THE VOYAGE OF H.M.S. CHALLENGER. ZOOLOGY-VOL. XXVI. REPORT iW, SCIENTIFIC RESULTS OF THE VOYAGE OF H.M.S. CHALLENGER DURING THE YEARS i 8 7 3-7 6 UNDER THE COMMAND OF Captain GEORGE S. NARES, R.N., F.R.S. AND THE LATE Captain FRANK TOURLE THOMSON, R.N. PREPARED UNDER THE SUPERINTENDENCE OF THE LATE Sir C. WYVILLE THOMSON, Knt., F.R.S., &c. REGIUS PROFESSOR OF NATURAL HISTORY IN THE UNIVERSITY OF EDINBURGH DIRECTOR OF THE CIVILIAN SCIENTIFIC STAFF ON BOARD AND NOW OF JOHN MURRAY, LL.D., Ph.D., &c. ONE OF THE NATURALISTS OF THE EXPEDITION Zoology— Vol. XXVI. IPublt'sfteti up ©ttier of ^)er jflajestp's ^ouernment PRINTED FOR HER MAJESTY'S STATIONERY OFFICE AND SOLD BY LONDON :-EYRE & SPOTTISWOODE, EAST HARDING STREET, FETTER LANE EDINBURGH :— ADAM & CHARLES BLACK DUBLIN :— HODGES, FIGGIS, & CO. 1 888 Price Fifty Shillings PRINTED BY NEILL AND COMPANY, EDINBURGH, AND MORRISON AND GIBB, EDINBURGH, FOR HER MAJESTY'S STATIONERY OFFICE. CONTENTS. I. — Report on the Crinoidea collected during the Voyage of H.M.S. Challenger, during the years 1873-1876. Part II. — The Comatul^e. By P. H. Carpenter, D.Sc, F.R.S., F.L.S., Assistant Master at Eton College. (The Manuscript ivas received in Instalments between 20th December 1886 and 30th March 1888.) II. — Report on the Seals collected during the Voyage of H.M.S. Challenger in the years 1873-1876. By Sir William Turner, Knt, M.B., LL.D., F.R.SS. L. & E., Professor of Anatomy in the University of Edinburgh, Member of the General Medical Council. (The Manuscript ivas received in Instalments between 29th January 1887 and 10 th January 1888 ; the Appendix, 13th December 1887 and 25th February 1888.) III. — Report on the Actiniaria dredged by H.M.S. Challenger during the years 1873-1876. Supplement. By Professor Richard Hertwig. (TJie Manuscript ivas received 21st January 1888.) 7i EDITORIAL NOTES. This Volume contains Parts LX., LXVIL, and LXXIII. of the Zoological Series of Keports on the Scientific Results of the Expedition. Part LX. — This Part comprises the second portion of the Report on the Crinoidea, by Dr. P. H. Carpenter, F.R.S., and deals with the Comatul^e. The First Part of the Report, dealing with the Stalked Crinoids, forms Part XXXII. of the Zoological Series of Reports, and was published in 1884 in Volume XI., Zoology. In the present Memoir Dr. Carpenter gives the results of his investi- gations, which have extended over thirteen years, and the Report may be regarded as practically a complete Monograph of the living species of Comatulag. The Report consists of 401 pages of letterpress, 70 lithographic plates, and other illustrations. Part LXVIII. — This Report on the Seals, by Professor Sir William Turner, F.R.S., completes the Reports on Marine Mammals, the First Part of which, on the Bones of the Cetacea, formed Part IV. of the Zoological Series of Reports, and was published in Volume I., Zoology, in 1880. The present Part consists of a description of the skeletons of the Seals collected by the Expedition ; of a revised classification of the Pinnipedia ; of a description of the brains of the Elephant Seal and Walrus, and a com- parison with the brains of the Carnivora generally and of Apes and Man ; also some observations on the viscera of the Elephant Seal. It is accom- viii THE VOYAGE OF H.M.S. CHALLENGER. panied by an Appendix on the Myology of the Pinnipedia, by Dr. W. C. Strettell Miller. The Report consists of 240 pages of letterpress, illustrated by 10 litho- graphic plates and several woodcuts. Part LXXIII. — The Report on the Actiniaria, by Professor Richard Hertwig, was published in 1882, forming Part XV. of the Zoological Series of Reports, in Volume VI., Zoology. The present Memoir forms the Supplementary Report promised at that time on a number of forms which reached Professor Hertwig too late for the descriptions to be included in the original Report. It consists of 56 pages of letterpress and 4 lithographic plates. The Memoir was translated from the German by G. Herbert Fowler, Esq., Ph.D., of University College, London. John Murray. Challenger Office, 32 Queen Street, Edinburgh, 21s/ June 1888. ERRATA FOR PART LX. Page 34, Hue 22, for " sctosa," read " multispina." Page 60, line 6 from bottom, for " Actinomctra conjungcns," read " Antcdon conjungcns." Page 90, line 15, for " Antcdon fluctuans," read " Antedon elegans." Page 90, line 23, for " the late Mr. Spedding," read " the Eev. T. E. E. Stebbing." Page 93, line 11, delete the words "of Actinometra diffwilis (PI. LII. fig. 2)." Page 94, line 5, for " costatus " read " costata." Page 94, lines 12, 16, for " Antedon fluctuans, n. sp.," read "Antedon elegans, Bell." Page 96, lines 1, 6, 12, 16, and page 97, line 6, for "fluctuans" read "elegans." (See p. 264.) Page 97, line 21, for "Antcdon lidentata" read "Antcdon variipinna." Page 110, line 8, for " Antedon dubia " read " Antedon variipinna." Page 205, line 6, for " Antedon variipenna," read " Antcdon variipinna" Page 252, line 5, for " Bidistichate," read " Tridistichate." Page 320, line 12, for " a.3.2br.^-," read " a.3.2br.^-." Page 322, line 8, for "figs. 1-3" read "figs. 1-3, 8." Page 325, line 22, for " figs. 4-6 " read " figs. 4-7." THE VOYAGE OF H.M.S. CHALLENGER ZOOLOGY. REPORT upon the Crinoidea collected during the Voyage of H.M.S. Challenger during the Years 1873-76. By P. Herbert Carpenter, D.Sc, F.R.S., F.L.S., Assistant Master at Eton College. PART II.-THE COMATULjE. PREFACE. The accompanying Report is the result of a study of the Comatulae which has been carried on, with occasional breaks caused by bad health and by the pressure of other work, since the latter part of the year 1875. Early in 1878 Sir Wyville Thomson was good enough to place the Challenger collection in my hands for description ; and in the following year a preliminary account of it was published in the Proceedings of the Royal Society. The group had been singularly neglected for many years previously. Midler's classical memoir, Ueber die Gattungen und Arten der Comatulen, appeared in 1849, and laid the foundation of all future systematic work, as well as of the descriptive terminology now in use. Isolated species have been described by various authors during the last forty years, but no serious revision of the group has ever been attempted, though in 1862 Midler's classification was modified in one or two points by Dujardin and Hupe. Thirty-five species were described by Midler in 1849, the types of which are scattered (ZOOL. CHALL. EXP, — PAKT LX.— 1888.) OoO a 11 THE VOYAGE OF H.M.S. CHALLENGER. through the various museums of the Coutiueut ; and by the kindness of Sir Wyville Thomson I was enabled to make a personal examination of almost all of these in the autumn of 1880. Twenty of them belong to Antedon and fifteen to Actinometra, as these genera are now understood. Four at least of Midler's species (1 of Antedon, 3 of Actinometra) appear to me to have no real value ; while 168 species belonging to these two genera are considered in the present Eeport, viz., 120 of Antedon and 48 of Actinometra. Of these there are only two which I have not personally examined, the type of one having disappeared, while I have not as yet been able to visit the museum which contains the other. Of these 168 species 79 were discovered by the explorations of the Challenger (Antedon 64, Actinometra 15), which also added two new genera, represented by 4 species, to the family Comatulidse. Professor Semper's dredgings in the Philippine Islands had previously made known the existence of a third generic type, and a fourth was obtained by the Gulf Stream explorations of the U.S. Coast Survey, though the fact was not recognised at the time. Other species of each of these two genera were obtained by the Challenger, making in all 180 species of this family, 88 of which were new to science. These numbers are considerably lower than those mentioned in the Preliminary Report. At the time when that was published I had only seen three large Comatula- collections besides that of the Challenger, viz., those of the British and Paris Museums, and that made by Professor Semper in the Philippines. Since then, however, I have examined many hundred Comatulse, including in many cases large numbers of individuals belonging to the same specific type, and the experience thus gained has been of the utmost value, by enabling me to unite under one specific name forms which at first had seemed distinct to the less trained eye. In one or two cases the result has been that the specific names appended to some of the plates which were first printed off have since required alteration ; and the same is true of some of the earlier sheets of the text. The preparation of this Report has been considerably delayed by the pressure of other work and by interruptions of various kinds. The first four years after the collection came into my hands were occupied pretty continuously by the framing of specific diagnoses. These were nearly all completed when Sir Wyville Thomson died, in March 1882 ; and my leisure time for the next three years was almost entirely devoted to the completion of the Report on the Stalked Crinoids which he had left unfinished. I hoped then that another year's work would enable me to revise my descriptions of the Comatulse and suffice for the completion of this Report. But this object has been seriously interfered with by a continual increase of professional duties, together with the necessity of completing some long-delayed paleeontological work for the Trustees of the British Museum. I have also been much hindered by a troublesome affection of the eyes, which has frecmently entailed a prolonged cessation from work. REPOET ON THE CRINOIDEA. iii These, and other causes for delay which I need not mention, have not, however, been altogether disadvantageous ; for various small and more or less local collections of Comatulse have come into my hands during the past five years, and the experience gamed by their examination has been of great value in causing me to modify some of my earlier judgments respecting specific characters. The seventy plates accompanying this Eeport have been drawn by the following artists — Messrs. Berjeau and Highley, Parker and Coward, George West and Sons, and Mr. W. S. Evans ; and I desire to express my thanks to all these gentlemen for the care with which they have always endeavoured to carry out my wishes. I am also greatly indebted to my friend Professor F. J. Bell, F.Z.S., of the British Museum, for the ready way in which he has always given me the utmost facilities for examining the collection of Comatula? under his care. I have likewise to acknowledge the courteous kindness of Professor S. Loven at Stockholm, Professor A. Schneider of Breslau, Dr. E. von Marenzeller of Vienna, Dr. Otto Hamann of Gottingen, and Dr. F. Nansen of Bergen, who have been good enough to send selected Comatulaa to me for examination from the collections in their charge. It is proper also that I should record my indebtedness to the authorities of the numerous Continental Museums which I visited in 1880, for the uniform courtesy with which their collections were placed at my disposal. It only remains, in conclusion, for me to express my sincere thanks to Mr. John Murray for the kind patience with which he has borne the numerous delays in the completion of this Report, to which I have referred above ; and also to Mr. W. E. Hoyle, M.A., of the Challenger office, for the careful manner in which he has supervised its passage through the press. Eton College, April 1888. TABLE OF CONTENTS. MORPHOLOGY. I. — Genekal Introduction, II- — The Centeo-Dorsal and Calyx, A. The Centro-dorsal, Inferior Surface, . Superior Surface and Interradial Symmetry External Form, Obliteration of Cirrus-Sockets, B. The Chambered Organ, C. The Rosette, .... Basal Star, D. TheRadials, .... Radials of Antedon, Radials of Actinometra, E. Abnormal Conditions of the Rays, III. — The Geographical and Bathymetrical Distribution of the Comatul^e, Thaumatocrinus, Promachocrinus, and Eudiocrinus, Antedon, Ten-armed Species, Antedon, Multibrachiate Species, . Actinometra, ..... IV. — The Geological History of the Comatul^;, V. — Classification, ..... General Rules of Co?reatfu/a-strueture, Methods of Formulation, List of Antedon Species, .... List of Actinometra Species, VI. — Description of the Specimens, Family Comatulidre, .... Definition of Genus Tliaumatocrinus, . Thaumatocrinus renovatus, P. II. Carpenter, Definition of Genus Atelecrinus, Synopsis of the Species, Atelecrinus balanoides, n. sp., wy villii, n. sp., . PAGE 1 6 6 7 10 13 14 16 19 22 23 24 25 27 29 31 32 34 35 37 41 44 46 53 57 63 63 66 66 68 70 70 72 VI THE VOYAGE OF H.M.S. CHALLENGES. Definition of Genus Eudiocrinus, Characters of the Calyx, The Cirri, Geographical Eange, . Synopsis of the Species, Eudiocrinus varians, n. sp., . semperi, n. sp., . japonicus, n. sp., . Genus Antedon, de Freniinville, Definition and History of the Genus, Oral Pinnules, Sacculi, Series I. Elegans-grou-p, Antedon elegans, Bell, multiradiata, n. sp., microdiscus, Bell, Series II. Ten-armed Species, Synopsis of the Groups, 1. The Ba$icurva-gco\\\>, Synopsis of the Species, . Antedon longicirra, n. sp., vcdida, n. sp., incerta, n. sp., gracilis, n. sp., . lusitanica, n. sp., breviradia, n. sp., spinicirra, n. sp., acutiradia, n. sp., bispinosa, n. sp., laiipinna, n. sp., multispina, n. sp., echifiata, n. sp., basicurva, n. sp., incisa, n. sp., tuberosa, n. sp., parvipinna, n. sp. flexilis, n. sp., aculeata, n. sp., denticulata, n. sp., pusilla, n. sp., 2. The .4c«?a-group, . Synopsis of the Species, Antedon acoela, n. sp., discoklea, n. sp., 3. The Eschrickti-groixp, Synopsis of the Species, Antedon eschrichti, Mull., sp., antarctica, n. sp., australis, n. sp., rhomboidea, n. sp., quadrata, n. sp., PAGE 73 75 76 79 81 81 82 84 85 88 91 92 94 94 93 97 99 99 100 102 103 104 106 107 109 110 112 113 115 116 117 119 120 124 126 127 128 128 130 131 131 132 132 134 136 138 138 144 146 148 149 REPORT ON THE CRINOIDEA. Vll PAGE 4. The Tenella-growp, . 156 Synopsis of the Species, . 157 Antedon phalangium, Miill., sp., . 158 hystrix, n. sp., . 165 tenella, Retzius, sp., 169 exigua, n. sp., . 178 alternata, n. sp., 179 C rosacea, Linck., sp., i | petasus, Diiben and Koren, sp., ) 181 dubeni, Bohlsche, 181 lineata, n. sp., . 183 remota, n. sp., . 184 longipinna, n. sp., 185 tenuicirra, n. sp., 186 Isevis, n. sp., 187 hirsuta, n. sp., . 188 angustipinna, n. sp., 189 abyssorum, n. sp., 190 abyssicola, n. sp., 191 5. The Millierti-gToxrp, 192 Synopsis of the Species, . 193 Antedon milberti, Miill., sp., 194 anceps, n. sp., . 198 variipinna, Carpenter, 198 carinata, Lamarck, sp., 199 parvichra, n. sp., 204 informis, n. sp., 205 Synopsis of Unclassified Species, 206 Antedon balanoides, n. sp., 207 Series III. Bidistichate Species, 208 6. The S/nHifera-grou-p, 211 Synopsis of the Species, . 211 Antedon maeronema, Miill., sp., 212 quinquecostata, n. sp., 215 lusitanica, n. sp., 217 flexilis, n. sp., . 217 patula, n. sp., . 219 robusta, n. sp., . 220 compressa, n. sp., 222 7. The Palmata-gToup, 223 Synopsis of the Species, . 225 Antedon manca, n. sp., . 226 disciformis, n. sp., 228 clemens, n. sp., . 229 marginata, n. sp., 230 tuberculata, n. sp., 232 conjungens, n. sp., 233 similis, n. sp., . 235 occidta, n. sp., . 236 regalis, n. sp., . 237 Vlll THE VOYAGE OF H.M.S. CHALLENGER. PAGE Series IV. Tridistichate Species, . 238 8. The Granulifera-group, 239 Synopsis of the Species, 241 Antedon angusticalyx, n. sp., 242 inxqualis, n. sp., 244 distincta, n. sp., 247 multispina, n. sp., 248 porrecta, n. sp., 250 9. The Savignyi-gvourt, 252 Synopsis of the Species, 252 Antedon angustiradia, n. sp., 253 anceps, n. sp., . 254 variipinna, Carpenter, . 256 quinduplicava, n. sp., - 262 Note on Antedon fiuduans (elegans), . 264 Genus Adinometra, Miiller, 266 Definition of the Genus, . 267 History, 268 Position of the Mouth, 273 Non-tentaculiferous Arms, 275 Ovoid Bodies, 275 Terminal Combs of Pinnules, 276 Centro-dorsal and Calyx, 276 Series I. Synopsis of the Groups, . 277 1. The Solaris-group, 278 Synopsis of the Species, 278 Adinometra pedinata, Retzius, sp., 284 Solaris, Lamarck, sp., 288 2. The Pcrac/aVra-group, 290 Adinometra paucidrra, Bell, 291 3. The Typica-gvoux), 294 Synopsis of the Species, . 295 Adinometra distincta, n. sp., 295 typica, Loven, sp., . 296 multibradiiata, n. sp., 299 Series II. Ten-armed Species, 300 4. The Echinopitera-gxowp, 301 Adinometra nieridionalis, Pourtales, sp., 301 Series III. Bidistichate Species, . 302 5. The Stettir/era-gvour), 303 Synopsis of the Species, . 304 Adinometra pidchella, Pourtales, sp., 304 mandata, n. sp., 307 stelligera, n. sp., 308 6. The Vidida-gxoux), 310 Synopsis of the Species, . 311 Adinometra elongata, n. sp., 311 simplex, n. sp., 312 rotalaria, Lamarck, sp., 313 valkla, n. sp., 314 REPORT ON THE CRINOIDEA. IX Series IV. Tridistichate Species, . 7. The Fimbriata-giQaj), Synopsis of the Species, . Aclinometra fimbriata, Lamarck, sp., cojppingeri, Bell, mulfiradiata, Linn., sp., sentosa, n. sp., lineata, n. sp., 8. The Parvicirra-group, Synopsis of the Species, . Actinometra parvicirra, Mull., sp quadrata, n. sp., triclwptera, Mull., sp., divaricata, n. sp, belli, n. sp., duplex, n. sp., nobilis, n. sp., parvicirra, Mull., sp., triclwptera, Miill., sp., littoralis, n. sp. regalis, n. sp., Definition of the Genus Promachocrinus, Synopsis of the Species, Promaclwcrinus kerguelensis, n. sp,, abyssorum, n. sp., naresi, n. sp., VII. — Bathymeteical Distribution and Station List, H.M.S. " Lightning," 1868, H.M.S. "Porcupine," 1S69, H.M.S. "Porcupine," 1870, H.M.S. "Valorous," 1875, H.M.S. "Alert," 1875, . H.M.S. " Knight Errant," 1880, H.M.S. "Triton," 1882, . H.M.S. Challenger, 1873-76, PAGE 315 316 317 317 320 322 325 327 329 330 331 331 332 332 334 335 336 338 345 346 347 348 350 350 351 352 353 353 353 354 355 355 356 356 357 INDEX TO WOODCUTS. Fig. 1 . Thaumatocrinus renovatus, P. H. Carpenter, .... Fig. 2. Antedon basicurva, n. sp.; side view of the calyx and arm-bases after removal of three rays, Fig. 3. The same, ......... Fig. 4. The fiftieth and next following brachials of Antedon quadrata and Antedon eschrichti, . Fig. 5. Pinnules of Antedon inxqualis and Antedon angusticalyx, .... Fig. 6. Diagrams showing the different positions of the mouth in Actinometra, (ZOOL. CHALL. EXP. — PART LX. — 1888.) Ooo b 67 100 122 154 246 274 MORPHOLOGY. I.— GENERAL INTRODUCTION. The Comatulse constitute a group of Neocrinoids, which is so extensive, and differs so much from the remaining members of the order, that a subordinal rank may not improbably come to be assigned to it. The great variety and extensive distribution of the species of Antedon and Actinometra at the present time recall similar facts about Pentacrinus and Millericrinus in the Mesozoic rocks, and about Actinocrinus and Platycrinus in the Palaeozoic series. Although a few Palseocrinoids, such as Agassizocrinus and Edriocrinus, seem to have been stemless and unattached in the adult condition, the enlargement of the top joint of the larval stem into a cirrus-bearing centro-dorsal is not known to have occurred in any Palaeozoic, or even in any Triassic Crinoid ; while the physiological condition of the young Edriocrinus has been frequently reproduced in the Mesozoic Holopidse and in the recent genus Holopus, which inhabits comparatively shallow water in the Caribbean Sea, side by side with the free Crinoids or true Comatulae. The real nature of the latter group was long misunderstood. Linck and Linnaeus followed Llhuyd in regarding them as peculiar forms of the Sea-stars, to which the general name Asterias was assigned by the great Swede. Early in the present century, however, the free Crinoids were separated from the Asterids and Ophiurids by Lamarck. But he entirely failed to recognise their relationship to Guettard's Pentacrinus, which he placed among the Polypes, together with the various species of fossil Crinoids. Five years before Lamarck wrote, the genus Antedon had been established by de Freminville1 for a Feather-star from tropical seas ; while in the next year Leach2 united all the known species of this type of the Echinodermata under the one genus Alecto. A similar step was taken in 1816 by Lamarck,8 who proposed the genus Comatula and assigned to it eight species, six of them being new. One of these had been previously 1 M«5moire sur un Nouveau Genre de Zoophites de l'Ordre des Radiaires, Bull. Soc. Philom. Paris, Bd. ii. pp. 349, 350, 1811. 2 The Zoological Miscellany, London, 1815, vol. ii. p. 61. 3 Histoire Naturelle des Animaux sans Vertebres, ed. 2, Paris, 1816, torn. ii. p. 530. (ZOOL. CHALL. EXP. — PART LX. 1887.) OoO 1 4* 2 THE VOYAGE OF H.M.S. CHALLENGER. called Antedon by de Fremiuville, and Alecto by Leach ; but Lamarck's authority as a zoologist, together with his description of six new species, was sufficient to make his genus more widely known than either de Freminville's Antedon or Leach's Alecto. The very appropriate name Comatula was afterwards used by Miller, Goldfuss, de Blainville, Agassiz, and Midler ; while d'Orbigny1 gave it an increased importance by founding the family Comatulidae. He referred to this family, however, not merely the various forms of Feather-star, both recent and fossil, in which the base of the calyx is closed below by the cirrus-bearing centro-dorsal piece, but also the remarkable genus Marsupites, which, in the adult condition at any rate, was totally devoid both of stem and of cirri. Further research has shown, however, that Marsupites represents a form of Crinoid which is altogether different from that of the Feather-stars ; and it is now generally considered as the type of another family altogether, the Marsupitidaa. The limits of d'Orbigny's family Comatulidaa have varied considerably at different times. Eugeniacrinus and its allies were referred to it by Dujardin and Hupe,2 whose classification has not been adopted by their successors ; whilst a variety of generic names have been proposed for the numerous fragments of fossil Coniatulse which occur in considerable abundance at certain horizons in the Jurassic and Cretaceous formations, viz., Glenotremites, Solanocrinus, Decacnemos, Decameros, Comaster, Hertlia, and Geocoma. All of these, with one or two possible exceptions, find their place within de Freminville's genus Antedon, as has been explained elsewhere.3 Some twenty-five years ago this name was revived by Mr. Norman4 in a more restricted sense than that in which it was proposed by de Freminville ; and this step has been generally followed, with the great advantage of simplifying tbe nomenclature considerably. In Midler's earlier writings upon the subject of the Feather-stars, the names Alecto and Comatula seem to have been employed indifferently and as equivalent to one another ; but he was subsequently led to distinguish two different types of Feather-star, one with five ambulacral grooves converging upon a generally central mouth, as in Pentacrinus, and the other with an excentric mouth and fewer than five disk-ambulacra. He therefore considered these as subgenera of Lamarck's original genus Comatula, and while distinguishing the first one by Leach's name Alecto, proposed to call the second type by the new designation Actinometra.5 Neither of these two subgenera were ever formally defined, and Midler only described three species of Actinometra. A fourth was 1 Cours elementaire de Paleontologie et de Geologie stratigraphique, Paris, 1852, vol. ii. fasc. 1, p. 138. 2 Histoire Naturelle des Zoophytes, l^chmodermes, Paris, 1862, p. 186. 3 See P. H. Carpenter, On the Genus Actinometra, Muller, with a Morphological Account of a new species (Actino- metra polymorpha) from the Philippine Islands, Trans. Linn. Soc. Lond. (Zool.), 1879, ser. 2, vol. ii. pp. 13, 14 ; and also On the Genus Solanocrinus, Goldfuss, and its relations to recent Comatula', Journ. Linn. Soc. Lond. (Zool.), 1880, vol. xv. pp. 196-201. 4 On the Genera and Species of the British Echinodermata, pt. i , Ann. and Mag. Nat. Hist, 1865, ser. 3, vol. xv. p. 98. 5 Ueber die Gattung Comatula, Lam., und ihre Arten, Abhandl. d. h. Akad. d. JViss. Berlin, 1849, p. 246. REPORT ON THE CRINOIDEA. 3 subsequently added by Bohlsche1 after the type had been accorded generic rank by Dujardin and Hupe,2 who improved considerably upon Midler's definition of it. The German zoologist had not considered the position of the mouth as a point of any systematic importance ; but he referred to Alecto both species like Antedon rosacea and Antedon eschrichti, which have five symmetrically distributed ambulacra radiating from a central mouth, and also species with an equally symmetrical grouping of the ambulacra, but with an excentric mouth. Dujardin and Hupe, however, took no account of the number of ambulacra diverging from the peristome, to which Mliller attached so much importance ; but they pointed out that the distinctive character of Actinometra rather lay in the excentric position of the mouth, which determined the course of the ambulacra round the margin of the disk, instead of towards its centre. Nevertheless, they did not transfer to Actinometra the various species of Alecto described by Muller with an excentric mouth and symmetrically grouped ambulacra ; so that they did not make any real addition to the genus, although they recognised its characters better than Muller had previously done. Single species were subsequently added to it by various writers, but it was never properly defined. Having assigned a generic value to Actinometra, Dujardin and Hupe" did the same for Midler's type Alecto, for which, however, they preferred Lamarck's name Comatula. But three years later Mr. Norman replaced this by Antedon, a name which was originally proposed earlier than either Alecto or Comatula; and at the same time he restricted it to those species only in which the mouth is central or subcentral and the anus lateral. Very nearly all subsequent writers have accepted this definition of Antedon ; but no attempt was ever made to modify the Mullerian descriptions of Comatula in accordance with it. Towards the end of 1875, ten years after the publication of Mr. Norman's precise definition of Antedon, I had the opportunity of studying a large collection of tropical Comatulse which had been obtained by Professor Semper in the Philippine Islands ; and it soon became evident that the number of ambulacra diverging from the peristome is so variable as to be useless for the purposes of generic discrimination. At the same time other characters seemed to be correlated with the central or excentric positions of the mouth respectively ; and I came to the conclusion that the real distinction between Antedon and Actinometra respectively is based upon this feature of their organisation, the number of groove trunks connected with the peristome being a character of very minor importance.8 I soon learnt that Professor Liitken had held this opinion for some time past; and he also pointed out to me certain characters of the oral pinnules which are always associated with the excentric position of the mouth. Since that time I have 1 Ueber Actinometra Bennettii unci eine neue Comatula Art (Autedou Dubenii), Archiv f. Naturgesch., 1866, Jahrg. xxxii. Bd. i. p. 90. 2 Op. cit., p. 208. 3 Trans. Linn. Soc. Lond. (Zool.), 1879, ser. 2, vol. ii. pp. 17, 18. 4 THE VOYAGE OF H.M.S. CHALLENGER. examined a very large number of Coniatuhe ; and I have almost always found a terminal comb on the oral pinnules of those species which have an excentric mouth ; while a variety of other characters are more or less constantly associated with these, as wTill be explained in detail further on. In the year 1866 a new Comatulid genus, Phanogenia, was established by Loven1 for a remarkable tropical species with a stellate centro-dorsal bearing a few rudimentary cirrus- stumps. The dredgings of the Challenger, however, have shown that this condition is common to several species of Actinometra, with which the genus Phanogenia corresponds in all essential respects. A third new genus of Comatulae was established in 1868 by Semper2 for a little five-armed type which he had discovered in the Philippines. He called it Ophiocrinus, and for some years it was regarded merely as a subgenus of Antedon. Eventually, however, after examination of the three species obtained by the Challenger in the Pacific, together with Semper's original specimen, I satisfied myself of its claim to generic rank, and I proposed to call it Eudiocrinus,5 instead of by Semper's name Ophiocrinus which had been preoccupied by Salter. But about the same time that this new generic name was proposed on account of all the known species being limited to the Pacific Ocean, another specific type was discovered by the " Travailleur " in European seas, and it was subsequently described by Perrier 4 as Eudiocrinus atlanticus. One other genus of recent Crinoids, has been described, besides those just mentioned {Antedon, Actinometra, Phanogenia and Eudiocrinus), viz., Comaster, Agassiz.5 The leading character of this genus, according to its proposer, depended upon the number of divisions in the arms, and was rightly disregarded by Goldfuss e who thought more of the presence of basals on the exterior of the calyx as a generic distinction. Miiller 7 adopted the genus in the sense in which it was understood by Goldfuss ; but he seems eventually to have abandoned it altogether.8 This will doubtless prove to be its ultimate fate, as it has not been seen by any naturalist since the time of Goldfuss, wdiose original specimen of it was dissected and has since disappeared. If his account of it is correct, Comaster must be a very remarkable type, differing in many respects from all other recent Comatulae, as I have explained elsewhere ; 9 but I am strongly inclined to believe that its apparent peculiarities are merely due to the wTant of knowledge respecting the internal structure of 1 Phanogenia, et hittills okiindt slagte af fria Crinoideer, Dfversigt. k. Vetensk. Akad. FbrhandL, 1866, p. 231. 