. 1-18. WILLS, L. J. 1910. On the fossiliferous Lower Keuper Rocks of Worcestershire. Proc. Geol. Ass. Lond., 21 : 249-332, pis. 10-26. PLATE 24 Pteruchus simmondsi (Shirley) FIG. i. A sporophyll showing alternate branching. V. 42681. X2. FIG. 2. The holotype. Queensland Geological Survey No. F.256. x 2. FIG. 3. The lower portion of the sporophyll shown in Fig. i, showing form of sporangial heads and of the pinnae, x 6. Pteruchus africanus Thomas FIG. 4. A sporophyll (in transfer) seen from the upper surface. .42682. X2. Pteruchus dubius Thomas FIG. 5. A sporophyll. .42683. x 2. FIG. 6. Base of the same specimen, showing basal pinnule (right), ? fragment of axis (left) and first pinna with pinnule just above its insertion (cf. Text-fig. 40). x 7. Bull. B.M. (N.H.) Geol. 6, 2 PLATE 24 PLATE 25 Pteruchus africanus Thomas FIG. i. Lower portion of a sporophyll showing single pinnule abo -t midway between sporophyll base and first pinna. V. 42684. x 6. FIG. 2. Portion of axis (horizontal) and base of a sporophyll (curving to run vertically). Photograph taken under NH 4 C1 ; illuminated from bottom left. .42685. x6. Pteruchus dubius Thomas FIG. 3. A sporangial head, sporangial surface exposed, showing insertion of pinna, marginal lobes devoid of pollen sacs (next pinna insertion and at distal end) and pollen sacs over rest of the surface. .42686. x 6. Xylopteris elongata (Carruthers) FIG. 4. The base of a leaf showing long but undivided basal pinnule (cf. Text-fig. 53). x6. FIG. 5. A leaf base attached to a short piece of axis (running to right), x 6. Bull. B.M. (N.H.) Geol 6, 2 PLATE 25 PLATE 26 Pteruchus dubius Thomas FIG. i. Pollen grain, polar view distal face, showing sulcus. An abnormally small specimen. .23389. x 500. Pteruchus africanus Thomas FIG. 2. Pollen grain, tangential longitudinal view, showing sulcus in optical section and insertion of sacci. .23384. x 500. FIG. 4. Pollen grain, polar view distal face, showing sulcus. .23384. x 500. FIG. 5. Section of a pollen sac showing single loculus. V. 42688. x 260. FIG. 6. Sporophyll base showing a single pinnule and an impression of another or (?) of part of the axis. .23385. xg. FIG. 7. The cuticle of the edge of a head showing small foldings and cuticle extending as a rim on to sporangial surface (at a). FIG. 8. A head, showing the rugose (non-sporangial) surface. .42682. x 7. FIGS. 9, 10. Two heads, sporangial surface seen free of pollen sacs, showing area of pollen sac attachment, and ridges marking course of veins. Note margin and lobes smooth, and in Fig. 9 little rings running more or less parallel with a vein. Photographs taken under NH 4 C1, illuminated from bottom left. .23394. x 7. FIG. ii. Part of pollen sac wall (in transfer) showing single layer of cells forming the wall at maturity. .42690. x 50. Pteruchus simmondsi (Shiiley) FIG. 3. Pollen grain, polar view distal face, showing sulcus. .42687. x 500. FIG. 12. A head, sporangial surface exposed, showing pinna insertion and large marginal lobes. .42681. X7- Bull. B.M. (N.H.) Geol. 6, 2 PLATE 26 ii 10 PRINTED IN GREAT BRITAIN BY ADLARD AND SON, LIMITED, BARTHOLOMEW PRESS, DORKING REVISION OF THE OLIGOCENE FLORAS OF THE ISLE OF WIGHT M. E. J. CHANDLER BULLETIN OF THE BRITISH MUSEUM (NATURAL HISTORY) GEOLOGY Vol. 6 No. 3 LONDON: 1963 BY MARJORIE E. J. CHANDLER Pp. 321-384 ; Pis. 27-35; 5 Text-figures BULLETIN OF THE BRITISH MUSEUM (NATURAL HISTORY) GEOLOGY Vol. 6 No. 3 LONDON: 1963 THE BULLETIN OF THE BRITISH MUSEUM (NATURAL HISTORY), instituted in 1949, is issued in five series corresponding to the Departments of the Museum, and an Historical series. Parts will appear at irregular intervals as they become ready. Volumes will contain about three or four hundred pages, and will not necessarily be completed within one calendar year. This paper is Vol. 6, No. 3 of the Geological (Palaeontological) series. Trustees of the British Museum, 1963 PRINTED BY ORDER OF THE TRUSTEES OF THE BRITISH MUSEUM Issued January, 1963 Price Thirty three Shillings REVISION OF THE OLIGOCENE FLORAS OF THE ISLE OF WIGHT By M. E. J. CHANDLER SYNOPSIS The beds from which plant remains have been obtained are listed ranging from the base of the Upper Headon to the top of the Hamstead Series. Reasons for excluding the Lower Headon from the Oligocene are briefly summarized. The poor representation of the Oligocene land flora in the Isle of Wight is mentioned and the plant beds of the successive horizons, Upper Headon, Osborne, Bembridge and Hamstead are described. Plant lists from these beds are incorporated and are discussed in turn. In the systematic section almost all the records in the Upper Headon are new as are the few from the Osborne Beds. In the Bembridge Series there is a small collection of plants to add from the Bembridge Limestone and a few new plant localities in the Bembridge Marls. There are one or two corrections to the plant lists from the Insect Limestone published in 1926 but this flora is due shortly for reappraisal. The Hamstead Bed flora is still little known and is represented almost entirely by water or marsh plants which give the minimum of information about contemporary conditions. INTRODUCTION THE horizons from which plant remains have been collected in the Oligocene Beds of the Isle of Wight are, passing downwards, The Hamstead Beds, The Bembridge Beds, especially the Insect Limestone, The Osborne Beds where only sparse dwarfed or battered specimens have been found, The Upper Headon Beds. The plants will be discussed chronologically starting at the Upper Headon and work- ing up through successive horizons. The Eocene plants, very few in number in the Island, have been described else- where except for the Alum Bay pipe-clay impressions which have not been revised in recent years so that a thorough study of the remains, mostly leaves, is needed but must await the attention of an expert in these organs. Unfortunately the macroscopic plant remains do not, at present at least, appear to help in the separation of Eocene and Oligocene. Whereas some geologists include the Lower Headon Beds in the Oligocene (Reid & Strahan, 1889 : 127 ; Arkell, 1947 : 217) others have preferred to retain them in the Eocene (Wrigley & Davis, 1937 : 220, pi. 18). The latter position was adopted by Chandler (1961, table on p. 8). In the type localities of the Barton and Hordle cliffs there is a continuous section from the Barton Beds through passage beds into the Lower Headon while the succeeding Marine Beds (if indeed they represent the Middle GEOL. 6, 3. 23 324 REVISION OF THE OLIGOCENE FLORAS OF THE ISLE OF WIGHT Headon Marine Series) are ill-developed. There are no Upper Headon strata. In the Isle of Wight the Upper Headon Beds are definitely and unmistakably separated from the Lower Headon by the well-developed marine Middle Headon with its " Venus " and Neritina Beds and Oyster banks, and the division between Eocene and Oligocene appears to be drawn more appropriately below these marine beds with Lattorfian mollusca than below the Lower Headon. RESTRICTED RANGE OF PLANT REMAINS AVAILABLE UP TO THE PRESENT The Oligocene plant remains of the Isle of Wight are disappointing after the rela- tively richer beds of the Eocene on the Mainland. Apart from the fine impressions of Bembridge age in the Insect Limestone at Thorness and Gurnard Bays (Reid & Chandler, 1926) very little evidence of the true land flora is preserved. The frequent mention of seed beds at a number of horizons in the Geological Survey Memoirs has in the past raised false hopes in the palaeobotanist for these invariably prove to be monotonous bands of gregarious water plants : Stratiotes, Bmsenia and Limnocarpus with a limited representation of other genera like Potamogeton, Aldrovanda and Typha. There are in addition occasional finds in the Hamstead Beds of Sequoia couttsiae represented either by carbonaceous twigs or by hollow impressions in cement- stone or ironstone blocks. No one has yet discovered lenticles or pockets rich in the fruits and seeds shed by trees and shrubs clothing the banks of rivers or growing in woodlands adjoining them, although search has been made for such by numbers of workers including C. Reid, J. Groves, G. W. Colenutt, E. M. Reid and M. E. J. Chandler. No typical patches dark with the remains of twigs and woody fruits have been observed. The nearest approach to such is a sandy band below a sewer pipe at Linstone Chine, Colwell Bay, where scattered fruits are easily removed from soft sands by sifting. That it may be worthwhile to continue to search is suggested by the unique but important find in a thin seam composed of tiny shreds of vegetation in the Upper Headon of Colwell Bay of Anemia colwellensis and of distinctive leaf fragments described as an unknown leaf. (p. 357). CHRONOLOGICAL REVIEW OF PLANT-BEARING BEDS AND LISTS OF ASSOCIATED PLANTS (a) The Upper Headon Beds All the plants hitherto found come from Colwell Bay where the beds present a very variable series of brown, green, greyish or variegated clays with some white sands and impure limestones. They are brackish, estuarine and freshwater deposits with an abundance of shells displaying the paucity of genera and species usual under such conditions coupled with an abundance of individuals . Among the genera are Paludina , Potamomya, Cyrena, Melania, Limnaea, Potamides and Planorbis (names used in the Survey Memoir now in some cases superseded). An excellent description of the section was given by Keeping & Tawney (1881) while a typical section in Colwell and Totland Bays is given in Reid & Strahan (1889 : 131). This locality does not show the massive limestones found at Headon Hill (see Reid & Strahan, 1889 : 129), but from REVISION OF THE OLIGOCENE FLORAS OF THE ISLE OF WIGHT 325 the point of view of the plants the limestone is insignificant. The sparse fruits and seeds were mostly collected between Linstone and Brambles Chines in the lowest beds of the Upper Headon Series, a laminated grey clay with Potamomya having a series of inconspicuous thin discontinuous fine carbonaceous seams. In addition to abundant water plants Sequoia couttsiae is common in places and is represented by twigs, seeds and cone scales. Among the rare land plants are seeds of Zanthoxylum hordwellense, Sambucus and the ubiquitous older Tertiary Hordwellia eocenica. Marsh plants are represented by various Cyperaceae and two Lythraceae. It was at this horizon that the unique fruiting specimen of Anemia colwellensis was obtained. In the overlying pale-buff sands carbonaceous seams are more conspicuous but up to the present the plants found are purely aquatic, e.g. Brasenia and Stratiotes. Below the sewer pipe at Linstone Chine there was an incoherent sandy matrix where seeds were more abundant and readily removable by washing and sifting. This was the chief source of the scarce land plants already mentioned. Water plants including Aldrovanda were also represented. In folded beds north of Linstone Chine a dense black patch of seeds yielded only Brasenia and Stratiotes. On the whole the flora so far as it is yet known is comparable with that in the more estuarine deposits of the Lower Headon but the scarcity of land plants makes comparison with the Lower Headon of little value. Almost invariably the plants are preserved as carbonaceous entities which can be isolated from the matrix. Very frequently the cells are replaced in part or even largely by soft amorphous pyrites which is liable to smear when wet and to burst and crack when dry. Consequently the specimens are extremely difficult to preserve permanently and there is a certain amount of distension and distortion. For reasons not understood some genera are more liable to pyritization than others, e.g. Zantho- xylum and Limnocarpus. The plant list is given on p. 326. Only about 38 species are known, including Carpolithus spp., not all of which are named. Twenty (including Rhamnospermum) appear to be marsh or water plants, Zanthoxylum and Sambucus may have grown on river banks. The conifers, always battered and broken, were probably carried down from the land behind the delta lying at a somewhat higher level together with the chance fragment of Anemia and the seeds of Ficus and Rubus. The Epacridaceae may well have grown on sandy flats or heath land. The plant assemblage is not a very remarkable or informative one. Sequoia couttsiae and Rhamnospermum bilobatum are common throughout the Hampshire Basin Tertiary Beds ranging from the London Clay (unpublished record) to the Hamstead Beds and of course occurring in superabundance in the isolated upland Bovey Tracey lake basin. Caricoidea obscura and Hordwellia crassisperma have been found from the Lower Bagshot upwards. Ficus lucidus is also known from the Lower Bagshot and Bournemouth Freshwater Beds. Myrica boveyana is present in the Bournemouth Beds, the Highcliff Sands, Lower Headon of Hordle and at Bovey Tracey. Potamogeton pygmaeus only becomes common from the Bournemouth Marine Beds upwards to the Upper Headon and Epacridicarpum headonense appears first at the same horizon. Brasenia ovula and Limnocarpus forbesi on the other hand 326 REVISION OF THE OLIGOCENE FLORAS OF THE ISLE OF WIGHT List of Upper Family Pteridophyta Filicales Schizaeaceae Gymnospermae Coniferales Araucarineae Taxodineae Abietineae Angiospermae Monocotyledones Potamogetonaceae Hydrocharitaceae Cyperaceae Dicotyledones Myricaceae Moraceae Centrospermae (Family ?) Nymphaeaceae Droseraceae Rosaceae Rutaceae Theaceae Lythraceae Caprifoliaceae Epacridaceae Family ? Incertae Sedis Headon Plants, Colwell Bay, Isle of Wight Genus and species Anemia colwettensis Chandler ? Araucarites gurnardi Florin Sequoia couttsiae Heer Pinus sp. Potamogeton pygmaeus Chandler Limnocarpus forbesi (Heer) Stratiotes headonensis Chandler Carex colwettensis n.sp. Carex sp. ? Scirpus sp. Caricoidea (? Cladium) colwettensis n.sp. Caricoidea maxima Chandler ? Caricoidea angulata Chandler ? Caricoidea obscura Chandler Genus ? Myrica boveyana (Heer) Myrica ? colwettensis n.sp. Ficus lucidus Chandler Genus ? Brasenia ovula (Brongniart) Genus ? (? Brasenia ovula) Brasenia spinosa Chandler Nymphaea sp. Aldrovanda ovata (Chandler) IRubus microspermus C. & E. M. Reid Zanthoxylum hordwellense Chandler Hordwellia crassisperma (Chandler) Decodon vectensis n.sp. ? Microdiptera parva Chandler Sambucus colwellensis n.sp. Epacridicarpum headonense Chandler Epacridicarpum colwellense n.sp. Rhamnospermum bilobatum Chandler Carpolithus colwellensis n.sp. Carpolithus spp. Unknown leaf. REVISION OF THE OLIGOCENE FLORAS OF THE ISLE OF WIGHT 327 while appearing in the Bournemouth Marine Beds range up to the top of the Ham- stead Series, although a single doubtful endocarp of the last named has been identified in Cuisian Beds at Whitecliff Bay and its endocarps are known in the Marine Beds of the Selsey peninsula at or about the horizon of the Lutetian-Auversian boundary. The former species again occurs at Bovey. Microdiptera parva is a species recorded from the Highcliff Sands, Lower Headon and Bovey, while Caricoidea maxima was first described from the Hengistbury Beds. Common to Lower and Upper Headon and scarcely as yet recorded elsewhere are Stratiotes headonensis (also in the highest Barton Beds), Brasenia spinosa, Aldrovanda ovata and Zanthoxylum hordwellense. Rubus microspermus is also a Bovey plant and Araucarites and Anemia colwellensis probably belong to the species recorded in the Bembridge Beds. Unique, so far, to the Upper Headon are Car ex colwellensis and other Car ex species. Caricoidea (? Cladium) colwellensis, Myrica ? colwellensis (if indeed it is a Myrica}, Decodon vectensis, Sambucus colwellensis. Epacridicarpum colwellense and Carpolithus col- wellensis. These species do not appear to have any particular significance ; indeed the flora as a whole agrees in a general way with the flora of the Bournemouth Marine and younger Beds, i.e. with that part of the Eocene flora from horizons where con- ditions of growth may have been affected by the proximity of the sea. The incoming of Hamstead and Bovey species may be noted, for Rubus and Potamogeton are both represented by other species in older beds. (b) The Osborne Beds These Beds lie between the Upper Headon Series and the Bembridge Limestone. At Headon Hill Reid & Strahan (1889 : 148) list a grey shale called the " Fish and Plant Beds " but no plants have so far been traced from this locality. Between Headon Hill and Linstone Chine they state (p. 150) the Osborne Series has been removed by denudation and the cliffs consist of the underlying Headon Series. However Osborne Beds reappear beneath the battery at Cliff End at the northern end of Colwell Bay and it is this section which has yielded all but one of the few plant species here described. The section given by Reid & Strahan (1889) mentions leaves in dark shales (" Probably the equivalent of the Fish Bed" noted above). The remains are poor and fragmentary, Acrostichum, Nelumbium and Dicotylo- phyllum having been recognized. From the Osborne Beds at Osborne a few undersized, immature and somewhat crushed and worn seeds of a Stratiotes have recently been obtained and referred provisionally to Stratiotes neglectus. Thus the small plant list of the Osborne Series (see p. 328) contains four species up to date. Acrostichum ranges from the Lower Bagshot throughout the Eocene where suitable sub-marine conditions prevailed and up into the Bembridge Beds. Stratiotes neglec- tus, if it is this species which is represented, is a typical Bembridge plant but has perhaps been found also in Hamstead Beds. Nelumbium buchi occurs at horizons both below wer Headon) and above (Hamstead) and Dicotylophyllum pinnatifidum is again a Bembridge species while a fragment has been reported from the Highcliff Sands ^ Chandler, in press). 