I I p#%-*1 ,, J» (» I »***. o= 1 O m ' m ! d a r^ a m a a • ILLUSTRATED CATALOGUE OF THE MUSEUM OF COMPARATIYE ZOOLOGY, AT HARVARD COLLEGE. Published by order of the Legislature of Massachusetts. No. II. NORTH AMERICAN ACALEPH^l. BT ALEXANDER AGASSIZ. CAMBRIDGE: FOR SALE BY SEVER AND FRANCIS. 1865. ILLUSTRATED CATALOGUE OF THE MUSEUM OF COMPARATIVE ZOOLOGY, AT HARVARD COLLEGE. Published by order of the Legislature of Massachusetts. No. II. NORTH AMERICAN ACALEPH^l. BY ALEXANDER AGASSIZ. CAMBRIDGE: FOR SALE BY SEVER AND FRANCIS. 1865. UNIVERSITY PRESS : WELCH, BICELOW, & Co., CAMBRIDGE. THE publication of the Illustrated Catalogue of the Museum of Comparative Zoology has been undertaken with a threefold object. In the first place, like the catalogues of most institutions of a similar character, it is intended to make the contents of our Museum generally known, and to facilitate our exchanges. In the second place, to be the medium of publication of the novelties received at the Museum, which require to be described and illustrated by diagrams or wood-cuts, or more elaborate plates. Finally, it is hoped that it may be the basis of a systematic revision of such natural groups of the animal kingdom as are most fully represented in our collections, and that it may, as far as possible, present to the scientific world the results of the investigations carried on in the Museum with a view of ascertaining the natural limits of the Faunae at the present time and in past ages, and the genetic relations which may exist between the order of succession of organized beings upon the earth, their mode of growth, and their metamorphoses during their embry- onic life, and the plan and complication of their structure in their adult condition. The means for publishing this work have been most liberally granted by the Legislature, at a time when, in a less enlightened assembly, the material cares of the community would have engaged their exclusive attention. L. AGASSIZ. CAMBRIDGE, March 28, 1865. PREFACE. HHHE progress of our knowledge of the Class of Acalephs is at present so closely linked with every new observation which may be brought up in the history of the development of these animals, that it has been thought advisable to extend this Catalogue some- what, and not make it simply an enumeration of the Acalephs in the collection of the Museum of Comparative Zoology at Cambridge. It has, however, been limited to the North American species ; and even many of the Sertularians, Campanularians, and Tubularians in the col- lection are not described or mentioned here, because our information with regard to them is too scanty to be available. The mere enu- meration, with short descriptions, of Hydroids, the development of which has not been fully traced, would probably only add, in the course of a few years, synonymes to some of the Medusce, the adult stages of which may be well known, and would not advance in the least degree our acquaintance with the North American Acalephs. To make this Catalogue useful to American students, a few species described by other authors, of which there are no specimens in the Museum collection, are added, to facilitate further investigations. This is done with the less hesitation, as it is hoped that in a short time most of the species thus enumerated will have been figured in the diagrams of the Museum. In the descriptions of the species, constant reference has been made to the bearing of the facts discussed, on the classification of Acalephs, and consequently much has been introduced which would be out of place in a descriptive catalogue. The wood-cuts, with the exception of a few borrowed from the Contributions to the Natural History of the United States by Professor Agassiz, have all been drawn on wood from nature by myself, and, though not highly finished, will yet generally give a better idea of the Acalephs, in this simple outline, than could have been done by a more finished wood-cut. Such an elaborate catalogue of Acalephs may seem somewhat out of place vi PREFACE. here, but as special attention has been