2 Ophiocrinus, eine neue Cornatuliden Gattung, Archivf. Naturgesch., 1868, Jahrg. xxxiv., Bd. i. p. 68. 3 Descriptions of new or little known Comatuhe. I. On the species of Atelecrinus and Eudiocrinus, Journ. Linn. Soc. Load. (Zool.), 1882, vol. xvi. p. 493. 4 Sur des Eudiocrinus de lAtlantique et sur la nature de la faune des grandes profondeurs, Comptes rendus, 1883, t. xcvi. pp. 725-728. 5 Prodrome d'une Monographie des Radiaires ou Echinoderraes, Mem. Soc. Nat. Sci. Neuch., 1835, t. i., p. 193. 6 Beitrage zur Petrefactenkiinde, Nova Acta Acad. Oses. Leop., 1839, Bd. xix. A. p. 348. 7 Ueber die Gattungen und Arten der Comatulen, Monatsber. d. k. preuss. Akad. d. wiss. Berlin, 1841, p. 180. 8 Abhandl. d. k. Akad. d. Wiss. Berlin, 1849, p. 244. 9 Journ. Linn. Soc. Lond (Zool.), 1877, vol. xiii. pp. 454-456. REPORT ON THE CRINOIDEA. 5 the calyx of Comatuke which was prevalent at the time of Goldfuss, and that Comaster is in reality nothing but a large Antedon or Actinometra. Apart from Phanogenia and Comaster, therefore — one, if not both, of which are merely synonyms — no other Comatulid genera except Eudiocrinus, Antedon, and Actinometra were known, to science before the collections of the Challenger and of the United States Coast Survey ships came into my hands for examination. But one species of Eudiocrinus was known, and only about twenty each of Antedon and of Actinometra had been described, though many others were awaiting description in various museums. Now, however, the number of recent species of Comatula is probably nearly four hundred, and three new genera have been established, thus doubling the number known at the time the Challenger returned. One of these generic types, Atelecrinus, was actually obtained so long ago as 1868, during the earliest explorations of the Gulf Stream by Count Pourtales ; but the single specimen dredged was so small and mutilated that its very striking peculiarities escaped notice at the time. Equally imperfect and isolated examples of two other species were dredged by the Challenger ; and it was not until several less mutilated individuals were obtained by the " Blake " in the Caribbean Sea, that I was able to realise that a new Comatula genus had been discovered.1 It presents so many larval characters that I have called it Atelecrinus, as will be explained subsequently. Atelecrinus can hardly be considered as a new genus discovered by the Challenger ; but with P romachocrinus and Thaumatocrinus the case is altogether different. The former genus 2 differs from all other Crinoids in the composition of the calyx, which has ten primary radials instead of five only, as is normally the case ; and it is represented by three distinct species, one from the North Pacific, one from Kerguelen, and one from a depth of 1800 fathoms at Station 158 in the Southern Sea. At this Station too, there was obtained a single specimen of another Comatula which I have no hesitation in regarding as by far the most remarkable of all the Crinoids that have been dredged of late years, viz., the extraordinarily archaic form TJiaumatocrinus, which presents certain characters only to be found in some of the Palaeocrinoids. Its peculiarities were fully described in the Report on the Stalked Crinoids,3 and I do not propose therefore to say much about it here. 1 Report on the Results of Dredging under the Supervision of Alexander Agassiz, in the Gulf of Mexico, and in the Caribbean Sea, 1877-79, and along the Atlantic Coast of the United States during the summer of 1880, by the United States Coast Survey steamer " Blake," Lieutenant-Commander C. D. Sigsbee, U.S.N., and Commander J. R. Bartlett, U.S.N., commanding. XVI. Preliminary Report on the Comatula?, Bull. Mus. Comp. ZooL, 1881, vol. ix. No. 4, p. 16. 2 Preliminary Report upon the Comatuhe of the Challenger Expedition, Proc. Roy. Soc, 1879, vol. xxviii. p. 385. 3 Zool. Chall. Exp., part xxxii., 1884, p. 370. THE VOYAGE OF H.M.S. CHALLENGER. II.— THE CENTEO-DORSAL AND CALYX. The principal morphological character which distinguishes the Comatulidse from the remaining families of Crinoids is the development of cirri upon the top stem-joint, and its separation from the remaining portion of the stem as the centro-dorsal plate. This supports the ring of united radials, and, in the recent forms at any rate, closes up below the dorsal extension of the body-cavity which is contained in their central funnel, as is well shown in PI. III. figs. 3a, 3b, and PI. V. fig. 2c. Most recent Comatulse are further distinguished from the Stalked Crinoids by the metamorphosis of the embryonic basals into the structure known as the " rosette," which is enclosed within the radial pentagon, and so is entirely invisible externally (PL I. fig. 8c; PL II. figs. 3c, 5c; PL IV. fig. 3c; PL V. figs. 2c, bd). It will be well to discuss these two structures separately, though they are naturally in very close relation with one another. A. The Centro-Dorsal. The term " centro-dorsal plate " is a very old one, and was for a long time used in various ways by different authors. In fact it was not till the remarkable developmental history of the uppermost stem-joint had been made out by the late Sir Wyville Thomson and Dr. Carpenter, that the term acquired any definite signification. Both these authors used it to denote the enlarged and cirrus-bearing top stem-joint1 which is at first in no way different from the remaining joints of the stem below it (PL XIV. figs. 1, 2, 8, 9). Eventually, however, it enlarges, and five cirri, which are radially situated, are developed upon it (PL XIV. figs. 3-6), so that it has very much the appearance of a nodal stem- joint of Pentacrinus. A second series of cirri, alternating in position with the first, subsequently appears (PL XIV. fig. 7), and others are afterwards developed in succession, so that as was well said by Wyville Thomson,2 " the centro-dorsal plate in Antedon does not belong to the cup. It represents a coalesced series of the nodal stem-joints in the Stalked Crinoids." At a certain period in the development of the young Comatula the centro-dorsal 1 The centro-dorsal plate of Comatula must not be confused with the dorsocentral plate of other Echinoderms. This name is now generally restricted to the central plate of the abactinal system in Urchins and Stellerids. I believe this to be represented in the Comatula? by the terminal plate at the bottom of the larval stem, as explained on p. 168 of Part I. It is shown in PI. XIV. figs. 1, 9. Comatul* thus have both a centro-dorsal and a dorsocentral, while the latter only is present in the remaining Echinoderms. Zittel has also given the name centro-dorsal to the enlarged uppermost stem-joint of Apiocrinus; but this bears no cirri, and though undoubtedly homologous with the centro-dorsal of Comatula;, should not, I think, receive a name which is now universally understood as denoting the presence of cirri. 2 On the Embryogeny of Antedon rosaceus (Linck, Comatula rosacea of Lamarck), Phil. Trans., 1865, p. 536. REPORT ON THE CRINOIDEA. 7 separates itself from the stem-joint below it. and the " head " of the Pentacrinoid larva becomes a free-swimming Feather-star, the rest of the larval stem being left to waste away. The precise epoch of growth at which this separation occurs varies greatly. Thus, for example, the young Antedon tenella retains its stem until twenty or thirty cirri have appeared on the centro-dorsal, which conceals the basals, and the pinnules are developed upon all the lower arm-joints ; whereas in Antedon rosacea and in other species, the stem is discarded when there are only ten cirri on the centro-dorsal, the basals are still visible, and the lowest portions of the arms devoid of pinnules ; while the absolute size which is reached by the mature larva before dropping off its stem varies considerably. After the formation of the first two whorls of cirri no special regularity can be traced in the manner of their development. The young ones normally appear between those previously formed and the radial pentagon, so that their sockets are close to the margin of the centro-dorsal (PI. I. fig. let; PL II. figs. 2a, 4a; PL IV. figs, la, 3a). But as the centro-dorsal grows and new cirri appear round its margin, the older cirri which are attached close to the dorsal pole drop away, and their sockets become gradually obliterated by calcareous deposit. The earlier stages of this process are seen in PL I. fig. 6a; PL II. figs, la, 3a, 5a; and PL III. figs. 6a7, 7a; and the result is that the dorsal surface is usually left comparatively smooth, as seen in PL IV. figs, la, lb, 2a, 3a, but in some species of Antedon the deposit of new material continues after the cirrus- sockets are obliterated, and causes the dorsal pole to become rough and irregular (PL III. figs. 4b, 5a ; PL XL fig. 3). On the other hand, the lower surface of the centro-dorsal in most species of Actinometra is almost flat and extremely smooth (PL V. figs. 16, Id, 2b, 2d, 2e, 4b, 5b, 5c). This is owing to the very extensive and uniform manner in which the new material is deposited, and it sometimes produces very singular results, as will be explained subsequently. During the Pentacrinoid stage of larval existence the young Comatula is provided with a stem which encloses a neuro- vascular axis just as in an ordinary Stalked Crinoid. This axis contains the downward extensions of the peripheral cavities of the chambered organ within the centro-dorsal and of its central axis. When the centro-dorsal separates itself from the lower part of the larval stem, a minute five-rayed perforation remains at its dorsal pole, which corresponds to the central canal in the stem of a Pentacrinus, and gave passage to the neuro-vascular axis above mentioned. In recent Coinatulse this opening is closed up very soon after the entry upon the free stage of existence, by a portion of the calcareous deposit already noticed ; though traces of it are sometimes visible internally upon the floor of the centro-dorsal cavity (PL II. figs. 2b, 3b). There are some fossil Comatulae, however, in which it seems to have remained permanently open throughout life, so far as we can judge from the material at our disposal ; while in other forms again it is extended into a large stellate impression which occupies a considerable space on the lower surface of the centro-dorsal, and in the fossil condition is 8 THE VOYAGE OF H.M.S. CHALLENGER. more or less obliterated. But there can, I think, be no question that in Antedon ■perforata, Antedon rugosa, Antedon striata, and other species from the English Chalk, together with some foreign species like Antedon tourtiie, Antedon semiglobosa, and Antedon retzii, the inferior surface of the centro-dorsal was marked during life by a large stellate opening which was considerably more than would be necessary for the simple downward passage of the neuro-vascular axis of the stem. It seems to me very probable, as I have explained elsewhere,1 that the peripheral parts of this opening, which are radially situated, may have given passage to tubular extensions of the body-cavity into the stem, such as existed in Barycrinus, Cuprcssocrinus, and in other Palaeocrinoids. An indirect confirmation of this view is afforded by the characters of the stem in the Bourgueticrinidge, which resembles that of the young Comatula in all essential points. The stem-joints of this family contain a set of five radial spaces which communicate with one another from joint to joint, and probably also through the top of the stem with the body-cavity within the calyx. The presence of these same radial spaces in the stems of fossil Comatula? would account for the perforation of the lower surface of the centro- dorsal, which would have effected the communication between the portions of the body- cavity derived from the right peritoneal sac, that lie in the stem and in the calyx respectively. In the ordinary species of Antedon the calycular portion of the ccelom is much broken up by the rosette, and by the calcareous network which rests above it and occupies the central funnel of the radial pentagon (PI. IV. fig. 36) ; but, as I have shown elsewhere,3 there are five median grooves on the ventral surface of the radials which extend outwards in a similar position over the skeleton of the rays and arms, and lodge the lowest portions of their cceliac canals. They are more distinct in some species than in others, but are well shown in Antedon carinata (PL III. figs, id, 3a), Antedon disciformis (PI. IV. fig. 26), and in Actinometra lineata (PL V. figs. 2a, 2c). When these grooves pass from the ventral to the inner faces of the radials and descend into the central funnel, they become closed into canals by the union of their edges with those of the spout-like radial processes of the rosette. These canals, which I have called the axial radial canals, are therefore the proximal ends of the five cceliac canals of the arms and their extensions into the pinnules. As a general rule they become closed up by calcareous tissue, and so do not reach the dorsal surface of the radial pentagon, which presents no real openings except the central one occupied by the rosette (PL I. fig. 8c). The five radial and five interradial processes of this structure are separated by passages which lodge the paired branches of the five primary cords proceeding from the nervous envelope of the chambered organ. These ten openings are well seen in PL I. figs. 6c, 8c ; PL III. figs. 4c, 56; and also in PL V. figs, lc, 2c, 2e, bd, 5e, but in Antedon quinquecostata and Antedon disciformis there are five additional openings on the lower surface of the 1 On some New Cretaceous Coniatulre, Quart. Journ. Geol. Soc, 1880, vol. xxxvi. pp. 556, 557. 8 Trans. Linn. Soc. Land. (Zool.), 1879, ser. 2, vol. ii. pp. 77, 78. REPORT ON THE CRINOIDEA. 9 radial pentagon, one at the inner end of each radial (PI. III. fig. 6?> ; PI. IV. fig. 2c). These are the dorsal ends of the radial axial canals, which do not become obliterated as is usually the case ; and in Antedon disciformis there is a small pit on the upper surface of the centro-dorsal corresponding to each of these canals which terminate blindly in this position (PL IV. figs. 2c, 2c/). Among recent Comatulse, however, the most striking development in this respect is presented by Antedon quinduplicava ; for the radial axial canals which pass over from the ventral to the inner faces of the radials turn outwards ao-ain at the bottom of the calyx, and expand into relatively large bilobate cavities which are formed by excavation in the apposed surfaces of the radials and the centro-dorsal respectively, as is well seen in PI. IV. figs, lc, id. Among the fossil Cornatulte there are several species in which the ventral surface of the centro-dorsal is marked by five small radial pits of this kind, that receive the ends of the radial axial canals. But in Antedon retzii they appear as actual perforations in the ventral surface of the centro-dorsal which reach downward to the bottom of its internal cavity, being in fact only separated from it by a narrow septum, and this is occasionally absent, so that the centro-dorsal cavity which is naturally decagonal or pentagonal in outline becomes stellate. This condition is very common in the stem-joints of some Palseocrinoidea, such for example as Cupressocrinus, and I think there can be no doubt that the radial openings or the extensions of the central canal in all such cases served for the passage of canals containing water in communication with that in the coelom above. Messrs. Wachsmuth and Springer ' suggested long since that the complex stem of many Palseocrinoids might have been " subservient to respiration " ; and the facts mentioned above respecting the Bourgueticrinidse and the Comatulae certainly go far towards supporting this view. The ventral surface of the centro-dorsal is usually flat or slightly hollowed, rarely very convex, except in species like Actinometra paucicirra, Actinometra typica, &c, in which the greater part of the centro-dorsal is enclosed within the radial pentagon, as will be explained shortly. The internal openings of the canals leading to the cirrus- sockets are frequently visible on the floor of its cavity, as is well shown in Promachocrinus kerguelensis and in Antedon antarctica (PI. I. figs, id, 6d). In both these species and also in others the walls of the centro-dorsal cavity are marked by strong ribs, the lower ends of which are more or less distinctly visible through the axial opening, projecting beneath its bp, which their upper ends help to support. Five of them, those at the interradial angles, are often considerably larger than the rest, and may be the only ones visible. In other cases, however, both these and numerous smaller intermediate ribs are visible through the axial opening, as is seen in PI. I. figs. Id, 6d. These ribs are much more distinct in some individuals than in others of the same species. Thus, for example, 1 Revision of the Palseocrinoidea, part i. p 15, Proc. Acad. Nat. Sci. Philad., 1879. (ZOOL. CHALL. EXP. — PART LX. — 1888.) *-*00 2 10 THE VOYAGE OF H.M.S. CHALLENGER. they do not appear within the middle portion of the centro-dorsal in the specimen of Anteclon eschrichti figured in PI. I. fig. Sd, though they are comparatively large in other forms of this type, as I have noticed elsewhere.1 The peripheral part of the ventral surface of the centro-dorsal is divided by ridges or grooves into the five trapezoidal areas in which the radial plates are lodged, and they are occasionally marked by more or less definite pits which receive the ends of the radial axial canals, as already explained (PI. IV. figs. Id, 2d). In most Comatulse every two fossse are separated by one of the five basal grooves which lodged the rays of the basal star, to be described subsequently. They are sometimes comparatively insignificant, as in Antedon antarctica (PI. I. fig. 6d), while in the Pacific species they are usually very strongly marked (PI. II. figs. 1-56). On the other hand, if no basal star is present, the radial fossse on the centro-dorsal are usually separated by tolerably sharp ridges as in Antedon eschrichti (PI. I. fig. 8d), Antedon quinduplicava (PI. IV. fig. id), and Antedon disciformis (PI. IV. fig. 2d). The last-mentioned species, however, has indications of basal grooves at the proximal ends of these ridges. The grooves are fairly distinct in both the species of Promachocrinus which I have examined, but though the radials are ten in number, there are only five fossse on the centro-dorsal, the ventral surface of which is distinctly pentagonal in outline, with its angles interradial, just as in Antedon (PI. I. figs. \c, Id, 5). In fact, I know of no Comatula in which the general shape of the centro-dorsal is not more or less distinctly pentagonal with its ventral ridges and angles interradial. Wachsmuth and Springer regard this fact as indicating the probable presence of radially situated under-basals in the Co matula -larva. Their extensive and important investiga- tions into the structure of the calyx in the Palseocrinoids have led them to formulate the following rule : 2 — " In species with under-basals, whenever the column is pentangular, its longitudinal angles are directed interradially, the sides and columnar cirrhi radially." They proceed to state3 that the centro-dorsal of Comatulse is interradial " and rests, as in the Apiocrinidse, against the outer face of the basals, not within the basal ring " ; while they continue — " upon this mainly we base the opinion that perhaps also the Comatula? in their early larva had rudimentary under-basals. That these plates, if present, were not observed, is not surprising, as they may have been very minute and been covered entirely by the column." Whether this be the case or not, the statement that the centro-dorsal of Comatulse rests against the outer face of the basals is a somewhat misleading one. The " outer face " can only mean that which appears on the outside of the calyx ; and this, from its very nature, cannot rest against the centro-dorsal, for it would then be internal and con- cealed. 1 Quart. Journ. Geol. Soc, 1880, vol. xxxvi. p. 47. 4 Revision of the Palaeocrinoidea, pt. iii. sect. 1, p. 7 (229); Proc. Acad. Nat. Sci. Philad., 1885. 3 Ibid., sect. 2, 1886, p. 298 (222). REPORT ON THE CRINOIDEA. 11 The centro-dorsal is at first a simple ring, in no way different from the other stem- joints ; but when the basals come to assume a definite shape and the calyx acquires the doubly conical form of the Cystic! phase, the centro-dorsal becomes distinctly wider than the annular stem-joints below it and takes on a pentagonal shape. The basals rest against the sides of the pentagon, and its angles which fit in between them are therefore radial in position, as seen in PI. XIV. figs. 1,8. At this early stage the basals are only in contact with the centro-dorsal by their lower edges ; but it soon begins to increase in diameter and extends itself over the bottom of the calyx in the manner described by Dr. Carpenter.1 It increases at the same time in vertical depth, and the first cirri make their appearance. These are radial in position, and the portion of the centro-dorsal between every two sockets rapidly enlarges, so that it comes to project beneath each basal plate, and the angles of the centro-dorsal thus become interradial instead of radial. This change is very clearly seen in larvae which have only one or two cirri, so that one part of the centro-dorsal shows the primitive radial symmetry, and another part the acquired interradial symmetry. Thus then the centro-dorsal of Comatula, when it first assumes definite form, has a most distinct radial symmetry. Its angles occupy the same position with regard to the basals as do those of the enlarged top stem-joint in Guettardicrinus and Apiocrinus, which are also distinctly radial in situation. I desire to lay particular stress upon this fact, because Wachsmuth and Springer, in support of their assertion that Neocrinoids are built upon the plan of dicyclic Crinoids, have stated that the top stem-joint " is disposed interradially in the Apiocrinidae, Pentacrinidae, and Comatulse, similar to dicyclic Palseo- crinoids." 2 But the ridges and angles of the top stem-joint are radial in every species of Apiocrinus, as is seen with especial clearness in Apiocrinus magnificus.3 Wachsmuth and Springer 4 say, however, that " the plate in Apiocrinus magnificus is not, as should be supposed from appearances, disposed radially, but interradially, as shown by comparison with species having a pentangular stem. It attained its radial angles accidentally by adapting its form to the basal concavity which is naturally angular." This is a form of teleological argument which is very easily employed but is very difficult to refute. Neither Wachsmuth nor Springer, nor any one else, is acquainted with the post-embryonic development of Apiocrinus, and the changes which may or may not have taken place in the symmetry of its top stem-joint ; though from the positive way in which the American authors write one would imagine that they had watched the whole process of the " accidental " change of symmetry which they describe. If the basal concavity "naturally" has radial angles, it is surely a "natural" and not an "accidental" circumstance that the top stem-joint which occupies this cavity should also have radial angles. This is the case in every species of Apiocrinus, in the single species of 1 Researches on the Structure, Physiology, and Development of Antedon rosaceus, Phil. Trans., 1866, p. 742. 2 Revision, pt. iii. p. 299. 3 See de Loriol, Paleontologie Franchise, Terrain Jurassique, t. xi. pis. 46-49. * Revision, pt. iii. p. 297. 12 THE VOYAGE OF H.M.S. CHALLENGER. Guettardicrinus, and in the majority of those of Millericrinus ; and yet it is considered by Wachsmuth and Springer as a merely " accidental " occurrence, and the real symmetry of the top stem-joint in the Apiocrinidse is described as interradial. It is actually and visibly so in some twenty species of Millericrinus. But they belong to that aberrant section of the genus which so closely approaches Pentacrinus in having a distinctly pentagonal stem with interradial angles, and articular faces the sculpture of which is very different from that of the typical Apiocrinidse and somewhat closely resembles that of the joint-faces in certain Pentacrinidae. In all of these species the top stem-joint, like those below it, has interradial angles, and the same is the case with the basal concavity into which it fits. But Wachs- muth and Springer tell us that the " natural " shape of this concavity in the Apiocrinidse is to have radial angles, and they have not attempted to explain its interradial symmetry in these aberrant and Pentacrinus-l\ke forms of Millericrinus by reference to any causes whatever, accidental or otherwise. Perhaps it has escaped their notice ; but whether this be the case or not, it is somewhat surprising to students of the Neocrinoidea to be told that the distinctive characters of the top stem-joint in the Apiocrinidse, presenting themselves in each of the three genera, and in by far the greater number of the species of this family, are due to " accidental " causes. Further discussion of this question, however, would be impracticable at present. I merely wish to point out that as soon as the centro-dorsal of the early larva of Comatula takes a definite shape its angles are distinctly radial, just as is permanently the case in the top stem-joint of Apiocrinus, and this is in itself an argument against the supposed change of symmetry in the latter type about which Wachsmuth and Springer write so positively. But when the cirri appear on the centro-dorsal and the basals begin to be transformed into the rosette, the outline of the centro-dorsal changes. The basals are no longer the principal plates in the calyx, but they undergo metamorphosis into the small rosette, and the centro-dorsal increases rapidly in size, more so than any other part of the skeleton, " so that it soon comes to pass beyond the circlet of basals, and to abut on the proximal edge of the first radials ; and instead of stopping here it continues to increase in diameter until it conceals the whole inferior surface of the first radials, and sometimes even encroaches somewhat on the second." l Here then we see the reason for the interradial angles of the centro-dorsal in the mature Comatula. It is an altogether secondary condition, and due to the fact that the fossae on the ventral surface of the centro-dorsal lodge the radial plates, so that the ridges separating them are interradial, just as in Apiocrinus the fossa? on the top stem -joint lodge the basals and are interradial, so that the intervening ridges and the angles in which they terminate are radial. Even in fossil Comatula? which have no rosette, but persistent basals, these plates are usually quite small and do not form a closed ring on the exterior of the calyx; so that the upper surface of the centro-dorsal is mainly occupied by the radial fossa? and has interradial angles as in recent Comatula? (PI. I. figs. 5, 6a, 8d; PI. II. 1 W. B. Carpenter, Phil. Trans., 1866, p. 742. REPORT ON THE CRINOIDEA. 