328 REVISION OF THE OLIGOCENE FLORAS OF THE ISLE OF WIGHT List of Osborne Plants, Cliff End, Colwell and Osborne, Isle of Wight Family Genus and species Pteridophyta Filicales Polypodiaceae Acrostichum lanzaeanum (Visiani) Angiospermae Monocotyledones Hydrocharitaceae ? Stratiotes neglectus Chandler Dicotyledones Nymphaeaceae Nelumbium buchi Ettingshausen Incertae Sedis Dicotylophyllum pinnatifidum Reid & Chandler According to Reid & Strahan (1889 : 157) at this horizon there is " an absence of truly marine beds . . . Purely freshwater strata are also rare. The mass of the clays seems to have been deposited in lagoons, varying in saltness, in which could live brackish-water molluscs like Melania and Potamomya, and a few of the more hardy freshwater and marine species. Lagoons of this character are at the present day favourite places for turtles and alligators, like those so abundant in this deposit." A reference then follows (p. 158) to the plants discovered by Clement Reid and Henry Keeping at Cliff End although they made no attempt at systematic collecting. The section is now overgrown and not accessible to the public. (c) The Bembridge Beds The Osborne Beds are succeeded by the Bembridge Beds, a very important member of the Oligocene fluvio-marine series of the Isle of Wight. The lower part of the Bembridge deposits is a massive limestone with shaley bands and some marly beds, the limestone being very definitely a freshwater deposit sharply divided from the mottled Osborne clays below. Although full of Cham it has yielded few other recognizable plant remains but Mr. J. F. Jackson obtained from a marly pocket in the limestone of Sticelett Ledge a tiny collection of fruits and seeds all of which occur in the rich Insect Limestone of the overlying Bembridge Marls with its finely preserved flora. Jackson's specimens were listed by Reid & Chandler (19260 : 378) and include the following: Sparganium sp. ? Stratiotes neglectus Chandler Cladium sp. [Caricoidea] Brasenia ovula (Brongniart) Aldrovanda {intermedia'] [Carpolithus sp. 2] [Rhamnospermum bilobatum] The information in square brackets was added subsequent to the publication of the note. Only one of the species (Carpolithus sp. 2) has been figured and described (see p. 368, PL 34, figs. 162-165). The Bembridge Marls are separated in places from the massive Limestone by some measure of erosion. They demonstrate a change in the conditions of sedimentation, REVISION OF THE OLIGOCENE FLORAS OF THE ISLE OF WIGHT 329 marine shells occurring at the base only. The basal beds are followed by a succession of freshwater and estuarine marls and clays. The bulk of the marls are estuarine in origin as evidenced by the fauna. Wood, fruits and seeds occur at intervals, notably seams comprising masses of Rhamnospermum bilobatum, Stratiotes neglectus or Brasenia ovula, other species being limited in numbers and variety (Reid & Chandler, 1926 : 3). However, the only really rich horizon, so far as present knowledge goes, is the Insect Limestone, a lenticular discontinuous band low in the Marls, a few feet only above the Bembridge Limestone proper. It is described in some detail by Reid & Chandler (1926) and in the various editions of the Geological Survey Memoir. To the information already published about the plants one or two new localities in the Bembridge Marls are now added : Wootton, Ashlake, Werror where Stratiotes or Limnocarpus or Brasenia only have been found (pp. 363-364, 367). There are en- docarps of Celtis from the Bembridge Limestone of Headon Hill and fine specimens of Carpolithus sp. 2 have been collected in the marly pocket in the Bembridge Limestone of Sticelett Ledge mentioned above. Apart from the above there is little to add to our knowledge of the flora. An unidentified fern (Filix incertae sedis sp. 5 ; Reid & Chandler, 1926 . 39) is now referred provisionally to Anemia colwellensis Chandler. Araucarites gurnardi Florin is regarded as including the cone scale formerly described as Doliostrobus sp. (Arauca- rites gurnardi ?) (Reid & Chandler, 1926 : 52). The pine cone described by Gardner (cf. Reid & Chandler, 1926 : 54) is now regarded as doubtfully belonging to Pinus dixoni (Bowerbank) and a Potamogeton leaf (Reid & Chandler, 1926 : 67, pi. 3, figs. 23, 24) should no longer be linked tentatively with P. pygmaeus as the genus is represented by more than one leaf species including the fine new but unnamed specimen found by the late G. W. Colenutt (PI. 33, figs. 148, 149). Epipremnum ornatum is now referred tentatively only to this genus, a possible alternative alliance being Raphidophora, while Spirematospermum wetzleri Heer may actually belong to S. headonense Chandler. Celtis edwardsi is an addition to the flora. The discovery by Colenutt of a finely preserved specimen has enabled the fruits formerly named Samaravectis ovalis to be placed in the genus Ranunculus. Carpolithus actinidiformis is almost certainly a species of Actinidia and has been referred tentatively to this genus but given no specific name. Hence there are altogether some 97 species listed including Dicotylophyllumpinnatifidum and 13 species of Carpolithus. Not all are named, while 15 unnamed species of Dicotylophyllum and an unnamed Phyllites (which would bring the numbers up to 113) are excluded from the number first mentioned above. Revised list of Bembridge Plants Excluding Charophyta. Localities as specified in systematic section. Family Genus and species Pteridophyta Filicales Polypodiaceae Acrostichum lanzaeanum (Visiani) Schizaeaceae Anemia sp. (? A. colwellensis Chandler) ? Lygodium sp. Filix Incertae Sedis 5 spp. 330 REVISION OF THE OLIGOCENE FLORAS OF THE ISLE OF WIGHT Family Hydropterideae Salviniaceae Equisetales Equisetaceae Gymnospermae Coniferales Araucarineae Abietineae Taxodineae Cupressineae Angiospermae Monocotyledones Typhaceae Sparganiaceae Potamogetonaceae Najadaceae Hydrocharitaceae Gramineae Cyperaceae Palmae Araceae Zingiberaceae Family ? Dicotyledones Juglandaceae Genus and species Azolla prisca Reid & Chandler Equisetum lombardianum Saporta Araucarites gurnardi Florin ? Pinus dixoni (Bowerbank) Pinus vectensis Gardner Pinus spp. (2 species) Pityospermum ambiguum Reid & Chandler Sequoia couttsiae Heer Cupressus sp. ? Libocedrus sp. Typha latissima Al. Braun Sparganium multiloculare Reid & Chandler Potamogeton pygmaeus Chandler Potamogeton sp. (formerly P. pygmaeus ?) ? Potamogeton spp. (2 species) Limnocarpus forbesi (Heer) Limnocarpus spinosus Reid & Chandler Naias oligocenica Reid & Chandler Ottelia britannica Reid & Chandler Stratiotes neglectus Chandler Genera (3 species at least) Carex gurnardi Reid & Chandler Carex sp. Cladiocarya foveolata Reid & Chandler Sabal major (Unger) Palmophyllum sp. Palaeothrinax mantelli Reid & Chandler Epipremnuml [or Raphidophora!~\ ornata Reid & Chandler ? Spirematospermum wetzleri (Heer) (or S. headon- ense Chandler) ? Costus sp. Genus ? Monocotylophyllum sp. Engelhardtia macroptera (Brongniart) Engelhardtia sp. Hooleya hermis (Unger) REVISION OF THE OLIGOCENE FLORAS OF THE ISLE OF WIGHT 331 Genus and species Carpinus sp. ? Fagus sp. ? Quercus sp. Celtis edwardsi n.sp. Ficus sp. Bmsenia ovula (Brongniart) Clematis vectensis Reid & Chandler Ranunculus heterostylus Reid & Chandler Ranunculus ovaliformis (Reid & Chandler) Cinnamomum lanceolatum (Unger) Neolitsea sp. Genus ? Papaver pictum Reid & Chandler Aldrovanda intermedia Reid & Chandler Zanthoxylum (?) costatum Reid & Chandler Zizyphus paradisiacus (Unger) var paradoxus ? Actinidia sp. Apocynospermum striatum Reid & Chandler Apocynospermum rostratum Reid & Chandler Apocynospermum elegans Reid & Chandler Apocynospermum dubium Reid & Chandler Phyllanthera vectensis Reid & Chandler Tylophora antiqua Reid & Chandler Melissa parva Reid & Chandler Ajuginucula smithi Reid & Chandler Catalpa rugosa Reid & Chandler Radermachera pulchra Reid & Chandler Incarvillea pristina Reid & Chandler Acanthus rugatus Reid & Chandler Abelia quadrialata Reid & Chandler Abelia quinquealata Reid & Chandler Abelia trialata Reid & Chandler Abelia sp.4 Dipelta europaea Reid & Chandler Genus ? Rhamnospermum bilobatum Chandler Flabellicula anglica Reid & Chandler Carpolithus spp.2-14 Dicotylophyllum pinnatifidum Reid & Chandler Dicotylophyllum spp.2-i6 Unknown leaf (Phyllites sp.) A reappraisal of this flora is now due having regard to facts and factors previously unknown or only partly recognized. As this is inevitably bound up with Family Betulaceae Fagaceae Ulmaceae Moraceae Nymphaeaceae Ranunculaceae Lauraceae Cruciferae Papaveraceae Droseraceae Rutaceae Rhamnaceae Dilleniaceae Apocynaceae Asclepiadaceae Labiatae Bignoniaceae Acanthaceae Caprifoliaceae ? Compositae Family ? Incertae Sedis 332 REVISION OF THE OLIGOCENE FLORAS OF THE ISLE OF WIGHT general considerations relating to the Eocene floras as a whole, the study of which is now nearing completion, it seems appropriate to defer the matter until the general discussion of these floras takes place in a forthcoming volume where the results of many years of work on fruiting organs in the Tertiary floras of Southern England will be summarized. (d) The Hamstead Beds The type locality for the Hamstead Beds (spelt Hempstead in older works) is the continuous cliff section at Hamstead and Bouldnor east of Yarmouth which is usually obscured in varying degrees by slipped material. The beds actually occupy a much wider area away from the cliff face, but there are virtually no exposures and in procuring information about the outcrop the Geological Survey officers have had to depend very largely on boreholes. The Hamstead Beds are now usually divided into a lower Freshwater and Estuarine Series with lagoonal deposits which yield a fauna of turtles, crocodiles and freshwater shells together with plant remains, and an upper, much thinner, Marine Series with a few plants in laminated clay near its base. These plants are chiefly the waterlily rhizomes and leaves named Nelumbium buchi from the so-called Waterlily Beds and a few palm leaves. In addition, masses of Brasenia, Stmtiotes and Rhamnospermum occur at more than one horizon in the Marine Series. There are a few other plants in the lower Estuarine Beds. A well- marked laminated carbonaceous clay called the "Black Band " has been adopted as the base of the Hamstead Beds. The separation here is in fact a matter of con- venience for there appears to be no real break between the lower Hamstead Estuarine and the underlying Bembridge Estuarine Beds in spite of some evidence of weathering between the two. Indeed Reid & Strahan state (1889 : 190) " Probably if the beds were now for the first time to be sub-divided, we should class the Bembridge Marls and the greater part of the Hamstead Beds together, and separate the marine beds as the commencement of a new series formed under different conditions." Neverthe- less, they continue, " though no palaeontological break occurs at the Black Band, it was so necessary to sub-divide the thick mass of clay above the Bembridge Lime- stone, that some marked and easily recognisable bed had to be traced. The Black Band proved to be the only horizon that could be followed, and that would give a satisfactory line from which to calculate dips and thicknesses". Almost all of the few plants so far known are either from the bed called the " White Band " or from the Waterlily Beds. A few species, collected by Colenutt, were in slipped material from an unspecified horizon but undoubtedly above the Black Band. Some specimens in older collections are labelled Lower, or Middle, Fresh- water Beds. These names originated with Forbes in the first edition of the Geological Survey Memoir (1856 : 39). Above the Black Band he subdivided the beds into a lower, middle and upper Freshwater Series with " Corbula Beds " above. He adopted the term " White Band " f or a " more or less consolidated, often highly ferruginous, band of mingled broken and entire shells, forming a white line in the cliff, and a white streak among the fallen and upturned beds on the shore " (Forbes, 1856 : 43) which he regarded as the junction between his Lower and Middle Freshwater Beds. As, however, the " White Band " has proved to be discontinuous the two horizons REVISION OF THE OLIGOCENE FLORAS OF THE ISLE OF WIGHT 333 cannot really be separated. Moreover, Forbes' Upper Freshwater Beds pass imper- ceptibly into the Corbula Beds and form together with them a single marine division which becomes more truly marine in passing upwards, Cerithium plicatum dying out gradually as Corbula increases in abundance. The Geological Survey Museum possesses Rhamnospermum and Stratiotes collected two feet below the White Band at Hamstead and Brasenia from the upper three feet of Forbes' Middle Freshwater Beds. The Nelumbium leaves and rhizomes of the Waterlily Bed are part impression and part actual carbonaceous substance now flaking away. Sequoia couttsiae may be carbonaceous entities or hollow casts in cementstone. The carbonaceous twigs if preserved in marl can be isolated by washing. This applies to the majority of plant remains which are carbonaceous fruits and seeds, but unfortunately all such are much pyritized and liable to decay. There are few but marsh or water plants known at all and virtually no information is available about the land vegetation of the period, only Sequoia, Sabal, Rubus and ? Ilex falling with any certainty into this category. The small plant list is given below. In addition Heer (1862) recorded leaves which he named Andromeda reticulata Ettingshausen, describing them as coriaceous and petiolate with reticulate nervation. These have not been included as the determination may need revision. List of Hamstead Plants Family Gymnospermae Coniferales Taxodineae Angiospermae Monocotyledones Typhaceae Sparganiaceae Potamogetonaceae Hydrocharitaceae Cyperaceae Palmae Dicotyledones Nymphaeaceae Rosaceae Leguminosae Droseraceae Aquifoliaceae Family ? Incertae Sedis Genus and species Sequoia couttsiae Heer Typha latissima Al. Braun ? Sparganium multiloculare Reid & Chandler Sparganium sp. Potamogeton tenuicarpus C. & E. M. Reid Limnocarpus forbesi (Heer) Stratiotes neglectus Chandler Stratiotes websteri (Brongniart) Stratiotes acuticostatus Chandler ? Caricoidea minima (Chandler) Sabal major (Unger) Brasenia ovula (Brongniart) Nelumbium buchi Ettingshausen Rubus sp. Genus ? Aldrovanda intermedia Reid & Chandler ? Ilex sp. Rhamnospermum bilobatum Chandler Carpolithus sp. (? Spirematospermum sp.) Carpolithus spp. 334 REVISION OF THE OLIGOCENE FLORAS OF THE ISLE OF WIGHT Among the Hamstead plants Sequoia couttsiae links the Beds with all earlier Tertiary horizons and with the Bovey Tracey lake basin further west. Its broken and battered remains suggest that it may have travelled a considerable distance. Species of Sabal and Rhamnospermum bilobatum also occur in older Tertiary beds and Limnocarpus forbesi in all down to at least the Bournemouth Marine stage. The water plants Potamogeton tenuicarpus, Stratiotes websteri and Brasenia ovula are also found at Bovey Tracey. Typha latissima, Sparganium multiloculare, Stratiotes neglectus, Aldrovanda intermedia occur in the underlying Bembridge Beds, Caricoidea minima, Nelumbium buchi in the Lower Headon of Hordle, the latter also in the Osborne Beds. Stratiotes acuticostatus has not yet been recorded at any other horizon. It is clear that up to date there are virtually no characteristics known by which the flora of the Hamstead Beds can be unmistakably distinguished but the most sig- nificant species appear to be Stratiotes websteri, S. acuticostatus and Potamogeton tenuicarpus which here appear for the first time. (e) Horizon ? Locality Headon Hill (in ironstone). Icacinaceae Stizocarya sp. As always my debt to others is great and I acknowledge, although inadequately, much help received from my friends and colleagues Dr. K. I. M. Chesters and Mr. F. M. Wonnacott in the preparation of this manuscript. SYSTEMATIC DESCRIPTIONS a i The Upper Headon Beds All material from Colwell Bay, Isle of Wight. PTERIDOPHYTA Order FILICALES Family SCHIZAEACEAE Genus ANEMIA Swartz Anemia colwellensis Chandler 1955 Anemia colwellensis Chandler, p. 304, pi. 35, figs. 39, 40, 42-53 ; pi. 36, figs. 59-64; text-fig. 2, i. The species was fully described and illustrated in the above work. The solitary pinnule fragment yielded sporangia and spores. Slides .31519-23 were figured in 1955. There are a few unfigured slides : .42034-35 show fragments of sporangia, .42036 shows also fragments of annulus and paraphyses. .42037 paraphyses, .42033 annulus and spores. The pinnule fragment came from the lowest Upper Headon Beds between Brambles and Linstone Chines. REVISION OF THE OLIGOCENE FLORAS OF THE ISLE OF WIGHT 335 GYMNOSPERMAE Order CONIFERALES Family ARAUCARINEAE Genus ARAUCARITES Presl, 1838 : 203 ? Araucarites gurnardi Florin (PI. 27, figs, i, 2 ; Text-fig, i) 1926 Doliostrobus sp. (Araucarites gurnardi ?) Reid & Chandler, p. 52, pi. 2, figs. 17, 18. DESCRIPTION. The upper (distal) part of a broadly oval cone-scale closely com- parable in form with scales from the Bembridge Beds but somewhat smaller. Length of scale incomplete ; maximum breadth (almost perfect), 6 mm. ; maximum thick- ness, 1-25 mm. (Length and breadth of Bembridge scales, n mm.) Form of base not seen ; apex with short conical mucro (? shortened by abrasion). Dorsal surface with conspicuous transverse projection about 2 mm. below the tip of the mucro, producing a facet between mucro and ridge which no doubt formed the " escutcheon " at the surface of the cone (PI. 27, fig. i) . Ventral surface with only a slight transverse ridge FIG. i. ? Araucarites gurnardi Florin. Diagrammatic longitudinal section of a scale perpen- dicular to the ovuliferous surface. about 1-25 mm. below the tip of the mucro (PI. 27, fig. 2). Beyond the ridges the distal end of the scale is smooth on both sides. Below the ridges the surfaces are longitu- dinally striate. There is a smooth marginal rim at the distal end on each side of the mucro along which the cells are aligned parallel with the margin, but elsewhere in this region of the scale there appear to be longitudinally elongate cells on the dorsal surface producing longitudinal striations, but the structure is much obscured by sand- pitting. Similar longitudinal striations are particularly conspicuous on the dorsal surface over the limb of the scale below the projecting ridge. On the ventral surface the cells are transversely aligned over the ridge, but immediately below it they are equiaxial, rounded and coarse (bordered pits ?), about 0-016 to 0-025 mm - in maximum diameter. Beyond, on the limb below the ridge on this surface they are rectangular oblong, narrow and small, often sunken but with raised walls. REMARKS. The scale (.43780) shows the characters of Araucarineae and agrees with Araucarites. It so closely resembles scales from the Bembridge Beds (Reid & Chandler, 1926 : 52, pi. 2, figs. 17, 18) named Doliostrobus sp. (Araucarites gurnardi ?) that in spite of its somewhat smaller size there can be little doubt that they belong to a single species. Comparable differences in size occur among scales of living Agathis and Araucaria and in the fossil form, Doliostrobus sternbergi Marion (1888), the size depending on the position in the cone. The Bembridge scales were not 336 REVISION OF THE OLIGOCENE FLORAS OF THE ISLE OF WIGHT referred definitely to Araucarites gurnardi (Reid & Chandler, 1926 : 48, pi. 2, figs. 6-19) because they were not in organic continuity with the foliage so named present on the same blocks of matrix. On the grounds of generic similarity reference was made to Marion's genus Doliostrobus from Alais where cones and cone-scales were in organic continuity with foliage of Araucarites type. In the light of further experience notably with associated foliage and a cone-scale at Selsey (Chandler, 19610 : 23, pi. 4, figs. 1-5 ; pis. 5, 6) it now appears reasonable to name the Bembridge scales Araucarites definitely and regard them as belonging to the