paid to them in the Museum at Cambridge, and as Professor Agassiz has introduced there a large number of diagrams, all copied from original drawings, to illustrate the structure and colors of animals which were too small or too perishable to be preserved in the ordinary way, these valuable mate- rials have been extensively used in the preparation of this Catalogue, as forming actually a part of the collections exhibited in the show- cases. The diagrams, as well as the authorities from which they are taken, are carefully enumerated below, after the specimens preserved in the collection. For the facilities I have enjoyed in collecting the materials for this Catalogue I am mainly indebted to Mr. and Mrs. J. M. Forbes, to Pro- fessor A. D. Bache, Superintendent of the Coast Survey, to Mr. T. G. Gary, and to Professor Agassiz. I have also to thank, for specimens and valuable information, Professor Joseph Leidy, Dr. Fritz Miiller of De- sterro, Dr. W. Stimpson, and Professor H. J. Clark, who had already arranged the greater part of the Hydroids before the collection of Aca- lephs was placed in my charge. The Museum is also indebted for specimens to many other persons, whose names will be referred to in connection with the different species. A. AGASSIZ. CAMBRIDGE, MASS., February, 1865. CONTENTS. PAGE LIST OF THE WOOD-CUTS ........... viii BIBLIOGRAPHY 3 CTENOPHOR^E 7 DISCOPHOR^E ............. 40 HYDROID^E .............. 64 GEOGRAPHICAL DISTRIBUTION. 221 SYSTEMATIC TABLE OF THE ORDERS AND FAMILIES 227 INDEX OF GENERA AND SPECIES «. . . 229 NO. II. LIST OF THE WOOD-CUTS. [NOTE. — Unless otherwise credited, the Figures are drawn from nature by Alex. Agassiz.] PAGE Fig. 1. Young BOLIXA ALATA, seen from the narrow side ... ... 15 " 2. BoEna in state of Fig. 1, seen from the broad side . . . . . . 16 " 3. Somewhat younger than Fig. 1, seen from the abactinal pole . . . . .16 " 4. Young Bolina, seen from the abactinal pole, older than previous figures . . 16 " 5. Formation of lateral tubes in young- Bolina 16 •/ O " 6. Bolina in which lobes begin to appear, seen from the narrow side, same state as Fig. 4 16 " 7. Somewhat more advanced than Fig. 6, seen from the actinal side . . . .16 " 8. The tentacular ambulacra have united, and the lobes project well beyond the open- ing of the mouth . ........... 1 7 " 9. About in the condition of Fig. 1, seen from the broad side . . . . . 17 " 10. Somewhat younger than Fig. 8, seen from the broad side . .... 17 " 11. Fig. 8, seen from the broad side .......... 17 " 12. Bolina showing first appearance of the auricles, seen from the broad side . . .17 " 1 3. Bolina in stage of Fig. 1 2, seen from the narrow side ...... 17 " 14. Fig. 13, seen from the actinal pole ..... .... 18 " 15. Adult Bolina, seen from the broad side. (L. Agassiz.) . . ... 18 " 16. Fig. 15, seen from the narrow side. (L. Agassiz.) ....... 18 " 17. Bolina, seen from the actinal pole. (L. Agassiz.) . 18 " 18. Bolina, seen from the abactinal pole. (L. Agassiz.) ... ... 18 " 19. BOLIXA VITREA, seen from the broad side. (L. Agassiz.) 19 " 20. MXEMIOPSIS GARDEN:, seen from the broad side. (L. Agassiz.) . . . .20 " 21. Fig. 20, seen from the actinal pole. (L. Agassiz.) 20 " 22. MXEMIOPSIS LEIDYI, seen from the broad side . .... 21 " 23. Same as Fig. 22, seen from the narrow side ........ 21 " 24. A part of the tentacular apparatus near the opening of the actinostome . . .22 " 25. LESUEURIA IIYBOPTERA, seen from the broad side . . . .24 " 26. Fig. 25, seen from the narrow side .......... 24 " 27. The same, seen from the abactinal pole ......... 25 " 28. Seen from the actinal pole 25 " 29. Adult MERTEXSIA OVUM, seen from the broad side . . ... 27 " 30. Young Mertensia, seen from the broad side . ...... 27 " 31. Fig. 30, seen from the abactinal pole ...... . 27 " 32. Somewhat more advanced Mertensia, seen from the narrow side . . .28 " 33. Same as Fig. 32, seen from the actinal pole . ... 28 " 34. Still more advanced Mertensia, seen from the narrow side ...... 28 " 35. Fig. 34, seen from the actinal pole .... .... 