13 figs. 1-5, 6). Thus then the interradial symmetry of the centro-dorsal is an altogether secondary condition, and is due not to the possible presence of radially situated under- basals, as supposed by Wachsmuth and Springer, but to the fact that the radials themselves rest upon the plate, the primary radial symmetry of which becomes altogether obscured when it begins to increase in diameter and to develop cirri, coincidently with the retromorphosis of the basals. The external form of the centro-dorsal varies very greatly among different species of Comatulge. It is very distinctly conical in Atelecrinus (PI. VI. figs. 5, 7). In the three chief of the remaining endocyclic genera (Antedon, Eudiocrinus, and Promacho- crinus) it is occasionally somewhat hemispherical or subcorneal, with the cirrus-sockets arranged rather irregularly (PI. I. figs, la, 6a, 8a; PI. II. figs. 1-3, a; PL III. figs. 46, 5a, la; PI. XXX. figs. 1, 2, 4); but in some cases, as in Antedon quinquecostata, it is more distinctly pentagonal and columnar, with the sockets grouped in alternating rows (PI. III. fig. 6d), while in Antedon balanoides it is distinctly conical (PI. XXXIII. fig. 6). In other forms again the dorsal pole is flattened (PI. II. fig. 4a), and this is especially the case in Antedon carinata and Antedon macronema (PI. III. figs, la, 36 ; PI. IV. fig. 3a), which in this character, as in some others, exhibit a variation in the direction of Actinometra. On the other hand, Antedon quinduplicava and Antedon disciformis, which are still more like Actinometra in the small number of functional cirrus-sockets and in the discoidal shape of the centro-dorsal, belong unmistakeably to the genus Antedon in the relative height of the radials (PL IV. figs, la, 2a). In most species of Actinometra the centro-dorsal is a thin flattened disc, often with only one row of functional cirrus-sockets (PL IV. fig. 4a ; PL V. figs. 16, Id, 26, 2a", 2e, 46) ; though in Actinometra stelligera it is thicker and bears a comparatively large number of sockets (PL V. figs. 56, 5c). As a general rule the shape of the centro-dorsal is tolerably constant in any individual species of Antedon, being hemispherical in Antedon eschrichti (PL I. fig. 8a; PI. XXIV. figs. 10, 11), columnar in Antedon quinquecostata (PL III. fig. 6d), and more discoidal in Antedon carinata (PL III. figs, la, 36). But in Antedon phalangium it exhibits a very considerable amount of variation, being hemispherical in some forms, but greatly elongated and conical in others (PL XXVIII. fig. 2). In some species of Actinometra the obliteration of the cirrus-sockets on the centro- dorsal is carried to a very much greater extent than in Antedon ; and the number of functional sockets, which is at no time large, is often extremely small. In some types the changes in the centro-dorsal do not stop here, but it is reduced to the condition of a flat pentagonal plate within the ring of radials as in Actinometra paucicirra (PL LIV. figs. 1-7) ; while in species like Actinometra typica (PL LVII. fig. 1), the sides of this plate undergo resorption, so that clefts appear between it and the radials. This gives the base of the calyx an appearance so different from that of the ordinary Comatulas 14 THE VOYAGE OF H.M.S. CHALLENGER. that the genus Phanogenia was instituted by Loven1 for the reception of species presenting these characters. It was pointed out in my preliminary report,2 however, that the stellate appearance of the centro-dorsal in Phanogenia (PI. LVII. fig. 1) "appears to be one of the concluding stages of a long series of changes in the shape and relations of the centro-dorsal, which do not commence until some time after the loss of the stem and the entry upon the free state of existence." The earlier stages of these modifications are well shown in a series of specimens of Actinometra 'paucicirra, which is very abundant at Cape York (PL LIV.). In the youngest individual of the series the centro-dorsal is a thin and slightly convex circular disc, about 2 mm. in diameter, which bears five pairs of cirri, one pair opposite each interradius. They reach 6 mm. in length and consist of about fifteen joints, which are tolerably mature in their general characters (PI. LIV. fig. 10); the next stage is a slightly older individual in which all the cirri have fallen away from the centro-dorsal and the obliteration of their sockets has commenced (fig. 9). This process has been carried further in the larger and more distinctly pentagonal centro- dorsal shown in fig. 8, though it has gone on rather unequally, some of the sockets being much more obliterated than others. Scarcely any trace of sockets can be made out in the original of fig. 5, but the centro- dorsal is a thin pentagonal disc with the appearance of processes at some of its angles, which are more probably, however, the ends of the basal rays. Its surface is much more nearly flush with that of the radials in the full-grown specimen shown in fig. 2, still, however, retaining its pentagonal shape. Fig. 1 shows another modification, each angle of the pentagon being marked by a more or less deeply impressed pit in which the basal ray is sometimes visible. The form represented in fig. 3 has a more rounded centro-dorsal, which is flush with the radials at its edges, and shows the basal rays at its angles; while there are indications of pits at the distal angles of the sutures between the first radials. The sides of the centro-dorsal in this specimen are slightly concave, and this character is much more distinct in figs. 6, 7, so that the shape becomes markedly stellate. In the former the centro-dorsal (as viewed from the dorsal side) is above the level of the radial pentagon; but in the latter it is relatively much lower, so that its surface is flush with that of the radials, the proximal edges of which are convex in correspondence with the stellate outline of the centro-dorsal. Fig. 4 shows a similar case in which the centro-dorsal is pentagonal. The effect of its complete withdrawal into the radial pentagon is to make it entirely invisible in a side view of the calyx, as seen in PL V. fig. 3 b ; while the dorsal surface of the united radials becomes very deeply hollowed for its reception (PL V. fig. 3c) instead of being slightly convex, as i3 more usually the case (PL V. figs, lc, 5d). 1 Phanogenia, ett hittils okandt slagte af fria Crinoideer, Ofvcrsigt k. Vetensk.-Akad. ForhandL, 1866, p. 231. *Proc. Roy. Soc, 1879, vol. xxviti. p. 390. REPORT ON THE CRINOIDEA. 15 The stellate condition of the centro-dorsal just described in Actinometra paucicirra is sometimes reached by that of Actinometra parvicirra before the cirrus-sockets are entirely obliterated. In one specimen of this variable type which was obtained by the Challenger, the mature cirri have disappeared and are replaced by a few rudimentary stumps, while the sides of the plate are so deeply hollowed by their sockets that its outline is rather stellate than pentagonal. But it is still distinctly above the level of the radials (PL LXI. fig. 3). The six examples of the large Actinometra nobilis which were dredged in the Philippines also exhibit a considerable amount of variation in the characters of the centro-dorsal (PI. LXV. figs. 1-6). In the least modified form it is a rounded pentagonal plate distinctly above the level of the calyx, with traces of about ten cirrus-sockets, one of which contains a very rudimentary stump, and a well-marked process at each of its angles (fig. 2). In another specimen it is distinctly sunk below the level of the radials, with which it remains united externally by the interradial processes at its angles ; but its sides are bevelled away, and most of them bear indistinct cirrus-sockets, in one of which a small stump is visible (fig. 3). In the other four examples, however, the centro-dorsal shows little or no trace of cirri, and is distinctly concave on its dorsal surface ; while it is completely enclosed by the radial pentagon, united to it by the interradial processes at its angles, but separated from it by very distinct clefts along its sides. Its shape, however, is more pentagonal than stellate (PI. LXV. figs. 1, 4-G). These clefts are rather deeper in Actinometra littoralis, though the centro-dorsal retains its distinctly pentagonal form, and is about flush with the radials, with which it is in contact by its lower angles (PL LXVII. fig. 1). On the other hand, in Actinometra divaricata the centro-dorsal is very markedly stellate, and remains above the level of the radials, the surface of which falls away considerably towards the sides of the centro- dorsal, but not so much so as to give rise to definite clefts (PL LXIII. fig. 6). In the Challenger specimen of Actinometra typica, however, in the original type of Phanogenia, and in others which I have seen, the centro-dorsal is both stellate and sunk below the radials, so that there are very distinct clefts between the latter and its incurved sides ; and no one would think from its present appearance that it had ever been a cirrus-bearing joint (PL LVII. fig. 1). But in Loven's specimen the metamorphosis was less complete, for a few cirrus-stumps are figured as still attached to the stellate centro-dorsal, which is slightly above the level of the radials. The facts stated above, however, concerning Actinometra paucicirra, Actinometra nobilis, and other forms, entitle us to assume that cirri were really present in the young Phanogenia, so that the genus ceases to have the extremely anomalous character which Loven not unnaturally attributed to it. These clefts which occur at the sides of the centro-dorsal in Actinometra typica and similar species must not be supposed to place the cavity of the calyx in communication 16 THE VOYAGE OF H.M.S. CHALLENGER. with the external medium. They occur in several species of Actinometra in which the centro-dorsal undergoes very little modification, as for example in Actinometra pectinata. The small centro-dorsal of this species, as I have shown elsewhere,1 retains its cirrus- sockets and its discoidal form, but has five minute openings round its margin ; and these lead into spaces between its ventral surface and the lower surface of the radial pentagon, which are formed by the apposition of depressions in each of these surfaces respectively. But sections through the calyx of this type show that the radial spaces leading inwards from these marginal openings terminate internally against the inner portion of the ventral surface of the centro-dorsal, and are completely shut off from the radial axial canals enclosed between the rosette and the inner faces of the radials. There is, therefore, no such communication between the body-cavity and the exterior as the presence of these radial spaces might be supposed to indicate. They are precisely homologous with the interarticular pores in the stem of Pentacrinus, which lead inwards some little way, as described in Part I., but are in no communication with the central canal of the stem. It is worth notice that in one fossil species, Actinometra loveni? from the Gault of Folkestone, the centro-dorsal approaches the Phanoge ma-condition. It is an almost pentagonal plate, scarcely above the level of the radials. from which it is separated by narrow clefts, just as in Actinometra typica (PI. LVII. fig. 1), and in Actinometra nobilis (PL LXV. figs. 3-5), and from the close resemblance of the calyx to that of these and similar species which are nearly all inhabitants of quite shallow water (20 fathoms or less), it would appear that the portion of the Gault Sea in which Actinometra loveni lived cannot have reached any great depth. B. The Chambered Organ. Reference has been made above to the radial axial canals which are enclosed between the rosette and the radials, and sometimes reach the ventral surface of the centro-dorsal. Their character and relations were minutely described by myself in 1879, in my memoir on Actinometra* They were shown both in longitudinal and in transverse sections, and figures were also given illustrating their openings on the under surface of the radial pentagon, together with the pits corresponding to these openings on the upper surface of the centro-dorsal in Antedon rosacea. They were clearly distinguished from the five cavities within the central capsule which were first discovered by Dr. Carpenter.4 He 1 Trans. Linn. Soc. Lond. (Zool.), 1879, ser. 2, vol. ii. pp. 89, 90, 102, 103. 2 See P. H. Carpenter, On some Undescribed Coruatulse from the British Secondary Rocks, Quart. Journ. Geol. Soc, 1879, vol. xxxvi. p. 51. 3 Trans. Linn. Soc. Lond. (Zool.), 1879, ser. 2, vol. ii. pp. 77, 78. 4 Phil. Trans., 1866, p. 738 ; and On the Structure, Physiology, and Development of Antedon rosaceus, Proc. Roy. Soc, 1876, vol. xxiv. pp. 218, 219. REPORT ON THE CRINOIDEA. 17 gave the name "five-chambered organ" or " quinquelocular organ" to the structure which had been described by Midler as a single-chambered heart. For he found it " to contain five chambers clustered like the carpels of an orange round a central axis ; " and he described these chambers as being surrounded by a fibrillar envelope which he regarded as nervous in character. Marshall ' again spoke of the cavity of the centro- dorsal as lodging " a sac divided by vertical septa into five radial compartments, and hence called the chambered organ " ; and he went on to explain how this is " surrounded by a thick fibrillar investment known as the central capsule." Ludwig had previously adopted the same terminology,2 and, in fact, he was the first to speak of the " chambered organ" without the numerical prefix, but he never used this expression to denote anything else than the five chambers with their central axis inside the central capsule ; while he further described and figured the radial axial canals,3 the relations of which to the coeliac canals of the rays and arms were subsequently pointed out by myself.4 Their connection with the body-cavity and their distinctness from the chambers of the so-called heart were clearly recognised by Greeff,5 both in his figures and in his descriptions ; while I am not aware that Teuscher,G the only other recent original writer ou the subject up to the time of Perrier and Jickeli, ever used the expression "chambered organ" at all, though he often referred to the " Kammern des Gefasscentrums," and he recognised the connection of the radial axial canals with the cceliac canals of the rays. Recently, however, Messrs. Vogt and Yung have figured not only the cavities with- in the central capsule but also the radial axial canals, and the whole system of spaces within the calcareous network occupying the centre of the radial pentagon, together with some accidental cavities within the solid base of the centro-dorsal piece and in the radials as " cavites dependantes de la cavite generale et constituant, dans leur ensemble, l'organe dit cloisonne." 7 They say " Ce sont les espaces qu'on est convenu d'appeler, fort improprement, l'organe cloisonne," and again " C'est la reunion de toutes ces excavations internes, qui sont revetues de membranes, envoyant de cloisons transversales et dessinant ainsi un systeme complique de lacunes cloisonnees, qui composent ce que les auteurs ont appele l'organe cloisonne (Gekammertes Organ). C'est une denomination eminemment impropre, vu que ce n'est pas un organe, mais une suite de cavites parcourues par l'organe dorsal avec ses vaisseaux, et formant la continuation de la cavite generale du corps, du coelome, qui entoure les intestins."8 The statements contained in the first passage 1 On the Nervous System of Antedon rosaceus, Quart. Joum. Micr. Sci., 1S84, vol. xxiv., N.S., p. 510. 2 Beitrage zur Anatomie der Crinoideen, Zeitschr.f. wiss. Zool, 1877, Bd. xxviiL pp. 315-326. 3 Ibid, p. 318. 4 Trans. Linn. Soc. Lond. (Zool.), 1879, ser. 2, vol. ii. p. 78. 6 Ueber das Herz der Crinoideen, Sitszungsb. d. Gesellsch. z. Beford. d. ges. Naturwiss. zu Marburg, 1876, No. 5, p. 93. 6 Beitrage zur Anatomie der EchinoJermen : I. Coniatula mediterranea, Jenaische Zeitschr., 1876, Bd. iii. pp. 244- 260. 7 Traite d' Anatomie comparee pratique, Livr. vii., 1886, p. 550, expl. of fig. 276. 8 Ibid., p. 530. (zool. CHAX.L. EXP. PART LX. — 1888.) Ooo 3 18 THE VOYAGE OF H.M.S. CHALLENGER. quoted and in the first paragraph of the second one are inaccurate, to say the least of it. Messrs. Vogt and Yung do not name the authors who have used the term " chambered organ" in this " very improper" sense ; but it is certainly neither Dr. Carpenter, Ludwig, Greeff, Teuscher, Marshall, Jickeli, Perrier, nor myself ; and I know of no other original writer on Crinoid morphology who has used the expression "chambered organ" at all. The space represented in the figures to which the Swiss authors refer 1 is the radial portion of the body-cavity within the calyx, which is clearly distinguished from the chambers within the central capsule in all the figures given by Ludwig, Greeff, and myself ; and not one of us has ever regarded this space as a part of the chambered organ, nor, so far as I know, has any other writer on the subject. But from the mode of reference employed by the Swiss authors it would apj^ear that Dr. Carpenter had made a great mistake, which had escaped notice for twenty years until it was rectified by Messrs. Vogt and Yung ; whereas in reality they are themselves in error, because they give a meaning to his name which neither he nor any one else ever intended it to bear. The term " (five-) chambered organ" as employed by him and by every one of his successors until now refers exclusively to the cavities within the central capsule, which lie on the dorsal side of the rosette and radial pentagon. But Messrs. Vogt and Yung erroneously interpret it as denoting the entire system of cavities within the centro-dorsal plate and the ring of radials that rests upon it; and this is certainly not a definite organ, but a part of the general ccelom, as stated by the Swiss authors. These facts, however, were perfectly well known both to Dr. Carpenter and to his successors, and I am entirely at a loss to know who the authors can be who have used the term "chambered organ" in the "eminently improper" sense described by Vogt and Yung. The Swiss authors seem to have entirely ignored or misunderstood the writings of their predecessors, and have attributed to them a mistake which never was made. But instead of rectifying this supposed mistake they have converted it into a real one, and have perpetuated it both in their text and in the explanations of their figures. Thus in fig. 276 the cavities within the central capsule on the dorsal side of the rosette, and the portion of the body-cavity which is on the ventral side of this structure and is enclosed by one of its radial processes, are marked alike " c,c, cavites dependantes de la cavite generale et constituant dans leur ensemble, l'organe dit cloisonne." No one but Vogt and Yung has used the term ' ' chambered organ" in this sense ; and as they rightly speak of it as " eminently improper," one cannot but regret that it should have been employed in a textbook of comparative anatomy for the use of students. But Messrs. Vogt and Yung go even further than this. The space on the dorsal side of the central capsule which is marked f in fig. 267 and c in fig. 276, and is described as one of the cavities of the chambered organ, is nothing; but a rent in the organic basis of the floor of the centro-dorsal piece. These rents often appear in the skeletal tissues when very thin sections are cut, and I have been familiar with them for years. But I 1 Op. cit.J, fig. 264 ; c, fig. 276. REPORT ON THE CRINOIDEA. 19 have many sections through the calyx, both of Antedon rosacea and of other species of Cornatulae in which there is no trace of them. Three such undamaged sections are figured in my Actinometra-memoir,1 and I certainly never expected to find an accidental fracture in the skeletal tissue outside the central capsule described as a part of the chambered organ, the cavities of which are entirely within this capsule, as explained above. If there really be such a diverticulum of the body-cavity within the calcareous substance of the centro-dorsal piece as is described by Vogt and Yung, i.e., between its inner floor on which the central capsule rests and its external surface, its presence could easily be demonstrated by rubbing away the outer surface of the centro-dorsal until this cavity was reached ; and I would commend this method of proving the accuracy of their anatomical descriptions to the attention of Messrs. Vogt and Yung. They have made a precisely similar error in their description of the anatomy of the arms, figuring a large rent in the skeletal tissue of an arm-joint as the " cavite de la syzygie." They will not find this cavity if they will take the trouble to rub away the syzygial surface of an arm- joint, which contains but one cavity, that of the axial canal. Another extraordinary blunder which is committed by these authors in the explanation of fig. 276 is their description of the fibres (b) which unite the first radials to the centro-dorsal as the " muscles entre le premier et le second radial." Their mono- graph contains many other errors of a similar kind, not only in their interpretation of well-known anatomical facts, as in this last case, which they might have avoided by consulting the works of their predecessors, but also misrepresentations of passages in these writings. These, however, are more fitly dealt with elsewhere.2 C. The Rosette. While the presence of a cirrus-bearing top stem-joint or centro-dorsal piece is common to all Cornatulae, even including the aberrant Thaumatocrinus, this genus, together with Atelecrinus (PI. VI. figs. 5, 7) and many fossil species, differs from the adult condition of all other recent Comatulas in the presence of the basals on the exterior of the calyx. It was for a long time supposed that the basals of other Crinoids were unrepresented in recent Comatulse ; but their existence in the Pentacrinoid larva was eventually recog- nised by Allman, Sir Wyville Thomson, and Dr. Carpenter ; and the last-mentioned observer discovered the remarkable changes which they undergo during the later part of Pentacrinoid life. These changes result in their transformation into the "rosette" which lies close to the dorsal surface of the central funnel within the radials, and covers in the upper opening of the centro-dorsal cavity that lodges the chambered organ (sensu stricto). It is well seen in the figures of Antedon eschrichti, Antedon accela, Antedon 1 Trans. Linn. Soc. Lond. (Zool.), 1879, ser. 2, vol. ii. pi. viii. figs. 3, 4, 7. 2 The Morphology of Antedon rosacea, Ami. and Mag. Nat. Hist^ 1887, ser. 5, vol. xix. pp. 19-41. 20 THE VOYAGE OF H.M.S. CHALLENGER. insequalis, and Antedon breviradia (PL I. fig. 8c ; PI. II. figs. 3c, 5c ; PI. III. figs. 4c, 56), and also in those of Actinometra maculata, Actinometra lineata, and Actinometra stelligera (PI. V. figs, lc, 2c, 2c, 5d, be). Owing to its homologies with the basals of other Crinoids, and through these forms with the corresponding plates in other Echino- derms (e.g., the genitals of Echini), it is a very important structure, apart altogether from its intimate relation to the great nerve centre lodged within the centro-dorsal plate and to the axial cords proceeding from it. One would have thought therefore that some account would have been given of it in Vogt and Yung's work upon practical comparative anatomy in which Antedon rosacea, the form studied by Dr. Carpenter, is taken as a type of all Crinoids. It is dismissed, however, in less than half a dozen lines, and not a word is said of its morphological relations. In fact the word "basals" does not once occur in the chapter on Crinoidea in the treatise by Messrs. Vogt and Yung, who pay no attention to the comparative anatomy of anything but the soft parts as revealed by thin microscopic sections. Unfortunately, however, this too exclusive reliance upon one method of investigation has led them into a serious but at the same time a somewhat ludicrous error. In the figure given by Messrs. Vogt and Yung 1 " pour montrer la disposition du systeme nerveux central et des organes dorsal et cloisonne " the chambered organ (as originally described) is covered by a structure marked o. No explanation of this letter is given, but I learn from Professor Carl Vogt that the missing explanation should be — o, tissu conjonctif areolaire entourant 1' organ e dorsal et les cavities c de l'organe cloisonne'. Now this structure which is marked o in Vogt and Yung's fig. 276 is in reality nothing more or less than a part of the rosette of modified basals, which in the natural position of the animal roofs in the internal cavity of the centro-dorsal that contains the chambered organ, as is well shown in PL V. figs. 2c, 2e, and 5c. The relations of this structure to the soft parts beneath it are entirely ignored by Messrs. Vogt and Yung, though they were described at length by myself in 1879 2 and again in 1881. In the latter year I published two sectional views3 showing the position of the rosette with respect to the chambered organ, and another similar figure and description were given later on by Marshall.4 But these have been altogether ignored by Messrs. Vogt and Yung, who have also neglected to work out the point for themselves ; and the consequence is that a structure which, though small and insignificant in Comatulse, is nevertheless homologous with the five genital plates of Echini, is figured in a textbook of comparative anatomy as " areolar connective tissue." In the same figure, too, a portion of the centro-dorsal piece, which is in immediate contact with the central capsule, is lettered " e, mesentere." There are many other points in the relations of the Crinoid skeleton which are 1 Op. tit., p. 550, fig. 276. 2 Trans. Linn. Soc. Lond. (ZooL), 1879, ser. 2, p. 78. 3 The Minute Anatomy of the Brachiate Eehinoderms, Quart. Journ. Micr. Sci., 1881, vol. xxi., N.S.,p. 186, pi. xii. figs. 14, 15. 1 Lot. cit., pp. 508, 511, pi. xxv. fig. 1. See also Ludwig, lot. tit., Taf. xix. fig. 74. REPORT ON THE CRINOIDEA. 21 altogether misunderstood by Vogt and Yung, who have apparently attempted to work out the anatomy of the type by one method only, that of thin sections, and have almost completely ignored its osteology. Had they devoted a little more attention to the characters of a prepared skeleton of Comatula they would have avoided not a few errors which are calculated to give the student an altogether erroneous conception, not only of Crinoid morphology, but of that of Echinoderms in general. The basal plates are among the earliest calcareous structures which appear in the larva of any Echinoderm, and their relation to the great nerve centre of a Crinoid renders them additionally important morphologically. But no student of Messrs. Vogt and Yung would ever learn of their existence at all. The gradual development of the rosette out of the original basal plates of the Pentacrinoid larva was fully described by Dr. Carpenter,1 who showed that it is " essentially formed at the expense of the secondary or ventral layer of the original basals, the ends of the curved rays being the sole residue of their primary or dorsal layer." Alternating with these spout-like processes, which are radial in position, are five others of a more triangular form, which occupy a somewhat deeper situation within the radial pentagon. The apex of each of them is attached to a suture between two con- tiguous radials, just between the two adjacent apertures of their central canals. Each of these canals receives a branch of the primary basal cord proceeding from the central capsule, that lies on the dorsal side of the interradial process of the rosette ; and when the rosette is in its natural position in the calyx, an opening for the passage of one of these secondary basal cords is visible between every two of the processes of the rosette. This is well seen in Antedon eschrichti (PI. I. fig. 8c). The example of this species which is here represented, has a comparatively simple rosette, which is almost entirely free from any trace of the accessory structures to which I have given the general name of the "basal star," such for instance as is represented in figs. 1-5, c on PI. II. In all these forms, and more especially in Antedon angusticalyx and Antedon insequalis (figs. 4c, 5c), a larger proportion of the embryonic basal has been left unabsorbed than is usually the case in . the European and Arctic Comatulae ; but the peripheral margins of each plate remain, and form, by their union with the corresponding parts of the adjacent plates, the structure which I have called the basal bridge. This is united to each radial along the inner margin of its dorsal face, and partially covers in the two secondary basal cords which are converging; on its single axial canal. It is well shown in Acti?iometra maculata and Actinometra stelligera (PI. V. figs, lc, 5d) and also in the rosette of the latter species disconnected from the radials as seen in fig. 5c ; and it appears, so far as I am aware, to be of pretty constant occurrence in this genus, though absent or at any rate undistinguishable in some species of Antedon (PI. III. fig. 6b). United with each angle of the pentagon formed by the five basal bridges is one of the 1 Phil. Trans., 1866, p. 745. 22 THE VOYAGE OF H.M.S. CHALLENGER. rays of the basal star, the relations of which are described at length in my memoir on Actinometra.1 At the time this was written (1877) I had only been able to dissect the calyx in a comparatively small number of Comatulse ; but a detailed examination of the large amount of duplicate material obtained by the Challenger has shown that a basal star is nearly always present both in Antedon and in Actinometra, so that species like Anteclon tenella, Antedon hageni, Antedon phalangium, and Antedon rosacea, in which it is not developed, are the exception rather than the rule ; while there may be traces of it in some varieties of Antedon eschrichti, though not in others. It occasionally happens that the rays of the basal star, or, more shortly, "the basal rays," appear on the exterior of the calyx between the centro-dorsal and the first radials. But there is no constancy about this character, even in individual species. Thus, for example, a basal ray is visible in the dissected calyx of Antedon antarctica shown on PI. I. fig. 6a, but there is no trace of it in either of the three specimens figured on PL XXV. figs. 10-12. The basal rays sometimes appear externally beneath the alternate radials of the ten-rayed Promachocrinus (PI. I. figs, la, lc), but this is not always the case. I have also seen them in some individuals of Antedon carinata, though not in that shown on PI. III. fig. la. They are generally to be seen in Antedon macronema (PI. IV. fig. 3a; PI. XXXVIII. fig. 5), in Antedon longicirra (PL XVII.), and also in Actinometra pulchella (PL IV. fig. 5c), and Actinometra stelligera (PL V. fig. 5b) ; while there are other species, such as Actinometra rnaculata and Actinometra lineata, in which they are only occasionally visible. I have shown elsewhere that the basal rays have an entirely different origin from either the primary or the secondary portions of the rosette. They are tertiary structures formed by calcification in the synostosis between centro-dorsal and radials. Sometimes, however, they are very substantial structures, and each of them becomes so firmly united with an interradial portion of the rosette that it is often possible to get the entire complex structure thus formed to break up into five separate parts, each representing one basal plate. The results of this operation are seen in Antedon antarctica (PL I. fig. 7), Antedon carinata (PL III. figs, lc, 2a, 2b, 3a, 3b), Actinometra nieridionalis, Actinometra pulchella, and Actinometra paucicirra (PL IV. figs. 4b, 5a, 6b). Each of the compound basals so isolated is a somewhat elaborate structure. The basal ray may be long and narrow as in Actinometra nieridionalis (PL IV. fig. 4b), or short and stout as in Antedon antarctica (PL I. fig. 7) and Actinometra paucicirra (PL IV. fig. 6b.) At the proximal end of the basal ray are two openings, one on each side, which give passage to the secondary basal cords ; and they are separated, when seen from the dorsal side, by the interradial process of the rosette with portions of the basal bridge (PL IV. figs. 4b, 6b, yS). The lateral boundaries of these openings are formed by the halves of two of the radial spouts of the rosette which extend outwards from the base of the interradial 1 Trans. Linn. Soc. Lond. (Zool.), 1879, ser. 2, vol. ii. pp. 95-100. REPORT ON THE CRINOIDEA. 