foliage A. gurnardi, the similar scale from Colwell being placed in this species also. The cone-scales of A. gurnardi differ both from A. selseyensis and Doliostrobus sternbergi in their less attenuated base, less elongate form and in the shorter less parallel-sided mucro although it is possible that the mucro of A . gurnardi may have suffered some reduc- tion by abrasion. Further the angle of inclination of the distal margins of the scale is not so sharp as in A. selseyensis or Doliostrobus. There now appears to be little or no doubt that Doliostrobus sternbergi should also be regarded as an Araucarites. Family TAXODINEAE Genus SEQUOIA Endlicher Sequoia couttsiae Heer (PL 27, figs. 3, 4) 1962 Sequoia couttsiae Heer : Chandler, p. 20, pi. 4, figs. 1-32; text figs. 1-6. See also for earlier references. Typical small twig tips which occasionally yield fragments of cuticle occur with a fair degree of frequency. They and their cuticles, also cone-scales and seeds were described and figured among material from other horizons by Chandler (1962 : 20, pis. 1-3 ; pi. 4 , figs. 1-32 ; text-figs. 1-6). A few twigs bear small tufts at their extremities which appear to be male cones (.43781-82). They are embraced by two falcate leaves the whole giving a subtriangular outline (PL 27, fig. 3). Within these basal leaves are branched structures with feathery extremities (slide .44841). On maceration in nitric acid they become somewhat translucent and are seen to bear elliptical anthers with large gaping mouths (PL 27, fig. 4) from which pollen could be obtained. The seeds are much pyritized, frequently with a curved seed-body. Some have split marginally, as for germination, into two equal valves. The wings are commonly battered and frayed and the surface is usually rather poorly preserved. Many specimens were collected between Brambles and Linstone Chines (.43783-84). The male cones were found between Colwell and Brambles Chines. Family ABIETINEAE Genus PIN US Linnaeus Pinus sp. (PL 27, fig. 5) DESCRIPTION. Seed : Sub-obovoid, somewhat compressed and bisymmetric, apparently dehiscing for germination into two valves. One margin of the seed is REVISION OF THE OLIGOCENE FLORAS OF THE ISLE OF WIGHT 337 convex, the other has a sigmoidal curvature near the narrow end which gives rise to a slightly curved beak. Micropyle at tip of beak. One surface of seed perfect, flat, with narrow elongate cells arranged in parallel groups. The cell groups are variously oriented producing a complicated pattern, as in many species of Pinus, on the side of the seed covered by the wing, i.e. the uppermost side as it lay on the cone- scale. These cells are about 0-7 mm. long, 0-007 to 0-009 mm - broad, they show single lines of pits about 0-006 to o-oo8mm. in diameter which give a finely toothed effect where they abut against the cell walls. The ends of the cells are often rectangular. Opposite lower surface of seed convex, now incomplete, this valve has been broken longitudinally in fossilization so that two-thirds of its breadth are missing and one- third adheres to the other valve along the natural suture plane. The suture plane of the opposite margin has been exposed where the valve separated and shows cells aligned parallel with its outer edge. The broken edge of the imperfect valve is formed of broad cells about 0-076 by about 0-038 mm. aligned at right angles to the surface (seen at c in PI. 27, fig. 5). Length of seed, 4-5 mm. ; breadth, 2-2 mm. ; thickness (not quite complete), 0-75 mm. Wing only preserved as a few decayed patches of tissue on the flat upper surface of the seed. REMARKS. The form and cell structure indicate the genus Pinus. The living P. breweriana resembles it in form and size but the cell structure of the upper surface is simpler. Many species of Pinus show the complex arrangement of wing cells seen in the fossil. Seed ( .43785) , preserved in soft pyrites mud, from between Brambles and Linstone Chines. ANGIOSPERMAE Class MONOCOTYLEDONES Family POTAMOGETONACEAE Genus POTAMOGETON Linnaeus Potamogeton pygmaeus Chandler (PI. 27, figs. 6-8) 19616 Potamogeton pygmaeus Chandler : Chandler, p. 103, pi. 24, figs. 3-6. See also for earlier references. The species has been fully described from the Lower Headon of Hordle, Hants., and the Bembridge Beds, Isle of Wight. It is also now recorded from the Bourne- mouth Marine Beds and Bournemouth Freshwater Beds (one only) (Chandler, in press) . The Upper Headon of Colwell has yielded the most beautifully preserved car- bonaceous endocarps yet seen, many showing the spine bases so often abraded in other material. The style, terminal on the ventral margin, is shown in PI. 27, figs. 6, 7 and the median ventral spine in PL 27, fig. 6. Spine bases on keel can be seen in PL 27, figs. 6, 7 the long slender tips being broken. Perfect spines have only been found as impressions in the Bembridge Insect Limestone (Reid & Chandler, 1926, pi. 3, fig. 21). GEOL. 6, 3. 24 338 REVISION OF THE OLIGOCENE FLORAS OF THE ISLE OF WIGHT The hyaline testa of the curved seed remains within the Colwell endocarps. The endocarps show externally the typical regular quadrilateral cells aligned parallel with the curvature. The great variation in size is noticeable and the slender form with large gap between the limbs is clearly visible in abraded material as the exocarp is almost invariably missing. The germination valve, crested medianly longitudinally, normally carries its spine bases but in some crushed specimens (PL 27, fig. 8) these are inconspicuous. These particular specimens are of unusual appearance as they are internal casts with only adherent remains of endocarp somewhat obscured by sand. Owing to compression the thickened limbs appear to lie closer together than in more normally preserved endocarps the gap between them being partly obliterated. These specimens lay on a flat bedding plane in beds with Potamomya and were associated with casts of Ostracods. The endocarp figured in PL 27, fig. 8 has been removed from its matrix. It and .43789-91 are from beds between Brambles and Linstone Chines, .43792 in folded beds near Fort Victoria boundary fence. The other figured specimens were below the sewer trench at Linstone Chine. Genus LIMNOCARPUS Reid emend. Reid & Chandler, 1926 : 68 Limnocarpus forbesi (Heer) (PL 27, figs. 9, 10) 19610 Limnocarpus forbesi (Heer) : Chandler, p. 28, pi. 7, figs. 22-24. See also for earlier references. 19616 Limnocarpus forbesi (Heer) : Chandler, p. 104, pi. 24, figs. 7-11. Endocarps of this species are among the common plants of the Upper Headon Beds. The specimens are exactly comparable in character with those from the Lower Headon at Hordle and there is nothing to add to previously published descrip- tions of the species. However, unlike the Hordle specimens, the Colwell endocarps are commonly pyritized in the same manner as are the Zanthoxyleae (p. 349). The soft amorphous pyrites has replaced the carbonaceous tissues, reproducing their form exactly, but it readily smears and on drying expands and cracks with resulting disintegration of the specimens. As at Hordle these water plants must have formed dense masses probably of floating weed growing in lagoons and stagnant channels of water. In addition to the figured specimens there are .43796-97 from beds between Brambles and Linstone Chines and .43798 from folded beds near the Fort ictoria boundary fence. Also 52898 Toulmin Smith Coll. 1877 " shale bed with seeds " which may be Upper or Lower Headon. Szafer (1961 : 172, pi. 22, figs. 16-21) has recently described a Ruppia (R. maritima L. var. miocaenicd) with a strongly papillate or rugose surface from the Miocene flora of Stare Gliwice, Poland. It bears some resemblance to Limnocarpus forbesi but is clearly a Ruppia rather than a Limnocarpus. He regards it as differing only from the living Ruppia maritima in its more papillate fruits. In the same work (1961 : 174, pi. 22, figs. 23-26) he also described a larger slightly papillate species Ruppia major. He considers it to be related to Limnocarpus. If so it is more closely akin to L. ? enormis (Chandler, 19610; : 29, pi. 7, figs. 25-33) tnan to L. forbesi, but L. ? enormis is even larger and belongs to Limnocarpus rather than to Ruppia. REVISION OF THE OLIGOCENE FLORAS OF THE ISLE OF WIGHT 339 Family HYDROCHARITACEAE Genus S TR A TIOTES Linnaeus Stratiotes headonensis Chandler (PL 27, figs. 11-19) 19616 Stratiotes headonensis Chandler : Chandler, p. 104, pi. 24, fig. 17. See also for earlier references. The species has been so fully described in 1923 and 19616 that it is unnecessary to repeat the information which is equally applicable to the new material from the Upper Headon of Colwell. Thus Stratiotes headonensis now ranges from the top of the Barton Beds to the Upper Headon. Typical Upper Headon specimens are illus- trated (PL 27, figs. 11-14) while seeds from the Lower Headon of Hordle are figured for comparison (PL 27, figs. 16-19). In addition to figured Colwell material there are .43804 from beds between Brambles and Linstone Chines ; .43805 in sand and clay south of Linstone Chine above the Oyster Bed ; .43806 from folded beds close to Fort ictoria boundary fence. One box of seeds labelled " Bembridge Series " certainly belongs to 5. headonensis but is probably from Colwell. Family CYPERACEAE Genus CAREX (Dill.) L. Carex colwellensis n.sp. (PL 28, figs. 26, 27) DIAGNOSIS. Endocarp triangular with obovate facets, of which the greatest breadth lay at about the middle. Surface cells with raised walls and central papillae. Length of cells variable, some equiaxial, breadth from o-oi to 0-016 mm. Length of endocarp, 1-5 mm. ; breadth, 0-75 by 0-5 mm. HOLOTYPE. .43808. DESCRIPTION. Endocarp : Three-angled, three-sided, each facet being obovate. One facet somewhat narrower than the other two. Greatest breadth at about the middle. Style patent very shortly trifid (worn). Splitting tends to occur along the angles starting at the base. Surface formed of somewhat elongate cells with slightly raised walls some of which show remains of a raised central papilla. Margins of cells very finely toothed. Length of cells variable some being equiaxial, breadth about o-oi6mm. at the middle of the endocarp, o-oi mm. near the apex. Length of endocarp 1-5 mm. including style base ; breadth, 0-75 by 0-5 mm. REMARKS. A typical triangular Carex. The most comparable living species seen wereCarexflava and C. oederi, both of which have smaller and more rounded surface cells. The solitary specimen is so beautifully preserved as to be " recent " in appear- ance but its pyritized condition established it as a genuine fossil. Round black patches on the surface suggest pustules due to fungus. From beds between Brambles and Linstone Chines. 340 REVISION OF THE OLIGOCENE FLORAS OF THE ISLE OF WIGHT Carex sp. (PI. 28, figs. 20-25) DESCRIPTION. Endocarp : Obovate in outline with one surface flat and the other slightly inflated at the middle with an obscure median longitudinal angle flanked by two facets. All now much compressed so as to be nearly flat. The greatest breadth is at about three-quarters of the length from the base. Apex rounded, style obscure (? due to abrasion). Surface formed of polygonal or hexagonal, somewhat elongate, longitudinally aligned cells about 0-016 to 0-025 mm - broad. The cells have slightly raised walls. One perfect endocarp was 1*3 mm. long, 0-8 mm. broad. Another endocarp (slightly imperfect at the base) was 1-3 mm. long, 0-75 mm. broad. Only one (.43807) is still extant owing to their poor condition on discovery. All from beds between Brambles and Linstone Chines. Genus SCIRPUS (Tourn.) L. ? Scirpus sp. (PI. 28, fig. 28) DESCRIPTION. Endocarp : Obovate, somewhat truncate at the base where there is a large aperture. Apex with stout stylar mucro about 0-2 mm. long. Surface orna- mented with about six rounded longitudinal ribs separated by deep sharp furrows. Coat forming ribs spongy, close-textured, of very minute cells having a tendency to produce transverse striations. Basal aperture closed by a small circular plug convex externally at its centre from which small cells radiate. Length of endocarp, 2 mm. ; breadth, I mm. REMARKS. The near relationship of this unique specimen (.43809) has not been conclusively established but it probably belongs to the group Caricoideae, or to Scirpoideae and perhaps to Scirpus as suggested by the basal aperture with plug and the apical mucro. It is quite distinct in the form of its rounded longitudinal ribs from Scirpus lakensis (Chandler, 1962 : 50, pi. 6, figs. 7-18) from the Lower Bagshot and Bournemouth Freshwater Beds and from Cuisian Beds in the Selsey Peninsula (Chandler, 19610 : 18, 33). Genus CARICOIDEA Chandler, 1957 : 86 Caricoidea (?Cladium) colwellensis n.sp. (PI. 28, figs. 31-35) DIAGNOSIS. More or less bisymmetric oburceolate endocarp resembling Cladium in form but having a plate-like expansion at the base of the neck, sometimes split radially in line with two longitudinal ridges in the plane of symmetry. Surface with irregular low rugosities. Length of endocarp, 1-5 to 2-25 mm. ; breadth, I to 1-75 mm. HOLOTYPE. .43810. DESCRIPTION. Endocarp : Oburceolate with marked apical mucro, conspicuous contracted neck spreading out below to form a circular plate-like base often broader than the endocarp itself. Approximately bisymmetric with rounded longitudinal REVISION OF THE OLIGOCENE FLORAS OF THE ISLE OF WIGHT 341 ridges extending from the mucro in the plane of symmetry on each side to the edge of the neck. Plate-like base sometimes indented or split radially along the line of these ridges forming in such specimens a pair of basal flanges rather than a plate (PI. 28, figs. 32, 34). Surface of endocarp covered with irregular low rugosities. Basal aperture small (PL 28, fig. 35). Rugose outer coat, about 0-15 to 0-2 mm. thick, formed of spongy hollow cells about 0-025 mm - m diameter. In section a thin coarsely columnar inner coat is seen about 0-025 mm. thick. Cavity lined by transversely oriented cells (testa of seed ?) which are finely toothed, the narrower diameter from top to bottom being about 0-016 mm. There is also a longitudinally striate layer with cell walls (striae) about 0-016 mm. apart. Dimensions of endocarps : i)Length, 1-7 mm. ; breadth, 1-5 mm. ; breadth of neck, 1-2 mm. 2) Length, 1-75 mm. ; breadth, i mm. ; breadth of neck, 1-2 mm. 3) Length, 1-5 mm. ; breadth, 1-15 mm. ; breadth of neck, 1-5 mm. 4) Length, 1-5 mm. ; breadth, i mm. ; breadth of neck, i-i mm. 5) Length, 1-75 mm. ; breadth, 1-25 mm. 6) One exceptionally large endocarp length, 2-25 mm. ; breadth, 1-75 mm. ; breadth of neck, 1-75 mm. REMARKS. The fruit (utricle) has not been seen. The endocarps obviously belong to Caricoideae and are closely related to and probably identical with Cladium. They differ from living representatives of this genus so far seen and from comparable fossil species in the irregular rugosities of the external surface and in the plate-like basal expansion of the neck. One specimen (now decayed) showed the basal expan- sion seated on a pillow-like receptacle. An expansion was present in a lesser degree in specimens from the Pliocene of Bidart (C. & E. M. Reid, 1915 : 424, pi. 7, fig. 30) and is developed in a peculiar way as a wide pierced plate with large foramina in Cladium reidiomm Nikitin (in Dorofeev, 1958 : 172, pi. i, fig. 33 from the Oligocene of Western Siberia ; 1959 : 168, pi. 3, figs. 9-11, from the Miocene of the Rostov Region) and in a slightly lesser degree in Cladium macrocarpum Dorofeev and C. europaeum Dorofeev from the Tertiary of Byelorussia (Dorofeev, 1960 : 1428, pi. 3, figs. 7-12). The apical mucro is very well developed also the longitudinal ribs. While therefore they may belong to Cladium it seems better until information about the fruit is forthcoming to refer them only provisionally to Cladium leaving them for the present in the form-genus Caricoidea. Szafer (1961 : 90, pi. 24, figs. 17-23) refers endocarps of this type without hesita- tion to Cladium mariscus R.Br.,/oss. They came from the Miocene of Stare Gliwice, Poland. In addition to the figured material there are .43813-14. All were found between Brambles and Linstone Chines. One endocarp (decayed) was from the folded beds near the Fort Victoria boundary fence. Caricoidea maxima Chandler (PI. 28, figs. 36-40) 1960 Caricoidea maxima Chandler, p. 207, pi. 31, fig. 35. EMENDED DIAGNOSIS. Fruit obovoid or truncate subovoid with deep depression in the truncate base. Length of fruit, 3-2to 4-25 mm. ; greatest breadth, 2-25 to 3-25 mm. Endocarp subglobular or shortly oburceolate, with or without apical mucro, with short basal neck and two opposite longitudinal ridges. Length of endocarp, 1-5 to 2 mm. ; breadth, 1-4 to 2 mm. SYNTYPE. .43815. DESCRIPTION. Fruit : Obovoid to truncate subovoid frequently somewhat flattened laterally, with basal truncation which is pierced by a large subcircular or circular opening. Obtusely pointed at the apex. Surface always abraded as no specimen has been seen showing the outer shining epidermal layer. Wall woody, up to at least 0-6 or 0-7 mm. thick, close-textured, formed of equiaxial cells about 0-022 mm. in diameter. Length of fruit, 3-2 to 4-25 mm. ; greatest breadth, 2-25 to 3-25 mm. Endocarp : Usually situated nearer to the apex than the base within the thick woody fruit. Shortly oburceolate or subglobular sometimes with small apical mucro. Basal aperture with neck which may be very short and is closed by a plug. Aperture opening into a short canal in the fruit wall leading to its basal opening. Surface close-textured, finely pitted, pits 0-012 to 0-016 mm. in diameter, with two longitudi- nal opposite external ridges. Formed, as seen in section, of a thin outer layer with obscure structure and an inner columnar coat which is about 0-23 mm. thick. Lining layers much decayed but showing traces of horizontally aligned digitate cells. Length of endocarp, 1-5 to 2-2 mm. ; breadth, 1-4 to 2 mm. REMARKS. One fruit and two detached endocarps, all figured. Two other figured specimens have now decayed. The species was based on a fruit from the Hengistbury Beds (reference given above), but information about the endocarp is now available for the first time. The diagnosis is therefore expanded. Caricoidea maxima resembles C. minima from the Lower Headon of Hordle, but the fruit is considerably larger and the endocarp is larger and more subglobular. It may also be present at Hordle as a similar specimen was seen there, but unfortunately it decayed before it could be described. ? Caricoidea angulata Chandler (PI. 28, figs. 41, 42) Caricoidea angulata Chandler (in press), p. 66, pi. 9, figs. 1-23; text-fig. 12. DESCRIPTION. Fruit : Not seen. Endocarp : Detached from fruits. Body of endocarp narrowing gradually or more suddenly to form a basal neck, apex narrowed to a mucro, well marked in some better preserved specimens (PI. 28, fig. 41) abraded in others (PI. 28, fig. 42). Surface abrasion makes it difficult to see the regular even pitting characteristic of Cariocoidea angulata. Dimensions of endocarps : i) Length, 1-5 mm. ; breadth, 1-25 mm. 2) Length, 17 mm. ; breadth, 1-3 mm. 3) Length, 1-75 mm. ; breadth, 1-3 mm. REMARKS. In addition to two figured specimens, there are .43820-23 all from between Brambles and Linstone Chines. In the absence of evidence about the fruit and in view of the abraded condition the determination of the species is provisional, but the size agrees with that of C. angulata and the endocarps are smaller than those of C. maxima and larger than those of C. obscura. REVISION OF THE OLIGOCENE FLORAS OF THE ISLE OF WIGHT 343 ? Caricoidea obscura Chandler (PI. 28, figs. 29, 30) 1960 Caricoidea obscura Chandler, pp. 207, 223, pi. 30, figs. 27-33 ; pi. 33, figs. 98-105. 