28 " 36. Still further advanced Mertensia, seen from the broad side ..... 29 " 37. Young Mertensia, about in the same condition as that of the preceding figure, seen from the narrow side ........... 29 " 38. Young PLEUROBRACHIA RHOPODACTYLA, seen from the broad side . 30 " 39. Same as Fig. 38, seen from the narrow side 30 " 40. Same as Fig. 38, seen from below ... 30 " 41. Somewhat more advanced, seen from the broad side .... . . 30 LIST OF THE WOOD-CUTS. ix Fig. 42. Fig. 43, seen from above ... 30 " 43. Fig. 42, seen from the broad side ..... . .30 " 44. Pleurobrachia, immediately before the escape from the egg . . 31 " 45. F!g. 44, somewhat less magnified, to show the relative size of the egg-case and the embryo ...... ..... 31 " 46. Fig. 44, seen from the actinal pole . . . ..... 32 •' 47. Pleurobrachia swimming freely about, seen from the broad side . 32 " 48. Somewhat less advanced than Fig. 47, showing the lateral tubes from the narrow side, as a prolongation of the ambulacra! cavity . . 33 " 49. Pleurobrachia about in state of Fig. 47, seen from the actinal pole . . . .33 " 50. Adult Pleurobrachia, natural size, from broad and narrow side . 33 " 51. Adult Pleurobrachia in a natural attitude, natural size . . 33 " 52. Young IDYIA ROSEOLA, seen from the narrow side . 36 " 53. Fig. 52, seen from the abactinal pole ......... 36 " 54. Young Idyia, with distinct ambulacral tubes, seen from the narrow side . 36 " 55. Fig. 54, seen from the abactinal pole . . . . . . . . .37 " 56. Somewhat more advanced than Fig. 54, seen from the broad side . 37 " 57. The long chymiferous tubes extend to the level of the actinostome . .37 " 58. The long chymiferous tubes have united with the lateral tubes ; first trace of the ramifications of the long tubes . . . . . . . . .37 " 59. The short ambulacra have nearly united with the circular tube . . . . 37 " 60. The circuit is now complete between the short and long ambulacra ; the spurs or ramifications of the chymiferous tubes are numerous, resembling somewhat those of the adult ....... . 37 " 61. Fig. 57, seen from the abactinal pole ... 38 " 62. Adult Idyia, reduced in size one half. (L. Agassiz.) ...... 38 " 63. IDYOPSIS CLARKII, seen from the broad side. (L. Agassiz.) ..... 39 " 64. Fig. 63, seen from the abactinal pole. (L. Agassiz.) 39 " 65. Profile view of AURELIA FLAVIDULA, much reduced. (L. Agassiz.) . . .42 " 66. Abactinal view of Aurelia navidula. (L. Agassiz.) ...... 42 " 67. CYAXEA ARCTIC A, very much reduced. (L. Agassiz.) . . 45 " 68. PELAGIA CYAXELLA. (L. Agassiz.) 47 " 69. DACTYLOMETRA QUIXQUECIRRA, reduced about one fourth ... .48 " 70. Profile view of CAMPAXELLA PACHYDERMA 53 " 71. Actinal view of Fig. 70 .53 " 72. A somewhat more magnified view of Fig. 71 ....... 53 " 73. View of part of the actinal surface .......... 53 " 74. Magnified profile view of portion of the base of a tentacle . . 53 " 75. View of basal portion of tentacle, seen from above .... .53 " 76. Profile view of TRACIIYXEMA CAMTSCHATICUM 56 " 77. One of the genital organs . ........... 56 " 78. Section of Trachynema ........... 56 " 79. Chymiferous cavity at the end of the gelatinous proboscis . . 56 " 80. View of Trachynema from above . ..... .56 " 81. Adult female TRACIIYXEMA DIGIT ALE, seen in profile . . . • • .57 " 82. Actinal view of the veil and circular tube of a very young Trachynema . . 57 " 83. Profile view of a part of the circular tube . . . . . . • .57 " 84. Profile view of a young Trachynema, about one eighth of an inch in height . 58 " 85. Somewhat more advanced than Fig. 84 .58 u 86. Young Trachynema, measuring over one third of an inch in height . 59 87. ? LIRIOPE SCUTIGERA. (L. Agassiz.) 60 88. HALICLYSTUS AURICULA, seen from the actinal pole .... 63 " 89. Different attitudes of Haliclystus auricula, attached to eel-grass . . 63 90. Young Haliclystus auricula, magnified ...... 63 91. TIAROPSIS DIADEMATA, natural size. (L. Agassiz.) ... .69 92. Young Tiaropsis, having twenty-four tentacles ... 