23 process and represent the unabsorbed lateral portions of the primary layer forming the embryonic basal plate. The ventral side of the basal ray in the three species of Actinometra which are figured on PL IV. figs. 5a, 46, Gb, a, is marked by a relatively large depression which forms the central end of the axial interradial canal. This descends into the calyx over the apposed lateral edges of two radials, as is well seen in PI. III. figs. Id, 7c, and PL V. fig. 2c. But in most cases it ends blindly without reaching the dorsal surface of the radial pentagon at alL D. The Radials. The radials of Comatulse differ considerably from those of the Pentacrinidae, the family of Stalked Crinoids to which the free forms are most closely allied. In Pentacrinus, as in the Pentacrinoid larva of Antedon (PL XIV. figs. 2-9), the first radials appear above the basals on the exterior of the calyx as relatively large convex plates. They retain this character in Thaamatocrinus and to a less degree in Atelecrinus (PL VI. figs. 5, 7). both of which are permanent larval forms in other respects. But in the two large genera Antedon and Actinometra there is a very considerable amount of variation in the extent to which the first radials appear externally. Some forms, such as Antedon eschrichti, show no indication of them at all (PL XXIV. fig. 11), or only traces of their angles in the interradial portions of the calyx (PL I. fig. 8a) ; while in other cases, such as Antedon elegans, Antedon longicirra (Pis. VIII. , XVII.), and Antedon macronema (PL IV. fig. 3a; PL XXXVIII. fig. 5), they exhibit a relatively large outer surface between the edge of the centro-dorsal and the second radials. Between these two extremes every intermediate gradation may be traced. The former is due to the gradual enlargement of the centro-dorsal, which spreads itself over the base of the calyx towards the end of Pentacrinoid life and sometimes conceals the first radials altogether, as described by Dr. Carpenter1 in Antedon rosacea. The second radials thus appear to spring directly from the centro-dorsal (PL XIII. fig. 2); and this has sometimes led to species of Comatidse being described as having only two radials. In fact d'Orbigny2 described a new genus Comatulina, for a fossil species in which there are no external basals and " les bras s'articulent immediatement sans intermediates a la piece centrale pourvue de ramules." The full-grown Antedon accela presents this appearance, but the younger specimen figured on the same plate (PL XVI.) shows comparatively large first radials; while a more mature individual (PL II. figs. 3a, 3c) shows relatively less of them, owing to the spread of the centro-dorsal. The figures of Antedon plialangivm on PL XXVIII. show similar differences of growth, though in a less degree. The various species of Actinometra exhibit among themselves essentially the same 1 Phil. Trans., 1866, p. 742. 2 Cours elementaire de Paleontologie et de Geologie Stratigraphique, 1850-52, vol. ii. p. 139. 24 THE VOYAGE OF H.M.S. CHALLENGER. differences as do those of Antedon in the extent to which the radials appear on the out- side of the calyx. In Actinometra maculata, Actinometra lineata, and Actinometra stelligera the oentro-dorsal is so large that it actually supports the proximal ends of the second radials, and nothing but the angles of the first radials can be seen externally (PI. V. figs. 1, 2, 5, a, 6). Small portions of their sides can be seen in Actinometra Solaris (PL V. figs. 4, 6, c) ; while in Actinometra paucicirra and in all the Phanogenia-\ike forms the centro-dorsal only occupies a comparatively small space in the centre of the radial pentagon, a considerable portion of which appears externally as seen in PL V. fig. 3c, and in Pis. LIV, LXV. Not only the centro-dorsal, but also the radials of Actinometra present very considerable differences from the corresponding parts of the Antedon-c&lyx, though these differences are less distinct in the fossil than in the recent forms of both genera. The outer or articular faces of the radials in Antedon are always much inclined to the vertical axis of the calyx, and are usually much wider at their dorsal than at their ventral ends, so that their outline is trapezoidal (PL I. figs. 6a, 8a ; PL II. figs. 1-5, a ; PL III. figs, la, 46, 5a, 6a7; PL IV. figs. 2a, 3a). Antedon carinata and Antedon macronema are, however, somewhat exceptional in this respect, the width of their articular faces being very much more uniform ; and they further differ from most species of Antedon and resemble Actinometra (PL V. figs. 1-5, o) in the relatively great diameter of the central funnel of the calyx (PL III. fig. id ; PL IV. fig. 3b). For as a general rule the opening of the central funnel which is bounded by the upper edges of the radials is very narrow, their ventral surfaces being quite small and having a steep inward slope. Hence when the calyx is viewed from above the greater part or even the whole of these inclined external faces is visible, always down to the opening of the central canal in the transverse articular ridge (PL II. fig. Ad ; PL III. fig. 6c); while sometimes even the fossae for the attachment of the dorsal ligament are visible in a superior view (PL I. figs. 6, 8, b; PL II. figs. 1-3, 5, d; PL III. fig. 4a). This last is especially the case in Antedon macronema (PL IV. fig. 3b), though the reverse is true of Antedon carinata (PL III. fig. id). Most species of Antedon have large muscle-plates, which greatly increase the height of the distal faces of the radials (PL I. figs. 6, 8, a ; PL II. figs. 1-5, a ; PL III. figs. 46, 5a, 6c/). They are fairly large in Antedon carinata (PL III. fig. la), but in Antedon macronema they are quite small and linear and barely distinguishable in side view from the pair of fossae immediately below them, though they are seen rnoi*e clearly when viewed from above (PL IV. figs. 3o, b). This lower pair of fossae was described by Dr. Carpenter 1 as serving for the attachment of the interarticular ligaments. The ridges which generally separate them from the upper fossae mostly start from the raised rim round the opening of the central canal and run more or less obliquely outwards to meet the sides of the radials (PL II. figs. 2-5, a ; PL III. figs. 46, 5a, 6d). In Antedon antarctica, however, 1 Phil. Trans., 1866, p. 714. REPORT ON THE CRINOIDEA. 25 they are almost perfectly horizontal (PI. I. fig. 6a), and so give the calyx a very different appearance from that of the closely allied Arctic species Antedon eschrichti (PL I. fig. 8a) ; though Promachocrinus kerguelensis, another southern form, resembles Antedon eschrichti in this respect (PI. I. fig. la), and the same may be said of Eudiocrinus semperi (PI. III. fig. 7a). In some forms of Antedon incisa the ridges do not, as is usually the case, start from the rim of the central canal, but curve upwards slightly from the median vertical ridge of the articular face, and the upper pair of fossae are therefore somewhat restricted (PI. II. fig. la). In Antedon disciformis (PL IV. fig. 2a) the ridges run upwards from the central canal for some little distance and then curve outwards, leaving a sort of furrow between them, the bottom of which is sometimes slightly raised.1 But in most species of Antedon there is a strong median ridge running down from the ventral edge of the articular face towards the opening of the central canal (PL I. figs. 6a, 8a ; PL II. figs. 1-5, a ; PL III. figs. 46, 5a, 6d). This is hardly traceable in Antedon carinata (PL III. fis;. la), which rather resembles Antedon disciformis in having a tendency to the intermuscular furrow that is so characteristic of Actinometra (PL V. figs. 1-5, b) ; while in Antedon macronema the muscular fossae are so very slight, that the notch between them reaches down to the upper margin of the raised rim of the central canal (PL IV. figs. 3a, b), a character which rarely occurs in Actinometra. Thus then the radials of Antedon carinata and Antedon macronema differ from those of other species of Antedon and approach those of Actinometra. There is much less difference than usual between the widths of the upper and lower ends of the distal faces, which are comparatively low, so that their long axes are horizontal and not vertical as is usually the case (PL I. figs. 6a, 8a). The centre of the upper surface is consequently occupied by a wide funnel, the walls of which are formed by the ventral surfaces of the radials (PL III. fig- 1^ ; PL IV. fig. 3b). Antedon carinata has fahiy large muscle- plates ; but they are quite small in Antedon macronema, and the ridges separating the muscle- and ligament-fossse are so slightly oblique as to be almost horizontal, though their orio-iu from the prominent and large rim of the central canal is very marked. In each case, however, the general appearance of the calyx is much more that of the Antedon than of the Actinometra type. The calyx of Antedon macronema further presents many resemblances to that of Pentacrinus, especially in the small size of the articular faces and in the large portions of the radials which appear externally (PL IV. fig. 3a). Of all recent Comatulse it is the one which most closely approaches the general type of the Jurassic forms of Antedon; and as it is only known to occur on the Australian Coast, this is a point of considerable interest. The radials of Actinometra differ very largely from those of the typical Antedon. Their distal faces are relatively low, and lie nearly or quite parallel to the vertical axis of the calyx, while there is but little difference in width between their ujjper and their lower 1 This is less distinctly seen in an interradial view of the calyx than in a face view of a single radial. (ZOOL. CHALL. EXP. — PART LX. 1888.) OoO 4 26 THE VOYAGE OF H.M.S. CHALLENGER. ends. The vertical position of the articular faces is well seen in some forms of Actino- metra lineata, which has an extremely "wall-sided" calyx (PI. V. fig. 2e) ; while in Actinometra paucicirra their lower portions actually slope inwards as seen in PI. V. fig. 3c. The ventral faces of the radials, which in Antedon have a steep inward slope (PI. I. fig. 86), are almost horizontal in Actinometra, sloping very gently inwards towards the central space. Hence the opening of the funnel becomes widely expanded, and when the radial pentagon is viewed from above little or nothing is seen besides the proper ventral faces of its component radials. All the species of Actinometra which I have examined have smaller muscle-plates than those of any Antedon except Antedon macronema (PI. IV. figs. 3a, b), so that the distal faces of the radials are very low and the muscular fossae often quite inconspicuous (PL IV. figs. 4a, 5c ; PI. V. figs. 1-5, b, 5c). They are separated from the lower pair of fossae by fairly prominent ridges which are either horizontal or curved slightly upwards. These start from the sides of the radial, run inwards towards the middle line, and then turn downwards so as to leave between them a wide furrow, which gradually dies away below with the disappearance of its bounding ridges. No recent Actinometra has the distinct rim on the ventral side of the opening of the central canal that exists in every Antedon, even in Antedon carinata (PI. III. fig. la) and in Antedon macronema (PL IV. fig. 3a), perhaps the nearest approach to it being in Actinometra meridionalis and Actinometra pulchella (PL IV. figs. 4a, 5c), where the lower edges of the ridges bounding the intermuscular furrow are somewhat thicker than usual. These differences in the structure of the calyx in the two chief genera of Comatulse are of considerable importance. For it is only by means of an acquaintance with them that the generic determination of the fossil Comatulae becomes at all possible. Every one hitherto found in the Tertiary strata and in the Chalk, of which the entire calyx is known, is an unmistakeable Antedon, both in the characters of the centro-dorsal and in those of the radials. Antedon sequimarginata from the Gault is as clearly an Antedon as Actinometra loveni from the same formation is an Actinometra. But some of the Neocomian and many of the Jurassic Comatulae are less easily identified. The wide and low radials with marked intermuscular furrows of Actinometra cheltonensis from the Inferior Oolite, and of Actinometra ivurtembergica from the Corallian of Nattheim, indicate the generic position of these types pretty clearly ; while Antedon scrobiculata with its high articular faces, much narrower above than below, is an undoubted Antedon. But on the other hand, the low and wide radials and thin centro-dorsal of Antedon picteti and Antedon infracretacea are very suggestive of Actinometra; though in both types the articular faces of the radials have a considerable slope and are altogether much like the corre- sponding parts of other species which are unquestionably referred to Antedon. For the present, therefore, the systematic position of these and of other somewhat generalised types of early Comatulas must remain in doubt. REPORT ON THE CRINOIDEA. 27 E. Some Abnormal Conditions of the Bays of Comatul^. In the two large genera Antcdon and Actinometra, just as in Apiocrinus, Pentacrinus, and Encrinus, there are normally five rays which divide upon the third joint above the basals, i.e., the third radial is the axillary (Pis. VIII., LXVII.) ; and this is the general rule among the Neocrinoids. The exceptions are Metacrinus and Plicatocrinus, the former with four or six radials (primitively five or eight, as some of them are syzygial joints), and the latter with only two as in one or two fossil Comatulse. It sometimes happens, however, that an additional radial is inserted into the normally three-jointed series, as for example in the Pentacrinus millleri mentioned in Part I.,1 and I have met with a nearly similar case in Antedon alternate/, (PL XXXII. fig. 5); while Wagner2 has noticed the same monstrosity in Encrinus gracilis. But the two outer radials of Antedon alternata remain separate and are not united by syzygy, as in the Pentacrinus millleri just mentioned. On the other hand, in one example of Antedon remota (PI. XXIX. fig. 6) and in the only specimen of Antedon incerta (PI. XVIII. fig. 4) and in one of Actinometra parvicirra (PI. LXI. fig. 1) the second radial is missing in one ray and the axillary rests directly against the first radial as in Plicatocrinus and in many Palseo- crinoids. Another and more common variation is in the number of the rays themselves. Excepting, of course, in Promachocrinus there are normally five rays in all Comatulidae ; but forms with four and six rays are occasionally met with. I have a tetraradiate specimen of Antedon rosacea, and one of a Japanese Antedon in Dr. Doderlein's collection, and also one of Actinometra paucicirra from Cape York. In all these three individuals the anterior ray (A) is missing, so that the mouth, instead of being radial in position, is placed interradially between the rays E and B. On the other hand the " Blake" collection contains a six-rayed form of Actinometra pulchella. The disc is unfortunately concealed, so that the symmetry of the ambulacra cannot be made out. But I am rather inclined to think from the appearance of the centro-dorsal that it has the usual pentamerous symmetry, one of the radials being rather larger than its fellows and also axillary, so that it bears two small rays, as sometimes happens in Allagecrinus.3 Another variation characteristic of this genus occurs in Actinometra midtibrachiata (PL LVI. fig. 3), one of the radials being considerably smaller than the other four. The only other six-rayed Comatula that I know is a small and dry Antedon in the 1 Zool. Chall. Exp., part xxxii. p. 311, pi. xv. fig. 2. 2 Die Encriniten des unteren Wellenkalkes von Jena, Jenaische Zdtschr., 1886, Bd. xx. (N.F. xiii.), p. 20, Taf. ii. fig. 13. 3 See Carpenter and Etheridge, Contributions to the Study of the British Paleozoic Crinoids, — No. I. On Allagecrinus, the Representative of a New Family from the Carboniferous Limestone Series of Scotland, Ann. and Mag. Nat. Hint., 1881, ser. 5, vol. vii. pp. 288, 292. 28 THE VOYAGE OF H.M.S. CHALLENGER. British Museum. But the disc is sufficiently well preserved to show that the additional ray is inserted between the two of the right side (D and E). The facts above mentioned may be usefully compared with similar variations which have been noticed in other Echinoderms. In the only six-rayed Blastoid that I have seen1 there are but five ambulacra, though a pseudo-radial plate without a sinus is intercalated between radials C and D, so that the dorsal surface of the calyx is very regularly hexagonal. On the other hand Blastoids with only four ambulacra are more common ; but the dorsal part of the calyx is more or less distinctly pentagonal, the fifth radial not being incised for an ambulacrum. The two postero-lateral and the right antero-lateral one (C, D, E) are the rays in which this modification has been noticed, C showing it twice and the other two once each. Two tetraradiate examples of Encrinus liliiformis have recently been observed by von Koenen ;2 but it is curious that variations from the normal pentamerous symmetry are rare among the Pelmatozoa, except in the genus Rhizocrinus. Four- and six-rayed Urchins are not uncommon; while Ludwig3 found half a dozen six-rayed individuals of Cucumaria planci in a collection of one hundred and fifty. In all cases the sixth ray was intercalated between the two forming the bivium, a fact which may be compared with the absence of the middle ray of the trivium in the three Comatulaa with abnormally interradial mouths mentioned above. 1 See Etheridge and Carpenter, Catalogue of the Blastoidea in the Geological Department of the British Museum (Natural History), London, 1886, pp. 40, 41. 2 Beitrag zur Kenntniss der Crino'iden des Muscheikalks, Abhandl. d. k. Gesellsch. d. IViss. Gottingen, 1887, Bd. xxxiv. p. 23 (of separate copy). 3 Ueber Sechsstrahlige Holothurien, Zool. Anzeiger, 1886, Jahrg. ix. p. 476. REPORT ON THE CRINOIDEA. 29 III.— THE GEOGRAPHICAL AND BATHYMETRICAL DISTRIBUTION OF THE COMATULSE. Our knowledge of the existing species of the Comatulse is at present so imperfect that it affords but a slight foundation for any generalisation respecting their geographical distribution and the origin of specific types. For they occur in the most extraordinary abundance over certain large areas, such as the Caribbean Sea, and more especially the Eastern Archipelago and Australasia. Every large collection that I have examined, and they are many, contains a number of forms from the latter district, the specific relations of which will require months of detailed work before they can be properly elucidated. Nearly all of these are littoral species, and it is chiefly with regard to them that any generalisation would be premature at present. But the dredgings of the Challenger have accumulated a large mass of information concerning the Comatulse of other seas than those of Australasia. This relates more especially to the Comatula-fawaa of the continental and abyssal regions, about which we cannot expect to gain very much additional knowledge in future. The Comatulse of the Arctic and Sub-Arctic seas are also pretty completely known ; while the Strait of Magellan and the Southern Indian Ocean between Marion Island and Melbourne have yielded some dozen species for comparison with those of the northern circumpolar fauna. The following conclusions, then, embody the condition of such knowledge of the Comatulse as I have been able to gain from the study of the Challenger collection and preliminary work upon the material dredged by the U.S. Coast Survey steamer "Blake"; together with my notes upon the Comatulse in the museums of London, Paris, Berlin, Vienna, Copenhagen, Lund, Stockholm, Amsterdam, Leyden, Hamburg, Dresden, Kiel, Munich, Stuttgart, and also upon the collections made by Professor Semper in the Philippines, Dr. Doderlein in Japan, Dr. Anderson in the Mergui Archipelago, and Dr. Hickson in North Celebes. The Comatuke range in latitude from 81° 41' N. to 52° 5' S., being represented in each locality by a ten-armed Antedon, a point which will be considered later. Although abundant near the coasts in the Arctic Ocean and on both sides of the North Atlantic, no Comatulse have been dredged there at a greater depth than 800 fathoms, nor were any met with in either of the Challenger's two traverses of the North Atlantic; while, though one species has been obtained at the Canaries and Madeira, there is no record of any from the Azores, Bermuda, or the Cape Verde Islands. The two Mediterranean species range as far north as Scotland, but I do not know of their passing the meridian of 20° E., either in the Mediterranean or in the Baltic. In the Florida Channel and in the Caribbean Sea, however, Comatulse have been dredged in abundance. But none arc known from the African Coast between Cape Verde (Goree) and the Cape of Good Hope, 30 THE VOYAGE OF H.M.S. CHALLENGER. except for one species of Anted 'on at the equatorial island Rolas. The only Actinometra common to both sides of the Atlantic occurs at St. Paul's Rocks, and a few Caribbean species both of this genus and of Antedon are common along the South American coast as far south as Cape Frio (lat. 23° 1' S.); while in mid-Atlantic Antedon was dredged in moderate depths near Tristan da Cunha and Ascension respectively. Closely allied to the North Atlantic species are those occurring at Kerguelen and Heard Island, together with a couple of forms inhabiting the Strait of Magellan. This Southern Ocean has also yielded Promachocrinus. the unique Tliaumatocrinus, and at 2600 fathoms a minute Antedon which was also found at 2900 fathoms in the North Pacific. Various Comatulae have been obtained at Simon's Bay, Natal, Madagascar, Zanzibar, Mauritius, St. Helena, Rodriguez, the Red Sea, the Seychelles and Ceylon, with a solitary species at Kurrachee, and in the Bay of Bengal. It is curious, however, that none were found by Mr G. C. Bourne on the coral reefs of the Chagos group. But the region in which Comatulae are most abundant is the great Eastern Archipelago, which may be roughly described as a triangular area reaching 100° from east to west and 65° from north to south, with its angles at Ceylon, Japan, and the Kermadec Islands. Within this large area, which includes the Challenger Stations 170 to 236, Comatulae occur in the most bewildering profusion. But, so far as I know, not one has been found on the coasts of New Zealand, although Eudiocrinus and a ten-armed Antedon were obtained by the Challenger at Station 169, within a comparatively small distance of the East Cape of the North Island. The Challenger's dredgings between the Admiralty Islands and Japan were among the deepest of the whole cruise, ranging between 1100 and 4475 fathoms, and no Comatulae were met with between the equator and lat. 35° N. Three species were obtained on the green mud off the Japanese coast between 345 and 775 fathoms, and one in 2900 fathoms at Station 244 in the North Pacific. This form, Antedon abyssicola, is the deepest Comatida known. From Station 244 until the Straits of Magellan were entered, the dredgings of the Challenger yielded no Comatida at all, a fact which is the more interesting because almost the same statement holds good for the Ophiurids.1 Single species of Antedon are known from the Sandwich Islands and Chile, and of Actinometra from Tahiti and Peru ; but except for these and for the two in the Strait of Magellan, I know of no Comatida in the Pacific east of long. 150° E., not even on the western shores of North America. Antedon rhomboidea and Antedon magellanica, if they can be called Pacific species at all, are the only ones in that ocean south of lat. 40° S. None occur in New Zealand nor in Tasmanian waters. These two Magellan species are therefore somewhat isolated, as on entering the Atlantic the Challenger dredged no Comatulae until reaching Station 320, in 600 fathoms, where three ten-armed species of Antedon were obtained. The Falkland Islands, however, seem to have yielded nothing. 1 Zool. Chall. Exp., 1882, part xiv. p. 309. REPORT ON THE CRINOIDEA. 31 The distribution of the two leading Comatula genera, Antedon and Actinometra, cannot yet be fully worked out, owing to the large number of species which are still undescribed ; but that of the other generic types is easily stated. The archaic Thaumatocrinus has only been found at 1800 fathoms at Station 158 in the Southern Ocean, where it was associated with Promachoerinus abyssorum, which also occurred at Station 147 (1G00 fathoms), together with three species of Antedon. Another species of Promachoerinus is common at Kerguehm, and a third was obtained at 500 fathoms off the Meangis Islands. Three species of Atelecrinus are known, two from the Atlantic and one from the Pacific. The unique specimen of the latter was found at Station 174c in the South, Pacific, at 610 fathoms ; while one of the Atlantic species is only known from Pourtales' dredgings in the Gulf Stream off Havana (450 fathoms). The other, found by the Challenger in 350 fathoms at Station 122 off Pernambuco, was subsequently met with by the " Blake " off Nevis, St. Lucia, and Granada, at depths of 291 to 422 fathoms. Eudiocrinus, first obtained in quite shallow water among the Philippines by Semper, was dredged by the Challenger both in the North and in the South Pacific, at depths varying from 565 to 1050 fathoms; while the " Travailleur " found Eudiocrinus atlanticus at 896 metres in the Bay of Biscay. In discussing the distribution of Antedon and Actinometra, the two principal genera of Comatulse, it must be remembered that each of them, but especially Antedon, contains a very large number of species, and they should be considered for this purpose to represent subfamilies rather than genera. Thus, for example, the name Antedon is now given to all recent endocyclic Comatulse with the basals metamorphosed into a rosette, and five rays bearing ten or more arms, just in the same way as the name Echinus was originally used for a variety of regular Urchins, which have now received different generic names. The difference between the tiny ten-armed Antedon abyssicola inhabiting depths of three miles and upwards in the Pacific (PI. XXXIII. figs. 1, 2), and the littoral Antedon clegans, Antedon multiradiata, or Antedon regalis (Pis. VIIL, IX., XLVL), is no doubt very considerable at first sight ; but there are so many intermediate links between the simple and the complex forms, that no hard and fast generic lines can be drawn. At the same time, a glance at the tabular keys to the species which are given in the following pages will show that they fall into certain very well defined groups ; and the range of each of these groups, both in depth and in space, may be profitably studied. In the first place, all the species of Antedon which have the two outer radials united by syzygy are limited to quite shallow water in the En stern Archipelago. They are comparatively few in number, and have perhaps the most restricted geographical range of any of the specific groups. On the other hand, the Antedon species of the simple ten- armed type like Antedon rosacea, are most remarkably abundant, and also extremely varied in their character, — Antedon abyssicola and Antedon tuberosa, or Antedon 32 THE VOYAGE OF H.M.S. CHALLENGER. carinata, presenting several very striking points of difference (PI. XXIII. fig. 2 ; PL XXXIII. figs. 1,2; PI. XXXIV.). They fall into several sets, each of which represents a different type of Comat u/a-structure, and in several cases the distribution of these sets is fairly well defined. The ten-armed species of Antedon have a wider range both in depth and in space than any other types of the genus. This is of course only to be expected ; for they represent a somewhat early stage in the development of the Pentacrinoid larva, the radial axillaries and the pairs of first brachials which they bear appearing soon after the opening of the tentacular vestibule, when the whole number of tentacles does not exceed twenty- five. These ten-armed forms are the only species of Antedon which occur outside the fortieth parallels of latitude, and at greater depths than 750 fathoms. There is one possible exception to this last statement. Some examples of Antedon insequalis with three distichals reached me, together with fragments of Pentacrinus naresianus and the label of Station 175 (1350 fathoms). But there is no record in the Station Book of their occurrence here, though two Comatulae are mentioned. But these [Antedon breviradia and Antedon acutiradia, PI. XI. figs. 3, 5) have the general facies of deep-water forms ; and this is not the case with Antedon insequalis and the arms of Antedon basicurva, which are labelled as coming from this station. It may then, I think, be safely assumed that the only Cornatulae dredged at Station 175 were the ten-armed Antedon acutiradia and Antedon breviradia, the multibrachiate Antedon insequalis not really occurring at that station. Disregarding this form, we find that out of twenty-nine stations where Antedon was dredged by the Challenger, "Porcupine," and other British expeditions, at depths exceeding 200 fathoms, twenty-eight yielded ten-armed species. Multibrachiate species occurred at six of these, and at one other station, this (Station 135g) being the only locality below 200 fathoms where the genus Antedon occurred, but was not represented by any ten-armed form. Eleven of the twelve " Porcupine " stations ' and two of the seventeen Challenger ones were beyond the parallels of 40°. But the remaining " Porcupine " station and six of the fifteen Challenger ones within these limits yielded multibrachiate forms, though never at a greater depth than 750 fathoms. The " Porcupine " species, however, Antedon lusitanica, is a curious one. It is dimorphic, some individuals having ten arms only, and some having one or more distichal series (PI. XXXIX. figs. 1, 3). The nine dredgings of the Challenger at which Antedon occurred at depths between 700 and 2900 fathoms inclusive, yielded nine species of the genus, all of them small and ten-armed, and half of them belonging to the group which contains the familiar Antedon rosacea and Antedon tenella. Four of the fifteen dredgings between the fortieth parallels at depths exceeding 200 fathoms were at 1000 fathoms and upwards, and they yielded 1 Under this general name I include all the dredgings of the " Porcupine," " Lightning," " Knight-Errant," and "Triton." REPORT ON THE CRINOIDEA. 