19610, Caricoidea obscura Chandler : Chandler, p. 33, pi. 7, fig. 34. 19616 Caricoidea obscura Chandler : Chandler, p. 106, pi. 24, figs. 22-24. 1962 Caricoidea obscura Chandler : Chandler, p. 52, pi. 6, figs 20-33 ' text-fig. 9. Caricoidea obscura Chandler : Chandler (in press), p. 65, pi. 8, figs. 42-56. DESCRIPTION. Endocarp : Oburceolate narrowing gradually to a mucronate apex and contracting suddenly to a narrow basal neck. Some specimens show a pair of longitudinal ribs. Outer surface smooth (although sometimes rough secondarily through decay in fossilization) showing traces of very fine cells and pitting. Wall in section about o-i mm. Locule lining obscure. Dimensions of endocarps : i) Length, 1-25 mm. ; breadth, 1-05 mm. 2) Length, 0-9 mm. ; breadth, 0-8 mm. 3) Length, i mm. ; breadth, 0-9 mm. 4) Length, I mm. ; breadth, 0-8 mm. 5) Length, 0-9 mm. ; breadth, 0-75 mm. REMARKS. The small size of these isolated endocarps suggests Caricoidea obscura but as the fruits have not been seen the determination is provisional. Endocarps from the Lower Headon of Hordle are equally small. Those from the Lower Bagshot are slightly larger. The Highcliff Sands specimens are closely comparable in size although some are relatively broader. In addition to two figured endocarps there are .43825 and .43827, all from between Brambles and Linstone Chines and .43828 an endocarp in folded beds close to Fort ictoria boundary fence. Family CYPERACEAE Genus ? (PI. 28, figs. 43, 44) DESCRIPTION. Fruit : Rounded elongate triangular in outline, apex broken, sides tapering gradually to the base which is somewhat blunt. Probably originally more or less pointed at the apex. The fruit may have been triangular in transverse section with one broad facet occupying the whole breadth and two narrow ones meeting in a longitudinal angle having a groove along its crest. External surface longitudinally striate, between the striae are lines of equiaxial cells about o-oi mm. in diameter. Internal surface where exposed by splitting on drying showing conspicuous transverse alignment of cells. Length of fruit, 2-2 mm. ; breadth, i-i mm. No endocarp has been seen. REMARKS. Cell structure and form suggest Cyperaceae and possibly Car ex but in view of the poor condition and the fact that there is only one specimen (.43829) it appears inadvisable to make more than a tentative reference to the family. .43830 is a small triangular endocarp belonging to the family Cyperaceae but it is unlike other species described. 344 REVISION OF THE OLIGOCENE FLORAS OF THE ISLE OF WIGHT Class DICOTYLEDONES Family MYRICACEAE Genus MYRICA Linnaeus Myrica boveyana (Heer) pars (PI. 29, figs. 45-48) i862a Carpolithus boveyanus Heer, p. 1077, pi. 70, figs. 7-14 (in part). 1957 Myrica boveyana (Heer) pars Chandler, p. 90, pi. 12, figs. 45-48. 19616 Myrica boveyana (Heer) pars : Chandler, p. no, pi. 25, figs. 33, 34. DESCRIPTION. Endocarp : Bisymmetric, germinating by splitting into equal valves in the plane of symmetry, oval in outline, somewhat compressed at right angles to the plane of symmetry. Outer surface with obscure rugosities over the central area, very slightly flattened around the margin. A few superficial fibres have a general longitudinal arrangement, some appear to enter the thickness of the endocarp near a small basal scar. Locule, as revealed on inner surface of valve after germination, urceolate in outline tapering into an apical stylar canal ; suture about 0-6 mm. broad, flat. Base with short funicular canal still carrying a fibre. Cells of locule lining diverge from style and funicle ; locule longitudinally striate, the striae due to elongate polygonal cells which appear to have finely toothed walls, largest at the middle of the endocarp where they may be 0-05 mm. long and 0-027 mm. broad. Length of endocarp, 3*75 mm. ; breadth, 3-1 mm. ; thickness, 2-25 mm. Second specimen (represented by one, slightly imperfect, much abraded valve): length, 3-25 mm. ; breadth, 2-75 mm. ; thickness (estimated), 2 mm. Small endocarp : length, 2-5 mm. ; breadth, 1-75 mm. (.43833). REMARKS. The endocarps are comparable with those from Bovey Tracey but are larger than the Hordle specimens. From between Brambles and Linstone Chines. Myrica? colwellensis n.sp. (PI. 29, figs. 49-55) DIAGNOSIS. Endocarp subovoid with about six regular low rounded external longitudinal ribs on each valve separated by sharp furrows which carry fibres. Length of endocarp about 2-8 to 3 mm. ; breadth about 2 to 2-5 mm. HOLOTYPE. .43834. DESCRIPTION. Endocarp : Bisymmetric, germinating by splitting into two valves in plane of symmetry. Subovoid but somewhat compressed at right angles to the plane of symmetry, having a slight basal mucro and evenly rounded apex. Ex- ternal surface with about six regular low rounded ribs on each valve with a longitu- dinal fibre in each of the sharp furrows between them. The fibres extend almost from the basal attachment scar to the apical style. Locule compressed urceolate, narrowed to the stylar canal, having a short funicular canal at the base. Suture plane 0-4 to 0-5 mm. broad near the base. Locule lining of finely toothed more or less equiaxial cells about 0-05 mm. in diameter. Texture of wall compact. Length of endocarp, 2-8 mm. ; breadth, 2 mm. REVISION OF THE OLIGOCENE FLORAS OF THE ISLE OF WIGHT 345 REMARKS. The holotype is represented by its two separated valves one slightly imperfect. There is also a single abraded valve of another slightly larger specimen (.43836) and the basal end of one valve of a third broader endocarp (.43835), .43837 is a broken and unfigured valve. The reference of this species to Myrica must be regarded as doubtful, but on the whole the resemblance is greater than to Carpinus which has a similar compressed urceolate locule. Carpinus may show uneven fluting of the surface as in C. betulus but not regularly longitudinal lobing, while the well marked fibres always overlie longitudinal ridges not the intervening furrows as in the fossil. The form of the endocarp in Carpinus is pointed ovate not a regular oval in outline. All specimens are shrunken and diminished in size through drying. Position of placenta not clear. Family MORACEAE Genus FICUS Tourn. Ficus lucidus Chandler (PI. 29, fig. 56) 1962 Ficus lucidus Chandler, p. 58, pi. 7, figs. 13-18 ; text-fig, n. Ficus lucidus Chandler : Chandler (in press), p. 76, pi. u, figs. 13-15. DESCRIPTION. Carpel : Subovoid originally, now crushed, both diameters being increased thereby. The carpel has burst and split marginally at the stylar end. Surface formed of minute equiaxial cells. Length, 1-5 mm. ; breadth, 1-25 mm. as crushed. REMARKS. The single specimen (.43838) from beds between Brambles and Lin- stone Chines is identical in general morphological characters and cell structure with better preserved material from the Dorset Pipe-clay Series and the Bournemouth Beds (references above). Order CENTROSPERMAE Family ? Genus ? (PI. 29, fig. 57) DESCRIPTION. Seed : Small curved, transversely oval in outline, with asymmetric- ally placed marginal hilum between the unequal limbs marked by a small projection. Surface smooth apparently formed of somewhat obscure digitate cells with few digitations, the cells about 0-027 mm - m diameter. Dimensions of seed, 0-9 by 0-75 mm. REMARKS. The form and digitate cells suggest Centrospermae, possibly even Caryophyllaceae, but the material is too poor and limited for further determination. The seed has begun to split starting at the hilum and in a direction between the limbs. The solitary specimen, .43839 came from beds between Brambles and Linstone Chines. Family NYMPHAEACEAE Genus BRASENIA Schreber Brasenia ovula (Brongniart) (PI. 29, figs. 58, 59) 1926 Brasenia ovula (Brongniart) Reid & Chandler, p. 99, pi. 6, figs. 15-18. See also for earlier references. 1957 Brasenia ovula (Brongniart) : Chandler, p. 96, pi. 13, fig. 75. 19616 Brasenia ovula (Brongniart) : Chandler, p. 116. The species is one of the commonest plants in the Lower Headon of Hordle and the Isle of Wight and successive beds of the Oligocene in the Isle of Wight and at Bovey Tracey. It usually occurs in seams blackened by its seeds and some of the seed-beds mentioned by Reid & Strahan (1889) are made up almost exclusively of these seeds. As in all localities where Brasenia ovula occurs there is very great variation in shape and size. The species is too well known for further description to be necessary as all previous accounts are equally applicable to the Upper Headon material. In addition to figured material which comes from beds south of Brambles Chine, there are seeds from between Brambles and Linstone Chines (.43842) and from folded beds close to Fort Victoria boundary fence (.43843). Genus ? (?Brasenia ovula) (PI. 29, fig. 62) DESCRIPTION. Seed : Crushed dorsiventrally so that the original form is obscured but the slightly conical embryotega is clearly seen with its central micropylar aper- ture. The embryotega is about 0-6 mm. in diameter. Its limits as it lies in the testa are rather obscure since it has not begun to separate from the surrounding tissues. Its cells are radially aligned around the central aperture, largest at the circum- ference where they are about 0-05 mm. in diameter, convex with rounded outlines having a slight tendency only to be sinuous. Surface of seed itself formed of digitate cells like those of Brasenia ovula with few (about five or six) digitations which are short and rounded. Each cell is somewhat convex superficially and the alignment is in longitudinal rows diverging from the embryotega. The cells show signs of separa- ting from each other perhaps as a result of crushing. They are coarser than those of typical B. ovula and more inflated, the larger ones about o-i mm. in diameter. Tegmen translucent. Diameter of crushed seed, 3 by 2-6 mm. REMARKS. The large seed falls within the range of size of Brasenia ovula. Its peculiar apperance may be the result of crushing, but it has been related to this species only provisionally. .43852 from between Brambles and Linstone Chines. Brasenia spinosa Chandler (PI. 30, figs. 63-69) 19616 Brasenia spinosa Chandler : Chandler, p. 117. See also for earlier references. DESCRIPTION. Seed : Subglobular to ovoid, anatropous with circular aperture at one end, often gaping but sometimes closed by an embryotega. External surface REVISION OF THE OLIGOCENE FLORAS OF THE ISLE OF WIGHT 347 with rounded longitudinal ridges sometimes corresponding with lines of cells and with rows of sporadic tubercles which may be blunt, short and rounded or longer and spiney. They are frequently broken. Tubercles may arise from the centre of a digitate cell 0-05 to o-i mm. in diameter although not every cell bears a tubercle. Sometimes the tubercles or rugosities are not related to the cell outlines but cover several cells. The longitudinal ridges may be partly the result of contraction on drying. Testa tending to break along the digitate outlines. A more conspicuous rounded longitudinal ridge marks the raphe. Testa about 0-15 mm. thick in section. The embryotega is convex externally with large median rimmed micropyle. It is formed of rectangular or square thick walled cells which sometimes appear slightly sinuous. They are about 0-05 mm. in diameter. Tegmen thin, translucent, yellowish finely striate. Dimensions : Length, 1-25 to 2-5 mm. ; breadth, I to 2 mm. REMARKS. The Upper Headon specimens fall approximately within the range of size of Brasenia spinosa from the Lower Headon of Hordle, a few seeds of which are here shown for comparison (PI. 30, figs. 64, 65, 67-69). Those in figs. 67-69 are small specimens with coarse tubercles which were originally separated as a distinct species B. antiqua. However, it later appeared that the two varieties, one with spiny tubercles, the other with short thick tubercles graded into one another so that they could not be separated (Chandler, 19616 : 117). On the whole the Lower Headon seeds tend to be smaller. Thus dimensions of B. spinosa from Hordle were originally given as 1-5 by 1-5 mm. and of B. antiqua as i by 0-75 to i mm. Recent measurements of Hordle seeds give length, i to 2-25 mm. ; breadth, 2-25 by 2-25 mm. In addition to figured material there are .43846-47, .43849 from between Brambles and Linstone Chines and .43848 from south of Linstone Chine. Genus NYMPHAEA (Tourn.) L. Nymphaea sp. (PI. 29, figs. 60, 61) DESCRIPTION. Seed : Ellipsoid, very slightly truncate at the hilar end where the burst aperture for a small embryotega can be seen. Embryotega present but obscure in .43850, the aperture not more than 0-3 to 0-4 mm. in diameter. Anatropous, the longi- tudinal raphe forming a slight ridge from base to apex. Surface of seed obscurely longi- tudinally ridged, the ridges lying along the junctions of longitudinal rows of digitate cells with interlocking claws which may be lobed or forked at their extremities. These cells, which are also aligned in distinct transverse rows, are often transversely elongate but sometimes equiaxial. They are about 0-05 to 0-15 mm. in diameter. The hilar end of the seed around the embryotegal aperture has distinct radially arranged crumples. A few fine sharply pointed tubercles are seen along the ridges closely adpressed to the surface. Length of seed, 275 mm. ; breadth, 1-25 to 1-5 mm. REMARKS. The two figured specimens are the actual carbonaceous seeds them- selves. An internal cast in pyrites of a third specimen has now decayed. On it the regularly arranged digitate cells were formerly beautifully preserved as impressions with shorter, more rounded swollen-ended digitations. The whole surface of the pyrites cast also showed rounded cells about 0-008 mm. in diameter, perhaps the 348 REVISION OF THE OLIGOCENE FLORAS OF THE ISLE OF WIGHT replacement of albumen cells. The elliptical aperture from which the embryotega had disappeared was represented by an impression with maximum diameter of about 0-03 mm. There is some resemblance to Brasenia oblonga Chandler from the Lower Headon of Hordle but these Colwell seeds have a more ellipsoid form, larger size and less regular tubercles. Form and arrangement of the surface cells appear to ally them with Nymphaea. Family DROSERACEAE Genus ALDROVANDA (Monti) L. Aldrovanda ovata (Chandler) (PL 30, figs. 70, 71) 19616 Aldrovanda ovata (Chandler) : Chandler, p. 119, pi. 26, figs. 53-55. See also for earlier references. DESCRIPTION. Seed : Oburceolate with a narrow neck about one-sixth to one- seventh of the length of the whole seed, closed by a circular plug having a central thick short mucro from which the small convex equiaxial cells of its outer surface radiate. Anatropous with conspicuous longitudinal raphe ridge terminating in a marked mucro at the apex over the chalaza at one end and in the basal hilum on the margin of the neck at the other. Surface black, shining, testa formed of two coats, an outer coat 0-05 to O'imm. thick, of radially arranged cells as seen in section whose slightly inflated outer ends give rise to flat or scarcely convex equiaxial cells about o-ooimm. in diameter on the external surface. On the internal surface there are cells about 0-002 to o-oo3mm. in diameter. An inner coat, 0-15 mm. thick is formed by a single layer of radially arranged prismatic cells about 0-02 to 0-05 mm. in diameter. Dimen- sions of several seeds : i) Length, 1-75 mm. ; breadth, 1-35 mm. ; length of neck, 0-25 mm. 2) Length, 1-76 mm. ; breadth, 1-4 mm. ; length of neck, 0-3 mm. 3) Length, 1-9 mm. ; breadth, 1-25 mm. ; length of neck, 0-25 mm. 4) Length, 2 mm. ; breadth, 1-25 mm. ; length of neck 0-25 mm. 5) Length, 1-75 mm. ; breadth, 1-25 mm. ; length of neck, 0-25 mm. 6) Length, 2 mm. ; breadth, 1-25 mm. ; length of neck about 0-3 mm. Average length of seeds, 1-83 mm. ; average breadth, 1-28 mm. REMARKS AND AFFINITIES. About a dozen seeds and some fragments. They agree in every respect with Aldrovanda ovata (Chandler) from the Lower Headon of Hordle (ChancLler, 1925 : 22, pi. 3, fig. 30, b ; Reid & Chandler, 1926 : 113, pi. 4, figs. 24-26) in their large size, conspicuous apical mucro and marked raphe ridge, relatively long neck and smooth surface and thick testa, the two coats of which together measure nearly a quarter of the diameter of the seed. The characters which distinguish this species from A. intermedia Reid & Chandler (Bembridge and Hempstead) and A. vesiculosa'L. (Recent) were discussed by Reid & Chandler (1926 : 111-113). In addition to figured material there is .43855, all from below the sewer pipe, Linstone Chine, also .43856-57 from between Brambles and Linstone Chines, and .43858 in folded beds close to Fort Victoria boundary fence. REVISION OF THE OLIGOCENE FLORAS OF THE ISLE OF WIGHT 349 Family ROSACEAE Genus RUBUS (Tourn.) L. ? Rubus microspermus C. & E. M. Reid (PI. 30, %s. 72, 73) 1910 Rubus microspermum C. & E. M. Reid, p. 169, pi. 15, figs, 13-17. 1957 Rubus microspermus C. & E. M. Reid : Chandler, p. 101, p. 14, figs. 100-109. DESCRIPTION. Endocarp : Laterally compressed, semicircular to narrow-ovate in outline ; ventral margin concave, straight or slightly convex, dorsal margin semi- circular or markedly convex. Base rounded. Apex sometimes narrower than base, sometimes curved towards the ventral side, margin rimmed all round. Surface reticulate with conspicuous angular pits separated (in unworn specimens) by clearly denned ridges. Dimensions of several endocarps are as follows : i) Length, 2-9 mm. when moist, 2-85 mm. after drying and shrinkage ; breadth, 1-25 mm (moist), 1-2 mm. (dry). 2) Length, 2-25 mm. (moist), 2 mm. (dry); breadth, 1-3 mm. (moist), 1-25 mm. (dry). 