69 93. Young Tiaropsis, having forty tentacles. (L. Agassiz.) .... .69 94. Two marginal tentacles of OCEAXIA LAXGUIDA, with a portion of the circular tube 70 95. Magnified view of the actinostome ..... .71 u it u u (1 x LIST OF THE WOOD-CUTS. Fig. 96. Young Medusa of OCEANIA LANGUIDA, immediately after escaping from the re- productive calycle . . . . . . . . . . .72 " 97. The same, seen from the actinal pole ......... 72 " 98. Somewhat more advanced Medusa 72 " 99. Quarter of the disk of a still more advanced Oceania ..... 72 " 100. Adult Oceania languida, natural size ......... 73 " 101. Magnified view of an ovary .......... 73 " 102. Peculiar attitude sometimes assumed by the Medusas ...... 73 " 103. One of the four lips of the actinostonie of OCEANIA GREG ARIA ... 74 " 104. EUCHEILOTA VENTRICULARIS 74 " 105. More magnified view of a quarter of the disk ...... 75 " 106. EUCHEILOTA DUODECIMALS 75 " 107. Junction of one of the chymiferous tubes with the circular tube ... 76 " 107". Female Medusa of Eucheilota duodecimalis . . . . . . . .76 " 108. CLYTIA BICOPHORA, immediately after its escape from the reproductive calycle 78 " 109. A somewhat older Medusa 78 " 110. An adult Medusa, measuring a quarter of an inch ...... 78 " 111. Sterile Hydra and reproductive calycle, seen from the broad side . ... 79 " 112. Reproductive calycle of PLATYPYXIS CYLINDRICA, seen from the broad side . 80 " 113. The same, seen from the narrow side ......... 80 " 114. Sterile Hydra of Platypyxis cylindrica. (L. Agassiz.) ..... 80 " 115. A EUCOPE DIAPHANA, seen in profile, just after its escape from the reproductive calycle 83 " 116. Quarter of the disk of the same, seen from above 83 " 117. A more advanced Eucope, with the second set of tentacles .... 83 " 118. An adult Eucope, seen in profile .......... 84 " 119. Quarter of Fig. 118, more magnified ......... 84 " 1 20. Magnified view of the circular tube of a young Eucope ...... 84 " 121. Spermaries of Eucope 84 " 122. Female genital organs ............ 84 " 123. Proboscis of an adult Medusa 85 " 124. Hydrarium of Eucope diaphana, natural size ........ 85 " 1 25. Magnified view of a sterile Hydra and reproductive calycle .... 85 " 126. Magnified view of part of main stem of EUCOPE POLYGENA 87 " 127. EUCOPE PYRIFORMIS, seen in profile 88 " 128. Quarter-disk of same Medusa 88 " 129. Portion of a Hydrarium of Fig. 127 88 " 130. Quarter-disk of EUCOPE ARTICULATA 89 " 131. Portion of a Hydrarium of Eucope articulata 89 " 132. Hydrarium of EUCOPE FUSIFORMIS 90 " 133. Quarter-disk of the Medusa of Fig. 132 90 134. Portion of stem of Hydrarium of OBELIA COMMISSURALIS 91 135. Quarter-disk of the Medusa of Fig. 134 92 136. Profile view, natural size, of RHEGMATODES TENUIS 95 " 137. Quarter-disk of Fig. 136, seen from the actinal side 96 " 1 38. Magnified portion of the circular canal ......... 96 " 139. RHEGMATODES FLORIDANUS, natural size. (L. Agassiz.) . . . . 97 " 140. Actinostonie of STOMOBRACHIUM TENTACULATUM, magnified .... 98 141. Stomobrachium tentaculatum, seen from the abactinal pole, natural size . 98 142. Same as Fig. 141. seen in profile 99 " 143. Portion of the disk of HALOPSIS OCELLATA, seen from the abactinal pole, some- what reduced 100 " 144. Cavity from which the chymiferous tubes radiate ... 100 " 145. Profile, natural size, of Halopsis ocellata ..... .100 " 146. Magnified part of circular tube ...... • 101 " 147. Magnified view of one of the eyes . ... .... 101 " 148. Young Halopsis ocellata, natural size .... • 101 " 149. Young Halopsis ocellata, one fifth of an inch in height . .101 " 150. Magnified portion of circular tube of Fig. 149 . . 101 u u tl it LIST OF THE WOOD-CUTS. xi 151. Profile view, somewhat magnified, of HALOPSIS CRUCIATA 102 " 152. Natural attitude of the same Medusa (Fig. 151) 102 "• 153. Abactinal view of ZYGODACTYLA GROEXLANDICA 104 '• 154. Profile view of Fig. 153, half natural size 104 " 155. Portion of the circular tube . . . . . . . . . . .104 " 156. Young Zygodactyla, greatly magnified ........ 105 " 157. Profile view of ZYGODACTYLA CRASSA, somewhat reduced in size . . .106 " 158. Quarter-disk of Zygodactyla crassa . . . . . . . . . 