33 four species of Antedon, three of which were each found at two or more different stations.1 Thus Antedon abyssicola, from 2900 fathoms (Station 244) in the North Pacific, also occurs at 2600 fathoms (Station 160) in the Southern Sea; and the remaining abyssal station south of lat. 40° S. (Station 147, 1600 fathoms), yielded three different species of the ten-armed Antedon-type. The species dredged at Station 135e in 1000 fathoms was only represented by Pentacrinoid larvae, but of the eight remaining abyssal forms (found below 700 fathoms), one that occurred at four stations in the Pacific is closely allied to Antedon tenella, which ranges down to 740 fathoms in the North Atlantic, between 30° N. and 75° N.; while three others belong to the same group as this species and Antedon rosacea, which ranges in shallow water from the Fseroe Banks to the Canary Islands, and possibly even to the equator. In like manner, the Magellan and Heard Island species from the furthest south are the Antarctic representatives of Antedon eschrichti and Antedon quadrata, which are widely distributed in the Arctic Ocean. In fact, the group to which these forms belong has the greatest geographical range of any set of the ten-armed Antedon-type,. Antedon eschrichti (PI. XXIV. fig. 11) and its close ally Antedon quadrata (PI. XXVI. figs. 2, 3), are common in the Arctic Ocean between the meridians of 80° W. and 70° E. They were found by the " Porcupine " in the Fseroe Channel, and by the Challenger off Halifax, which is their furthest southern range (lat. 43° N.). No other Comatulae but the dimorphic Antedon lusitanica were found in the North Atlantic below 650 fathoms, but this form does not at all approach the Eschrichti-gvowp. The Straits of Magellan, however, contain two species belonging to it ; while Antedon australis, and Antedon antarctica from the neighbourhood of Heard Island are also very closely allied to, though not identical with Antedon quadrata and Antedon eschrichti, and are the southernmost Comatuhe known (PI. XXV.; PI. XXVI. fig. 4). None of these species, however, nor in fact any of the Eschrichti- group, extend down to any greater depth than 650 fathoms; but some of the Comatulse from depths below this belong, as we have seen, rather to the North Atlantic than to the Arctic fauna. Certain of them, however, find their places in the group of ten-armed species which have the sides of the rays flattened and more or less closely approximated. One of them {Antedon bispinosa, PI. XX. fig. 3) was obtained at Station 147, together with two species of the Tenella- group, and two others {Antedon acutiradia and Antedon breviradia, PI. XL figs. 3, 5) were the only two dredged with certainty at Station 175.'2 All these three occurred below 1300 fathoms. With the exception of Antedon bisjnnosa from the Southern Sea and Antedon lusitanica and Antedon multispina of the Atlantic, all the twenty forms with laterally compressed rays {Basicurva-growp) inhabit the Western Pacific and Australasia; and only 1 The Antedon breviradia and Antedon alternata occurred both at 630 and 1070 and at 1350 fathoms respectively. ■ See ante, p. 32. (ZOOL. CHALL. EXP. — rABT LX. — 1888.) Ooo 5 34 THE VOYAGE OF H.M.S. CHALLENGER. one (Antedon denticulate), from 49 fathoms at Station 190 in the Arafura Sea, can be called a littoral species. The remainder all belong to the continental or to the abyssal zone. Most of them have covering plates and generally also side plates to the ambulacra ; and the two ten-armed forms of Antedon from the Challenger dredgings which have plated ambulacra but the rays not flattened laterally (Accela-growp) are even more restricted in their distribution. One was found in 140 fathoms at Station 192 in the Arafura Sea, and the other in 500 fathoms off the Meangis Islands (Station 214). Not only are the ten-armed species of Antedon the most widely distributed as a group, but they also have the most extensive individual range. Antedon eschrichti and Antedon quadrata of the Arctic Ocean were dredged by the Challenger in lat. 43° N. Antedon phcdangium ranges from the north of Scotland to Morocco and throughout the western basin of the Mediterranean. The Protean Antedon rosacea also occurs in the Mediterranean, extends from the Fseroe Banks to the Canaries, possibly even to Cape Verde and the equator, and is perhaps also found on the American coast; whde Antedon carinata is distributed between the parallels of 15° N. and 35° S., through the Indian Ocean from Java1 to Zanzibar, along the Atlantic coast of South America from St. Lucia to Eio Janeiro, and is also found at Valparaiso. None of the multibrachiate forms of Antedon have anything like this geographical range. In the western North Atlantic there is no species with more than ten arms north of Florida, and the dimorphic Antedon lusitanica is the only one known on the eastern side. This last and those from Japan are the most northerly multibrachiate forms, while Antedon setosa from off Tristan da Cunha and the various species inhabiting Port Jackson and near the Kermadecs are the most southern representatives of these many -armed types of Antedon, which have almost exactly the same range in latitude as the genus Actinometra. Examples of each of the two great groups, those with two and those with three distichal joints, occur in the Caribbean Sea, and they are abundant between the Society Islands and the Red Sea. But, as we have just seen, they have a very limited bathymetrical range, only appearing at seven Challenger stations between 100 and 630 fathoms, and at none where the depth exceeded this latter limit. In some of the Antedon-syyecies dredged at all these seven stations the secondary arms consist of three distichal joints, the axillary with a Syzygy, but at two of them bidistichate forms also occurred, together with species of Actinometra ; and the single " Porcupine " Antedon with more than ten arms is Antedon lusitanica from 740 fathoms, in the North Atlantic, which sometimes has a distichal series of two joints. There are no tridistichate species of Antedon in the North Atlantic, outside the Caribbean Sea ; though they occur in the South Atlantic at Tristan da Cunha and Ascension, and at five stations below 100 fathoms in the Western Pacific and Australasia. On the other hand, the bidistichate series represented by Antedon lusita?iica does 1 See the remarks on this subject on p. 202. REPORT ON THE CRINOIDEA. 35 not range further south in the Atlantic than 10° S., though it has the same distribution as the tridistichate series in the Pacific and is generally more fully represented, forms like Antedon palmata, Antedon elongata, and Antedon indica being often met with in considerable abundance and variety. This group is also much more common than the tridistichate group in the Caribbean Sea, especially below 100 fathoms ; and it ranges down to 270 fathoms, at least 120 fathoms deeper than any member of the tridistichate group has yet been found in that locality. The range of the genus Actinometra, both in depth and in space, is very much more limited than that of Antedon. It corresponds very closely, however, with the geographi- cal and bathymetrical ranges of the multibrachiate species of this genus, though both alike are slightly more extensive than the range of Actinometra. Thus, for example, the multibrachiate forms of Antedon almost reach the parallels of 40°; while the northernmost Actinometra does not reach 36° N., either in the Atlantic or in the Pacific, and the southernmost are those of the Cape of Good Hope (34° 24' S.) and Port Philip (37° 48' S.). In like manner no Actinometra has been obtained with certainty at a greater depth than 533 fathoms ; though it is possible that this should be extended to 610 fathoms in the Pacific.1 But as we have just seen, the tri- and bidistichate groups of the multi- brachiate species of Antedon extend down to 630 and 740 fathoms respectively. Like these forms too, Actinometra is far more extensively developed in the eastern than in the western hemisphere. Several species are known from Southern Japan, and the genus is abundant all through the Eastern Archipelago and down the east coast of Australia as far as Port Jackson ; whde a single species from the latter locality also occurs at Port Philip and in King George's Sound (Actinometra trichoptera). A few more are scattered at Ceylon, the Eed Sea, Madagascar, Port Natal, and the Cape of Good Hope ; but they are not known at all from the West African coast, nor from South America south of Cape Frio. From this region, however, a couple of species occur abundantly up to the Caribbean Sea and the Gulf Stream, but they do not pass the parallels of 25° N.; though in the East Atlantic one species has been dredged four times beyond the thirty- fourth parallel and at much greater depths than in the Caribbean Sea, e.g., 1500 metres 2 ( = 812 fathoms). This type (Actinometra pulcliella) is one of special interest, not only from its singularly Protean character, but because it is the only Actinometra common to the two sides of the Atlantic ; while it is also, with one exception, the only Actinometra ranging below 300 fathoms. The genus has been dredged eleven times at depths below 200 fathoms, four times by English, once by French, and six times by American expedi- 1 There is no record of the particular dredging at the Station numbered 174 which yielded Comatulse, the depths being 210, 255 and 610 fathoms, except that the last one yielded Atelecrinus wyvillii. Three species of Actinometra were obtained, together with five of Antedon, and from their general facies I should be decidedly inclined to refer them to one of the two lesser depths. 2 According to H. Filhol (La Nature, 1884, p. 330), an Actinometra, which I take to be Actinometra pulchella, was obtained by the " Talisman " off Rochefort at this very unusual depth. 36 THE VOYAGE OF H.M.S. CHALLENGER. tions. Actinometra pulchella occurs at every one of these eleven stations, excepting No. 174 in the South Pacific; while it is the only Actinometra represented at six at least of them, including three of the deepest ones. This may be partly explained by the fact that only one of these stations was in the Pacific, all the remainder being in the Atlantic and the Caribbean Sea, but it is especially noteworthy because Actinometra jmlchella is a dimorphic species, some forms having only ten arms, and some having bidistichate series on one or more rays. The three species obtained by the Challenger at Station 174 were all multibrachiate forms expressing widely different types of the genus ; but the "Blake" dredged a ten-armed species at 450 fathoms, off Havana, and the two deepest stations in the Caribbean Sea where Actinometra pulchella occurred also yielded ten-armed species. These ten-armed forms of Actinometra which occur in the Caribbean Sea and along the South American coast, represent an entirely different type of the genus from the ten- armed species of the eastern hemisphere. The latter mostly belong to the type of Actino- metra Solaris, with syzygies between the two outer radials, though a few forms occur in which these joints are united by bifascial articulation, as in nearly every Antedon and in the Actinometra meridionalis of the Caribbean Sea (PI. LVI. fig. 1). The Solaris- type, however, has not yet been discovered in the Atlantic. Of the multibrachiate species of Actinometra the tridistichate type seems to be the more extensively distributed and not the bidistichate one as in the case of Antedon. Thus, for example, Actinometra parvicirra (o.3.(3).(3)) occurs in South Africa, Timor, Ceram, the Philippines, Japan, the Friendly Islands, and even on the coast of Peru, so that it has a range in longitude of some 260°, occurring everywhere but in the Atlantic. This is only approached by the ten-armed Antedon carinata, which occurs on both coasts of South America and across the Indian Ocean from Java to Zanzibar. REPORT ON THE CRINOIDEA. 37 IV.— THE GEOLOGICAL HISTORY OF THE COMATULtE.1 So far as our present information goes the family Coniatulidse first appeared in the time of the Middle Lias and is therefore of somewhat less antiquity than the Penta- crinidae which date back to the Trias. Comatulee were fairly abundant all through the Jurassic and Cretaceous epochs and were especially so at certain periods, that of the Corallian in Germany and Switzerland, for instance. The geographical distribution of recent Comatulse is far more extensive than that of their predecessors. The distribution of the former is practically world-wide ; but so far as is yet known, with the exception of an Antedon from Algeria and another from Syria, no fossil Comatulse have been discovered out of Europe, not even in the Indian Tertiaries, which contain so many Echinoderm remains. None are known in America, though stem-joints of the remarkable Pentacrinus asteriscus are very common at certain horizons of the Jura-Trias over wide areas of the western territories; and this shows that the conditions of that long-distant age were not altogether unfavourable to the development of Crinoid life. On the other hand, the Middle Lias of France contains two species of Antedon, the oldest yet known ; and the genus occurs, together with Actinometra, in the lower Oolites of both France and England ; while if Bourgueticrinus ooliticus, M'Coy, is a Thiolliericrinus, as supposed by de Loriol, it is the earliest known species of this very singular genus. Both Antedon and Actinometra, especially the former, are well represented in the Corallian of the Jura, and there are several species of Antedon in the Neocomian of the continent, together with a few in Britain. The Gault of Folkestone has yielded typical forms of both genera, and there are several Cretaceous species of Antedon scattered through Europe, the formerly obscure Glenotremitcs paradoxus being the best known. We are only acquainted with one Eocene Comatida; though three species occur in the French Miocene, and there are others in the Pliocene both of England and of Italy. In the majority of cases only the centro-dorsal is preserved, though it is not uncommon for the radials to remain attached to it. But individuals with any arm- joints preserved beyond the calyx-radials are decidedly rare ; and in this respect the Comatulse differ widely from the Pentacriims-type, isolated calyces of which are not often met with, though the arms are frequently extraordinarily well preserved. One singular instance of the retention of the arms or arm-bases is afforded by Eudiocrinus hyselyi.2 But for this fact the existence of Eudiocrinus in the fossil state x I am indebted to the kindness of M. P. de Loriol for much information respecting the fossil Comatulidae of France and Switzerland, some of it being as yet unpublished. 2 See de Loriol, Monographic des Crinoides fossiles de la Suisse, Geneva, 1877-79, pi. xxi. fig. \4. 38 THE VOYAGE OF H.M.S. CHALLENGER. would have remained unknown, as the characters of the calyx in the recent species have not yet been sufficiently studied to give any satisfactory clue to the detection of their fossil representatives. Most of the fossil Comatulae have more or less well defined basals appearing externally, which have not undergone metamorphosis into a rosette as is the case in very nearly all the recent forms ; and it is probable that species like Antedon tessoni and Antedon orhignyi, although they show no basals externally, will in reality prove to be no exceptions to the rule. I feel some doubt, however, with regard to the Tertiary species, only two of which arc represented by more than the centro-dorsal ; and this affords but Uttle information respecting the presence or absence of a rosette. I am inclined to think myself that in the matter of basals the Tertiary species resembled their predecessors rather than their successors. But this view cannot be confirmed till the discovery of a type which shows basals at the interradial angles of the calyx, or of one in which these plates are visible on the under surface of the isolated radial pentagon. But no Tertiary species of this kind are known, and neither Antedon alticeps nor Antedon italica shows any traces of basals between the radials and the centro-dorsal. The determination of the generic position of a Mesozoic Comatula is often a matter of considerable difficulty ; and this is especially the case when only the centro-dorsal is preserved. In most fossil Cornatulse this part bears a considerable number of cirri which are distributed over the greater part of its surface ; and it reaches a fair degree of thickness ; so that there can be no doubt that these types have been correctly referred to Antedon. But there are a few forms in which the centro-dorsal is relatively much thinner and the number of cirri, which are almost or entirely limited to its sides, is reduced. This is the case, for example, in two species from the Great Oolite and Bradford Clay respectively, which I take to belong to Actinometra, rather than to Antedon. Specimens which have the radials preserved can in some cases be referred to Antedon without any difficulty, owing to the large proportion of height to width on the articular faces of the radials. Such are Antedon sequimarginata, Antedon incurva, and Antedon scrobiculata, the calyces of which closely resemble those of the typical forms of Antedon figured on PL II. On the other hand, the generic identity of Actinometra loveni from the Gault is equally indisputable. For there is no living Antedon yet known in which the centro- dorsal loses all traces of its cirri and becomes separated from the flattened radial pentagon by clefts at its sides ; while these changes are not uncommon in Actinometra (PI. L VII. fig. 1 ; PI. LXV.). But in by far the greater number of Comatulas which have the radials preserved, the height of these plates is quite small relatively to their width, as is invariably the case in the living Actinometra (PL V.). When these radials rest on a thick centro-dorsal which is marked by a number of cirrus-sockets [Antedon decameros, Antedon greppini) there can be no question that the type in question belongs to Antedon. But REPORT ON THE CRINOIDEA. 39 there are a few species with low and wide radials, the distal faces of which have a steep slope, so that they do not enter largely into the ventral aspect of the calyx. Such are the two which I have described as Actinometra cheltonensis and Actinometra imrtem- bergica. Only the radials of the former species are known and the slope of the articular faces is scarcely as steep as in most recent examples of the genus. It is steeper in Actinometra wurtembergica, which seems to have had a thicker centro-dorsal and more numerous cirri than is usually the case in recent species of the genus. One might also be inclined to refer to this genus the Antedon picteti, de Loriol, and Antedon infracretacea, Ooster, both of which occur in the Valangian and have low wide radials with a thin centro-dorsal, bearing but few cirri. They retain, however, the sloping articular faces which are so characteristic of Antedon; and I think therefore that, for the present at any rate, they should be referred to that genus. Table showing the Distribution of the Fossil Coniatxdee in Space and in Time. A. = Antedon. a. = Actinometra. E. = Eudiocrinus. T. = Thiolliericrinus. Lias, . Middle Lias, 13 a « a O a & o Ph c N w .2 CO < •A p V m OS 'E ) a. (3) ; a.^; a.3.(2); a.3.7^ ;x a.3(3) ; a.2.7^ ; a.2.(3), and so on. Such a collection of formula? would be worse than useless from its confusion, and very far from being the shorthand system which Bell rightly wishes to see employed. It would be much easier to refer to the specific diagnosis at once than to try and make out the predominant characters of the arm-divisions from a supposed shorthand of this kind. Two points must therefore be noted in determining the formula of a species. 1. What are the characters of the majority of the arm-divisions in a given individual, or better still, in a number of individuals ? 2. Whether examples ever present themselves in which a given character, such as the occurrence of distichal, palmar, or post-palmar divisions, is sometimes entirely absent 1 In this case, but only in this, the corresponding symbol should be put between brackets in the formula, e.g. — Antedon lusitanica, A.(2). Actinometra parvicirra, a.3.[3.(3)]. Actinometra multiradiata, a.3.2{p.(pf)br}. But the fact that all the ten distichals or twenty palmars do not always occur in every individual of a species is no reason for placing the corresponding symbol in brackets. Were this done, I have no hesitation in saying that both symbols would have to be enclosed in brackets in the formula of every species with less than forty-one arms and no post-palmar divisions. This of course would be absurd, and render the use of formulae altogether futile. The principles of classification which have been explained above 2 enable us to divide the numerous species of Antedon and Actinometra respectively into groups of very variable size. These are arranged in the following lists, which contain the names of all the species described by myself and my predecessors, Eetzius, Lamarck, Muller, 1 This is similar to the expression given by Bell for Antedon elegans, in which there are generally two palmars, but sometimes three. His figured specimen presents one case of the latter to four of the former ; and it is therefore clear that the formula should be written A.3.2. 2 I may just remark here that I cannot at all agree with the dictum of Walther that " Wer sich je mit Crinoiden besehaftigt hat, der wird wissen, wie wenig specifischen Werth die Gabelungen der Arme besitzen" (Palreontographica, 1886, Bd. xxxii. p. 182). Walther's experience seems to have been limited to a comparatively small number of fossil Crinoids, not always in the best state of preservation. But so far as concerns the recent Crinoids, both stalked and free, the number and characters of the arm-divisions afford points of much importance in the discrimination of species. I am convinced that the same may be said of the fossil Neocrinoids, if not of the Palaeocrinoids too, provided that a sufficient range of specimens is brought under consideration. REPORT ON THE CRINOIDEA. 53 Bohlsche, Pourtales, Grube, Bell and others, so far as my knowledge of them extends. A few of my own undescribed species, from the " Blake " collection and elsewhere, are also added, as they have received names somewhat prematurely, owing to their being the hosts of Myzostomida, which have been described by Professor von Graff. One or two of Professor Liitken's MS. names are included, as they belong to easily recognisable types, e.g., Antedon protecta ; but others, such as Actinometra mutabilis and Actinometra trachygaster, are omitted, as I have found a considerable variety of types under each of these names in the different collections that I have examined. I have added a few remarks respecting the absence of certain well-known names, such as Antedon sarsii and Actinometra timorensis, and also with regard to the presence of certain species in altogether different groups, both specific and generic, from those to which they have been referred by their original describers — (See the numbers before the names). In order to exhibit more completely the range of structural variation which is to be met with among the Comatuke, I have included the formulae for various species that I have examined but have not j^et described. Some rather variable species appear in more than one group, 1 and to draw attention to their peculiarities the name is followed in each case by the formula of the other group in which the species also occurs. Thus Actinometra pulchella (10),2 and (2.(2).^- In one or two cases I have departed from the strict numerical sequence in order to avoid separating too widely species which are really very closely allied, on the sole ground that one has an axillary more than the other. Thus A. 3. ^-jp immediately succeeds A^y, while a.3.2(p.br) and a.3.2(p,p',br) follow most naturally directly after a.3.2.6r., instead of being separated from the latter group by several inter- vening ones, as was the case in my preliminary list.3 List of Species. Genus ANTEDON. I. A.R.2.2.2. A.R.3.2.(2). 1. elegans A.R.3.3.3. midtiradiata A. R. 3. 3. 3. 3. 2. microdiscus 'It has not been worth while to repeat the name in one or two cases, e.g., Antedon elegans (A.R.3.2.(2)), and I have therefore used brackets for the last figure. 2 The 10 is not used here to indicate that there are ten joints in the distichal series, but as a short way of denoting the presence of only ten arms. I trust that the abbreviation will not be misunderstood. See p. 47. 3Proc. Zool. Soc. Lond., 1882, pp. 746, 747. 54 THE VOYAGE OF H.M.S. CHALLENGER. i. A. 10. [only ten arms]. abyssicola discoidea 4. milberti abyssorum diiheni milleri accela aculeata duplex (2) echinata mvltispina ( 3— ) acutiradia eschrichti parvicirra adeonse exigua parvipinna alternata jlexilis (2) perspinosa anceps (3) gracilis petasus angustipinna hageni 5. phalangium antarctica hirsuta pinniformis armata hystrix prolixa australis impinnata pumila bcdanoides incerta pusilla bar en t si incisa 6. quadrata basicurva informis remota bidens Isevipinna rhomboidea bispinosa Isevis rosacea brevipinna (2) Isevissima serripinna breviradia latipinna spinicirra carinata lineata 7. tenella carpenteri longicirra tenuicirra columnaris longipinna tessellata cubensis 3. loveni tvberosa dejecta lusitanica (2) valida denticulata magellanica 8. variipinna [3(2)]. . A. 2. brevipinna (10) Jlexilis (10) patula clemens lusitanica (10) pourtalesi (2.2) compressa macronema quinquecostata (2.2) disciformis marginata robusta duplex (10) A. 2. 2. articulata (2.2.2) imparipinna palmata (2.2.2) bimacidata indica pourtalesi (2) brevicuneata Isevicirra protecta elongata manca quinquecostata (2) REPORT ON THE CEINOIDEA. 55 A. 2. 2. regalis similis spinifera (2.2.2) regime spicata tuberculata A. 2. 2. 2. sequipinna Jiagellata palmata (2.2.) articulata (2.2.) gyges spinifera (2.2.) conjungens occulta TV. A.S.% a angusticalyx 10. hmqualis (s.^^j ,.„ ( f.br. \ 9. granulifera I 3. — t~ J multispina (10) A. 3.*f. distincta A.3. anceps (10) angustiradia A.3.1. A.3.2. acuticirra ludovici A. 3. 2. 3. A.3.2{(».)6r} A.3.3. A.3.3.3. 9. p>e. Some curious points of contrast may be noticed in the two lists given above. There are three very distinct types of Actinometra in which the two outer radials are united by syzygy. (l) The ten-armed (Actinometra Solaris) ; (2) those with two distichals (Actinometra paucicirra) ; and (3) those with three (Actinometra typica). In the latter case each subsequent division (if present) consists of only two joints united by syzygy. On the other hand, all the recent species of Antedon yet described which have the radials a syzygy have three distichals, while the palmars and subsequent divisions either resemble the distichals, or consist of two articulated joints. Species of Antedon like Actinometra paucicirra and Actinometra typica are, like those of the Solaris-ty\>Q, yet to be described. More than half the species of Antedon belong to the simple ten-armed type with articulated radials like Antedon eschrichti (PI. XXIV. fig. 11) ; while half the remainder have only two joints in each of the first three arm-divisions, as in Actinometra conjungens (PI. XLV. fig. l). But there are not ten described ten-armed species of Actinometra which have articulated radials, nor ten with two-jointed distichal series. Both these types, which together include over three-quarters of the species of Antedon, thus present themselves but rarely in Actinometra. On the other hand, we find in this genus a much greater number and variety of the 1 List of the Crinoids obtained on the Coasts of Florida and Cuba by the United States Coast Survey Gulf Stream Expeditions in 1867, 1868, 1869, Bull. Mus. Comp. Zool, 1869, vol. i. No. 11, p. 356. 2 Proc. Zool. Soc. Lond., 1882, p. 535. 3 Ibid., p. 747. ♦ Ibid., p. 535. 6 u Aiert » Report, pp. 155, 163. 6 Zool. Chall. Exp., part xxxii. pp. 110, 111. REPORT ON THE CRINOIDEA. 