3) Length of much abraded hooked endocarp, 2-1 mm. ; breadth, i-i mm. REMARKS. These endocarps agree, so far as they are known, with Rubus micro- spermus from Bovey Tracey but they appear to be larger on the whole. They are less narrow and pointed at the apex than R. acutiformis from the Dorset Pipe-clay Series at Studland, the Bournemouth Freshwater Beds of Branksome Dene and the Lower Headon of Hordle. R. acutiformis, dry, measures 1-55 by 1-2 mm. ; 2 by 1-25 mm. ; 1-5 by i mm. The dimensions when wet were 2 to 2-25 by 1-3 mm. Typical Bovey specimens of R. microspermus dry measure 2-1 by 1-25 mm. ; 2-25 by i mm. ; 2 by 1-25 mm. In the absence of a larger range of material showing variations of size and form the Colwell species is referred provisionally only to R. microspermus. In addition to the figured specimens from below the sewer trench, Linstone Chine, there are endo- carps .43861 from beds between Brambles and Linstone Chines, only one now complete. Family RUTACEAE Genus ZANTHOXYLUM Linnaeus Zanthoxylum hordwellense Chandler (PI. 30, figs. 74-80) 1925 Zanthoxylon cf. ailanthoides Sieb. & Zucc. Chandler, p. 26, pi. 4, fig. 3 figs. 1-4, 24-26, 28-32 ; text-fig. 2(1) ). This material and .42344-48 was obtained by G. W. Colenutt from blocks of cement- stone fallen from the cliff at Hamstead. Heer (1862) figured cones, twigs and seeds prior to the publication of his fuller account of better preserved material from Bovey Tracey, Devon, so that Hamstead is in fact the type locality for this species (Chandler, 1962 : 21). Most of Heer's material came from the Lower Hamstead Marls from a bed yft. above the " Black Band " of Forbes. Heer identified with his own species " Taxites parisiensis Brongn." recorded by Forbes (1886 : 47) from the "Hempstead Beds ". There are also slides 410450-^ prepared by Bandulska showing fragments of cuticle from Gardner's figured material 41045 (1883, pl. 6, fig. 2) see also 41423, .15121-23. Sequoia twigs from 7ft. above the Black Band and specimens figured by Heer (1862, pl. 18, fig. 2) and by Gardner (1883, pl. 6, fig. 3) are in the Geological Survey Museum. ANGIOSPERMAE Class MONOCOTYLEDONES Family TYPHACEAE Genus TYPHA Linnaeus Typha latissima Al. Braun (Pl. 34, figs. 166-170) 1851 Typha latissima Al. Braun in Stizenberger, p. 75. 1926 Typha latissima Al. Braun : Reid & Chandler, p. 60, pl. 3, figs. 4-11. DESCRIPTION. Seed : Pendulous, anatropous, elongate-ovoid, truncate at the micropyle, pointed at the chalaza which is indicated by a darkening and thickening of the testa. Micropyle large, closed by a flat disc with a central mucro ; raphe GEOL. 6, 3. 26 370 REVISION OF THE OLIGOCENE FLORAS OF THE ISLE OF WIGHT lateral, filiform. Testa formed of an outer light brown layer with hexagonal, trans- versely elongate cells, the angled ends of which alternate so as to produce zig-zag longitudinal ridges, these cells are about 0-05 mm. in transverse diameter and about 0-016 to 0-025 mm. in longitudinal diameter. One specimen shows a network of equiaxial cells with raised walls about 0-016 to 0-025 mm - m diameter. There is an inner delicate hyaline layer (tegmen ?) formed of long slender cells tapering at both ends. Dimensions of seeds : i) Length, i-i mm. ; breadth, 0-5 mm. 2) Length, i mm. ; breadth, 0-4 mm. 3) Length, I mm. ; breadth, 0-45 mm. 4) Length, 0-8 mm. ; breadth, 0-35 mm. 5) Length, 0-95 mm. ; breadth, 0-45 mm. REMARKS. Numerous seeds, identical with those from the Bembridge Beds. The relationship to living species is fully discussed by Reid & Chandler (1926 : 60). In addition to the figured material there are eight seeds from the Waterlily Bed at Hamstead (.43945) and five from the same horizon at Bouldnor (.43946). Family SPARGANIACEAE Genus SPARGANIUM Linnaeus ? Sparganium multiloculare Reid & Chandler (PI. 34, fig. 171 ; Text-fig. 5) 1926 Sparganium multiloculare Reid & Chandler, p. 63, pi. 3, figs. 12-18. See p. 340. DESCRIPTION. Endocarp : Woody, truncate ovoid, four-loculed, conspicuously grooved and angled longitudinally, the grooves lying between the locules emphasized by abrasion so that the locule cavities are in part exposed (Text-fig. 5). Carpels distinct and obconical at the base, truncate and slightly concave at the apex which is pierced by the large stylar canals, one to each carpel. Locule cavity ovoid, lined by small transversely aligned cells. Length of endocarp, 2-5 mm. ; breadth, 1-9 by 0-9 mm. Seed not seen. al FIG. 5. ? Sparganium multiloculare Reid & Chandler. Diagrammatic drawing of the apex of endocarp showing apertures of four locules /, those marked al partly exposed on sides by abrasion. REMARKS. One endocarp (.43947) now collapsed. Although a small example, this endocarp agrees in other respects with Sparganium multiloculare from the Bembridge Beds, a species normally about 4 mm. long, to which therefore it is provisionally referred. From the White Band, Bouldnor. REVISION OF THE OLIGOCENE FLORAS OF THE ISLE OF WIGHT 371 Sparganium sp. (PI. 34, fig. 172) DESCRIPTION. Endocarp : Woody, originally obovoid ? but base incomplete, contours smooth, not conspicuously furrowed longitudinally, narrower at one side than at the other giving a suboval transverse section. Apex truncate pierced by a large circular stylar aperture leading into a solitary locule. Wall very thick, maximum thickness about i mm., texture close and compact, structure somewhat obscure but near the exterior formed of parenchyma with cells about 0-014 to 0-018 mm. in diameter. Locule lining concealed by decay. Length of endocarp incomplete (broken transversely just below the level of its maximum diameter). Diameter, 2-75 by 2 mm. Diameter of stylar aperture, 0-7 mm. REMARKS. The upper part of an endocarp, too imperfect for specific definition is undoubtedly a species of Sparganium. The solitary locule and smooth contours distinguish it from 5. multiloculare. The single incomplete specimen (.43948) is from the White Band, Bouldnor. Family POTAMOGETONACEAE Genus POTAMOGETON Linnaeus Potamogeton tenuicarpus C. & E. M. Reid (PI. 34, figs. 173-176) 1910 Potamogeton tenuicarpus C. & E. M. Reid, p. 173, pi. 16, figs. 53, 54. 1957 Potamogeton tenuicarpus C. & E. M. Reid : Chandler, p. 85, pi. u, figs. 12-14. DESCRIPTION. Fruit : Broadly obovate, originally somewhat inflated but now much flattened, curved through almost a complete circle about a subcircular or oboval central depression, the curved area forming the locule ; dorsal margin semi- circular or gibbous, ventral margin slightly convex above and below, conspicuously indented between the ends of the limbs, i.e. between the convexities, at a distance of about a third of the length from the base of the fruit ; sometimes there is a spine just above the indentation. Style small patent, terminal on the ventral margin. Surface having a conspicuous ridge around the central depression, around the dorsal margin adjoining the keel and along the middle of the keel, the ridges thin, forming sharp flanges. Keel broad reaching from the base almost to the apex, its median ridge flanked by a groove on each side. Surface cells about 0-012 by 0-02 mm. in diameter, somewhat irregular in shape aligned parallel with the curvature of the cavity, but also diverging from it. Length of endocarp, i to 1-5 mm. ; breadth, 0-75 to 1-2 mm. Seed : Narrow, elongate, curved like the locule ; testa smooth shining, light brown, semitranslucent. REMARKS AND AFFINITIES. Numerous specimens. In size, form and in every detail of structure there is exact agreement with Potamogeton tenuicarpus C. & E. M. Reid from the Bovey Tracey Lignite to which species it is therefore referred. The width of the keel indicates that in life the degree of inflation may have been con- siderable. For comparison with P. pygmaeus see Chandler (1957 : 85). Szafer com- 372 REVISION OF THE OLIGOCENE FLORAS OF THE ISLE OF WIGHT pares endocarps from the Miocene of Gliwice, Poland, with P. tenuicarpus (1961 : 84, pi. 23, figs. 19-21). In addition to figured material from the Waterlily Bed of Hamstead (.43949-50) and Bouldnor (.43954-55) there are numerous unfigured endocarps from this horizon, .43951 and .43953 from Hamstead, .43956 from Bouldnor and a few from the White Band, Hamstead (.43952). Genus LIMNOCARPUS C. Reid emend. Reid & Chandler, 1926 : 68 Limnocarpus forbesi (Heer) (PI. 33, fig. 153 ; PI. 34, figs. 177, 178) See p. 338. REMARKS. It seems unnecessary to repeat a description of this now familiar species but three figures for comparison with material at other horizons are given. Reasons for reverting to Heer's specific name have already been stated (Chandler, 19610 : 28, 29). In view of this discussion Hamstead must be regarded as the type locality for Limnocarpus forbesi even although most of the material from this locality and horizon is crushed and flattened and preserved on flat surfaces in which the carbonaceous remains are embedded. An exception to this rule is seen in the speci- men in PI. 34, fig. 177 collected by Colenutt at Hamstead cliffs, a fully inflated carbonaceous endocarp washed out of the matrix and now decayed. In addition to figured material from the Waterlily Beds of Hamstead (.43960) and Bouldnor (.43957) there are the following unfigured numerous crushed specimens : .43958 (from Bouldnor), .43961-64 from Hamstead, all from the Waterlily Beds, and .43959 from the White Band of Bouldnor. All the above Groves Collection. Also 41040, labelled Cyperites forbesi, in grey marl, much crushed and others from Middle Freshwater Marls. 41039, H. Keeping Collection. The early collectors invariably collected this species on slabs thickly beset with crushed endocarps (cf . Geological Survey Museum specimens referred to by Chandler, 19610 : 28) like the original holotype. A block with endocarps in the Sedgwick Museum, Cambridge is from the Middle Freshwater Beds Hamstead and is labelled Cyperites ? forbesi by E. A. N. Arber. Family HYDROCHARITACEAE Genus STRATIOTES Linnaeus Stratiotes neglectus Chandler (PI. 34, figs. 181, 182) See p. 359. Some peculiarly well preserved and characteristic seeds were found at Hamstead by A. G. Davis in association with Potamaclis turritissima. They were labelled Hamstead Beds. Prior to this Stratiotes neglectus had been found only in the under- lying Bembridge Beds, with some doubtful immature seeds in the Osborne Beds (see pp. 359, 363). If the horizon is indeed Hamstead the range of 5. neglectus is extended upwards, but it should be noted that although the species Potamaclis (Melania) turritissima is listed by Reid & Strahan (1889 : 292) from both the Bembridge and REVISION OF THE OLIGOCENE FLORAS OF THE ISLE OF WIGHT 373 Hamstead Series it is recorded abundantly from the Bembridge Marls only, with the possible exception of beds they described on p. 198. Hence the horizon may be doubtful in a section where Bembridge and Hamstead Beds are both exposed having regard to the fact that in the seam, gastropods and Stratiotes both abounded. There is no need to repeat the description of the species already given by Chandler in 1923 and Reid & Chandler in 1926. Typical seeds from the Bembridge Marls are shown in PI. 34, figs. 154, 155. Figured specimens labelled Hamstead Beds are .43968-69 and unfigured material .43970. Stratiotes websteri (Brongniart) (PL 35, figs. 183-186) 1923 Stratiotes websteri (Brongniart) : Chandler, p. 128, pi. 5, figs. 7-12, 31 ; pi. 6, figs. 1-5, 26. See also for earlier references. 1957 Stratiotes websteri (Brongniart) : Chandler, p. 86, pi. u, figs. 15-19. REMARKS. The species has been fully described in the above references and there remain only a few minor alterations or additions : viz. the longitudinal ridges which ornament the surface are rounded and interrupted ; occasionally traces of ridges or tubercles are seen on the collar ; the pitting on body, collar and keel is more or less uniform, typical pits measuring about 0-05 mm. in diameter. Length of seed varies from 5-25 to 7-5 mm. ; breadth from 2-25 to 3 mm. A small probably abortive seed measured only 3-1 mm. in length ; 2 mm. in breadth. The seeds are very abundant at certain horizons and include among normally developed specimens a few which are exceptionally small. They are no doubt un- developed and abortive specimens such as occur in the many-seeded fruits of living Stratiotes. A few of the large seeds show a thin adherent layer of clay with filmy light brown tissue embedded within it. This tissue arises from the woody testa and may be an outer dried up mucilaginous coat not commonly preserved in fossilization. The presence of these filmy remains suggests that the rounding of the longitudinal ridges and the shortness of the transverse raphe canal in the hard testa are not due to abrasion but are original characters in this species. Many seeds from Hamstead have been compared with seeds from Bovey Tracey and from the Cyrena-maxls of Offenbach on Main. Specimens from the three localities are indistinguishable although the Offenbach seeds tend to be somewhat smaller and rougher with a slightly smaller collar. No holotype has ever been designated so .43971 (PI. 35, fig. 183) has been chosen. It was collected in the White Band at Hamstead and is a very typical well developed seed. In addition to figured material which includes .43976 (Chandler, 1923, pi. 5. figs. 7-9), .40070 (Chandler, 1923, pi. 5, fig. 31) and .42039 (Chandler, 1923, pi. 6, fig. i) there are the following : numerous seeds from the White Band .16543, .40072-73, .43972 Hamstead, and .43973, .43977 Bouldnor and two from the Waterlily Bed (.43978 Bouldnor). 14235 includes impressions of seeds ? S. websteri alleged to come from the Eocene of the Isle of Wight, presented by the Marchioness of Hastings, probably from the Hamstead Beds and .40071, .42040 from the Hamstead Beds 374 REVISION OF THE OLIGOCENE FLORAS OF THE ISLE OF WIGHT Allusions to Stratiotes, under the names Carpolithes thalictroides, Carpolithes websteri and Folliculites thalictroides are found in the Geological Survey Memoirs (Forbes, 1856 ; Bristow, 1862 ; Reid & Strahan, 1887) in accounts of the Hamstead Beds. As they are without figures or descriptions it is not possible to tell to which species (S. websteri or S. acuticostatus} the seeds in question really belonged. Refer- ences to these names are given in detail in the synonymy by Chandler (1923). Stratiotes acuticostatus Chandler (PI. 35, figs. 187-192) 1923 Stratiotes acuticostatus Chandler, p. 127, pi. 5, figs. 5, 6, 29, 30 ; pi. 6, fig. 25. (Possible earlier allusions to the species (all doubtful) under the names Folliculites thalictroides, F. websteri or Carpolithes websteri are listed among the synonyms published by Chandler (1923). See note under Stratiotes websteri above.) DIAGNOSIS. Seed oblong, oval or narrow-oval, often much flattened, very slightly hooked at the base ; keel usually broad, collar small, testa with conspicuous sharp serrated ridges, pitting coarse, pits up to o-i mm. in diameter, micropyle sub-basal, oblique ; hilum dorsal near the base, raphe marginal to the middle of the dorsal side, thence diagonal, diagonal portion normally less concave to the interior than in S. neglectus ; cells of the interior of the keel straight with their length parallel to the length of the keel. Length about 5-5 to 6-75 mm. HOI.OTYPE. .40075. REMARKS. The species was first described by Chandler in 1923. There is little to add to this account except that the surface pits of mature seeds are much coarser than those of 5. websteri and S. neglectus and are commonly o-imm. in diameter on the general surface and may be even larger on the keel. The length varies from about 5-5 to 6-75 mm. ; the breadth from 2-5 to 3 mm. Abortive small and ill developed specimens are however common(Pl. 35, figs. 190-192) and are sometimes segregated in separate pockets. A typical immature seed measures 4-25 mm. in length and 1-75 mm. in breadth. In addition to the holotype (figured PI. 35, fig. 187 and Chandler, 1923, pi. 5, fig. 5) and other figured material (.44653 PI. 35, fig. 189 and Chandler, 1923, pi. 5, fig. 6 ; .40074 PL 35, fig. 188 and Chandler, 1923, pi. 5, fig. 30 ; .44654 Chandler, 1923, pi. 5, fig. 29 now partly broken ; small seeds .44174, .44176, .44179, PI. 35, figs. 190-192) there are .16541-42, .44175, .44180-83 comprising numerous seeds varying in degree of abrasion, all from Bouldnor Cliff and .44184 from Hamstead. .44177 are from the White Band, Bouldnor and .44178 from the Waterlily Bed, Bouldnor. Stratiotes websteri and S. acuticostatus occur intermingled in the White Band, Hamstead Beds. 52613 is an indurated shaly slab of ironstone, not localized, but almost certainly Hamstead Beds. .841 with an admixture of Brasenia : the Stratiotes sp indeterminable ? but may be a mixture of 5. websteri and S. acuticostatus. .44651 ? 5. acuticostatus " Hempstead Beds ". 52614 ? S. acuticostatus labelled Colwell Bay but is almost certainly from Hamstead. REVISION OF THE OLIGOCENE FLORAS OF THE ISLE OF WIGHT 375 Family CYPERACEAE Section CARICOIDEAE Genus CARICOIDEA Chandler, 1957 : 86 ? Caricoidea minima (Chandler) (PI. 34, figs. 179, 180) 19616 Caricoidea minima (Chandler) : Chandler, p. 105, pi. 24, figs. 18-21. See p. 340. DESCRIPTION. Endocarp : Oburceolate, broadest at about the middle, pointed above, truncate below where it is narrowed into a short neck with spreading margin, pierced by a basal aperture. Length of neck more than one-sixth the length of the whole endocarp, width in the narrowest part about half that of the endocarp. Some specimens show two longitudinal ridges from base to apex, in others they are seen only on the neck dying out above. Sometimes they are absent altogether (abrasion ?). A tendency for the neck to be bilobed is noted, the lobes being continued into that part of the endocarp between the ridges when these are present, the concavities between the lobes marking the termination of the ridges. Surface rough, cells equi- axial, about 0-012 mm. in diameter, arranged in longitudinal rows especially on the neck so as to give an obscurely striate appearance. Walls thick, formed of parenchyma. Length of endocarp, 1-25 to 1-5 mm. ; diameter, 0-9 to 1-2 mm. Seed : Represented by thin testa formed of transversely elongate cells which produce transverse striations. REMARKS. Thirteen specimens, all but one much compressed, They are referred to the form-genus Caricoidea and provisionally to the species C. minima (Chandler). It is doubtful whether the spreading split neck is itself a specific character which could separate the Hamstead material from this Lower Headon species in view of the fact that varying degrees of spreading may be observed among living specimens of Cladium mariscus. A greatly exaggerated degree of spreading is apparent in Caricoidea (? Cladium) colwellensis from the Upper Headon (p. 340). The fruit characters seen in material from the Lower Headon of Hordle appear to separate these fossils definitely from the living Cladium (Chandler, 19616 : 106). In addition to two figured specimens there are extant .43967 from the Waterlily Beds of Bouldnor cliff and .44842 from Hamstead Beds, Hamstead cliff. Family PALMAE Genus SABAL Adanson Sabal major (Unger) (PI. 35, fig. 193) 1847 Flabellaria major Unger, p. 42, pi. 14, fig. 2. 1855 Sabal major (Unger) Heer, p. 88, pi. 35 ; pi. 36, figs, i, 2. 