107 " 159. Portion of the disk of ZYGODACTYLA CYAXEA, from the abactinal pole. (L. Ag.) 107 " 159". CREMATOSTOMA FLAVA, in profile 109 " 160. Portion of the disk of ^EQUOREA ALBIDA, from the abactinal pole . . . 110 " 161. A natural attitude of zEquorea albida 110 " 162. Magnified view of the marginal tube ........ Ill " 163. EIRENE CCERULEA. (L. Agassiz.) 112 " 164. TIMA FORMOSA, half natural size 113 " 165. Quarter of the disk, from the abactinal pole, natural size . . . . .113 " 166. Digestive cavity and actinostome ......... 113 " 167. Portion of the ovary . . . . . . . . . . . .114 " 168. Magnified portion of the circular tube ........ 114 " 169. Young Tima formosa, natural size . . . . . . . . . .114 " 170. Digestive cavity of Fig. 169 114 " 171. Young Planula; of Tima ........... 115 " 172. Single Hydra of the tuft of a Tima Hydrarium, greatly magnified . . . 115 " 173. Profile of EUTIMA LIMPIDA, reduced in size 116 " 174. Quarter-disk of Fig. 1 73 . 116 " 175. Magnified view of proboscis and genital organs . . . . . . .117 " 176. Magnified portion of a part of the circular canal . . . . . . 117 " 177. Magnified marginal capsule . . . . . . . . . . .117 " 178. Magnified view of the rudimentary tentacles 117 " 179. Profile view, somewhat magnified, of POLYORCHIS PENICILLATA . . .119 " 180. Ovaries of one of the chymiferous tubes 119 " 181. Section of bell ............. 120 " 182. Part of disk of Fig. 1 79, seen from the abactinal pole • . . . . 120 " 183. Two of the marginal tentacles in a contracted state 120 " 184. Adult Medusa of LAFCEA CALCARATA 122 " 185. One of the ovaries and the actinostome . . . . . . . .123 " 186. Actinostome, actinal view .......... 123 187. Magnified view of a portion of the circular tube ... ... 123 " 188. Actinostome and rudimentary ovaries, seen in profile . . . . . 123 " 189. Different attitude of Medusa of Fig. 184 124 " 1 90. Hydrarium of Lafoea calcarata .......... 1 24 " 191. Reproductive calvcle . . . . . . . . . . . .125 " 192. Medusa immediately after its escape from the reproductive calycle . . . 125 " 193. Medusa somewhat more advanced, from the abactinal pole . . . . .125 '• 194. Young Medusa still further advanced than Fig. 193 126 " 195. LAODICEA CELLULARIA 127 " 196. One of the lips of the actinostome ......... 127 " 197. GOXIONEMUS VERTENS, attached by its tentacles 129 " 198. The same in motion, natural size 129 " 199. Base of a contracted tentacle . 130 " 200. A portion of the genital organs ......... 130 " 201. One of the chymiferous tubes and half the digestive cavity . . . 130 " 202. Profile of MELICERTUM CAMPANULA, natural size .... 131 " 203. Profile view of a very young Melicertum campanula ...... 132 " 204. Half the disk of the same, seen from the actinal pole ... 132 " 205. Young Melicertum, having only four completely formed chymiferous tubes . .132 " 20fi. Same, seen from the abactinal pole .133 " 207. Magnified view of the two chymiferous tubes and genital glands . . . .133 " 208. Mode of carrying the lips of actinostome ..... . 133 u u U xii LIST OF THE WOOD-CUTS. Fig. 209. Magnified view of marginal tentacles 133 " 210. Spherical embryo . 134 " 211. The same, somewhat more advanced ......... 134 " 212. The same before it becomes attached ........ 134 " 213. Group of embryos attached, in different stages of development . . . .134 " 214. Different stages of growth beyond those of Fig. 213 134 " 215. Profile of MKLICERTUM GEORGICUM, natural size 135 " 21(5. Digestive cavity and point of junction of the chymiferous tubes . . . 135 " 215a. STAUROPHORA LACLNIATA, having eight tentacles 136 " 216*. Quarter of the disk of a young Staurophora, with sixteen large tentacles . 136 " 217. Young Medusa somewhat more advanced than Fig. 21 6a ..... 136 218. Different stages of actinostome intermediate between that of Figs. 215* and 219 136 219. Young Staurophora, having the aspect of the adult 137 220. Profile view of PTYCHOGENA LACTEA, somewhat reduced .... 138 " 221. Magnified view of the genital organs, seen from the abactinal pole . . .138 " 222. Same as Fig. 221, seen in profile 138 " 223. Actinostome 138 " 224. Magnified base of tentacles and club-shaped appendages 138 " 225. Cluster of DYXAMEXA PUMILA. (L. Agassiz.) 