01 tridisticnate species than occur in Antedon. I do not know any species of the latter genus with articulated radials in which there is a fourth post-radial axillary, such as occurs in Actinometra alternans, Actinometra variabilis, Actinometra magnified, and Actinometra bennetti ; and it is decidedly rare to find a third axillary ; while the singular variations presented by Actinometra belli and Actinometra nobilis are altogether unknown in Antedon. The above tables show that it is possible to make a preliminary classification of the species of Comatuke by using the characters of their successive arm-divisions. But how are we to deal with the seventy odd species of Antedon which have only ten arms, or with the thirty more which have bidistichate primary arms ? The characters of systematic value which may be employed for this further classification are those of the cirri, arms, and pinnules. The number of the cirri themselves and also that of their component joints are very useful characters within certain limits. Antedon valida and Antedon parvipinna, which are both figured on PI. XV., are obviously cmite distinct specific types; and the same maybe said of Antedon alternata and Antedon incerta, represented on PI. XVIII. , not only as regards the cirrus-characters, but with respect to the pinnules also. The shape and the relative sizes of these latter organs, especially at the bases of the arms, often afford characters of much systematic value, as will be seen by comparing the flagellate lower pinnules of Antedon quadrata and Antedon australis (PI. XXVII. figs. 8-16) with the stiffer ones of Antedon occulta and Antedon variipinna (PI. XLVIII. figs. 2, 3) ; while those of Antedon valida, Antedon incerta, and Antedon macronema (PI. XV. figs. 5, 6; PI. XVIII. fig. 5; PI. XXXVIII. fig. 4) are of an altogether different type from either of the others just mentioned. Another very useful character for systematic purposes is to be found in the shape of the arm-joints. In one large group of Antedon-species the radial axillaries and the next few joints beyond them have their apposed sides much flattened, as is well seen in PI. XV. fig. 6. In the absence of this very striking peculiarity, the shape of the arm- joints, as seen from the dorsal side, is often of much use in classifying species. Thus, for example, the elongated joints of Antedon phalangium (PI. XXVIII. fig. l), the short compressed triangular joints of Antedon patula (PI. XLIIL), and the rounded joints of Antedon variipinna (PI. XLIX. fig. 1) all afford good specific characters ; while in the genus Actinometra the contrast is strong between the short discoidal joints of Actino- metra Jimbriata and the triangular ones of Actinometra elongata (PI. LVII. fig. 2; PL LXII. fig. 3). The condition of the ambulacra in the arms and pinnules is also of much use in classification. Thus, for example, Antedon accela, Antedon incerta, Antedon insequalis, and other forms have both side plates and covering plates on the pinnule-ambulacra, which are often better defined than in the Pentacrinida) ; while in other species, such as 62 THE VOYAGE OF H.M.S. CHALLENGER. Antedon eschrichti and Antedon carinata, the ambulacral plating is reduced to small and irregular spicules without definite arrangement. By means of these various characters, then, it is possible to subdivide the large specific groups, both in Antedon and in Actinometra, and to make out a detailed classification of the numerous species belonging to each genus. Except in a few cases, however, it would be premature as yet to make any attempt at distinguishing the structural and the adaptive characters respectively among those which we are at present inclined to regard as of specific value. VI.— DESCRIPTION OF THE SPECIMENS. Class CRINOIDEA. Order NEOCPJNOIDEA. Family Comatulid^e, d'Orbigny, 1852; emend. P. H. Carpenter, 1888. Crinoids with the calyx closed below by the enlarged top joint of the larval stem, which develops cirri and generally separates from the stem joints below it, so that the calyx is free. The basals may form a more or less complete ring on the exterior of the calyx, or be only represented by an internal rosette. Five or ten rays, either simple or more or less divided. The first axillary is the second, or (very rarely) the first joint above the calyx-radials. Definite interradial plates usually absent. The mouth central, except in one genus. Remarks. — The family Comatulidse, which was established by d'Orbigny1 in 1852, is practically equivalent to a group which was proposed more than twenty years previously by de Blainville,2 under the name of the " Asterencrinides libres." So far as I am aware, de Blainville was the first author to make any definite separation of the Feather-stars from the remaining Stellerids. He divided this order into three families, the Asteridea, the Asterophydea, and the Asterencrinidca, which last Miller had previously called Crinoidea. De Blainville further subdivided the Asterencrinidea into two sections, the first of which was " les Asterencrinides libres." He defined it as having a " corps libre, et sans tige qui servirait a le fixer " ; and he referred to it the single genus Comatula, Lamarck. In the great work of Goldfuss,3 which was published a few years later, there is, however, no special separation of the genus Comatula from the other Stellerids, and it simply appears as the first genus in his order " Asterites liberi," altogether separate from the Stalked Crinoids, which are classed as the Stilasteritae, though the resemblance between them and Comatula did not escape the notice of Goldfuss. He gave an account of the anatomy of two recent species, and referred to the genus some fossils from Solenhofen, 1 Cours elementaire de Geologie et de Paleontologie stratigraphique, 1852, t. ii. fasc. i. p. 138. 2 Diet. d. Sei. Nat., 1830, t. lx. p. 229. 3 Petrefacta Germanise, Diisseldorf, 1826-35, vol. i. p. 201. 64 THE VOYAGE OF H.M.S. CHALLENGER. while he also gave the names Solanocrinus and Glenotremites to some other fossil forms of which only parts of the calyx were preserved. Some of Goldfuss's species were made the types of new genera by Agassiz,1 and Miiller referred to them as follows in his first communication to the Berlin Academy on the subject of the Crinoidea :2 — ■ "Die ungestielten Crinoiden mit Armen bilden 3 Familien (l) Articulata, gen. Comatula, Lam., und Comaster, Ag. (2) Costata mit schaligem gerippten Kelch und entgegengesetzten Pinnulse, wovon sonst bei alien ubrigen Crinoiden kein Beispiel vorkommt, gen. Saccocoma, Ag. (3) Tessellata, gen. Marsupites." The above passage must not be understood as meaning that " Articulata," Miiller, is a synonym of " Comatulidae," d'Orbigny, and should therefore take precedence of it. For there were Stalked as well as Unstalked Crinoidea Articulata and Crinoidea Tessellata ; and in the subsequent memoir on Pentacrinus Miiller made these the two primary divisions of the Crinoidea, altogether apart from the question of the presence or absence of a stalk. But in his second preliminary communication 3 he made a passing reference to " die in der Familie cler Comatulinen enthaltenen Gattungen Comatula und Comaster," the latter genus being regarded by him as identical with Solanocrinus, Goldfuss. Miiller never said anything more definite about the family Comatulinse, however, though he recognised Alecto and Actinometra as two subgenera of Comatula, Lamarck. The Stalked Crinoids remained in an equalhy chaotic condition for many years. But about 1850 Bronn and d'Orbigny made separate attempts to class them into families. The former author4 established the family Astylidse, though without defining it, and referred to it the recent Comatula and three fossil genera. Among these were Marsupites and Saccocoma, both of which, as we have seen above, had been made the types of separate families by Miiller. This was also clone by d'Orbigny,6 who divided the Crinoidea into ten families, one of which was the Comatulidse, and this name, or its shortened form " Comatuke," has been in use for the family of the Feather-stars ever since, though the number of genera referred to the family has varied enormously. D'Orbigny included in it the recent Comatula, Lamarck, and three other genera which were based on the characters of various fossil species. None of these, however, are now recognised ; and the same is true of a number of genera established by other palaeonto- logists ; for with one exception all the true Comatulids which have been as yet discovered in the fossil state can be referred either to de Freminville's genus Antedon, which has priority over Comatula, or to Midler's subgenus Actinometra, which has gradually acquired generic rank. The exception is the five-armed species from the Valangien of Switzerland, 1 Mem. Soc. Sci. Nat. Neuchatel, 1835, t. i. p. 193. 2 Monatsber. d. k. preuss. Akad. d. Wiss. Berlin, 1840, p. 91. 3 Ibid., 1841, p. 179. 4 Lethasa Geognostica, 1851, Bd. i. Tb. 1, p. 23. 6 Cours elementaire de Paleontologie et de Geologie stratigraphique, 1852, vol. ii. fasc. i. p. 138. REPORT ON THE CRINOIDEA. 65 which represents a recent generic type first discovered by Semper and named by him Ophiocrinus. In consequence, however, of the preoccupation of this name it has been since changed to Eudiocrinus. Thus then the great number of generic names which have been given to the fossil Comatulse become reduced to three, Antedon, Actinometra, and Eudiocrinus. Three new genera have been established by myself for new types of recent Comatuke, viz., Atelecrinus, Promachocrinus, and Thaumatocrinus ; and these six are all that could strictly be included in the family Comatulidas until quite recently. Pictet1 has also referred to it both Marsupites and Saccocoma, but Dujardin and Hupe2 removed Marsupites to the Cyathocrinidae, and added to the Comatulidae the sessile Eugeniacrinus and its allies, which had been grouped under the Eugenia- crinidae in Bronn's " Thierreich." Zittel a restored this family to its proper position and restricted d'Orbigny's name to the Feather-stars proper; while Saccocoma was replaced in Midler's group, the Costata, which had been established for- its: reception in 1840. Quite recently, however, it has become necessary to add a seventh genus to the family, viz., the fossil Thiolliericrinus, which represents a permanent form of a late stage in the development of the Antedon-laYva. It has been well described by de Loriol4 as an Antedon with a Bourgueticmius-stera. The stem-joints of the larval Antedon are closely similar to those which are characteristic of the family Bourgueticrinidae, their faces bearing strong transverse ridges with a deep fossa on each side. In ordinary Comatulae the centro-dorsal, after separating from the stem beneath it, soon loses all trace of its previous connections, owing to a more or less extensive deposi- tion of limestone at its dorsal pole ; whereas in Thiolliericrinus the connection between the lower stem-joints and the cirrus-bearing centro-dorsal seems to have been maintained much longer, if not throughout life. For the under surface of the centro-dorsal bears a well-developed articular facet like that on an ordinary stem-joint of Bourgueticrinus or Rhizocrinus. It would appear therefore that the centro-dorsal with the few cirri which were developed upon it remained permanently attached to the stem below, so that Thiolliericrinus would represent the permanent condition of an Antedon-larva during the development of its second whorl of cirri. We cannot be absolutely certain about its characters, however, until an entire example of the genus has been discovered. But the presence of an articular facet on the under surface of its centro-dorsal is a feature which is sufficient to distinguish it very markedly from the six genera of recent Comatulae. 1 Traite de Paleontologie, Paris, 1857, vol. iv. p. 287. 2 Op. cit., p. 186. 3 Handbueh der Palaeontologie, Bd. i., Abth. 1, p. 395. 4 Description de quatre Echinodermes Nouveaux, Mem. Soc. Pal. Suisse, 1880, vol. vii. p. 10. (ZOOL. CHALL. EXP. — PART LX. — 1887.) 000 0 66 THE VOYAGE OF H.M.S. CHALLENGER. The general relations of these seven genera of Comatulidse are expressed in the following table : — I. Centro-dorsal has no articular facet on its lower surface. A. Five rays. i. Mouth central or subcentral. Oral pinnules have no comb. a. Kadials separated by interradials, . . . . 1. Thaumatocrinus, n. gen. b. Radials united laterally. (1) Basals persist as a closed ring. No pinnules on lower brachials, . . . .2. Atelecrinus, n. gen. (2) Basal ring incomplete or invisible externally. a. Five arms only, . . . .3. Eudiocrinus, Carpenter. j3. Ten arms, . . . . .4. Antedon, de Freminville. ii. Mouth excentric or marginal. Oral pinnules have a terminal comb, . . . . . . .5. Actinometra, Miiller. B. Ten rays, . . . . . . . .6. Promarhocrinus, n. gen. II. Centro-dorsal has an articular facet below, . . . . .7. Tldolliericrinus, fitallon. Genus 1. Thaumatocrinus, P. H. Carpenter, 1883. 1883. Thaumatocrinus, P. H. Carpenter, Phil. Trans., 1883, pt. iii. p. 919, pi. lxxi. Definition. — Calyx composed of a centro-dorsal, basals, radials, and primary inter- radials, the latter resting on the basals and so separating the radials laterally. That on the anal side bears a short jointed appendage. Mouth central and protected by five large oral plates which occupy the greater part of the disk, and are separated from the calyx-intei'radials by two or three rows of small irregular plates. Five arms only. Remarks. — Thaumatocrinus has already been described and its peculiarities discussed in Part I. of this Eeport (pp. 370-372), and it is not necessary therefore to refer again to the reappearance of certain Palseocrinoidal characters in this remarkable genus. As compared with the more typical Comatulse it is peculiar in having persistent basal and oral plates, the latter occurring in no other Comatulid, and in the simplicity of the rays, which remain undivided, so that there are only five arms, as in Eudiocrinus (PI. VII.). Thaumatocrinus renovatus, P. H. Carpenter, 1883 (fig. 1; Part I. pi. lvi. figs. 1-5). Description of an Individual. — The total width of the calyx across the disk is barely 2 mm.; and the height of the centro-dorsal and radials together is about the same. The former is rounded below, with its central canal completely closed up, so that it must have been detached for some little time from the remainder of the stem. The bases of half a dozen cirri are attached to it, and there are pits for the reception of two or three more. In the largest stump which is preserved the first two joints are quite short, as is usually the case in all cirri ; but the third reaches a length of 1"5 mm., so that the cirri must have been very like those of some species of Eudiocrinus, which have a succession of very long joints followiug the short basal ones (PI. VII. figs. 2, 7). REPORT ON THE CRINOIDEA. 67 The basals are almost trapezoidal, much wider below than above, and in contact with one another by their truncated lower angles. The middle of the lower edge of each is slightly tubercular. On their narrow upper edges rest the interradials. which are oblong and a little higher than wide. Four of them terminate in a free edge at the margin of the disk, where they are in contact with the lowest anambulacral plates. But that on the anal side bears a small tapering appendage of four or five joints, the last of which seems to end freely. The radials are larger than the interradials and somewhat strongly arched. There is a muscular articulation between them and the first brachials ; but the articulation between these and the next joints appears to be only bifascial. The arm-joints are long, slender, and cylindrical. One arm seems to be broken at a syzygy in the sixth brachial ; while another has a syzygy in the fourth, and again in the eighth brachial. The second brachial bears the first pinnule, which is on the right side in three arms, and on the left in the other two. The pinnules are very delicate and composed of long slender joints. Fig. \.—Thaumatocrinus rcnovatus, P. H. Carpenter. A, The calyx, anal side. B, The disk from above, aa, anal appendage; an, anambulacral plates; at, anal tube; b, basal ; i2, second brachial ; al, centro-dorsal ; i, interradial; o, oral ; r, radial, x 15. The central portion of the disc is occupied by five relatively large oral plates which stand up around the peristome ; while between them and the margin are two or three irregular rows of small anambulacral plates, some of them extending up on to the lower part of the long anal tube. The brachial ambulacra are not plated, however, and lie in the arm-grooves, close down between the muscles but with no traces of sacculi. Colour in spirit. — Dirty white. Locality.— Station 158, March 7, 1874; kit, 50° 1' S., long. 123° 4' E.; 1800 fathoms; Globigerina ooze ; bottom temperature, 33°-5 F. One specimen, much muti- lated and probably young. 68 THE VOYAGE OF H.M.S. CHALLENGER. Genus 2. Atelecrinus, P. H. Carpenter, 1881. 1869. Antedon, Pourtales (pars), Bull. Mus. Comp. Zobl., 1869, vol. i. No. 11, p. 356. 1878. Antedon, Pourtales {pars), Bull. Mus. Comp. Zobl., 1878, vol. v. No. 9, p. 214. 1881. Atelecrinus, P. H. Carpenter, Bull. Mus. Cornp. Zobl., 1881, vol. ix. No. 4, p. 16. 1882. Atelecrinus, P. H. Carpenter, Journ. Linn. Soc. Lond. (Zool.), 1882, vol. xvi. p. 488. Definition. — Centro-dorsal acorn-shaped, and bearing five vertical double rows of cirrus-sockets, those of each row alternating with one another, and with those of adjoining rows. They have horseshoe-shaped rims, the arches of which are directed upwards while the two ends slant downwards and outwards. Radials separated from the centro- dorsal by a complete circlet of basals. The first six or more brachials bear no pinnules. Remarks. — The first example of this genus which was actually obtained was dredged by Pourtales1 in 1869 off Cojima on the coast of Cuba. Two small ten-armed Comatulae were brought up from a depth of 450 fathoms, and were briefly described by Pourtales under the name of Antedon cubensis. But the description given by him only applies to the larger and more perfect specimen, which differs considerably from the smaller and much mutilated one. He seems to have recognised that the two were different, for in his description2 of the Crinoids obtained by the "Blake" expedition of 1877-78 he wrote as follows : — " To this species (i.e., Antedon cubensis) I refer j^rovisionally two specimens very much mutilated, having lost the cirrhi and the arms, differing somewhat from my type specimen, but possibly the differences may be due to age." He then described an individual dredged at Station 43 ("Blake") in 339 fathoms, to which I shall refer directly, and added that a smaller and equally mutilated one had been previously dredged by himself in 450 fathoms near Havana. These two specimens are quite different from the type of Antedon cubensis, and also, though in a less degree, from one another. Not only are the first radials visible, and the second but little shorter than broad, as was mentioned by Pourtales, but the first radials are separated from the acorn-shaped centro-dorsal by a complete circlet of basals, and there are no pinnules upon any of the first six arm-joints, which are the only ones preserved. An equally mutdated specimen of Pourtales' second type was dredged by the Challenger (1873) in 350 fathoms, off Barra Grande (PL VI. fig. 7); seven more perfect ones, making nine in all, were obtained off Nevis, St. Lucia, and Granada, during the cruise of the "Blake" in 1878-79, between 291 and 422 fathoms; while a single example of a third species (PI. VI. fig. 5) was dredged by the Challenger in the neighbourhood of Fiji, in the year 1874. These eleven individuals, representing three different species, are distinguished from all other living Coniatulse by certain very definite morphological peculiarities, which impart an interest to this type second only to that of the archaic Thaumatocrinus. Its 1 Bidl. Mm. Comp. Zobl, 1869, vol. i. No. 11, p. 356. * Ibid., 1878, vol. v. No. 9, p. 214. REPORT ON THE CRTNOIDEA. GO two leading characters are — (1) the persistence of the embryonic basals which do not undergo transformation into a rosette, but remain on the exterior of the calyx between the centro-dorsal and the radials ; and (2) the absence of pinnules from the lowest joints of the arms (PI. VI. figs. 5, 7). A third character, of no great morphological value, but important from its apparent constancy, is the acorn-like shape of the centro-dorsal, and the arrangement of the cirrus-sockets upon it in alternating double rows, with the ends of their horseshoe-like rims projecting somewhat outwards. The extent of development of the basals of Atelecrinus varies with the size of the individual, apparently diminishing with age as in the Pentacrinoid larvse of ordinary Comatulse (PI. XIV. figs. 5-7). In the smallest specimen of Atelecrinus balanoides they are wide but low pentagons which fall away very rapidly from their interradial apices to the points where they meet one another beneath the radials. The middle of each basal rests on the top of one of the interradial ridges at the upper end of the centro-dorsal, just as the basals of Pentacrinus rest on the upper ends of the interradial ridges of the stem. In older individuals, however, just as in the Antedon-larva (PI. XIV. figs. 5-7), the amount of the first radials which is visible on the exterior of the calyx becomes relatively less and less, and the same is the case with the basals. These are best described as triangular, with their lower angles extended so as to meet those of their fellows and separate the radials from the centro-dorsal by what is practically little more than a line, only visible at all under specially favourable conditions of light. Each of the basals, when isolated, has the form of a short triangular prism with a flattened plate- like extension on each side. They are in complete lateral contact, so as to form an unbroken ring on the under surface of the radial pentagon, very much as in Pentacrinus alternicirrus or in Pentacrinus wyville-thomsoni. Atelecrinus cubensis has comparatively large basals which are of nearly uniform height (0-5 mm.) all round the calyx, rising very slightly at the interradial angles; while in Atelecrinus ivyvillii each basal is slightly arched, with its apex interradial, and it is only in contact with the outer edge of the centro-dorsal at the interbasal sutures (PI. VI. fig. 5). All three species agree, however, in the absence of any rosette and in the persistence of the basals upon the exterior of the calyx, a feature which appears in no other recent Comatula except Thaumatocrinus and the very doubtful Comaster ; while a further peculiarity lies in the complete closure of the basal ring so as to separate the radials altogether from the centro-dorsal. Several, if not all, fossil Comatulae have persistent primary basals in the form of prismatic rods, which meet one another in the centre of the under surface of the radial pentagon, and extend outwards towards its interradial angles. But they do not always reach the periphery so as to appear externally between the radials and the centro-dorsal, as they gradually thin out ; and there is only one described form in which there is a complete ring of united basals on the exterior of the calyx. As regards the characters of its calyx, therefore, Atelecnnus is certainly to be 70 THE VOYAGE OF H.M.S. CHALLENGER. regarded as a permanent larval form. The absence of the pinnules from the lower parts of the arms points to the same conclusion, as has been explained elsewhere.1 I have only been able to examine the disk in the two Challenger specimens, and in one of these it is not very well preserved. But they both agree in the slightly excentric position of the mouth, and in the large size of the peristome, so that the anal tube is pushed backwards behind the centre about as much as the mouth is in front of it (PL VI. figs. 4, 6). Unlike the two Endocyclic Comatulse with five rays and a rosette (Antedbn and Eudiocrinus), Atelecrinus is not a littoral type at all, nor does it extend upwards above 200 fathoms. On the other hand it is not known to occur below 610 fathoms ; so that bathymetrically it falls very far short of the archaic Thaumatocrinus (1800 fathoms). Apart from this last type, however, the geographical range of Atelecrinus, although fairly extensive, is the least so of the five-rayed Coniatulse. In the Caribbean Sea and the East Atlantic it ranges from 24° N. to 9° S.; while it also occurs in the Pacific near Fiji in 19° S. If the fossil calyx mentioned by Schliiter 2 as having persistent basals also belong to this genus, it will date back to the Cretaceous period. The three existing species of A telecrinus may be distinguished from one another as follows : — I. Second radials transversely oblong and but little incised. Basals not specially prominent at the angles of the calyx, . . . . .1. balanuides, n. sp. II. Second radials markedly incised and about as long as wide. A. Basals separated from the centro-dorsal at its interradial angles, . 2. wyvillii, n. sp. B. Basals produced outwards at the interradial angles, . . .3. eubensis, Pourtales, sp. 1. Atelecrinus balanoides, n. sp. (PL VI. figs. 6, 7). 1879. Antedon eubensis, Pourtales (pars), Bull. Mus. Comp. Zobl., 1879, vol. v. No. 9, p. 214. 1881. Atelecrinus balanoides, P. H. Carpenter, Bull. Mus. Comp. Zool., 1881, vol. ix. No. 4, p. 16, pi. i. figs. 1-6. 1882. Atelecrinus balanoides, P. H. Carpenter, Journ. Linn. Soc. Lond. (Zool.), 1882, vol. xvi. p. 489. Centro-dorsal acorn-shaped, reaching 5 mm. high by nearly 35 mm. in diameter. It bears five vertical double rows of cirrus sockets, the upper ends of which are separated by more or less distinct interradial ridges. Four to six sockets in each row, the dorsal pole, though rough, being free from functional sockets. The ends of their horseshoe- shaped rims slant downwards and outwards, but are much more prominent in some individuals than in others. The cirri have three or four quite short, almost triangular basal joints. The next is two or three times as long as wide, and its successors are much elongated, reaching 2"5 mm., with a slight tendency to overlap one another on the ventral side of the cirrus. 1 Bull. Mus. Comp. Zobl., 1882, vol. ix. No. 4, pp. 14, 15. 2 Zeitschr. d. deutsch. gcol. Gesellsch, 1878, p. 60. REPORT ON THE CRINOIDEA. 71 There are probably about thirty-five joints, the length much exceeding the breadth till the penultimate, which is followed by a very small terminal claw. The last six joints taper rapidly. The basal ring is a very thin plate, rising at the interradial angles into triangular elevations, which are produced slightly outwards and rest upon the upper ends of the interradial ridges of the centro-dorsal. First radials broad and tolerably flat, their size varying with the age of the individual. Second radials more arched, oblong, and quite free laterally, their breadth in the adult being one and a half times their length. Axillaries pentagonal, sometimes twice the length of the second radials, into which they have a slight backward projection. Their width is about equal to their length, but their proportions and also those of the second radials vary slightly in different individuals. First brachials well separated laterally, with their inner sides shorter than the more rounded outer ones. Second brachials irregularly quadrate, projecting slightly backwards into the first. The following joints have oblique ends and markedly unequal sides. Except in the syzygial joints, the length is at first less than the breadth, but gradually becomes more equal, and exceeds it after the fifteenth joint. Terminal joints relatively longer and more equal-sided. Arm-bases smooth, but the middle and later joints overlap slightly. The first syzygium on the third brachial. The following syzygies at intervals of from one to six, usually of two or three joints. First pinnule nearly always on the twelfth brachial, and consisting of about a dozen elongated joints. The following ones increase in size and in the number of joints, decreasing again towards the arm-ends. The lower joints of the middle and later pinnules bear irregular spinous processes on their dorsal edges. Mouth somewhat excentric, and surrounded by a large peristome. A little way behind this is the anal tube, which is also slightly excentric in position. Disk 6 mm. in diameter. In the Challenger specimen a very few minute calcareous granules are visible on its ventral surface, and also on its sides between the rays. The " Blake " specimens are more naked. The brachial ambulacra lie close down upon and between the muscular bundles, and have a few scattered sacculi at their sides. Colour of skeleton white or brownish-white. Locality. — Station 122, September 10, 1873; off Barra Grande ; lat. 9° 5' S., long. 34° 50' W.; 350 fathoms; red mud. One specimen. Also obtained by the U.S. Coast Survey steamer "Blake" at five stations in the Caribbean sea, between 291 and 422 fathoms. Remarks. — Although this species was not dredged till four years after Pourtales had published his description of Antedon cubensis, I have preferred to regard it as the type of the genus Atelecrinus for the following reasons. Pourtales' description of 72 THE VOYAGE OF H.M.S. CHALLENGER. Antedon cubensis, which has pinnules on the second and following brachials, does not correspond to the characters of the smaller specimen which he called by this name, as it has a complete basal ring, and there are no pinnules on any of the arm -joints which are preserved; while another reason is that the dredgings of the "Blake" in the years 1877-79 have led to the discovery of eight examples of Atelecrinus balanoides, all of them better preserved than the single individual which was referred by Pourtales to Antedon cubensis. The first specimen of Atelecrinus balanoides known to science was dredged by the Challenger in 1873 ; but its cirri had disappeared, together with the whole of the arms above the fifth brachials (PL VI. fig. 7). The Pacific species {Atelecrinus wyvillii) was not much better (PL VI. fig. 5), and it was not till I received the " Blake " collection in 1880 that I was able fully to reahse the singular peculiarities of the type represented by the two Challenger specimens which are figured on PL VI. The distinctive characters of Atelecrinus balanoides are (l) the transversely oblong- shape of the second radials, wdiich are but slightly incised to receive the bluntly angular proximal edges of the axillaries ; and (2) the outline of the lower part of the calyx, which slopes uniformly downwards from the radials on to the centro-dorsal, without the basals being specially prominent at the interradial angles as they are in Atelecrinus cubensis. The difference is very much of the same kind as that between the basals of Pentacrinus wyville-ihomsoni and Pentacrinus miilleri respectively. The nine individuals of Atelecrinus balanoides which I have examined, all agree very well in their general characters, but differ considerably in the relative proportions of the two outer radials and of the lowest brachials respectively. In all of them which have enough of the arms preserved, the first pinnule is on the twelfth brachial, except in one arm of one individual, in which the tenth joint bears the first pinnule. 