1862 Sabal major (Unger) : Heer, pp. 373, 376. Several leaves were found by Pengelley 7ft. above the Black Band which was taken by Forbes as the base of the Hamstead Series. They were described, but not figured, by Heer. Two he referred undoubtedly to Sabal major, they showed the 376 REVISION OF THE OLIGOCENE FLORAS OF THE ISLE OF WIGHT end of a petiole and base of a leaf with long tapering rachis having a maximum breadth of 44mm., with pinnules attached on both sides agreeing wholly in their insertion, form and nervation with 5. major, so he stated. A third specimen was doubtfully determined. It represented the central part of a leaf with pinnules 10 to 12 mm. broad, each with a median ridge and with numerous longitudinal nerves between each pair of which were four finer nerves. These specimens have not yet been traced but one of them may be in the Geological Survey Museum (XXI 2/3). Another specimen was collected by Henry Keeping in 1888 from the Middle Hamstead of Hamstead (PI. 35, fig. 193). It is still in the Sedgwick Museum, Cam- bridge. It shows the impression of the lower surface with long tapering rachis extending throughout the length of the fragment. The base of the blade is markedly asymmetric, there are about thirty pinnules but their distal ends are not preserved so it is not clear whether they are multifid or multiplicate away from the centre. There is no evidence about the stalk nor about the ligule. Remains only of the car- bonaceous substance of the leaf can be seen, most of it having flaked away as the specimen dried taking with it the remains of the ligule. The length of the fragment along the rachis is 105 mm. and the breadth at right angles to this about the same. It appears to be a species of Sabal and is comparable with the Bembridge specimens described by Gardner 76582 (1888 : 423, pi. 5, fig. 2) and Reid & Chandler .17560 (1926 : 79, pi. 4, fig. 26) as Sabal major. .42038 is an imperfect leaf showing the rachis. DICOTYLEDONES Family NYMPHAEACEAE Genus BRASENIA Schreber Brasenia ovula (Brongniart) (PL 35, fig. 194) See p. 346. Seeds are as common in the Hamstead Beds as in the Lower and Upper Headon and Bembridge. All the tj^pical characteristics of the species are shown. One seed (.44185) is figured from Hamstead. In addition there are specimens from the White Band (.44186) and Waterlily Bed (.44188-89) Bouldnor ; from the White Band (.2881), Waterlily Bed (.44190), " Middle Freshwater Marls " (41422) and un- specified horizons (49902 internal casts only, 41041-42, 41044, .44191) at Hamstead ( =Hempstead) . Some of the older material is labelled "Nymphaea Doris". .841 from Hamstead is associated with Stratiotes, possibly 5. acuticostatus. Genus NELUMBIUM Juss. Nelumbium buchi Ettingshausen See p. 360. Rhizomes and leaves attributed by Heer to Nelumbium occur, the former in abun- dance, especially in the strata which succeed the basal " Black Band ". They are found chiefly 7 ft. above this horizon. Usually the leaves are immature or represented REVISION OF THE OLIGOCENE FLORAS OF THE ISLE OF WIGHT 377 by imperfect fragments only, but one all but perfect leaf (52712) was figured by Gardner (1888, pi. 4). According to the old label it was collected by H. Keeping in the Middle Freshwater Marls. Its actual margin was preserved in many places and the leaf was described in the following terms : " peltate, nearly circular in outline, notched on the uppermost margin and with radiating venation, the vein proceeding to the base of the notch being stronger than the rest. The principal veins fork, but reunite near the margin, and the secondary venation is obscure. The articulation with the petiole is very visible at the centre of the leaf ". At an earlier date, however, Heer (1862 : 374) had stated that delicate veins united the principal veins, the areas between them being filled up with fine reticulations [as in living Nelumbium] . The rhizomes, Heer states, are from 10 to 14 mm. thick but at the nodes, which may be 3 ft. apart, as much as 23 or 24 mm. thick. From the nodes numerous roots arise which fall away leaving crowded circular scars. Heer did not doubt the relation- ship of these rhizomes to Nelumbium, but Gardner (1888 : 417) pointed out that they appear to have been quite hollow, not fleshy and succulent as in Nelumbium. While accepting the leaves unhesitatingly as Nelumbium, he appears to have doubted the relationship of the rhizomes. Their hollow condition may however have been due to decay of pithy tissue in fossilization. The rhizomes were associated with macerated fragments of sword-shaped leaves (Sparganium ? Typha ?) ; hence it is clear that more than one genus was represented in the bed. Possibly therefore more than two genera were present so that if Gardner's doubt was justified the rhizomes may have belonged to another plant. Gardner (1888) in his description of plate 4 comments that the rhizomes were identified by Heer and by Saporta as those of Nelumbium but " hitherto no trace, either of the remarkable fruit, or of the seeds, has accompanied them ". The striking abundance of Nymphaeaceae seeds, now referred to Brasenia ovula has been commented upon by older workers as well as by collectors at the present day. It is a peculiar phenomenon that abundant seeds of the family occur in certain beds of the Hamstead Series and rhizomes with leaves and abundant leaf fragments in another bed. It inevitably raises the question whether the supposed Brasenia seeds and Nelumbium leaves and rhizomes belong to the same plant and if they do should they really be referred to one of these genera or to some extinct genus. The answer to this query cannot at present be provided. Apart from Gardner's figured leaf there are the following rhizomes in the British Museum (Natural History) : 41043, 41421, 41425, .1844-46, .44828-30 labelled Middle Freshwater Marls. Family ROSACEAE Genus RUBUS Linnaeus Rubus sp. A single small, curved, laterally compressed spine with elongate base and smooth finely longitudinally striate surface, the striae being formed by small oblong longitud- inally aligned cells. Length of spine, 2 mm. Similar spines were found at Hordle and Bovey Tracey both of which localities yielded Rubus endocarps. The spine has been compared with those of Rubus and Rosa, it agrees in cell structure with Rubus. 378 REVISION OF THE OLIGOCENE FLORAS OF THE ISLE OF WIGHT Family LEGUMINOSAE Genus ? (PI. 35, fig. 195) DESCRIPTION. Seed: Subglobular originally (now compressed). Hilum not seen owing to the compression. Surface smooth, cells small equiaxial producing a fine granulation, testa columnar in section, the ends of the columns producing the surface cells, breadth of columns about 0-006 mm., thickness of testa varying from 0-05 to o-i mm. Diameter of compressed seed, 3-3 by 2-5 mm. Two other specimens (decayed) possibly referable to the same species measured 3-2 by 3mm. and 27 by 2-6 mm. respectively. REMARKS AND AFFINITIES. These seeds at first sight resemble Brasenia, but no embryotega could be seen nor any digitate cells. When fractured to show the testa in section, the radial columns appear to be much narrower and longer than in Brasenia. The difficulty of detecting a hilar scar along the flattened edge suggests that this organ was very small, probably situated at the split in the margin. The relationship seems to be with Leguminosae, but there is insufficient evidence on which to base generic determination. .44192 from the Hamstead Beds of Hamstead. Family DROSERACEAE Genus ALDROVANDA (Monti) L. Aldrovanda intermedia Reid & Chandler (PI. 35, fig. 196) 1926 Aldrovanda intermedia Reid & Chandler, p. 113, pi. 6, figs. 27-29. DESCRIPTION. Seed : Oburceolate, with a narrow neck about one-seventh the length of the seed ; anatropous with longitudinal raphe ridge terminating in an apical mucro. Surface glistening, flatly tubercled, the tubercles about 0-025 mm - m diameter and less convex than those of Aldrovanda ovata. Inner coat not seen. Length of seed, 1-65 mm. ; diameter, 1-2 mm. ; length of neck, 0-2 mm. REMARKS. One seed (.44193) slightly broken at the neck. It agrees in size and shape and in the character of the tubercles with Aldrovanda intermedia Reid & Chandler from the Bembridge Beds. It is smaller than A. ovata from the Lower Headon of Hordle and Lower and Upper Headon of Colwell Bay. Family AQUIFOLIACEAE Genus ILEX (Tourn.) L. ? Ilex sp. (PL 35, fig. 197) DESCRIPTION. Endocarp : Rounded-oblong in outline, inflated, rounded triangular in section, with a median ventral angle, the angle being formed by a thick fibro- vascular strand which gives off two alternating branches one on each side. The REVISION OF THE OLIGOCENE FLORAS OF THE ISLE OF WIGHT 379 vascular strand passes from a large oval basiventral scar of attachment to the apex of the ventral ridge where it makes a slight prominence. The carpel wall adjacent to this fibre strand is formed externally of coarse parenchyma beneath which the cells are aligned transversely. The dorsal surface is covered by a closely adherent layer of longitudinally striate fibres, the striations being parallel, not converging at the two ends, slightly oblique. It is not clear whether this layer forms part of the carpel wall or is accidentally adherent to it. Length of endocarp, 3 mm. ; breadth, i mm. (increased by compression). REMARKS. One endocarp (.44194) from Hamstead represented by an internal cast in coarse-grained pyrites to which the carpel wall adheres on the ventral side. Size and form, position and character of attachment, the ventral vascular strand and its mode of branching, are identical with the characters seen in certain species of Ilex but there is nothing in the living carpels to correspond with the longitudinally striate dorsal layer described above. In Ilex all the inner horny layers are formed of transverse fibres with an admixture of oblique fibres. If, however, as suggested by the strict parallelism of these fibres with no hint of convergence to the attachment scar the longitudinal layer is not organically connected with the endocarp, but is only accidentally adherent to the specimen, then the structure indicates relationship with Ilex. Family ? Genus RHAMNOSPERMUM Chandler, 1925 : 30 Rhamnospermum bilobatum Chandler See p. 355. Additional material has been found in the Hamstead Beds where some seams are crowded with this plant which is often associated with Stratiotes acuticostatus. .40937 (figured Chandler, 1962, pi. 24, fig. 5) from Hamstead. .40938 (figured Chandler, 1962, pi. 24, fig. 6), .44195-96 from Bouldnor cliff. .44197-99 from the Waterlily Beds, Bouldnor. INCERTAE SEDIS Genus CARPOLITHUS Linnaeus Carpolithus sp. (? Spirematospermum sp.) (PI. 35, fig. 198) DESCRIPTION. Pod : Lanceolate, curved, incomplete at one end (apex ?), tapering to the other where there is a rounded point which appears to have been abraded. Angled longitudinally (original ?) above and below with about four strong longitu- dinal ribs on the exposed surface, narrowly ellipsoid in transverse section. Number of locules almost certainly one. Surface formed of hexagonal cells arranged in regular longitudinal rows, cells about 0-038 to 0-057 mm. parallel with the length of the pod, 0-057 mm - a * right angles to it. Wall about 0-5 mm. thick. Seeds not seen. Length preserved, 70 mm. ; maximum breadth, 9 mm. ; thickness, 3 mm. REMARKS. The specimen lies with one surface embedded in matrix. It is not certain which end of the pod is broken but it seems probable that it is the apex which 380 REVISION OF THE OLIGOCENE FLORAS OF THE ISLE OF WIGHT is missing. The surface cells very closely resemble those of Spirematospermum headonense from the Lower Headon of Hordle (Chandler, 19616 : 108, pi. 24, figs. 28-30 ; pi. 25, figs. 31, 32) . It is possible that this pod belongs to the genus Spiremato- spermum but the evidence to establish this relationship is missing. In any case a different species is indicated as the Hamstead pod is much longer and narrower. Its original length cannot be estimated as, if it belongs to Spirematospermum, the apex would probably have terminated in a wide perianth disc without any appreci- able narrowing of the pod towards it. One carbonaceous specimen (41424) from the Lower Hempstead Marls, Hempstead. Carpolithus sp. 1888 Gardenia? Wetzleri Gardner, p. 417, pi, 3, figs. 11-15. A fruit figured by Gardner and described as a rounded or subangular capsule with thick valves and two or more cells is ligneous, leathery and indehiscent. It had two rows of black and shining, angular, closely fitting seeds. Gardner records that on removing some of these a second layer of seeds was disclosed beneath a thin wall, hence his statement that the fruit was two-celled with four rows of seeds. Plate 3, fig. ii (Gardner, 1888) shows the pod. Beside it but separate from it lies a thick stalk which does not appear to belong. Figs. 12-15 show the seeds natural size but there is no hint of the spiral striae seen in Spirematospermum (formerly Gardenia] wetzleri as represented on seeds from Bovey Tracey or the German lignite, on those of Spirematospermum headonense from the Lower Headon of Hordle or on detached seeds from the Bembridge Beds. As this characteristic feature is not mentioned either it does not seem probable that the pod (no longer extant) can have belonged to Spirematospermum. Indeed Gardner (1888 : 418) states " I am more inclined to place it under the Iridaceae ". Carpolithus sp. (PI. 35, fig. 199) DESCRIPTION. Seed : Obovoid, now much compressed, truncated by a gaping aperture at the narrow end. Testa formed superficially of pits or concave cells with sinuous outlines 0-025 to 0-05 mm. in diameter. Length of seed, 2-4 mm. ; breadth, 2-05 mm. One seed (.44187) from the White Band, Hamstead. It has not been determined but may conceivably be a peculiarly preserved Brasenia in which case the aperture is that of the embryotega. As the form is not typical of a Brasenia seed the specimen has been referred to Carpolithus sp. Carpolithus sp. (PL 35, fig. 200) A small flattened ovate seed or carpel, slightly asymmetric, with rough coat; attachment or chalazal scar at the middle of the broad end. Length, 2-1 mm. , breadth, 1-5 mm. The systematic position has not been discovered. .44200 from Hamstead Beds of Hamstead cliff. REVISION OF THE OLIGOCENE FLORAS OF THE ISLE OF WIGHT 381 Carpolithus sp. (PL 35, figs. 201-204) Small ovoid semitranslucent integuments (flattened in fossilization) with a pro- jecting short cylindrical black organ at one end, often splitting median longitudin- ally at the other end. Cell structure obscure, but two coats can be distinguished, an outer (structureless ?) layer broadest near the chalaza, which forms a narrow marginal flange and an inner somewhat denser yellow coat. Dimensions of three typical specimens are as follows : i) Length, 0-95 mm. ; breadth, 0-52 mm. 2) Length, i-i mm. ; breadth, 0-55 mm. 3) Length, 1-3 mm. ; breadth, 0-6 mm. These integuments suggest a tegmen with a large thick black chalaza. If this is a correct interpretation the testa must have decayed and vanished completely. It must, however, be borne in mind that the absence of any cell structure may indicate a chitinous substance. If so, they may perhaps represent egg cases, possibly of an insect, not a seed at all. At present their true relationship is quite obscure. They are abundant in the Hamstead Beds. In addition to figured material from the Waterlily Bed, Hamstead, there are .44204 from the same horizon and locality and .44205 from Bouldnor. (e) Horizon ? Locality Headon Hill. Family ICACINACEAE Genus STIZOCARYA Reid & Chandler, 1933:336 Stizocarya sp. (PI. 35, figs. 205, 206) DESCRIPTION. Endocarp : Globular with a slight bisymmetry about a plane in which the funicle lies. Dehiscence into equal valves along this plane. External surface much abraded, smooth (secondarily ?) with numerous inconspicuous small pits marking the outer ends of cylindrical canals. These traverse the thickness of the wall at right angles to its surface and form similar but more conspicuous pits on the interior about 0-3 to 0-4 mm. apart. Canals occupied by compact oblong cells or fibres which form hair bases. Wall woody, 0-75 to o-i mm. thick, compact, formed of small parenchymatous cells, 0-016 mm. in diameter. Funicle only preserved near the apex where it traverses the wall diagonally to the apical placenta (PI. 35, fig. 206). Length of endocarp, 15 mm. ; breadth, 14 mm. REMARKS. Two endocarps, both broken so that the internal characters are dis- played. They were in a box containing two differently preserved specimens obviously from other horizons. On the box lid was " F. E. Edwards Coll." and the late W. N. Edwards stated that it was in a batch of material which was sent to the British Museum (Natural History) as " Searles . Wood Collection ". Inside the box was a label in F. E. Edwards' hand " Headon Hill ". The preservation and colour of these carbonaceous endocarps strongly suggest that they were. derived from an ironstone nodule. 382 REVISION OF THE OLIGOCENE FLORAS OF THE ISLE OF WIGHT The form of the endocarp, mode of dehiscence and position of the funicle indicate the family Icacinaceae. The cylindrical canals which pierce the wall place the specimens in Stizocarya Reid & Chandler, a genus based originally on London Clay material. The endocarps agree closely in size and shape with S. communis, but in that species the canals are about 0-6 to i mm. apart and not therefore so close as in the species here described. In view of the uncertainty as to the origin of the specimens no specific name has been given. Nevertheless they are of interest and importance as they indicate the presence of Icacinaceae in the Tertiary of the Isle of Wight and are certainly from a younger horizon than the London Clay. The probable occurrence in ironstone nodules suggests the Headon Beds. It is much to be hoped that further material will be found which will elucidate the origin of these endocarps. In addition to .43928 which is figured, there is an endocarp .43929. REFERENCES ARKELL, W. J. 1947. The Geology of the Country around Wey mouth, Swanage, Corfe and Lulworth. (Explanation of Sheets 341-343, with small portions of Sheets 327-329). 386 pp., 19 pis. [Mem. Geol. Surv. G.B.] BANDULSKA, H. 1923. A Preliminary Pape ron the Cuticular Structure of certain Dicotyle- donous and Coniferous leaves from the Middle Eocene Flora of Bournemouth. /. Linn. Soc. Lond. (Bot.), 46 : 241-269, pis. 20, 21. BRAUN, AL. 1851. In STIZENBERGER, E. Uebersicht der Versteinerungen des Grossherzogthums Baden. 144 pp. Freiburg i./B. BRISTOW, H. W. 1862. The Geology of the Isle of Wight. (Sheet 10.) xix + 138 pp., 7 pis. [Mem. Geol. Surv. U.K.] BRONGNIART, AD. 1822. Sur la classification et la distribution des vegetaux fossiles en general, et sur ceux des terrains du sediment superieur en particulier. Mem. Mus. Hist, nat., Paris, 8 : 203-348, pis. 12-17. CHANDLER, M. E. J. 1923. The Geological History of the Genus Stratiotes : An Account of the Evolutionary Changes which have occurred within the Genus during Tertiary and Quaternary Times. Quart. J. Geol. Soc. Lond., 79 : 117-138, pis. 5, 6. 