141 " 226. Magnified portion of stem of Fig. 225. (L. Agassiz.) 141 " 227. Young NEMOPSIS BACIIEI, with four tentacles 149 " 228. Somewhat more advanced Nemopsis . ........ 150 " 229. Magnified view of the sensitive bulb 150 " 230. Nemopsis in which the genital organs extend a considerable distance along the chymiferous tubes 150 " 231. Magnified view of the genital organs, the actinostome, and the oral tentacles . 151 " 232. Magnified profile view of adult BOUGAIXVILLIA SUPERCILIARIS . . . .153 " 233. Hydromedusarium of Bougainvillia ......... 154 " 234. Young elongated Medusa 154 " 235. Somewhat more advanced than Fig. 234 154 " 236. Appearance a short time before separating from the stem . . . . .154 " 237. Same as Fig. 236, expanded 154 " 238. Young Bougainvillia, immediately after its liberation from the Hydromedusarium 154 " 239. Magnified view of sensitive bulb 155 " 240. Tentacular bulb, with young tentacles . . . . . . . . .155 " 241. Adult MARGELIS CAROLINENSIS, seen in profile, magnified .... 156 " 242. Digestive cavity, genital pouches, oral tentacles, and actinostome . . . .156 " 243. Sensitive bull) at base of one of the chymiferous tubes 156 " 244. Young Margelis, having only two marginal tentacles at the base of each chymif- erous tube . . . . . . . . . . . . 157 " 245. Young Margelis, seen from the abactinal pole, in condition of Fig. 244 . . . 157 " 246. Proboscis of a Margelis, having already six tentacles at each sensitive bulb . 158 " 247. Hydrarium, greatly reduced in size . . . . . . . . .158 " 248. Magnified heads and Medusae buds of Margelis cai'olinensis . . . . 158 " 249. Female MedusEe buds of EUDEXDRIUM DISPAR, in different stages of development 159 " 250. Part of a male colony of EUDENDRIUM TENUE, magnified .... ICO " 251. Adult male of LIZZIA GRATA, seen in profile, magnified 161 " 252. Quarter-disk of a young Lizzia ...... 161 " 253. Magnified view of sensitive bulb . . . . . . . • • .161 " 254. Proboscis of male Lizzia, magnified ......... 162 " 255. One of the four lobes of the actinostome, seen from above . . . • .162 " 256. Actinal view of proboscis of young Lizzia ....... 162 " 257. Actinal view of proboscis of an older specimen . . . • . . .162 " 258. Abactinal view of Fig. 257, somewhat less magnified ..... 162 " 259. Adult DYSMORPHOSA FULGURANS, magnified . . . . • • .163 " 260. Magnified proboscis, showing young Medusa? of the second and third generations 163 " 261. TURRIS VESICARIA, natural size, seen in profile .... . 165 " 2G2. The same, with the bell contracted I65 " 263. A portion of the disk, seen from the abactinal pole ... . . 165 LIST OF THE WOOD-CUTS. xiii Fig. 264. Magnified profile view of genital organs and actinostome 165 " 265. Magnified view of a part of a chymiferous tube . . . ." . 166 " 266. Base of one of the chymiferous tubes, and part of the circular tube . . .166 " 267. One of the tentacles, in a profile view 166 " 268. One of the tentacles, seen from the abactinal pole . . . . . .166 " 269. Young TURRITOPSIS NUTRICULA, with four marginal tentacles . . . 167 " 270. Somewhat more advanced, having sixteen tentacles ....*.. 167 " 271. STOMOTOCA ATRA, somewhat magnified, seen in profile ..... 169 " 272. Magnified view of genital organs . . . . . . . . . .169 " 273. Stomotoca atra . ............ 169 " 274. CLAVA LEPTOSTYLA. (L. Agassiz.) 170 " 274a. Young WILLIA ORNATA, having only the second set of tentacles developed . 171 " 275. Young Willia, nearly in the stage of Fig. 276, seen from the abactinal pole . .171 " 276. Profile view of a young Willia . ......... 172 " 277. Part of the circular tube . . . . . . . . . . .172 " 278. View of ovary of Fig. 276 172 " 279. Same as Fig. 278, seen from the abactinal pole . . . . . . .172 " 280. PROBOSCIDACTYLA FLAVICIRRATA 173 " 281. Actinostome and digestive cavity . . . . . . . . . .173 " 282. Portion of disk to show mode of branching of chymiferous tubes, and tubes con- taining lasso-cells, as in Willia . . . . . . . . 