2. Atelecrinus wyvillii, n. sp. (PL VI. figs. 4, 5). 1882. Atelecrinus wyvillii, P. H. Carpenter, Journ. Linu. Soc. Lond. (Zool.), 1882, voL xvi. p. 492. Description of an Individual. — Centro-dorsal acorn-shaped, 4 mm. high by 3 mm. wide. The double rows of cirrus-sockets are well separated from one another by intervening spaces, and do not reach the dorsal pole. Four, or rarely five, sockets in each row, the ends of which stand out prominently and give a serrate appearance to the lateral edge of the plate. The upper portion is uniformly smooth, without any interradial ridges ; but the edge is marked by five slight incisions situated interradially. The basals are nearly uniform in height throughout their whole width, but are some- what arched in form. The apex of each arch is interradial, and the interval between it and the notched edge of the centro-dorsal below is only occupied by perisome. Hence the basal ring is really only in contact with the centro-dorsal at its five lowest points, REPORT ON THE CRINOIDEA. 73 i.e., at the interbasal sutures, immediately beneath the middle points of the first radials. The latter have exceedingly high muscle-plates projecting inwards ; but their dorsal surface is barely half as long as that of the second radials. These are nearly square, but deeply incised to receive the strong backward projections of the axillaries, which are roughly rhombic and slightly wider than long. First brachials well separated laterally, with the inner sides much shorter than the outer ones, and the distal edge much incised to receive the strong backward projections of the quadrate second brachials. The following joints have markedly unequal sides, with a syzygy in the third or fourth, and again in the fifth, sixth, or seventh brachial. Disk almost naked, 4 mm. in diameter. Mouth somewhat excentric and surrounded by a large peristome, immediately behind which is the anal tube. Brachial ambulacra close down upon and between the muscular bundles. Skeleton light brownish-white. Locality.— Station 174c, August 3, 1874; lat. 19° 7' 50" S., long. 178° 19' 35" E.; 610 fathoms ; coral mud ; bottom temperature, 39° F. One mutilated specimen. Remarks. — This type differs from the other two species of the genus in the greater squareness of the second radials, and in the curious relation of the basals to the centro- dorsal. They are of uniform height, as in Ateleerinus cubensis, but are not in contact with the centro-dorsal at the interradial angles of the calyx, being separated from it on the exterior by a gap which is filled up by perisome (PI. VI. fig. 5). Apart from its purely morphological importance, this Pacific species is also interesting as showing the wide distribution of the genus ; and it is the only one of the three which is known as yet to extend below the limit of the continental line (500 fathoms), though each of the others has been dredged below 400 fathoms. *&v Genus 3. Eudiocrinus, P. H. Carpenter, 1882. 1868. Ophiocrinus, C. Semper, Archiv f. Naturgesek., 1868, Jalirg. xxxiv. Bd. i. p. 68. 1869. Comatula (Ophiocrinus), P. de Loriol, Denksckr. d. allg. Schweiz. Gesellsch. f. d. ges. Nature"., 1869, Bd. xxiii. p. 57. 1879. Ophiocrinus, P. H. Carpenter, Proc. Roy. Soc, No. 194, 1879, p. 385. 1879. Ophiocrinus, P. de Loriol, Monographie des Crinoi'des fossiles de la Suisse, Geneva, 1877-79, p. 277. 1882. Eudiocrinus, P. H. Carpenter, Journ. Linn. Soc. Lond. (ZooL), 1882, voL xvi. p. 493. 1883. Eudiocrinus, E. Perrier, Comptes rendus, 1883, t. xcvi. No. 11, p. 725. 1886. Eudiocrinus, E. Perrier, Les Explorations sous-marines, Paris, 1886, p. 275. Definition. — Centro-dorsal and calyx like those of Antedon; but the radials bear the brachials directly without the intervention of axillaries, so that there are only five undivided arms. Mouth central. Sacculi abundant, scanty, or absent altogether. Remarks. — The genus Ophiocrinus was established by Semper in 1868 for an elegant little Comatula with five undivided rays, which he had discovered in the Philippine Islands ; and in the following year a fossil species was described by de Loriol from the (ZOOL. CHALL. EXP. PART LX. 1887.) Ooo 10 74 THE VOYAGE OF H.M.S. CHALLENGER. Neocomian of Switzerland. The generic value of the type was doubted by Schliiter j1 and I had formerly myself some hesitation in regarding it as equivalent to Antedon, Actinometra, and Promachocrinus.2 For there is no definite character, except the simplicity of the rays, which can separate Eudiocrinus from the ordinary ten-armed Antedon ; and in one of the three species of the ten-rayed Promachocrinus the rays divide so as to form twenty arms (PI. LXX.), while in the two others there are ten undivided rays (PL LXIX. figs. 5, 9, 10). But this character alone would hardly justify the separation of the simpler type of Promachocrinus from the twenty-armed form ; while I have an abnormal specimen of an Antedon with only nine arms, owing to one of the rays not dividing, which is the case with all the rays of Eudiocrinus. Nevertheless, it sometimes happens that a character, which is only of specific value in one type, may be of generic value in another. Five recent species of Eudiocrinus are known, four of which range from Japan into the South Pacific Ocean (lat. 37° S.), while one occurs in the East Atlantic, and another has been found fossil in the Neocomian of Switzerland. The simplicity of the rays thus appears to be a character of some morphological importance, and I am, therefore, disposed to admit the generic position which was originally assigned to the type by Semper. Unfortunately, however, it cannot continue to bear the name by which he described it. For Salter, fifteen years before Semper's description of Ophiocrinus, had designated by the same generic name an obscure Crinoid from the Devonian of South Africa ; and the confusion thus existing was increased by the posthumous publication in the year 1878 of the late Professor Angelin's monograph of the Swedish Silurian Criuoids, in which the name Ophiocrinus is connected with a third and totally distinct type. Professor Semper's genus being thus preoccupied, I proposed in 1882 to call the type Eudiocrinus (evStos, calm), in allusion to the fact that the four recent species of it, which were then known, were limited to the Pacific Ocean. Curiously enough, however, a few months before I suggested this name, several specimens of a new species of Eudio- crinus were dredged by the French exploring vessel " Travailleur " in the Gulf of Gascony, and, therefore, in European Seas. The type was naturally designated as Eudiocrinus atlanticus by Professor Perrier,3 who gave a brief description of the characters which distinguish it from the Pacific species. Eudiocrinus, like Antedon, has a central mouth (PI. VI. fig. 2), and a more or less hemispherical or conical centro-dorsal, an isolated specimen of which could not be distinguished from the corresponding part of an Antedon (PI. III. fig. 7a; PL VI. fig. 1; PL VII. figs. 1, 3, 4). The radials, however, in the only recent species which I have been able to examine, differ slightly from those of the ordinary Antedon-type which is illustrated on Pis. I. -IV. The articular faces are low relatively to their width (PL III. 1 Zeitschr. d. deutsch. geol. Gesellsch., 1878, p. 4(1. s Quart. Journ. Gcol. Soc, 1879, vol. xxxvi. p. 41. 3 Comptes rendus, 1883, t. xcvi. No. 11, p. 725. REPORT ON THE CRINOIDEA. 75 fig. 7a), a character which presents itself in Antedon carinata (PI. III. fig. la) and in Antedon macronema (PI. IV. fig. 3a), and is more especially distinctive of the genus Actinometra, in which the muscle-plates, well marked in Eudiocrinus, are very much reduced in size (PI. V. figs. 1-5, b). The special peculiarity of the calyx in Eudiocrinus semperi, however, is the way in which the muscle-plates stand up above the sides of the radials, owing to their edges being strongly folded in towards the central articular ridge which separates them (PI. III. figs. 7a, 7c). In many species of Antedon the articular facets of adjacent radials are in close contact along the whole length of their sides, as for example in Antedon eschrichti (PL I. fig. 8a), Antedon basicurva (PI. II. fig. 2a), and Antedon breviradia (PL III. fig. 4b). But in other cases the ventral edges of the muscle-plates are more or less folded outwards from the centre of the calyx, so that its interradial angles are marked by five notches, which lie at the upper ends of the sutures between the radials as in Antedon antarctica (PL I. figs. 6a, 6b), Antedon incisa and Antedon angusticalyx (PL II. figs, la, Id, 4a, Ad), the young Antedon breviradia and Antedon quinquecostata (PL III. figs. 5a, 5c, 6c, 6d). But in Eudiocrinus semperi this notch is continued down to the dorsal surface of the radials as a wide groove between the everted muscle-plates of every two adjacent radials (PL III. figs. 7a, 7c) ; so that in a dorsal view of the calyx (PL III. fig. 7b) its interradial angles are not sharp but deejay incised. An indication of the same character appears in Antedon quinquecostata (PL III. fig. 6b) ; but on the other hand the young calyx of Antedon breviradia, which has the ventral edges of its muscle-plates strongly folded outwards (PL III. figs. 5a, 5c), pre- sents a very sharply pentagonal outline in dorsal view (PL III. fig. 56). The same is the case in Antedon carinata, which has rather markedly everted muscle-plates (PL III. figs, la, lc, id); while on the other hand Antedon incisa, in which this latter character is less evident, has slight notches at the interradial angles of the dorsal surface of the radials (PL II. figs. la, lc, Id). The Eudiocrinus-c&lyx, therefore, presents no characters which do not occur in some one or other of the many species of Antedon; but they are all considerably exaggerated, and are combined together in a somewhat unusual manner. The interradial sutures on the dorsal surface of the radials are marked by slight grooves, and there are corresponding grooves on the upper face of the centro-dorsal. But they do not appear to have been occupied by any tertiary basals in the form of a star (PL III. fig. 7b). The rosette is tolerably distinct, with a large central opening and well marked radial spouts. But the interradial processes are scarcely visible, so that there appear to be only five openings, one at the inner end of each interradial suture (PL III. fig. 76). The calyx of the fossil species of Eudiocrinus {Eudiocrinus hyselyi) like that of nearly all the secondary species of Antedon and Actinometra, is of a very generalised type ; and, but for the discovery of specimens with the arms attached, it would have 76 THE VOYAGE OF H.M.S. CHALLENGER. been impossible, as de Loriol 1 remarks, to differentiate the species from the numerous forms of Antedon which occur associated with it. Neither arms, pinnules, nor cirri of Eudiocrinus present any characters which can be said to distinguish them from the ordinary Antedon-tj-pe ; and the disc with its central mouth might be readily taken for that of an Antedon, except for the fact that the primary ambulacra do not divide, but proceed straight on to the five arms (PI. VI. fig. 2). The sacculi which are usually so abundant at the sides of the ambulacra in Antedon, are, however, far less constant in Eudiocrinus. Abundant in Eudiocrinus indivisus, and Eudiocrinus atlanticus, they are scanty in Eudiocrinus varians, and altogether absent in the two remaining species, so far as my knowledge of them extends. The cirri of Eudiocrinus atlanticus are described by Perrier 2 in the following terms : — "II n'existe egalement entre les longues pieces des cirrhes dorsaux que de tres faibles coussinets charnus, et les cirrhes, dans le plupart des echantillons, se montrent etendus en ligne droite et rassembles dans une attitude qui rappelle celle que certaines araignees donnent frequemment a leurs pattes." " UE. atlanticus est, au point de vue de la locomotion, une interessante modification du type Comatule ; il ne peut en effet, se fixer solidement aux corps etrangers, comme le font les autres animaux du meme groupe, et il est probable qu'il repose le plus souvent les bras et les cirrhes etendus sur le limon de l'Oeean, n'ayant a craindre, dans les profondeurs ou il vit, ni les vagues ni les courants ; mais les masses musculaires de ses bras indiquent qu'il doit etre aussi un habile nageur. La plupart des Antedon, et surtout les Actinometra, sont au contraire organises pour s'accrocher solidement aux corps sous-marins et nagent peu." It appears to me that Perrier has (as usual) drawn a somewhat hasty conclusion from the majority of his fifteen specimens of Eudiocrinus atlanticus, with their cirri fully extended. A large collection of Comatulaa at any particular locality is sure to contain a number of individuals with the cirri stretched out in a straight line. Antedon phalangium, for example, has cirri very like those of Eudiocrinus, composed of elongated joints with small interarticular bundles (PI. XXVIII. figs. 1-3). Great numbers of this species, with which Perrier is well acquainted, were dredged by the " Porcupine " off the coast of Tunis. The cirri of some are spread out horizontally ; while in others they are turned directly downwards, so as to form a sort of basket below the centro-dorsal, and in yet others the cirri are mostly bent upwards, so as to lie alongside the arms, as in the examples of Antedon gracilis, and Antedon valida, figured on PI. XV. Indeed all the three positions may occur in the same individual. The same variations appear in the long-jointed cirri of Antedon macronema from Sydney Harbour (PI. XXXVIII. fig. 5). I have seen individuals of this type in which some cirri are horizontally extended, while others make two or three coils round the stem of a sea-weed or other support. The same 1 Mono£. Crin. foss. Suisse, p. 279. 2 Comptes rendus, 1883, t. xcvi. No. 11, p. V26. REPORT ON THE CRINOTDEA. 77 difference of position occurs in the short cirri of Antedon carinata, numbers of which were found by the Challenger at Bahia ; while many instances of the same kind occur among the Comatulse dredged by the Challenger in the Eastern Archipelago and by the " Blake" in the Caribbean Sea. (See also PL XXXIII. fig. 6, and PI. LXX.) I do not think therefore that Perrier is entitled to consider Eudiocrinus atlanticus as a specially interesting modification of the Comatula-type with regard to its locomotive powers, for it presents no peculiarities which do not occur in several species of Antedon. It is true that like other species of the genus (PL VI. fig. 1 ; PL VII.) it has large and powerful muscular bundles between the successive arm-joints ; and from this perhaps we may draw the conclusion that it was " un habile nageur." But the last sentence of the passage quoted above, wherein Eudiocrinus atlanticus is contrasted with Antedon and Actinometra as regards its swimming powers and mode of life, entirely ignores all that has been written upon the subject of late years. It is true that the muscular bundles of Eudiocrinus, as also those of Atelecrinus (PL VI. figs. 4, 7) and of many deep-sea Coinatulas, appear large by contrast with those of other types in which they do not appear prominently on the ventral surface of the arms, owing to their being covered by a thick and more or less opaque perisome. But when this is removed the large muscular bundles become visible, as seen in Dr. Carpenter's figure of Antedon rosacea.1 The same is the case in Antedon eschrichti, the muscular bundles of which, when properly exposed, have at least as great a relative size as those of any Eudiocrinus ; and if the size of the muscle-plates on the arm-joints be any criterion of the strength of the muscular bundles attached to them, there is little to choose in this respect between Antedon eschrichti, Actinometra paucicirra, and Actinometra nobilis. The position assumed by the cirri, and the appearance of the muscular bundles on the ventral surface of the arms of Eudiocrinus atlanticus, are not therefore characters of such importance as Perrier seems to think, when he contrasts this type with " la plupart des Antedon." I do not see that this species, with its cirri between 15 and 20 mm. in length, is any less well adapted for fixing itself to submarine bodies, than Antedon phalangium and many other species of the same genus which have cirri like those of Eudiocrinus atlanticus (PL XXVIII. ; PL XXX. figs. 4. 8 ; PL XXXIII. fig. 6). Neither do I know what authority Perrier has for his statement that most species of this genus swim but little, while implying that Eudiocrinus atlanticus swims a good deal. It certainly cannot be anything more than a somewhat hasty generalisation, which he could not possibly have made had he stopped to consider why the muscular bundles of Eudiocrinus appear so large in contrast to those of " la plupart des Antedon." But when he goes on to speak of the species of Actinometra as being those which are specially adapted to fix themselves and to swim but little, he falls into very considerable error. For, as will be shown immediately in reference to another part of his description of Eudiocrinus, he has not 1 Phil. Trans., 1866, pi. xxxiv. fig. 2. 78 THE VOYAGE OF H.M.S. CHALLENGER. taken the trouble to make himself sufficiently acquainted with the works of his pre- decessors, and has therefore committed himself to various statements which will not bear investigation. I do not know what grounds of fact he has for his assertion that the species of Actinometra swim but little. If, as I believe, it is merely an inference from the supposed small size of the muscular bundles between the arm-joints, his premises are wrong, as I have explained above ; while I do not know that he has ever been able to observe living species of the genus, and to notice their abstention from the performance of swimming movements. On the other hand, Professor Semper has kept various forms of Actinometra in an aquarium for weeks together, and his observation of the regular alternating movements of their arms while swimming was mentioned by myself as long ago as 1877. 1 I pointed out in the same memoir, and again five years later'" that the cirri of Actinometra are few in number, and almost entirely limited to the margin of the discoidal centro-dorsal ; while those of Antedon are numerous and more or less extensively distributed over the under surface of the centro-dorsal. But yet Perrier tells us that ' ' surtout les Actinometra " as compared with Antedon are adapted to fixing themselves by their cirri. The extreme inconsistency of this assertion with the real facts of the case becomes still more apparent, when it is remembered that in many species of Actinometra the cirri borne on the centro-dorsal duricg early life drop off, and their sockets become gradually obliterated (PI. LTV. figs. 1-9 ; PL LXV. figs. 1-6). It was mentioned in my preliminary Eeport3 that I had found the centro-dorsal of many Actinometra-s\>ecies to be in the form of a simple flat plate, more or less stellate in form, but entirely devoid of cirrus-sockets ; while in other individuals only a few imperfect sockets are present, owing to their not having been completely obliterated. The occurrence of a fossil Actinometra presenting these characters was also noticed ; 4 and other references were made to this peculiarity as it was found in a successively increasing number of species of the genus.5 Copies of the papers in which this character was described were sent to Professor Perrier, who seems nevertheless to be altogether unacquainted with its occurrence. For it is difficult to see how Actinometra paucicirra or Actinometra divaricata (PL LIV. fig. 1 ; PL LXIII. fig. 8), with its perfectly flat centro- dorsal entirely devoid of cirri, can be regarded as one of those Comatulae which are especially "organises pour s'accrocher solidement aux corps sous-marins." After making these somewhat ill-considered remarks, Perrier goes on to describe the disc of Eudiocrinus atlanticus, which is not more than 5 mm. in diameter and is thus very small in proportion to the size of the arms, which attain 120 mm., while the cirri are from 15 to 20 mm. long.6 Perrier then adds " II resulte de ce que nous venons de 1 Journ. Linn. Soc. Lond. (Zool.), 1877, vol. xiii. p. 446. * Bull. Mus. Gomp. Zool., 1882, vol. ix. No. 4, p. 13. 3 Proc. Roy. Soc, 1879, pp. 389-391. 4 Quart. Journ. Zool. Soc, 1880, vol. xxxvi. p. 51. 6 The Comatulae of the Leyden Museum. Notes from the Leyden Museum, 1881, vol. iii. pp. 196, 208. QComptes rendus, 1883, t. xcvi. No. 11, p. 727. REPORT ON THE CRINOIDEA. 79 dire que, malgre la simplicite de leurs bras, les Eudiocrinus, loin d'etre un type primitif de Comatules, representent au contraire un type notablement modifie." I do not quite know what Perrier would regard as a primitive type of Comatula, and I have not been able to arrive at any fixed ideas upon that subject myself. But if his inference that Eudiocrinus is a much modified type has qo better foundation than is given in his description of Eudiocrinus atlanticus, as would appear from his own remarks just quoted, I do not think that much can be said for it. This species approaches more nearly to Antedon than any of the other four comprising the genus ; for it has a bifascial articulation between the first two joints above the radials like Eudiocrinus semperi and Eudiocrinus japonicus; but it also possesses what these have not, viz., abundant sacculi ; and these organs are abundant in Eudiocrinus indivisus as in Antedon. This latter form is, however, much further removed from the ordinary Antedon-type than Eudiocrinus atlanticus, owing to the syzygial union of the two joints above the radials, which only occurs in a very few species of Antedon. Perrier's inference as to the notably modified character of Eudiocrinus appears, however, to be entirely founded upon his knowledge of the single Atlantic species ; while he makes some considerable errors in his comparison of it with the other Comatula genera, Antedon and Actinometra. Eudiocrinus has a somewhat wider geographical range than Atelecrinus, extending over more than 70° of latitude in the West Pacific, and occurring at about 45° N. in the Atlantic. The type of the genus was found near Bohol in the Philippine Islands by Professor Semper some twenty years ago. A second species (Eudiocrinus semperi), was dredged by the Challenger shortly after leaving Sydney, and again off New Zealand. A third (Eudiocrinus varians), was met with off the north-east part of the Philippine Group, at the lowest bathymetrical limit of the genus ; while a fourth came up from 565 fathoms, to the south of the Bay of Yedo, and has also been collected at lesser depths in Japanese waters. To these must now be added the Atlantic species dredged by the " Travailleur " in 896 metres l (486 fathoms). The bathymetrical range of the type is thus very considerable, and it has been dredged four times below 500 fathoms, on two of which occasions the depth exceeded 900 fathoms. The only fossil species known occurs in the Valanp-ien and Lower Urgonien of Switzerland. The species of Eudiocrinus fall into two unequal groups. The first one comprises Semper's type (Eudiocrinus indivisus), in which the first two joints beyond the radials are united by syzygy ; while in the four remaining species there is a bifascial articulation between these two joints. In describing the other three Pacific species, I spoke of the fourth brachials as being traversed by a syzygy and bearing a pinnule in Eudiocrinus 1 This depth (896 metres) is that mentioned by Perrier in his first description of Eudiocrinus atlanticus (Comptes rendus, 1S83, t. xcvi. p. 725). Recently, however, he has said :— " Les Eudiocrinus viventa environ 1200 metres de pro- fondeur, dans les regions vaseuses " (Les Explorations Sous-marines, p. 275), and on the same page is figured a specimen of Eudiocrinus atlanticus from 1000 metres. It may be well to remember that Eudiocrinus indivisus and Eudiocrinus japonicus have both been dredged in less than 50 fathoms. 80 THE VOYAGE OF H.M.S. CHALLENGER. semperi and Eudiocrinus japonicus, while in Eudiocrinus varians the first pinnule is on the second brachial.1 But in his description of Eudiocrinus atlanticus, Perrier2 says " La premiere syzygie se trouve entre la quatrieme et la cinquieme piece des bras ; c'est la cinquieme qui porte la premiere pinnule ; la place de la premiere syzygie distingue V Eudiocrinus atlanticus de YE. indivisus, Semper ; celle de la premiere pinnule la distingue des trois autres especes." In reality, however, the position of the first syzygy and that of the first pinnule in Eudiocrinus atlanticus are exactly the same as in Eudiocrinus semperi and Eudiocrinus japonicus. In describing the fourth brachial of these two species as a syzygy I was using precisely the same terminology as was employed by Muller3 in his diagnoses of Antedon rosacea, Antedon phalangium, and Antedon eschrichti, when he wrote " Das erste Syzygium befindet sich am dritten Armglied." Perrier however employs a different terminology, which, as I have explained in Part I. and elsewhere,4 has several disadvantages from a morphological point of view. He describes the fourth and fifth brachials as united by syzygy. It is perfectly true that these are primitively the fourth and fifth joints of the arm, exactly in the same way as the composite third brachial of Antedon rosacea consists of the united third (hypozygal) and fourth (epizygal) joints of the growing arm, as described by Dr. Carpenter.5 But since the hypozygals of all the brachial syzygies of Eudiocrinus atlanticus, Eudiocrinus semperi, or of Antedon rosacea entirely lose their individuality as arm-joints, bearing no pinnules and taking no part in the movements of the arm, I believe that it is more correct for descriptive purposes to follow Muller and to consider the compound or syzygial joint as one arm- segment only. In accordance with the Midlerian terminology, therefore, I described the fourth brachial of Eudiocrinus semperi as being or having a syzygy, after going into the subject rather fully in two memoirs which were published in 1882.6 Perrier, however, in apparent ignorance of all that had been written on the subject by Muller, Dr. Carpenter, and myself, not only introduces, though seemingly without knowing it, a new descriptive terminology, but also imagines that I had used it before him. He has made a very similar error in his description of Democrinus (Rhizocrinus) , and it is much to be desired that for the sake of future workers he would take the trouble to acquaint himself with the current nomenclature before writing his descriptions ; or at any rate that if he decides to introduce a new descriptive method, he would make some statement to that effect. The present result is that he describes a difference between Eudiocrinus atlanticus and Eudiocrinus semperi or Eudiocrinus japonicus, which does not exist in reality. In all three species alike there is a syzygy in the fourth brachial, as Midler would have described it, with a pinnule on the epizygal. 1 Joum. Linn. Soc. Lond. (Zool.), 1882, vol. xvi. p. 495. 2 Comptes renins, 1883, t. xevi. No. 11, p. 725. 3 Abhamdl. d. k. Akad. d. Wiss. Berlin, 1849, p. 252. tProc. Zool. Soc. Lond., 1882, pp. 734, 735. 5 Phil. Trans., 1866, p. 721. 6 Joum. Linn. Soc. Lond. (Zool.), 1882, vol. xvi. p. 515 ; and Proc. Zool. Soc. Lond., 1882, pp. 734, 735. REPORT ON THE CRINOIDEA. 81 Although the principal diagnostic character on which Perrier established Eudiocrinus atlanticus thus turns out to be due to an erroneous method of nomenclature, he men- tions a subsidiary one which merits more attention. For he finds that " L'JE. atlanticus se distingue egalement de ces dernieres especes par le nombre et la grandeur des organes, si repandus chez les Crinoides, nomnies corps sp>hcriques ou saccules. Les saccules manquent aux E. japonicus, et E. Semperi ; ils sont petits et rares chez YE. varians."1 In this respect, therefore, the Atlantic species is sharply distinguished from both Eudiocrinus semperi and Eudiocrinus japonicus, which resemble it most closely in the structure of the skeleton ; while they have over twenty-five cirrus- joints, of which there are only fifteen in Eudiocrinus atlanticus. The mutual relations of the five species of Eudiocrinus may, therefore, be expressed as follows : — I. First two brachials united by syzygy. First pinnule on the second brachial, . 1. indivisus, Semper, sp. II. First two brachials united by a bifascial articulation. A. First pinnule on the second brachial, . . . . .2. varians, n. sp. B. First pinnule on the fourth brachial. 1. Sacculi absent. Twenty-five or more cirrus-joints. a. Disk plated. First brachials nearly oblong, . . .3. semperi, n. sp. /?. Disk naked. First brachials trapezoidal, . . .4. japonicus, n. sp. 2. Sacculi abundant. Fifteen cirrus-joints, . . . .5. atlanticus, Perrier. Eudiocrinus varians, n. sp. (PI. VII. figs. 3-7). 1882. Eudiocrinus varians, P. H. Carpenter, Journ. Linn. Soc. Lond. (Zool.), 1882, voL xvi. p. 496. Centro-dorsal low, nearly hemispherical, bearing about twenty cirri in two rows which leave the dorsal pole free. Two forms of cirrus occur in the same individual. — (l) With two or three short basal joints, the last of which is nearly square, while the following joint is considerably longer, and the succeeding ones still more so, reaching 3 mm. in length. Terminal joints unknown. (2) Eight at least of the lower joints are quite short, few of them being longer than wide, and that but slightly so. Remainder unknown. Radials partially visible. First brachials nearly oblong, inclined to be trapezoidal, with small lateral processes which are the edges of the muscle-plates for articulation with the radials. Second brachial also nearly oblong, with traces of a backward process into the preceding joint, a pinnule on the right and a small process on the left side. The following joints have somewhat unequal sides, with a pinnule on the shorter and a large wing-shaped process on the longer side, which ceases on the sixth, or may go on to the eighth joint. Succeeding brachials quadrate and unequal-sided, with the pinnule on the longer side. The twelfth and following joints are distinctly longer than wide. Syzygia in the fourth and eighth or ninth brachials ; then an interval of two to five joints between successive syzygia. 