1925. The Upper Eocene Flora of H or die, Hants., 1. 32 pp., 4 pis. [Mon. Palaeontogr. Soc., London.] 1955- The Schizaeaceae of the South of England in Early Tertiary times. Butt. Brit. Mus. (Nat. Hist.) Geol., London, 2 : 291-314, pis. 32-38. 1957- The Oligocene Flora of the Bovey Tracey Lake Basin, Devonshire. Bull. Brit. Mus. (Nat. Hist.) Geol., London, 3 : 71-123, pis. 11-17. 1960. Plant Remains of the Hengistbury and Barton Beds. Bull. Brit. Mus. (Nat. Hist.) Geol., London, 4 : 191-238, pis. 29-35. 1961. The Lower Tertiary Floras of Southern England. 1. Palaeocene Floras. London Clay Flora (Supplement), xi + 354 PP-, atlas 34 pis. Brit. Mus. (Nat. Hist.), London. 1 96 1 a. Post-Ypresian Plant Remains from the Isle of Wight and the Selsey Peninsula, Sussex. Bull. Brit. Mus. (Nat. Hist.) Geol., London, 5 : 13-41, pis. 4-11. - 19616. Flora of the Lower Headon Beds of Hampshire and the Isle of Wight. Bull. Brit. Mus. (Nat. Hist.) Geol., London, 5 : 91-158, pis. 24-30. 1962. The Lower Tertiary Floras of Southern England. 2. Flora of the Pipe-clay Series of Dorset. (Lower Bagshot.) xi + 175 pp., 29 pis. Brit. Mus. (Nat. Hist.), London. [In press.] The Lower Tertiary Floras of Southern England. 3. Flora of the Bournemouth Beds, the Boscombe and the Highcliff Sands. DOROFEEV, P. I. 1958. A new data on the Oligocene flora of the village Rezhenka in Western Siberia. [In Russian.] Doklady Akad. Nauk. SSSR, 123 : 171-174, pi. I. REVISION OF THE OLIGOCENE FLORAS OF THE ISLE OF WIGHT 383 DOROFEEV, P. I. I958a. A new data on the Oligocene flora of the village Byeloyarna on the River Tavda in Western Siberia. [In Russian.] Doklady A had. Nauk. SSSR, 123 : 543-545, pi. i. 1959- On the Oligocene flora of the village Koziulino on the Tom river in Western Siberia. [In Russian.] Doklady Akad. Nauk. SSSR, 127 : 1103-1105, pi. i. - I959a. Contribution to the study of the Miocene flora of the Rostov region. [English summary.] Palaeobotanika, 4 : 144-189, pis. 1-6. 1960. On the Tertiary Flora of Byelorussia. [English summary.] Bot. Zh., Moscow, 45 : 1418-1434, pis. 1-4. FORBES, E. 1856. On the Tertiary Fluvio-Marine Formation of the Isle of Wight, xviii + 162 pp., 7 pis. [Mem. Geol. Surv. U.K.] GARDNER, J. S. 1883-86. A Monograph of the British Eocene Flora, 2 : Gymnospermae. 159 pp., 27 pis. [Mon. Palaeontogr. Soc., London.] 1888. Report on the Higher Eocene Beds of the Isle of Wight. Rep. Brit. Ass., London, 1887 : 414-423, pis. 3-5. HEER, O. 1855. Flora Tertiaria Helvetiae, 1. 117 pp., 50 pis. Winterthur. - 1862. On Certain Fossil Plants from the Hempstead Beds of the Isle of Wight. Quart. J. Geol. Soc., Lond., 18 : 369-377, pi. 18. i862a. On the Fossil Flora of Bovey Tracey. Philos. Trans., London, 152 : 1039-1086, pis. 55-71- KEEPING, H. & TAWNEY, E. B. 1881. On the Beds at Headon Hill and Colwell Bay in the Isle of Wight. Quart. J. Geol. Soc., Lond., 37 : 85-127, pi. 5. KIRCHHEIMER, F. 1957- D* e Laubgewdchse der Braunkohlenzeit . ix + 783 pp., 55 pis. Halle (Saale). KOLESNIKOVA, T. D. 1960. The Tertiary Plants from the lignite deposits of the Bashkirian Autonomous Republic. Bot. Zh., Moscow, 45 : 117-123, i pi. 1961. A contribution to the knowledge of the Tertiary Flora of Zaobsky Yara (a steep eastern bank of the Ob river) in Western Siberia. Bot. Zh., Moscow, 46 : 125-130, i pi. KRYSTOFOVICH, A. N. 1957. Paleobotanika. 650 pp., 444 figs. Leningrad. MARION, A.-F. 1888. Doliostrobus Sternbergii. Nouveau genre de coniferes fossiles tertiaires. Ann. Sci. geol., Paris, 20 : 1-20, pis. i, 2. PRESL, C. B. 1838. In STERNBERG, G. K Versuch einer geognostisch-botanischen Darstellung der Flora der Vorwelt, 8 : 81-220, pis. 27-68. Leipzig & Prag. REID, C. & E. M. 1910. The Lignite of Bovey Tracey. Philos. Trans., London, 201, B : 161-178, pis. 15, 16. 1915. La flore pliocene de Bidart et Cenitz. Bull. Soc. giol. Fr., Paris, 15 : 420- 427, pi. 7. REID, C. & STRAHAN, A. 1889. The Geology of the Isle of Wight. 2nd edition, xiv -f 349 pp., 5 pis. [Mem. Geol. Surv. U.K.] REID, E. M. & CHANDLER, M. E. J. 1926. The Bembridge Flora. Catalogue of Cainozoic Plants in the Department of Geology, I. viii + 206 pp., 12 pis. Brit. Mus. (Nat. Hist.), London. 19260. A Note on Certain Plants from a Clay-bed in the Bembridge Limestone near Gurnard, Isle of Wight. Proc. Is. Wight Nat. Hist. Soc., Newport, 1 : 378. 1933. The Flora of the London Clay, viii + 561 pp., 33 pis. Brit. Mus. (Nat. Hist.), London. SZAFER, W. 1961. Miocene Flora from Stare Gliwice in Upper Silesia. Trav. Serv. giol. Pologne, Warsaw, 33 : 1-205, P^ 3 - 1-26. UNGER, F. 1841-47. Chloris protogaea. Beitrdge zur Flora der Vorwelt. 150 pp., 50 pis. Leipzig. WHITE, H. J. O. 1921. A Short Account of the Geology of the Isle of Wight, vi + 219 pp., i pi. [Mem. Geol. Surv. U.K.] WRIGLEY, A. & DAVIS, A. G. 1937. The Occurrence of Nummulites planulatus in England, with a Revised Correlation of the Strata containing it. Proc. Geol. Ass., Lond., 48 : 203- 228, pis. 17, 18. EXPLANATION OF PLATES FIGS. 1-141 all from the cliffs of Colwell Bay, Isle of Wight, except figs. 16-19, 64, 65, 67-69 from the Lower Headon of Hordle, Hampshire (for comparison) . Unless otherwise stated Colwell specimens are from Upper Headon Beds between Brambles and Linstone Chines. PLATE 27 ? Araucarites gurnardi Florin FIGS, i, 2. Distal end of cone-scale, base broken ; short rounded apical process may be abraded. Fig. i dorsal surface, escutcheon above, e. Fig. 2 ventral, x 6-5. (.43780.) Below sewer pipe, Linstone Chine. Sequoia couttsiae Heer FIG. 3. Twig tip with remains of male cone showing anthers. X36. (.44841.) FIG. 4. Part of same at x in fig. 3. x 161. Between Colwell and Brambles Chines. Pinus sp. FIG. 5. Seed, upper surface showing cell structure ; m, micropyle ; c, cells of testa seen in section in edge of broken valve fragment. X 20. (.43785.) Potamogeton pygmaeus Chandler FIGS. 6, 7. Endocarps with spines, keel, k, gaping ; p, spiny process on ventral margin ; s, style. X 18-75. (.43787-88.) Below sewer pipe, Linstone Chine. FIG. 8. Abraded endocarp with almost smooth contours crushed so that median gap between limbs appears small, x 18-75. (".43793.) Limnocarpus forbesi (Heer) FIGS. 9, 10. Two endocarps in pyrites ; s, style ; k, keel, x 14. (V-43794-95-) Stratiotes headonensis Chandler FIGS. 11-19. Seeds. Fig. 15 small abortive specimen (.43803). All others represented by one valve only. Figs, u, 13, 14, 16, 19 show external surface. Figs. 12, 17, 1 8 internal surface with raphe canal, marginal in lower part, diagonal to apical chalaza above. Exceptional width of keel well shown in figs. 12, 18, 19. Figs. 16, 17 outer and inner surfaces respectively of a single seed and figs. 18, 19 of another. Figs. 11-15 X 6-5. Figs. 16-19 X 8. Figs, n, 12 between Brambles and Linstone Chines. (.4379g-.438oo.) Figs. 13-15 below sewer pipe, Linstone Chine. (.43801-03.) Figs. 16-19 f r comparison from Lower Headon of Hordle. (.42073, .42078.) Bull. B.M. (N.H.) Geol. 6, 3 PLATE 27 is 19 GBOL. 6, 3. 2 7 PLATE 28 Car ex sp. FIGS. 20, 21. Endocarp, opposite surfaces. Fig. 20 is the facetted side, x 20. (Decayed.) FIGS. 22, 23. Another, slightly broken at base. Facetted surface in fig. 23. x 20. (Decayed.) FIGS. 24, 25. Endocarp, slightly imperfect at apex. Facetted surface in fig. 25. x 20. (V. 43 8o 7 .) Carex colwellensis n.sp. FIGS. 26, 27. Holotype. Endocarp, s, styles, x 20. (V. 43808.) ? Scirpus sp. FIG. 28. Fruit with longitudinal ridges, x 20. (.43809.) ? Caricoidea obscura Chandler FIGS. 29, 30. Two endocarps. x 15. (.43824, .43826.) Caricoidea (? Cladium) colwellensis n. sp. FIG. 31. Broad endocarp. x 14. (.43812.) FIG. 32. Holotype. Endocarp. x 14. (.43810.) FIG. 33. Small endocarp. x 14. (.43811.) FIG. 34. Endocarp showing longitudinal ridge, x 14. (Decayed.) FIG. 35. Endocarp tilted to show basal aperture, x 14. (Decayed.) Caricoidea maxima Chandler FIG. 36. Fruit, side, x 14. (.43815.) FIG. 37. Another fractured longitudinally but irregularly so that upper half of endocarp, e, is exposed in longitudinal section. Its lower end lay about one-quarter of the length of the fruit from its base. Some coarse polygonal cells preserved in pyrites seen near the base of the cavity may be adherent foreign tissue, x 14. (Decayed.) FIG. 38. Another fruit abraded at base so that endocarp is exposed showing basal aperture. X 14. (Decayed.) FIG. 39. Endocarp released from fruit tilted to show apex, so that neck, n, almost hidden. X 14. (.43816.) FIG. 40. Another endocarp with conspicuous neck but no apical mucro. Tilted to show apex, x 9- (^".43817.) ? Caricoidea angulata Chandler FIGS. 41, 42. Two endocarps. x 14. (.43818-19.) Cyperaceae. Genus ? FIGS. 43, 44. Opposite sides of a crushed triangular fruit, apex incomplete. X20. (.43829.) Bull. B.M. (N.H.) Geol 6, 3 PLATE 28 21 22 W 23 38 PLATE 29 Myrica boveyana (Heer) FIG. 45. Valve of endocarp, much abraded, x 9-5. (.43832.) FIG. 46. Same, inner side showing characteristic form of locule; stylar canal at apex; v, vascular canal. Note broad sutures, x 9-5. FIG. 47. Better preserved fruit, exterior of valve (cut off on left by edge of plate), x 15-5. (V.4383I-) FIG. 48. Inner surface of one valve of the above, st, stylar canal ; v, vascular canal, x I5'5- Myrica ? colwellensis n.sp. FIG. 49. Holotype. Endocarp, exterior, showing longitudinal furrows with fibres, x 15. (.43834.) FIG. 50. Valve of same, inner surface, showing typical locule and coarse cells of locule lining ; st, stylar canal ; s, crumpled seed ; v, vascular canal, x 15. FIG. 51. Second valve of same, exterior, bitten by insect (?), on right, x 15. FIG. 52. Valve of endocarp, exterior, imperfect above, x 9-5. (.43835.) FIG. 53. Same, inner face ; v, vascular canal, x 9*5. FIG. 54. Valve of abraded endocarp, exterior, x 9-5. (.43836.) FIG. 55. Same, inner surface, st, stylar canal. (Cavity full of sand grains.) x 9-5. Ficus lucidus Chandler FIG. 56. Crushed endocarp, burst at p overlying placenta, x 20. (.43838.) Centrospermae. Family ? Genus ? FIG. 57. Seed bursting at hilum. x 20. (.43839.) Brasenia ovula (Brongniart) FIG. 58. Seed without embryotega, aperture for which is at a. x 15-5. (.43841.) FIG. 59. Smaller seed, x 15-5. (.43840.) Both the above from south of Brambles Chine. Nymphaea sp. FIG. 60. Seed with embryotega, e. x 15. (.43850.) FIG. 61. Another, embryotega missing, x 15. (.43851.) Nymphaeaceae. Genus ? (? Brasenia ovula) FIG. 62. Hilar end of dorsiventrally crushed seed with embryotega just below centre of figure showing micropyle surrounded by radially arranged cells, x 15. (.43852.) Bull. B.M. (N.H.) GeoL 6, 3 PLATE 29 PLATE 30 Brasenia spinosa Chandler FIG. 63. Seed, tilted to show aperture for embryotega. x 15. (.43844.) FIG. 64. A seed, somewhat laterally compressed, apex showing aperture as in Fig. 63. X 15. (.421210.) FIG. 65. Another tilted to show fine basal spines, x 15. (V. 42 121.) FIG. 66. Apex of a seed with embryotega preserved showing small rimmed micropyle. X 15. (Decayed.) FIG. 67. Smaller seed tilted to show embryotega at apex. Stout tubercles are seen, x 15. (V. 200420.) FIG. 68. Another, side, x 15. (.20041.) FIG. 69. Another, tilted to show aperture for embryotega. x 15. (.200416.) Figs. 64, 65, 67-69 from Lower Headon, Hordle for comparison. Figs. 64, 65 show seeds with slender spines. Figs. 67-69 are the variety with stout tubercles formerly separated as Brasenia antiqua. Aldrovanda ovata (Chandler) FIG. 70. Typical seed with long neck, x 15. (.43853.) FIG. 71. Another, bursting so as to show inner coat, x 15. (.43854.) Below sewer pipe, Linstone Chine. ? Rubus microspermus C. & E. M. Reid FIG. 72. Endocarp. x 20. (.43859.) FIG. 73. Another, abraded showing curved form, x 20. (.43860.) Below sewer pipe, Linstone Chine. Zanthoxylum hordwellense Chandler FIG. 74. Seed, side. Long hilar scar at h. x 9. (.43862.) . FIG. 75. Another, h as above, x 9. (Decayed.) FIG. 76. Seed with more rounded outline, x 9. (.43863.) FIG. 77. Seed tilted to show hilar scar near right margin of figure, x 9-5. (.43864.) FIG. 78. More elongate seed tilted to show ventral margin with long narrow hilar scar in upper half. Hilar aperture in both at lower end of scar, x 9-5. (.43865.) FIG. 79. Same, side, hilar scar on left, a, position of hilar aperture, x 9. FIG. 80. Seed in Fig. 77, side, hilar scar on right, x 9. Hovdwellia crassisperma (Chandler) FIG. 81. Fruit, apex, with small subcircular perianth scar, x 20. (.43868.) FIG. 82. Seed, slightly broken at top of figure. Hilum at base, x 20. (.43869.) FIG. 83. Seed differently preserved in pyrites, x 20. (Decayed.) FIG. 84. Somewhat crushed seed, x 20. (Decayed.) FIG. 85. Typical larger seed, x 20. (.43870.) Decodon vectensis n.sp. FIG. 86. Holotype. Seed, side, somewhat tilted to show valve on right beginning to gape at v. X 20. (.43873.) FIG. 87. Same, opposite side in true profile. alve, v. x 20. FIG. 88. Slender seed, valve, v, on left with concave outline, x 20. (.43874.) FIG. 89. Same, with valve on right, tilted so that it occupies half breadth of figure, x 20. FIG. 90. Another, valve, v, gaping on right at base, x 20. (.43875.) Bull. B.M. (N.H.) Geol. 6, 3 PLATE 30 PLATE 31 Decodon vectensis n.sp. FIG. 91. Same seed as in PI. 30, fig. 90. Valve on left, x 20. FIG. 92. Seed with dorsal angle on right, x 20. (Decayed.) FIG. 93. Ungerminated seed with closed valve on right, x 20. (.43876.) FIG. 94. Seed, ? abortive, looking onto slightly concave valve which extends almost to apex as shown by crack along its left margin, x 20. (.43877.) FIG. 95. Abortive seed, x 20. (Decayed.) FIG. 96. Seed with cavity turned to left exposed by loss of valve, x 20. (.43878.) FIG. 97. Seed, edge of valve on left, dorsal angle forms outline on right, x 20. (.43879.) FIG. 98. Same, left edge is the dorsal angle, locule lies behind on right, x 20. ? Microdiptera parva Chandler FIG. 99. Seed, dorsal, showing pitted germination valve in lower half, x 20. (.43881.) FIG. 100. Same, ventral, showing broad longitudinal seed-body carrying raphe ridge, x 20. FIG. 101. Seed, dorsal, with longer valve, x 20. (.43882.) FIG. 102. Same, ventral, x 20. FIG. 103. Subquadrangular seed, dorsal, valve partly hidden by distortion of specimen. X 20. (.43883.) FIG. 104. Same, ventral, showing broad seed-body flanked by depressions, x 20. FIG. 105. Seed, dorsal, valve slightly swollen and cracked towards its apex, x 20. (.43884.) FIG. 106. FIG. 107. Same, ventral, broad body clear, x 20. Seed, dorsal, seed-cavity, c, exposed by loss of valve. X 20. (Decayed.) X 20. (.43889.) (.43891.) Below sewer Sambucus colwellensis n.sp. FIG. 108. Holotype. Seed, ventral, x 20. (.43886.) FIG. 109. Another, dorsal, x 20. (.43887.) FIG. no. Seed, ventral, h, hilum. x 20. (.43888.) FIG. in. Small seed, ventral, splitting marginally as in germination. FIG. 112. Seed, ventral, h, hilum. x 20. (.34890.) FIG. 113. Crushed seed, ventral, splitting as in Fig. in. X 20. pipe, Linstone Chine. Epacridicarpum headonense Chandler FIG. 114. Fruit tilted to show apex with loculicidal splitting, x 20. (.43894.) FIG. 115. Another, side, showing flat apex, domed base, x 20. (.43895.) FIG. 116. Base of a fruit with median attachment scar, x 20. (.43896.) Epacridicarpum colwellense n.sp. FIG. 117. Holotype. Fruit, apex, showing winged angles over locules alternating with con- cavities, s, over septa, x 20. (.43898.) FIG. 118. Another, base, somewhat distorted, x 20. (.43899.) FIG. 119. Another, basilateral view. Distorted, x 20. (.43900.) Bull. B.M. (N.H.) Geol. 6, 3 PLATE 31 91 92 Iff ^93 ^94 9! 96 118 PLATE 32 Carpolithus colwellensis n.sp. FIG. 1 20. Holotype. Fruit showing tiny perianth segments, p ; median angle with furrow, flanked by lateral facets. Faintly rippled surface due to fine tubercles seen on left. Base somewhat abraded, x 20. (.43905.) FIG. 121. Same, opposite flat surface. Two perianth segments clearly shown, x 20. FIG. 122. Another, angled surface, median furrow filled by white matrix. Broken at apex so that locule is exposed at /. Excavated base complete, x 20. (V.439O6.) FIG. 123. Same, flat surface, base well shown, x 20. FIG. 124. Smaller fruit, facetted surface, x 20. (.43907.) FIG. 125. Same, opposite flat surface, x 20. FIG. 126. Another, imperfect at base, in longitudinal section, x 20. (.43908.) Carpolithus spp. FIG. 127. Valve of ? capsule, bearing subterminal spine, x 9. (V. 43909.) FIG. 128. Same, opposite, internal, surface, x 9. FIG. 129. Another, exterior, split below and somewhat collapsed, x 9-5. (.43910.) FIG. 130. Same, opposite side with ? ruptured septum, x 9-5. FIG. 131. Small ovoid seed, x 20. (.43912.) FIG. 132. Similar but more elongate specimen, x 20. (.43913.) FIG. 133. Abraded fruit or seed with scar truncating apex, x 20. (.43914.) Unknown leaf FIG. 134. Lobed or segmented leaf or pinnule fragment, upper surface, x 20. (Decayed.) FIG. 135. Same, lower surface, showing broad convex midrib delimited by furrows, x 20. FIG. 136. Three lobes of a larger specimen, upper surface, x 20. (.43917.) FIG. 137. Same, lower surface, showing broad midrib flanked by hollows partly concealed by recurved margins of lobes. (White patch a sand grain.) x 20. FIG. 138. Fragment near base of leaf with lobes diminishing in size downwards. Upper surface, x 20. (.43916.) FIG. 139. Same, lower surface, showing conspicuous convex midrib, x 20. Bull. B.M. (N.H.) Geol 6, 3 PLATE 32 PLATE 33 Carpolithus sp. FIG. 140. Fruit showing cavity exposed by partial splitting into two valves, one now in- complete, a, attachment scar, x 14. (V. 43915.) FIG. 141. Same, opposite side, with obscure ribbing. Broken valve projects at v. x 14. Figs. 142-147 from Osborne Beds, Isle of Wight. Acrostichum lanzaeanum (Visiani) FIG. 142. Fragment of pinnule showing characteristic nervation, cf. Text-fig. 3. x 2-5. No. 377 Geological Survey Museum from Cliff End near Colwell Bay. ? Stratiotes neglectus Chandler FIGS. 143-146. Seeds or valves, small, crushed, probably abortive. Figs. 143-145 external surface. Fig. 146 internal surface. Figs. 144, 146 have the keel partly broken at b along the line of the raphe. h, position of hilum. x 6. (V. 43923-26.) From Osborne. Dicotylophyllum pinnatifidum Reid & Chandler FIG. 147. Terminal fragment of leaf. X 6 approx. No. 376 Geological Survey Museum, from Cliff End, Colwell Bay. Figs. 148-165 from Bembridge Beds, Isle of Wight except Fig. 153 from Hamstead Beds for comparison. ? Potamogeton sp. FIG. 148. Impression of upper surface of tuft of leaves still attached to stem. Crushed so as to give appearance of a whorl. X i. (V.23428.) FIG. 149. Part of leaf at x in Fig. 148 showing toothed margin at m and series of nerves and bast bundles, x 3. From Insect Limestone, Thorness Bay. Limnocarpus forbesi (Heer) FIG. 150. Endocarp, side, keel on right, s, style. Large lateral foramen, /, filled with