1 74 " 283. Adult CORYNE MIRABILIS, seen in profile. (L. Agassiz.) . . . . 175 " 284. Coiyne, with proboscis contracted. (L. Agassiz.) . . . . . .175 " 285. Coryne, with expanded proboscis. (L. Agassiz.) . . . . . . 175 " 286. Cluster of Hydraria of Coryne mirabilis. (L. Agassiz.) 176 " 287. Young Hydrarium of Coryne. (L. Agassiz.) ....... 176 " 288. Magnified view of head, with Meduste buds attached. (L. Agassiz.) . . .176 " 289. CORYNE ROSARIA, natural size 177 " 290. Hydromedusarium of SYXDICTYON RETICULATUM, greatly magnified . . .178 " 291. Syndictyon reticulatum, immediately after it has become freed from the Hydro- medusarium, in profile . . . . . . . . . .178 " 292. One of the tentacles of Fig. 291, magnified 178 " 293. Sensitive bulb of Fig. 291 178 " 294. Digestive cavity of Fig. 291 .178 " 295. Fig. 291, from actinal pole 178 " 296. Fig. 291, from abactinal pole . 179 " 297. Part of net-work of lasso-cells of surface of spherosome . . . . .179 " 298. Adult Medusa in a natural attitude 180 " 299. Same Medusa (Fig. 298) with the tentacles contracted 180 " 300. Actinostome of adult Medusa 180 " 301. Young DIPURENA CONICA . . . . . . . . . . .181 " 302. Digestive cavity of a young Dipurena conica . . . . . . . 181 " 303. Tentacle of Dipurena conica .......... 182 " 304. Digestive cavity of a Medusa in which the constriction has already separated the upper and lower halves . . . . . . . . . .182 " 305. Adult Dipurena conica, in which the two digestive cavities are widely separated 182 " 306. Profile view of half a young GEMMARIA GEMMOSA 184 " 307. Profile view of GEMMARIA CLADOPHORA, magnified 184 " 308. Quarter-disk of same, seen from the abactinal pole . . . . . .185 " 309. Actinostome of Gemmaria, enlarged ........ 185 " 310. Cluster of lasso-cells of the marginal tentacles . . . . . . .185 " 311, Fertile Hydra of PENNARIA TIARELLA 187 " 312. Medusa distended by eggs 187 " 313. Profile view of Medusa of Pennaria tiarella . . . . . . . 187 " 314. Different attitude of the Medusa, seen from the actinal pole 188 " 315. Fig. 313, seen from the abactinal pole 188 " 316. EUPHYSA VIRGULATA, seen in profile 190 " 317. Magnified proboscis of Fig. 316 190 " 318. Actinal view of Euphysa virgulata ......... 190 u II II t( II xiv LIST OF THE WOOD-CUTS. Fig. 319. One of the tentacles, seen in profile 190 " 320. Profile of ECTOPLEURA OCHRACEA, magnified 191 " 321. The same, seen from the abactinal pole . . . . . . .192 " 322. The same, seen from the actinal pole . . . . . . . . 192 " 323. The base of one of the tentacles, magnified . . . . . . . .192 " 324. Medusa of CORYMORPHA PENDULA, seen in profile. (H.J.Clark.) . . 193 " 325. Single Hydra of HYBOCODON PROLIFER. (L. Agassiz.) 193 326. Ilybocodon prolifer, seen from the broad side. (L. Agassiz.) . . . . 194 327. Hybocodon prolifer, seen facing the long tentacle. (L. Agassiz.) . . .194 328. Medusa bud of Ilybocodon prolifer. (L. Agassiz.) 194. " 329. Part of male community of HYDRACTINIA POLYCLINA. (L. Agassiz.) . . 198 " 330. Part of female community. (L. Agassiz.) ....... 198 " 331. Oil-float of NANOMIA CARA, magnified 200 " 332. Nanomia cara, natural size 201 " 333. Swimming-bell of Nanomia cara, seen facing the side of the straight chymiferous tubps 202 " 334. The same bell, from the actinal pole 202 335. Portion of the same bell, seen from the abactinal pole 202 336. Same bell as Fig. 333, seen from the other side 203 337. Group of swimming-bells in different stages of development . . ... 203 338. Cluster of Medusas (Polyps) of first kind formed, with knob-shaped tentacles . 204 " 339. Enlarged view of the knob of a tentacle of the first kind of Medusas . . 205 " 340. Second kind of Medusas, with cork-shaped tentacles ...... 205 " 341. Third kind of Medusa, having a single thread-like tentacle .... 205 " 342. Cluster of Medusas (Polyps), in different stages of development, before the ap- pearance of the scale and of the tentacles ....... 206 " 343. Knobs like those of Fig. 339, in different stages of development . . . 