1 Comptes rendus, 1883, t. xcvi. No. 11, p. 726. (ZOOL, CHALL. EXP. — PART LX. — 1887.) OoO 11 82 THE VOYAGE OF H.M.S. CHALLENGER. The first few pinnules have wide basal joints, the fourth and fifth of which are sometimes expanded towards the dorsal side. This is most marked in the larger specimen. The later pinnule-joints are elongated, but very much more slender in the small specimen than in the larger one. The lower pinnules appear to be the longer, containing more numerous, though shorter joints. That on the fourth brachial in the larger specimen is almost 12 mm. long, and consists of twenty-five joints. Disk 5 mm. wide. It bears numerous calcareous nodules, but the brachial ambulacra only have delicate rods and networks of limestone at their sides. Saccidi are present, though small, inconspicuous, and few in number Skeleton white. The smaller specimen is 3 "2 mm., and the larger 4 "5 mm. across the centro-dorsal. Locality— Station 205, November 13, 1874; lat. 16° 42' N., long. 119° 22' E.; 1050 fathoms; grey ooze; bottom temperature, 37° F. Two mutilated specimens. Remarks. — This is a very singular species. The two mutilated individuals described above resemble one another very closely in the characters of the calyx and arms, while the cirri and pinnules vary considerably. In the smaller one I can find no certain trace of any but the long-jointed cirri like those of Eudiocrinns semperi and Eudiocrinus japonicus (PI. VI. fig. 1 ; PI. VII. figs. 2, 7). But in the larger form, which retains the bases of two, if not more of these, the majority of the remaining cirrus-stumps consist of numerous short joints but little longer than wide (PI. VII. figs. 3, 5). In the smaller form again, most of the pinnules are quite slender and delicate, with somewhat glassy joints, which are twice, or more than twice, as long as wide (PI. VII. fig. 4). But in the larger one they are usually considerably stouter and more massive, though one or two of the lowest pinnules are much more slender than their fellows, and somewhat resemble those of the smaller individual (PI. VII. fig. 3). This species is at once distinguished from Eudiocrinus semperi and Eudiocrinus japonicus, which resemble it in having an articulation between the first two brachials, by the presence of a pinnule on the second one. Eudiocrinus semperi, n. sp. (PL III. fig. 7 ; PL VI. figs. 1-3). 1882. Eudiocrinus semperi, P. H. Carpenter, Journ. Linn. Soc. Lond. (Zool.), 1882, vol. xvi. p. 497. Centro-dorsal small, nearly hemispherical, or somewhat flattened, thickly covered with cirrus-sockets, except at the dorsal pole. These have strongly marked articular rims around the opening of the central canal, and are from twenty to thirty in number. Cirri probably 30 mm. long, and tapering, of twenty-six joints ; the first three or four quite short, the next more than twice as long as wide, and the four following ones the longest, sometimes exceeding 2 mm. The remainder diminish slowly in size, but exhibit no traces of any dorsal spines. REPORT ON THE CRINOIDEA. 83 Eadials partially visible. First brachials nearly oblong, widening slightly and then narrowing a little. Second brachials quadrate, and appearing in a side view of the specimen to project strongly backward into the first brachials, as the surfaces of both joints rise towards the middle of their line of junction. The following joints have unequal sides, the fourth having a syzygy and bearing a pinnule on the shorter side, usually the right. The seventh joint is more oblong, while the eighth and following brachials become more distinctly unequal-sided, the breadth being about equal to the length of the longer side which bears the pinnule. Further out on the arms the length gradually increases in proportion to the breadth, and the joints become more and more cylindrical. Second syzygy from the seventh to ninth brachial ; and the later syzygial intervals vary from one to four joints. The lower pinnules are all about equal in length, and consist of some twenty joints. Except in the first four or five pinnules all but the lowest joints are twice as long as broad, or slightly longer, and more transparent and glassy than the cirrus-joints. Ovaries short, not extending over more than three or four joints. Towards the arm ends the pinnules gradually decrease both in length and in the number of joints. Mouth central. Disk and arm-bases rather closely plated, but the brachial ambulacra merely have irregular rods and networks of limestone at their sides. They lie close down between the muscles and show no traces of sacculi. Skeleton white. Disk 5 mm. in diameter. Radial pentagon 4 mm. Spread probably about 150 mm. Localities.— Station 164, June, 12, 1874; lat. 34° 8' S., long. 152° 0' E.; 950 fathoms ; green mud ; bottom temperature, 36°"5 F. One specimen. Station 169, July 10, 1874; lat. 37° 34' S., long. 179° 22' E.; 700 fathoms; blue mud ; bottom temperature, 40°'0 F. Two specimens. Remarks. — I have named this species after Professor C. Semper of Wiirzburg, to whom we owe the discovery during his residence in the Philippine Islands of the type species of Eudiocrinus {Eudiocrinus indivisus). The absence of pinnules on the second and third brachials distinguishes Eudiocrinus semperi both from the type and also from Eudiocrinus varians. Furthermore, both these species have sacculi, which are abundant in Eudiocrinus indivisus, but rare in Eudiocrinus varians ; while I have not been able to find them even on the pinnules, either of Eudiocrinus semperi, or of the closely allied Eudiocrinus japonicus, though they are abundant in the Atlantic species. Eudiocrinus semperi, like other Coinatulse, exhibits a certain amount of local variation. All three specimens were obtained in a very mutilated condition, hardly anything remaining of one of them but the calyx and the bases of the arms. But sufficient remains of the other two to indicate a considerable amount of flexibility in some of their characters. That from the lesser depth (Station 169) is the larger of the two, and its disk bears larger and more numerous plates ; while there are fewer cirri on the centro- 84 THE VOYAGE OF H.M.S. CHALLENGER. dorsal, and the pinnule-joints are somewhat shorter and less glassy than those of the individual from Station 164. In the former also both the antero-lateral rays have the first pinnule on the left side ; while the latter presents a curious variation. The first pinnule is on the right side in the two posterior rays, and on the left in the left anterior one, the right anterior one being broken at the syzygy in the fourth brachial. The anterior ray has been repaired at this syzygy, but no pinnule has been developed on the epizygal. The fifth brachial, however, bears a pinnule as usual on the left side, but that on the sixth is on the same side ; so that the first pinnule on the right of the ray does not come till the seventh brachial. Eudiocrinus japonicus, n. sp. (PI. VII. figs. 1, 2). 1882. Eudiocrinus japonicus, P. H. Carpenter, Journ. Linn. Soc. Lond. (Zool.), 1882, "vol. xvi. p. 499. Centro-dorsal relatively large, conical, and covered except at the dorsal pole by from forty to fifty cirrus-sockets, each with a well-marked articular rim around the opening of the central canal. Cirri more than 35 mm. long, tapering, and consisting of twenty-seven joints. The first three are quite short, the fourth a good deal longer than wide, and the next four the longest, but scarcely reaching 2 mm.; the following ones diminish slowly in size, but have no traces of any dorsal spine. Radials just visible. First brachials trapezoidal, the sides commencing to slope inwards almost immediately beyond the proximal edge. The second brachials, as seen from below, are also trapezoidal, being narrower along their proximal edges, where they project backwards into the preceding joints, both surfaces rising towards the line of junction. The next four or five joints have unequal sides, the fourth being a syzygy, and bearing a pinnule on its shorter side. In the only specimen with all the arm-bases preserved, one of them has the first pinnule on the left side. The fifth and one or two following joints also have the pinnule on the shorter side. The next is more oblong, and its successor again a syzygy, with the pinnule on its longer side. The succeeding joints have still more markedly unequal sides, the breadth being about equal to the length of the longer side. After the second syzygy there is an interval of four or five joints between successive syzygia. The lowest pinnules are apparently tolerably equal, consisting of some twenty stout joints, of which only a few middle ones are longer than wide. Beyond the eighth brachial, the pinnule-joints become relatively longer and thinner and the pinnules more slender. Ovaries short, not extending over more than three or four joints. Mouth central or subcentral. Disk naked, 7 mm. in diameter ; the brachial ambulacra close down between the muscles, with a few supporting rods and networks of limestone, but no traces of sacculi. Skeleton white. REPORT ON THE CRINOIDEA. 85 Locality. — Station 235, June 4, 1875; lat. 34° 7' N., long. 138° 0' E.; 565 fathoms; green mud; bottom temperature, 38°-l F. Three much mutilated specimens. Remarks. — It is with some hesitation that I have separated this species from the preceding one. It is altogether larger and more massive than Eudiocrinus semperi, with a larger and more distinctly conical centro-dorsal and more numerous cirri. The first brachials have larger muscle-plates for articulation with the radials, and are more trapezoidal in outline ; and as the second brachials are relatively longer than those of Eudiocrinus semperi, and at the same time more trapezoidal in form, the base of each arm is considerably constricted at the junction of its first two joints (PI. VII. fig. 1). The general proportions of the remaining arm-joints and of the pinnules appear to be much the same in the two types, excepting that in the smaller Eudiocrinus semperi the joints of the lower pinnules are rather longer relatively to their width than in Eudiocrinus japonicus. Of the twelve arms which are preserved in three individuals of the latter species, only one has the first pinnule on the left side ; while in Eudiocrinus semperi this appears to be normally the case in the two antero-lateral rays. There are some specimens of Eudiocrinus in the University Museum at Berlin, which were kindly shown to me by Dr. Hilgendorf, who had collected them in Japan. I think that they are probably identical with the type just described. They have rather fewer cirrus-joints, and the junctions of the first eight brachials are distinctly tubercular. The tubercle between the first two is in the middle line, and those between the following- joints lie alternately on either side of the arm. The three Challenger examples, however, show no traces of these tubercles, with the exception of the median one, which is far less marked than in the Berlin specimens. Genus 4. Antedon, de Freminville, 1811. 1733. AcKaw^os, Linck, De Stellis Marinis liber singularis, Lipsice, 1733, p. 53. 1733. Caput Medusx, Linck, Ibid., p. 57. 1758. Asterias, Linnfeus (pars), Systema Naturae, 10th ed., Holniise, 1758, t. ii. p. G63. 1777. Asterias, Pennant (pars), British. Zoology, 2nd ed., London, 1777, vol. iv. p. 55. 1783. Asterias, Retzius (pars), K. Svensk. Vetensk. Akad. Handl., Ar 1783, t. iv. p. 241. 1805. Asterias, Retzius (pars), Dissertatio, sistens Species Cognitas Asteriarum, Lundae, 1805, pp. 33-35. 1811. Antedon, de Freminville, Bull. Soc. Philom. Paris, 1811, t. ii. p. 349. 1813. Asteriatites, von Schlotheim (pars), Taschenbuch fur die Gesammte Mineralogie, 1813, Jahrg. vii. Abth. 1. p. 68. 1815. Alecto, Leach, Zool. Miscellany, London, 1S15, vol. ii. p. 01. 1816. Comatula, Lamarck (pars), Histoire Naturelle des Animaux sans Vertebres, Paris, 1816, t. ii. p. 530. 1820. Ophiurites, von Schlotheim (pars), Die Petrefactenkunde, Gotha, 1820, p. 326. 1821. Comatula, Miller, A Natural History of the Crinoidea, Bristol, 1821, p. 128. 1823. Comatulithes, von Schlotheim, Nachtrage zur Petrefactenkunde, Gotha, 1823, Abth. ii. p. 17. 1825, Aledro, Say, Journ. Acad. Nat. Sci. Philad., 1825, vol. v. p. 153. 1827. Pentacrinus, Thompson, Memoir on the Pentacrinus Europaeus, Cork, 1827, p. 10. 86 THE VOYAGE OF H.M.S. CHALLENGER. 1828. ComatuJa, Fleming, History of British Animals, London, 1828, p. -190. 182S. Pentacrinus, Fleming, Ibid., p. 493. 1828. Hibernula, Fleming, Ibid., p. 494. 1830. Comatida (Astrocoma), de Blainville (pars), Diet. d. Sci. Nat., 1830, t. lx. p. 229. 1830. Alerto, Cuvier, Regne Animal, Paris, 1830, t. iii. p. 228. 1830. Phytocrinus, de Blainville, Ibid,, p. 235. 1832. Comatida, Goldfuss (pars), Petrefaeta Germanise, Dusseldorf, 1832, t. i. p. 201. 1832. Glenotremites, Goldfuss, Ibid., p. 159. 1832. Solanocrinites, Goldfuss, Ibid., p. 166. 1834. Comatula (Astrocoma), de Blainville (pars), Manuel dActinologie, Paris, 1834, p. 248. 1834. Phytocrinus, de Blainville, Ibid., p. 255. 1834. Ganymeda, Gray, Proc. Zool. Soc. Lond., 1834, pt. ii. No. 14, p. 15. 1835. Comatula, Agassiz, Mem. de la Soc. d. Sci. Nat. de Neuchatel, 1835, t. i. p. 193. 1835. Pterocoma, Agassiz, Ibid., p. 193. 1835. Glenotremites, Agassiz, Ibid., p. 194. 1835. Ganymeda, Agassiz, Ibid., p. 194. 1835. Phytocrinus, Agassiz, Ibid., p. 194. 1835. Solacrinus, Agassiz, Ibid., p. 196. 1836. Comatula, Thompson, Edin. New Phil. Journ., 1836, t xx. p. 295. 1837. Solanocrinites, Bronn, Lethaea Geognostica, 2nd ed., 1837, p. 272. 1837. Decac7iemos, Bronn, Ibid., p. 273. 1839. Comatula, Goldfuss (pars), Nova Acta Acad. Cass. Leop., 1839, Bd. xix. pars 1, p. 348. 1839. Solanocrinus, Goldfuss, Ibid,, p. 349. 1839. Comaturella, von Miinster, Beitriige zur Petrefactenkunde, 1839, p. 97. 1840. Hertha, von Hagenow, Neues Jahrb. f. Mineral., 1840, p. 664. 1840. Comatula, Miiller, Monatsber. d. k. preuss. Akad. d. Wiss. Berlin, 1840, p. 91. 1841. Comatula, Forbes, History of British Starfishes, London, 1841, p. 5. 1841. Comatula, Goldfuss (pars), Neues Jahrb. f. Mineral., 1841, p. 818. 1841. Solanocrinus, Goldfuss (pars), Ibid., p. 819. 1841. Alecto, Miiller (pars), Monatsber. d. k. preuss. Akad. d. Wiss. Berlin, 1841, p. 182. 1843. Alecto, Miiller (pars), Abhandl. d. k. Akad. d. Wiss. Berlin, Jahrg. 1841 [1843], p. 203. 1843. Alecto, Miiller (pars), Archiv f. Naturgesch., 1843, Jahrg. ix. Bd. i. p. 131. 1844. Alecto, Philippi, Neues Jahrb. f. Mineral., 1844, p. 540. 1846. Alecto, Diiben and Koren, K. Svensk. Vetensk. Akad. Handl. Stockholm, 1844 [1846], p. 229. 1846. Comatida, Miiller (pars), Monatsber. d. k preuss. Akad. d. Wiss. Berlin, 1846, p. 178. 1848. Antedon, Gray, List of the species of British Animals in the collection of the British Museum, pt. i., London, 1848, p. 28. 1849. Comatula (Alecto), Miiller (pars), Abhandl. d. k. Akad. d. Wiss. BerliD, Jahrg. 1847 [1849], p. 246. 1849. Ganymeda, Bronn, Index Palseontologicus, Stuttgart, 1849, p. 182. 1849. Glenotremites, Bronn, Ibid., p. 182. 1849. Solanocrinus, Bronn, Ibid., p. 182. 1849. Comaturella, Bronn, Ibid., p. 182. 1849. Alecto, Bronn, Ibid., p. 183. 1849. Comatida, Bronn, Ibid., p. 183. 1850. Decameros, d'Orbigny, Prodrome de Paleontologie stratigraphique universelle des Animanx Mollusques et Rayonnes, Paris, 1850, torn. ii. fasc. 1, p. 121. 1850. Comatula, Ibid., pp. 180, 274. 1851. Decacnemus, Bronn, Lethrea Geognostica, 3rd ed., 1851, Bd. i. Th. iv. p. 133. 1851. Comatida, Broun, Ibid,, Th. v. p. 176. 1851. Glenotremites, Bronn, Ibid., p. 177. REPORT ON THE CRINOIDEA. 87 1852. Comahda, Forbes, Monograph of the Echinodermata of the British Tertiaries, 1852, p. 19. 1852. Comatula, Quenstedt, Handbuch der Petrefactenkunde, Tubingen, 1852, p. 599. 1852. Solanocrinites, Quenstedt, Ibid., p. 600. 1852. Comatula, d'Orbigny, Cours element, de Paleontol. et de Geol. stratigr., Paris, 1852, torn. ii. fasc. 1, p. 139. 1852. Comatulina, d'Orbigny, Ibid., p. 139. 1852. Decameros, d'Orbigny, Ibid., p. 139. 1852. Pterocoma, d'Orbigny, Ibid., p. 139. 1857. Comatula, Barrett, Ann. and Mag. Nat. Hist., 1857, ser. 2, vol. xix. p. 33.. 1857. Comatula, Pictet, Traite de Paleontologie, 2me ed., Paris, 1857, t. iv. p. 288. 1857. Comaturella, Pictet, Ibid., p. 289. 1857. Decameros, Pictet, Ibid., p. 289. 1857. Pterocoma, Pictet, Ibid., p. 289. 1857. Glenotremites, Pictet, Ibid., p. 290. 1857. Alecto, Lutken, Vid. Meddel. Nat. Foren. Kj0benhavn, 1857, p. 55. 1858. Solanocrinites, Quenstedt, Der Jura, Tubingen, 1858, p. 657. 1859. Comahda, Sars, Nyt Mag. f. Naturvid., 1857 [1859], Bd. x. p. 17. 1860. Comatula, Bronn {pars), Klassen und Ordnungen des Thierreichs, 1860, Bd. it., p. 233. 1860. Comaturella, Bronn, Ibid., p. 233. 1860. Glenotremites, Bronn, Ibid., p. 233. 1861. Alecto, Sars, Oversigt af Norges Echinodermer, Christiania, 1861, p. 1. 1861. Allionia, Michelotti, Rev. et Mag. Zool., 1861, ser. 2, t. xiii. p. 353. 1862. Comatula, Dujardin and Hupe (pars), Hist. Nat. des Zoophytes, Echinodermes, Paris, 1862, p. 192. 1862. Comaster, Dujardin and Hup6 (pais), Paid., p. 211. 1864. Alecto, Lutken, Vid. Meddel. nat. Foren. Kjpbenhavn, 1864, p. 213. 1865. Antedon, Norman, Ann. and Mag. Nat. Hist., 1865, ser. 3, vol. xv. p. 101. 1866. Antedon, Bohlsche, Archiv f. Naturgesch., 1866, Jahrg. xxxii., Bd. i. p. 92. 1866. Antedon, W. B. Carpenter, Phil. Trans., 1866, p. 695. 1866. Antedon, Loven, Ofversigt k. Vetensk.-Akad. Forhandl., 1866, No. 9, p. 224. 1868. Hi/ponome, Loven, Forhandl. Skand. Naturf. Christiania, 1868, t. x. p. liv. 1868. Comatula (Alecto), Pourtales, Bull. Mus. Comp. Zool., 1868, vol. i. No. 6, p. 111. 1868. Antedon, Sars, Memoires pour servir h la connaissance des Crinoides vivants, Christiania, 186S, p. 47. 1868. Solanocrinus, de Loriol, Monographie des Couches de l'etage Valangien des carrieres d'Arzier (Yaud), Geneve, 1868, p. 84. 1869. Antedon, Pourtales (pars), Bull. Mus. Comp. Zool., 1869, voL i. No. 11, p. 355. 1871. Glenotremites, Geinitz, Palaxmtographica, Bd. xx. Abth. ], Cassel, 1871, p. 91. 1872. Antedon, Geinitz, Ibid., Abth. 2, 1872, p. 18. 1872. Antedon, Wyville Thomson, Proc. Roy. Soc. Edin., 1872, vol. vii. p. 764. 1874. Comaster, Lundgren, Ofversigt k. Vetensk.-Akad. Forhandl., 1874, p. 66. 1876. Comatula, Quenstedt, Petrefactenkunde Deutschlands, Bd. iv., 1876, Asteriden und Encriniden, p. 163. 1876. Solanocrinites, Quenstedt, Ibid., p. 171. 1877. Antedon, P. H. Carpenter, Journ. Linn. Soc. Lond. (Zool.), 1877, vol. xiii. p. 439. 1877. Eallispo7igia, Wright, Proc. Roy. Irish Acad., 1877, ser. 2, vol. ii. p. 114. 1878. Antedon, von Marenzeller, Denkschr. d. k. Akad. d. Wiss. Wien, 1877 [1878], Bd. xxxv. p. 380. 1878. Antedon, Schliiter, Zeitschr. d. deutsch. geol. Gesellsch., Jabrg. 1878, p. 40. 1878. Geocoma, Fraas, Aus dem Orient, Stuttgart, 1878, Th. ii. p. 89. 1878. Antedon, Pourtales (pars), Bull. Mus. Comp. Zool., 1878, vol. v. p. 214. 1879. Antedon, de Loriol, Monographie des Crinoides fossiles de la Suisse, Geneva, 1877-79, p. 253. 1879. Antedon, Fontannes, Ann. Soc. d' Agriculture, Hist. Nat., et Arts utiles de Lyon, 1879, p. 50. 1879. Antedon, P. H. Carpenter, Trans. Linn. Soc. Lond. (Zool.), ser. 2, 1879, vol. ii. p. 16. 88 THE VOYAGE OF H.M.S. CHALLENGER. 1879. Antedon, P. H. Carpenter, Proc. Roy. Soc, 1879, vol. xxviii. p. 385. 1879. Antedon, Rathbun (pars), Trans. Connect. Acad., 1879, vol. v. p. 156. 1879. Antedon, Ludwig, Mitth. Zool. Stat. Neapel, 1879, Bd. i. p. 536. 1879. Antedon, Zittel, Handbuch der Palaeontologie, Palseozoologie, Bd. i. Abth. 2, 1876-1880, p. 395. 1880. Antedon, P. H. Carpenter, Quart. Journ. Geol. Soc, 1880, vol. xxxvi. p. -10. 1880. Antedon, Claus, Grundztige der Zoologie, 4tb ed., 1880, Bd. i. p. 335. 1880. Antedon, P. H. Carpenter, Journ. Linn. Soc. Lond. (Zool.), 1880, voL xv. p. 191. 1881. Antedon, Duncan and Sladen, Memoir Arctic Ecbinodermata, London, 1881, p. 73. 1881. Antedon, P. H. Carpenter, Notes from tbe Leyden Museum, 1881, vol. iii. p. 178. 1882. Antedon, P. H. Carpenter, Journ. Linn. Soc. Lond. (Zool.), 1882, vol. xvi. p. 501. 1882. Antedon, P. H. Carpenter, Bull. Mus. Comp. Zool. 1882, vol. ix. No. 4, p. 13. 1882. Antedon, Bell, Proc. Zool. Soc. Lond., 1882, p. 532. 1882. Antedon, P. H. Carpenter, Ibid., p. 746. 1884. Antedon, Bell, Rep. Zool. Coll. H.M.S. "Alert," Lond., 1884, p. 155. 1884. Antedon, Cams, Prodromus Faunoe Mediterraneas, Pars I., Leipzig, 1884, p. 84. 1884. Antedon, P. H. Carpenter, Proc. Roy. Soc. Edin., 1884, vol. xii. p. 360. 1885. Antedon, P. H. Carpenter, Zool. Chall. Exp., part xxxii., vol. xi., 1884 [1885], p. 137. 1885. Comatula, Quenstedt (pars), Handbuch der Petrefactenkunde, Aufl. 3, Tubingen, 1885, p. 913. 1885. Antedon, Ludwig, Leunis, Synopsis der Thierkunde, Dritte Auflage, Hannover, 1885, Bd. ii. p. 947. 1886. Antedon, P. H. Carpenter, Bijdragen tot de Dierkunde, 1886, Aflevering 13, vi. p. 5. 1886. Solanocrinus, Walther, Palajontographica, Stuttgart, 1886, Bd. xxxii. p. 175. 1886. Antedon, Walther, Ibid., p. 177. 1886. Antedon, Levinsen, Dijniphna-Togtets zoologisk-botaniske Udbytte, Kj0benhavn, 1886, p. 410. 1886. Antedon, Stuxberg, Vega-Expeditionens Vetenskapliga Arbeten, Stockholm, 1886, Bd. v. p 162. 1887. Antedon, P. H. Carpenter, Ann. and Mag. Nat. Hist., 1887, ser. 5, vol. xix. p. 83. Definition. — Centro-dorsal usually somewhat hemispherical or conical, rarely discoidal, and generally bearing at least twenty cirri, often several more, which leave but little of its under surface free. Outer faces of the radials relatively high, with large muscle- plates, and much inclined to the vertical axis of the calyx. Disk with a central or subcentral mouth and five equal ambulacra, which extend on to all the arms. These are ten or more in number, all of the same length, and may have an ambulacral skeleton which is most differentiated on the pinnules. Sacculi almost always present on the pinnules, if not elsewhere. History. — This genus was established in 1811 by de Frdminville,1 who was the first to remove the Feather-stars from the confusion of the Linnean genus Asterias and to give them a definite generic rank. A similar course was taken three years later by Leach, who was probably unaware of de Freminville's work, and established the genus Alecto for the Feather-stars ; but the same can hardly be said of Lamarck, who deliber- ately rejected de Freminville's generic name, replacing it by one of his own making, viz., Comatula, and he doubtfully referred de Freminville's species Antedon gorgonia to his own 1 Memoire sur un nouveau genre de Zoophites de l'ordre des Radiaires, Bull. Soc. Philom. Paris, 1811, t. ii. p. 349. In this note de Fr^minville referred to an illustration of Antedon in the Encyclop^die Methodique ; and Perrier has consequently been led to mention the latter work as that in which the name Antedon was first proposed Now. Archiv. Mus. Hist. Nat., t. ix., 1886, p. 79). REPORT ON THE CRINOJDEA. 89 new species Comatula carinata,1 which he had established in apparent ignorance of the fact that Leach had proposed Alecto carinata in the previous year. The authority of the great French zoologist and the appositeness of the name which he proposed both contributed to cause this somewhat ostentatious neglect of the work of a fellow-countryman to be overlooked by naturalists in general ; and Lamarck's name was used in succession by J. S. Miller, von Schlotkeim, de Blainville, Goldfuss, Agassiz, and Minister. Among these authors Miller deserves especial mention, for he was the first naturalist after Llhuyd and Linck who distinctly recognised the morphologic; il resemblance between the Feather-stars and the Stalked Crinoids, a point which Lamarck had entirely failed to notice ; and Miller accordingly drew up a new generic definition of Comatula which was based upon this idea.2 He seems to have preferred this name to Alecto, which genus he regarded as less precisely defined than Lamarck's Comatula. Johannes Midler also used Comatula in his first communication to the Berlin Academy upon the subject of the Crinoidea; but in the next year (1841) he formally adopted Alecto, Leach, as the generic name of several new species, while in the year 1843 he applied it to the six Lamarckian species which he had not previously mentioned in this relation, and subsequently also to the Asterias multiradiata of Linnasus. When Midler first proposed the name Actinometra he regarded it as denoting a genus equivalent to Alecto; but he eventually reduced both these names to subgeneric rank and assigned a generic position to Comatula. Dujardin and Hupe, however, dropped Alecto altogether and restored generic rank to Actinometra, making it equivalent to Comatula. Soon afterwards, Norman very rightly restored de Freminville's name, Antedon, which had been suffered to fall into disuse ; and it is now universally used for the typical Endocyclic Comatulse with five dividing rays, both recent and fossil. There are, however, a very large number of generic names which have been applied to the centro-dorsals of fossil Comatula?, both with and without the radials attached, e.g., Glenotremites, Solanocrinus, Hertha, Decameros, Decacnemos, Allionia, Comaster, &c. Pterocoma and Geocoma were the names given by Agassiz and Fraas to species from the Solenhofen Slate and the Chalk of the Lebanon respectively. Ganymeda, Gray, is in all probability the centro-dorsal of Antedon rosacea ; while on the other hand, Hyponome, Loven, is the detached visceral mass of an Antedon common at Cape York. The stalked larva of Antedon was first described as a dwarf species of Pentacrinus, which name Fleming proposed to change into Hibernida, this genus being distinguished from Pentacrinus as then known by the presence of two openings to the digestive canal. De Blainville, on the other hand, noticed the differences between the characters 1 In his description of Antedon gorgonia de Fn'minville referred to the Encyclopt'die Mt'thodique, partie des Vera, pi. cxxiv., fig. 6. But Lamarck quoted this figure as representing his Comalula mediterranean s Op. cit., p. 128. (ZOOL. CHALL. EXP. — PART LX.- 1887.) OoO 12 90 THE VOYAGE OF H.M.S. CHALLENGER. of the larval stem and those of the West Indian Pentacrinus, and so proposed to call the European form Phytocrinus. This was rendered unnecessary, however, by J. V. Thompson's discovery that Pentacrinus europieus is the young stage of Antedon rosacea; and it is now clear that Kallispongia, Wright, is a real Comatulid larva, and not a mimetic Keratose sponge, as was at first supposed. An attempt has recently been made by Walther1 to re-establish Solanocrinus, Goldfuss, as a genus distinct from Antedon. I do not think, however, that there are any really good reasons for this change. The fossil species which Walther refers to Solano- crinus appear to him to present no syzygial unions in the arms, and this is the only character of any real generic value which he can bring forward as separating Solanocrinus from Antedon. I have explained elsewhere,2 however, that the absence of syzygies in the arms of Solanocrinus costatus, Solanocrinus imperialis, and Solanocrinus gracilis, is to my mind less certain than Walther believes ; while I strongly suspect from his figures and descriptions that in all these three types the two outer radials are united by syzygy, just as in Antedon Jluctuans and Antedon multiradiata (Pis. VIIL, IX.). I cannot therefore yet acquiesce in Walther's restoration of Goldfuss's genus, though it is quite possible that this course may become necessary at some future time. De Freminville did not give any etymology for his new generic name Antedon, and no clue as to its gender is to be obtained from the name of his single species Antedon gorgonia. But when the genus was re-established by Mr. Norman in 1865 he used Antedon as a masculine noun, and in this course he was followed by Sir Wyville Thomson, Dr. Carpenter, M. Sars, Liitken, Marion, von Marenzeller, Greeff, Ludwig, and others. In 1877, however, it was determined by the late Mr. Spedding3 that Antedon is really a feminine name, and should be more correctly spelt Anthedon. Since that date it has been used as a feminine noun by Pourtales, Ludwig, Duncan and Sladen, Bell, Verrill, J. V. Carus, Greeff, Dr. Carpenter and myself; though Schliiter, Rathbun, Marshall, Herdman, Dendy, Vogt and Yung, Walther, and, till lately, Perrier, have continued to use it in the masculine gender. In Perrier's latest publication,4 however, the following passage occurs about the name : — "Antedon rosaceus qui, selon la remarque de Victor Carus doit etre remplace par celui d' Antedon rosacea, Antedon etant une nymphe. Ce savant expose est suivi d'une etude des niceurs des Antedon qui contient plusieurs constatations interessantes." As I was unable to find the authority for Perrier's statement in any of the zoological works of Professor Carus, I wrote to him upon the subject, and he was good enough to inform me that the facts referred to by Perrier had been contained in a letter and not in any of his published works. He also kindly gave me a reference to the 1 Untersuchungen ttber den Bau der Crinoideen, Palseontographica, 1886, Bd. xxxii. p. 175. 2 The Generic Position of Solanocrinus, Ann. and Mag. Nat. Hist, 1887, ser. 5, vol. xix. pp. 81-88. 3 Nature, 1877, vol. xv. p. 366. 4 Memoire sur l'Organisation et le Developpement de la Comatule de la Mediterranee (Antedon rosacea, Linck) Nouv. Archiv. Mus. Hist. Nat, Paris, 1S86, t. ix. fasc. 1, p. 79. REPORT ON THE CRINOIDEA. 91 following passage in Pausanias where Anthedon occurs as the name of a nymph (ix. 22, 5):— " Trj? Se Boiwn'as r