matrix. Crushed but surface rugosities well preserved, x 15. (.43930.) FIG. 151. Another, dorsilateral view, showing ridged keel. Style broken, x 15. (.43931.) FIG. 152. Another, crushed and tilted to show tip of ridged keel, x 15. (.43932.) Marls below Chapel Corner, Wootton. FIG. 153. Similar crushed endocarp for comparison with Fig. 151. Style broken, x 15. (V. 43960.) Waterlily Bed of Hamstead Beds, Hamstead cliff. Bull. B.M. (N.H.J GeoL 6, 3 PLATE 33 148 PLATE 34 Stratiotes neglectus Chandler FIG. 154. Valve, exterior, typical seed. x 6-5. (.40079.) FIG. 155. Same, interior, showing diagonal raphe crossing keel on left, m, micropyle. x 6-5. Marls, Hamstead Ledge. Celtis edwardsi n.sp. FIG. 156. Holotype. Endocarp, side, showing reticulate surface. Margin lies in plane of symmetry, a, one of a pair of apical depressions, x 6-5. (V. 43919.) FIG. 157. Same at right angles to the above ; a,a, apical depressions (part of system of retic- ulations. X 6-5. FIG. 158. Same, apex, plane of symmetry vertical. Pair of depressions seen just above equator of figure. X 6-5. FIG. 159. Same, base, plane of symmetry vertical. X 6-5. FIG. 1 60. Internal cast of another endocarp (virtually equals seed) viewed at right angles to plane of symmetry, p, placenta, x 6-5. (V.4392O.) Bembridge Limestone, Headon Hill. Ranunculus ovaliformis (Reid & Chandler) FIG. 161. Impression of achene with large recurved style, basal attachment and impressions of small tubercles in central area, x 6-5. (.23429.) Insect Limestone, Thorness Bay. Carpolithus sp. FIG. 162. Valve of fruit or endocarp showing apical style, s, and basilateral flanges, x 4. FIG. 163. Same, inner surface, showing basal canals and coarse network of fibres impressed on cavity wall. Also smooth marginal suture, x 5-5. FIG. 164. Exterior of another specimen, x 4. FIG. 165. Same, opposite side with near valve broken so that cavity and basal canal are shown, x 4. From marly pocket in Bembridge Limestone, Sticelett Ledge, Isle of Wight. All in Sandown Museum, J. F. Jackson Coll. Figs. 166-204 from Hamstead Beds, Isle of Wight. Typha latissima Al. Braun FIGS. 166-170. Five seeds truncated above by micropylar disc with central mucro, pointed chalazal end at base, x 15. (V. 43940-44.) " Waterlily Bed ", Hamstead. ? Sparganium multiloculare Reid & Chandler FIG. 171. Endocarp, side, x 15. (.43947.) Sparganium sp. FIG. 172. Endocarp, apex, showing aperture of stylar canal leading into locule. x 6-5. (V-43948.) " White Band ", Bouldnor cliff. Potamogeton tenuicarpus C. & E. M. Reid FIGS. 173-176. Four endocarps, v, valve, x 15. .43949-50 from " Waterlily Bed ", Hamstead. .43954-55 from same at Bouldnor cliff. Limnocarpus forbesi (Heer) FIG. 177. Uncrushed pyritized endocarp. x 12. (Decayed.) Hamstead Beds, Hamstead cliff. FIG. 178. Another, side, s, stalk ; st, style ; keel on right, x 15. (.43957.) " Water- lily Bed ", Hamstead cliff. ? Caricoidea minima (Chandler) FIGS. 179-180. Two endocarps. Fig. 180 shows lateral ridge and basal flange, x 12. (.43965-66.) Hamstead cliff. Stratiotes neglectus Chandler FIG. 181. Seed, exterior, x 6-5. (.43968.) FIG. 182. alve of seed, interior, x 6-5. (.43969.) In beds full of Potamaclis turritissima Hamstead cliff, said to come from the Hamstead Series. Bull. B.M. (N.H.) Geol. 6, 3 PLATE 34 W.66 ^7 ' 68 T 6 9 ^ 163 PLATE 35 Stratiotes websteri (Brongniart) FIG. 183. Typical valve of seed, exterior. Keel on left. Collar, c. x 6. (.43976.) FIG. 184. Another, inner surface, showing short transverse raphe. h, hilum ; m, microyple. x 6. (.40072.) FIG. 185. Narrower small seed. Lettering as above, x 6. (.43974.) FIG. 186. Relatively unabraded seed. Keel on right, x 6. (".43975.) Hamstead cliff. Stratiotes acuticostatus Chandler FIG. 187. Holotype. Seed, exterior, showing sharp interrupted ridges ; k, broad keel. Note coarse pitting, x 6. (.40075.) FIG. 1 88. alve of another, inner surface, showing conspicuous raphe traversing keel on left ; m, micropyle. X 6. (.40074.) FIG. 189. Long narrow seed, exterior, with typical crested ridges, x 6. (.44653.) FIGS. 190-192. Three small seeds, ? immature. Figs. 190, 191 show exterior, fig. 192 interior. X 6-5. (.44174. V. 44 i76, .44179.) Bouldnor cliff. Sabal major (Unger) FIG. 193. Impression of central part of a leaf with scanty carbonaceous remains. Shows tapering rachis and asymmetry at top of petiole, x 0-66. Middle Hamstead Beds, Hamstead. Sedgwick Museum, Cambridge, H. Keeping Coll. Brasenia ovula (Brongniart) FIG. 194. Crushed seed with embryotega, e. X 12. (.44185.) Hamstead cliff. Leguminosae. Genus ? FIG. 195. Much crushed seed, x 12. (.44192.) Hamstead cliff. Aldrovanda intermedia Reid & Chandler FIG. 196. Seed looking onto raphe ridge, x 15. (.44193.) Hamstead cliff. ? Ilex sp. FIG. 197. Dorsiventrally flattened endocarp. Scar of attachment median near base, x 12. (.44194.) Hamstead cliff. Carpolithus sp. (Spirematospermum sp. ?) FIG. 198. Part of pod ; s, stalk ? White infilling lies within locule and is exposed where carpel wall has broken away. X i. (41424.) Lower Hempstead Marls, Hempstead. Carpolithus spp. FIG. 199. Crushed seed, possibly peculiarly preserved Brasenia with aperture for an embryo- tega at e. x 15. (.44187.) Hamstead cliff. FIG. 200. Crushed seed with basal scar, x 12. (.44200.) Hamstead cliff. FIGS. 201-204. Translucent tegmens of unidentified seed ? with conspicuous scar (chalaza ?) at one end. Two have split longitudinally at opposite end (Figs. 203, 204) perhaps as result of crushing, x 15. (.44201-03, Fig. 201 decayed.) "Waterlily Bed", Hamstead cliff. FIGS. 205, 206. F. E. Edwards Collection Headon Hill in ironstone nodule ? Horizon ? possibly Lower or Upper Headon. Stizocarya sp. FIG. 205. alve of endocarp, exterior, x 3. (.43928.) FIG. 206. Same, inner surface, showing apical part of funicular canal traversing wall to sub- apical placenta. Canal abraded below /. x 3. Bull. B.M. (N.H.) Geol. 6, 3 PLATE 35 205 198 206 INDEX TO VOLUME VI New taxonomic names and the page numbers of the principal references are printed in Bold type. An asterisk (*) indicates a figure. Abelia quadrialata 331 quinquealata 331 sp-4 33i trialata 331 Abietineae 326, 330, 336 Acanthaceae 331 Acanthus rugatus 331 Acrostichum 327, 358 aureum 316 lanzaeanum 328, 329, 358, 359* ; PI. 33, fig. 142 Actinidia 329 Aeolopora 15, 23, 24, 29*, 30, 40, 52, 53, 54, 272 distincta 33*, 43, 44, 54, 55, 56*, 57*, 58*, 64, 272 ; PI. 2, figs. 1-7 nebulosa 15, 33*, 55, 62, 63*, 272 ; PI. 2, figs. 8, 9 stellata 58, 59 Agathis 335 Ajuginucula smithi 331 Aldrovanda 324, 325, 348, 378 intermedia 328, 331, 333, 348, 378 ; PI. 35, fig. 196 ovata 326, 327, 348, 378 ; PI. 30, figs. 70, 71 vesiculosa 348 Amphiblestrum 36 cervicorne 37* ancestrulae 45 Andriopora 23, 266 frequens 55 gallica 55 major 33*, 268, 269* ; PI. 23, fig. 5 minor 32, 33*, 266, 267*, 269 ; PI. 23, fig. 6 Andromeda reticulata 333 Anemia 325, 334, 361 colwellensis 324-327, 329, 334, 358, 361 sp. 329, 361 sp ; 3 361 Angiospermae 326, 328, 330, 333, 337, 359, 362, 309 Anornithopora 54 Antevsia 317 apertural bars 32 Apocynaceae 331 Apocynospermum dubium 331 elegans 331 rostratum 331 striatum 331 Aquifoliaceae 333, 378 Araceae 330, 364 Araucarineae 326, 330, 335, 362 Araucarites 327, 335, 362 goepperti 362 gurnardi 326, 329, 330, 335*, 336, 362 ; PI. 27, figs, i, 2 selseyensis 336 sternbergi 362 ARBER, E. A. N. 372 ARCHANGELSKY, S. 318 Asclepiadaceae 331 avicularia 41 Azolla prisca 330 Baiera tenuifolia 297, 300 Barroisina galeata 106 Batrachopora 52, 240, 241, 244, 264 coaxans 253 crassa 250, 252, 253, 266 hyla 260 ornata 260 peltaia 266 perforata 266 rantwctt/MS 242 royawewsfs 242, 265 ultima 242, 265, 266 Belemnella lanceolata, Zone of 12 Belemnitella mucronata, Zone of 1 1 Bembridge Beds 323, 328, 361 Betulaceae 331 Bignoniaceae 331 Brasenia 324, 325, 329, 332, 333, 346, 366, 374, 376-378. 38o antiqua 347 oblonga 348 ovula 325, 326, 328, 329, 331, 333, 334, 346, 366, 376, 377 ; PI. 29. figs. 58, 59, 62 ; PI. 35, fig. 194 spinosa 326, 327, 346, 347 ; PI. 30, figs. 63-69 BRYDONE, R. M. 19, 20 Burnera Waterfall, Natal 289 Canupora prima 66, 67 Caprifoliaceae 326, 331, 353 Carex 339, 343 colwellensis 326, 327, 339 ; PI. 28, figs. 26, 27 flava 339 gurnardi 330 386 INDEX Carex contd. oederi 339 sp. 326, 327, 330, 340 ; PI. 28, figs. 20-25 Caricoidea 340, 341, 375 angulata 326, 342 ; PL 28, figs. 41, 42 colwellensis 326, 340, 375 ; PL 28, figs. 31-35 maxima 326, 327, 341, 342 ; PL 28, figs. 36-40 minima 333, 334, 342, 375 ; PL 34, figs. 179, 1 80 obscura 325, 326, 342, 343 ; PL 28, figs. 29, 30 sp. 328 Caricoideae 340, 341, 375 Carpinus 345 betulus 345 sp. 33i Carpolithus 368, 379 actinidiformis 329 boveyanus 344 colwellensis 326, 327, 355; PL 32, figs. 120-126 sp.2 328, 329, 331, 368 spp. 325, 326, 329, 331, 333, 356*, 357, 368, 379, 380, 381 ; PL 32, figs. 127-133 ; PL 33, figs. 140, 141 ; PL 34, figs. 162-165 .' PL 35, figs. 199-204 thalictroides 374 websteri 374 Carydiopora 54, 170 Caryophyllaceae 345 Castanopora 15, 24, 29*, 40, 41, 43, 52, 53, 202, 203, 274 artnata 41, 205, 206, 207* ; PL 16, fig. i aviculosa 15, 206, 226, 227* ; PL 19, fig. 3 castanea 15, 33, 39, 203, 205, 211, 212*, 274 ; PL 1 6, figs. 3-5 dibleyi 15, 39, 205, 215, 218*, 274 ; PL 16, figs. 6-8 ; PL 17, figs, i, 2 faujasi 15, 206, 236 glandulosa 15, 206, 225, 226* ; PL 18, fig. i guascoi 15, 205, 219 jurassica 15, 206, 223, 224* ; PL 17, figs. 3-5 labiata 15, 41, 42*, 205, 208 magnifica 15, 25, 33*, 206, 228, 230*, 274 ; PL 18, figs. 2-7 ; PL 19, figs, i, 2, 4-6 ; PL 20, fig. i multicostata 16, 206, 221 nucifera 214 retrorsa 205, 209, 210, 217, 274 ; PL 16, fig. 2 spooneri 16, 206, 220 voigti 16, 22, 206, 236 Catalpa rugosa 331 Caytonanthus 317 Caytoniales 318 Cellepora perforata 206, 237 (Discopora) signata 242, 264 Celtis 329, 365, 366 australis 366 ed wards! 329, 331, 365 ; PL 34, figs. 156-160 occidentalis 366 rubronervia v. integrifolia 366 sinensis 366 Cenomanian 8 Centrospermae 326, 345 Genus? 345 ; PL 29, fig. 57 Cerithium plicatum 333 CHALONER, W. G. 318 CHANDLER, M. E. J. 321-384 Chaperia 36 cervicornis 37* galeata 37* quadrispinosa 36* Char a 328 CHESTERS, K. I. M. 334 Cinnamomum lanceolatum 331 Cladiocarya foveolata 330 Cladium 341, 375 colwellensis 326, 327, 340, 375 ; PL 28, figs. 31-35 europaeum 341 macrocarpum 341 mariscus 341, 375 reidiorum 341 sp. 328 Clematis vectensis 331 COLENUTT, G. W. 324, 329, 368, 369 Colletosia bellula 1 1 1 Colwell Bay, I.o.W. 326, 334 Compositae 331 Coniferales 326, 330, 333, 335, 362, 369 Corbula Beds 332, 333 Corymbopora 23 Corystospermaceae 289, 317 costae 26 Costus sp. 330 Cribrilina 264 alcicornis 36* annulata 27* balzaci 27* brachiata 255 cacus 234 fragilis 139, 144 furcifera 82 galanthis 163 gregoryi 163 innominata 27* insignis 155, 156 labiata 209 perforata 255 radiata 26 repleta 153, 154, 163 suffulta 154, 163 tumuliformis no, in valida 209 Crossotheca 316, 318 Cruciferae 331 Cupressineae 330 Cupressus sp. 330 Cycadofilicales 316 Cyperaceae 325, 326, 330, 333, 339, 343, 375 Genus? 343 ; PL 28, figs. 43, 44 Cyperites forbesi 372 INDEX 387 Cyrena 324 Czekanowskia tenuifolia 300, 304*, 310-312 DAVIS, A. G. 13, 372 Decodon 351 gibbosus 352 globosus 351 vectensis 326, 327, 351, 352 ; PI. 30, figs. 86-90 ; PL 31, figs. 91-98 verticillatus 351, 352 Decurtaria 54 Diacanthopora 30 Dicotyledones 326, 328, 330, 333, 344, 360, 365, 376 Dicotylophyllum 327, 360 pinnatifidum 327-329, 331, 360, 361* ; PI. 33, fig- M7 spp. 329, 331 Dicroidium 308, 313 coriaceum 308 feistmanteli 296*. 306*, 308, 309*, 310, 312, 313 odontopteroides 302*, 306*, 308, 309*, 310, 312, 313 superbum 308 talbragarense 310 -Xylopteris Group 289, 308, 310, 312, 315 Dictyothalamus schrollianus 316, 317 Dilleniaceae 331 Dipelta europaea 331 Dishelopora 24, 30 Disteginopora 54, 241 horrida 241 Doliostrobus 336 sp- 329, 335, 3 6 2 sternbergi 335, 336 Doratophyllum tenison-woodsi 310 Droseraceae 326, 331, 333, 348, 378 EDWARDS, F. E. 366, 381 EDWARDS, W. N. 381 Electro, pilosa 23 Engelhardtia macroptera 330 sp. 330 Epacridaceae 325, 326, 354 Epacridicarpum 354 colwellense 326, 327, 354 ; PI. 31, figs. 117-119 headonense 325, 326, 354 ; PI. 31, figs. 114-116 mudense 355 Epipremnum 364 ornatum 329, 330, 364 Equisetaceae 330 Equisetales 330 Equisetites 313 Equisetum lombardianum 330 Escharipora chrysalis 133 guascoi 220 magnified 220 mumia 137 pretiosa 220 striata 133, 137 Escharoides peltata 242, 266 Eucheilopora 55 Fagaceae 331 Fagus sp. 331 Ficus 325, 345 lucidus 325, 326, 345 ; PI. 29, fig. 56 sp- 331 Figularia in philomela in spatulata in Filicales 326, 328, 329, 334, 358, 361 Flabellaria major 375 Flabellicula anglica 331 Folliculites thalictroides 364, 374 webster i 374 frontal shield 25 wall 25 Gangamopteris 317 CASTER, C. T. A. 5, 19 Geological Survey & Museum 360, 369, 372 Gephyrotes nitido-punctata 27* Gleichenia 358 Glossopteris 317 Gonioteuthis quadrata, Zone of n Gramineae 330 Granulatensenon 19 GROVES, J. 324 gymnocyst 25 Gymnospermae 326, 330, 333, 335, 362, 369 Hamstead Beds 323, 325, 332, 369 Haplocephalopora 42 HARRIS, T. M. 318 Harrisiothecium marsiloides 317 HASTINGS, Anna B. 7 Headon Beds 323, 324, 325, 326, 334 Hesperopora 54 heterozooecia other than avicularia 43 Hexacanthopora 16, 24, 25, 30, 31, 40, 52, 53, 65, 97. 272 brightonensis 99, 100 kintburiensis 99, 100 sexspinosa 16, 25, 32, 33*, 39, 43, 97, 272 ; PI. 5, figs. 3-6 viginticostata 16, 97, 102, 272 Hippiopora 34 Histricopora 30 Hoegia 313 Holaster planus, Zone of 9 subglobosus, Zone of 8 Hooleya hermis 330 Hordwellia 350 crassisperma 325, 326, 350 ; PI. 30, figs. 81-85 eocenica 325 Hydrocharitaceae 326, 328, 330, 333, 339, 359, 363, 372 Hydropterideae 330 Hyphantoceras reussianum, Subzone of 9 388 INDEX Icacinaceae 334, 381 Ichnopora 54 denticulata 263 Ilex 333, 378, 379 sp. 333. 378 ; PI. 35, fig. 197 Incarvillea pristina 331 intercostal spaces 31 interzooecial secondary tissue 40 JACKSON, J. F. 328, 368 Juglandaceae 330 KEEPING, H. 328 Labiatae 331 Lagynopora 16, 24, 25, 30-32, 35, 39, 40, 43, 52, 53, 65, 66, 97, 272 amphora 39, 66, 77* ; PI. 3, fig. 9 ampulla 33*. 39, 66, 78, 79* ; PI. 3, fig. 7 birlingensis 39, 66, 74, 75* ; PI. 3, fig. 6 furcifera 16, 39, 66, 81* ; PI. 4, figs, i, 2 horsleyensis 16, 66, 68, 69*, 250, 272 ; PI. 3, figs. 2, 3 lagena 16, 39, 65, 66, 86, 87* ; PI. 4. figs. 4-6 ollula 39, 66, 82, 83, 84, 95, 97 ; PI. 4, fig. 3 praecursor 39, 66, 71* ; PI. 3, fig. 5 prima 1 6, 67, 96, 97 pustulosa 33*, 66, 67*. 272 ; PI. 3, fig. i saltdeanensis 66, 73*, 76, 272 ; PI. 3, fig. 4 urceolus 39, 66, 90, 91*, 92* ; PI. 4, fig. 7 ; PI- 5. fig- i vasculum 39, 66, 82, 83, 93, 94* ; PI. 5, fig. 2 LANG, W. D. 5, 7 LARWOOD, G. P. 1-285 lateral costal fusions 30 Lauraceae 331 Leguminosae 333, 378 Genus? 378 ; PI. 35, fig. 195 Lepidopteris stormbergensis 310, 312 Lepralia otto-mulleriana 26, 28*, 30 pediculus 66, 67, 95 Leptocheilopora 16, 25, 30, 31, 40, 43, 52, 53, 97, 102, 272 arcuata 114 filliozati 16, 32, 33*. 34, 35, 39, 103, 112, 113, 115*, 272, 273 ; PI. 7, figs. 3, 4 ; PI. 8 gasteri 109 longuessensis 106, 118 magna 16, 25, 30, 35, 39, 103, 104*, 105*, 113, 115, 272, 273 ; PI. 6, figs. 1-7 regular is 119 tenuilabrosa 35, 41, 43, 44, 103, 107, 108*, 109*, no*, in*, 115, 272, 273 ; PI. 6, figs. 8-1 1 ; PI. 7, figs, i, 2 vulnerata 33*, 39, 97, 103, 115, 116, 117*, 272, 273 ; PI. 9, figs, i, 2 Librocedrus sp. 330 Limnaeu 324 Limnocarpus 324, 325, 329, 338, 363, 372 enormis 338 forbesi 325, 326, 330, 333, 334, 338, 363, 372 ; PI. 27, figs. 9, 10 ; PI. 33, figs. 150-153 ; PI. 34, figs. 177, 178 spinosus 330 Linguifolium lilieanum 310, 312 Lithothamnienkalk of Haidhof 19 London Clay 325 lumen pores 27 Lyginopterideae 316, 318 Lygodium sp. 329 Lythraceae 325, 326, 351 Maastrichtian 12 Mammillatensenon 19 Manebachia polysporangiata 317 Marsupites testudinarius, Zone and Subzone of 10 median area of fusion 31 Medulloseae 316 Melania 324, 328 forbesii 364 turritissima 364, 372 Melanopsis 364 Melissa parva 331 Membranipora 223 crenulata 119 meudonensis 255 nitida 26, 31 ocellata 255 reticulata 255 Micraster cor-anguinum, Zone of 9 cortestudinarium, Zone of 9 Microdiptera major 352 parva 326, 327, 352 ; PI. 31, figs. 99-107 M0en Chalk 19 Monasteroideae 364 Monoceratopora 41 Monocotyledones 326, 328, 330, 333, 337, 359, 362, 369 M onocotylophyllum sp. 330 Moraceae 326, 331, 345 Murinopsia 54 Myrica boveyana 325, 326, 344 ; PI. 29, figs. 45-48 colwellensis 326, 327, 344 ; PI. 29, figs. 49-55 Myricaceae 326, 344 Naias oligocenica 330 Najadaceae 330 Nelumbium 327, 333, 360, 376, 377 buchi 327, 328, 332-334, 360, 376 Neolitsea sp. 331 Neritina Beds 324 Nymphaea 347, 348 doris 376 sp. 326, 347 ; PI. 29, figs. 60, 6 1 Nymphaeaceae 326, 328, 331, 333, 346, 360, 366, 3?6. 377 Genus? 346 ; PI. 29, fig. 62 INDEX 389 Oligocene floras 323 Offaster pilula, Zone of 10 oral shields 39 spines 35 orifice, primary 34 secondary 35 Osborne Beds 323, 327, 328, 358 Ostrea lunata, Chalk with 13 Ottelia britannica 330 ovicells 43 Pachydera 54 Palaeothrinax mantelli 330 Palibinia densifolia 360 Palmae 330, 333, 375 Palmophyllum sp. 330 Paludina 324 lenta 364 Pamelreuthia halbevfelneri 317 Pancheilopora 55 Papaver pictum 331 Papaveraceae 331 pelmata 27 pelmatidia 27 Pelmatopora 17, 22, 25, 30, 32, 34-36, 39-41, 43, 52, 53, 119, 272, 273 bidens 181 brydonei 17, 21, 38, 123, 150, 164, 165, 166, 273, 274 ; PI. 12, fig. 3 calceata 40-42*, 122, 123, 124*. 129, 273 ; PI. 9, ng. 3 chrysalis 17, 122, 132, 133*, 136, 137, 273 ; PI. 9, fig. 7 collium 181 coryli 38, 123, 168, 169* ; PI. 12, fig. 4 crepidaria 40, 122, 125, 126*, 273 ; PI. 9, fig- 4 damicornis 198 daniensis 17, 200, 202 danktonensis 192 d'orbignyi 17, 33, 122, 140, 141*, 142*. 273 ; PI. io, fig. 3 fecampensis 17, 40, 44, 122, 145, 146*, 147*, 148*. 273 ; PI. io, fig. 6 filliozati 139, 144 fragilis 17, 122, 138*, 273 ; PI. io, figs, i, 2 gasteri 122, 130, 131*, 273 ; PI. 9, fig. 8 grandiporosa 201 gregoryi 21, 38, 40, 42*, 44, 123, 146, 154, 166, 175, 178*, 179*, 180*, 192, 193, 198, 200, 274 ; PL 13 ; PI. 14, figs. 1-4 gyrijoides 181 incerta 200 insignis 154, 155 interrupta 136 lacuum 181 lancingensis 181 larva 17, 22, 122, 134*. 142, 273 ; PI. 9, fig. 9 marsupitorum 17, 38, 42*, 44, 123, 171, 172*. 192, 274 ; PI. 12, figs. 2, 5 palmata 33*. 38, 123, 193, 196, 197*, 274 ; PL 15, figs. 3, 5, 6 pauciclavia 139 pero 120, 123, 148, 149*, 167, 273, 274 ; PL io, fig. 7 plantaris 123, 159, 160*, 273 ; PL n, fig. 4 promontoriorum 181 quadrata 17, 44, 122, 143, 144*, 273 ; PL io, figs. 4. 5 quadrivolucris 38, 123, 161, 162*, 273, 274 ; PL ii, figs. 5, 6 ; PL 12, fig. i ranunculoides 181 repleta 153-155 roedeanensis 173 saltdeanensis 181 simplex 123, 157, 158*. 161, 273, 274 ; PL n, figs. 2, 3 solearis 33*, 40, 122, 127*, 128*, 273 ; PL 9, figs. 5, 6 somptingensis 21, 24, 31, 33*, 38, 41, 42*, 44, 123, 146, 188, 190*, 191*, 274 ; PL 14, figs. 5, 6 ; PL 15, figs, i, 2, 4 spp. 199, 201 ; PL 15, fig. 7 striata 17, 122, 136, 273 ; PL 9, fig. io suffulta 1