207 " 344. Same kind of knob, still further developed . . . . . . . .207 " 345. Young scale, seen from different sides ........ 207 " 346. Youngest Nanomia found swimming on surface ....... 208 " 347. Somewhat more advanced .......... 208 " 348. The terminal Hydra is open, tentacles are developed as well as clusters of small swimming-bells ........... 209 " 349. Still more advanced Nanomia 209 " 350. Young Nanomia, where we find several Medusas of the first kind . . . 209 " 351. PHYSALIA ARETHUSA Til. (L. Agassiz.) 214 352. Bunch of single Hydras and clusters of Medusas of Physalia. (L. Agassiz.) . 215 353. Bunch of Hydras. (L. Agassiz.) 215 " 354. Bunch of Medusas in various stages of development. (L. Agassiz.) . . 215 " 355. Enlarged view of one of the fertile Hydras of VELELLA MUTICA. (L. Agassiz.) 216 " 356. Velella, seen from below, to show the Hydras. (L. Agassiz.) . . . . 216 " 357. Magnified view of a free Medusa of Velella mutica. (L. Agassiz.) . . . 216 " 358. Magnified view of extended Hydroids of MILLEPORA ALCICORNIS. (L. Agassiz.) 219 " 359. Branch of Millepora alcicornis, natural size. (L. Agassiz.) . . . . .219 360. Transverse section of a branch. (L. Agassiz.) 219 it it u NORTH AMERICAN ACALEPH.E. IBLIOGRAPHY. AGASSIZ, L. ALDER, J. ALLMAX, J. G. No memoirs published previous to 1800 have been included in this list, as they can be found in AGASSIZ'S Bibliographia Zoologice et Geologice, and in CARUS and ENGEL- MANX'S Bibliotheca Zoologica. AGASSIZ, A. The Acalephian Fauna of the Southern Coast of Massachusetts, Buzzard's Bay ; in Proc. Bost. Soc. Nat. Hist., VIII. p. 224. 1861. " " Mode of Development of the Marginal Tentacles of the Free Medusse of some Hy- droids ; in Proc. Bost. Soc. Nat. Hist., IX. p. 81. 1862. " " Nanomia cara ; in Proc. Bost, Soc. Nat. Hist,, IX. p. 181. 1863. Halopsis ocellata ; in Proc. Bost. Soc. Nat. Hist., IX. p. 219. 1863. Contributions to the Natural History of the United States (Acalephae). Yols. HI. and IV. Boston. 1860-1862. Methods of Study in Natural History. Boston. 1863. Supplement to a Catalogue of Zoophytes of Northumberland and Durham ; in Trans. Tyneside Nat. Club, V. p. 225. Description of some New and Rare Zoophytes found on the Coast of Northumberland ; in Ann. & Mag. N. II., IX. p. 311. 1862. Observations on British Zoophytes ; in Edinb. New Phil. Journ., p. 144. 1862. Descriptions of a Zoophyte and two Species of Echinodermata new to Britain ; in Ann. & Mag. N. H., V. p. 73. 1860. On Laomedea tennis ; in Rep. Br. Ass. Adv. Sc. for 1859, p. 143. Trans. Sec. On the Generative Zooid of Clavatella ; in Br. Ass. Adv. Sc. for 1862, p. 100. Note on the Structure and Terminology of the Reproductive System in the Corynidae and Sertularidae ; in Ann. & Mag. N. H., VI. p. 1. 1860. On the Reproductive System in the Hydroidea ; in Rep. Br. Ass. Adv. Sc. 1863. London. 1864. p. 351. Note on Carduella cyathiformis ; in Ann. & Mag. N. H., VI. p. 40. 1860. On the Structure of Carduella cyathiformis, a Contribution to our Knowledge of the Lucernariadaj ; in Trans. Mic. Soc., p. 125. London. 1860. Notes on the Hydroid Zoophytes ; in Ann. & Mag. N. II., VIII. p. 168. 1861. Notes on the Phosphorescenee of Beroe ; in Proc. Roy. Soc. Edinb., IV. p. 528, Jan. 1862. Same in Edinb. New Phil. Journ., 1862, XV. p. 284. Contributions to our Knowledge of the Structure and Development of the Bero- ida; ; in Proc. Roy. Soc. Edinb., IV. p. 519, Jan. 1862. Same in Edinb. New Phil. Journ., 1862, XV. p. 287. On the Structure of Lucernariada; ; in Rep. Brit. Ass. Adv. Sc. for 1859, p. 143. London. 1860. Trans. Sec. On Dicoryne stricta, a new Genus and Species of the Tubularida? ; in Rep. Br. Ass. Adv. Sc. for 1859, p. 142. London. 1860. Notes on the Hydroidea. I. On the Structure of Corymorpha nutans. II. Diag- nosis of new Species of Tubularidaj obtained, during the Autumn of 1862, on the Coasts of Shetland and Devonshire ; in Ann. & Mag. N. II., Jan. 1863, XI. p. 1. Notes on the Hydroidea ; in Ann. & Mag. N. II.. July, 1864. On the Structure of Corymorpha nutans ; in Rep. Br. Ass. Adv. Sc. for 1862, p. 101. Trans. Sec. " "