HARVARD UNIVERSITY LIBRARY OF THE Museum of Comparative Zoology OCT 13 1927 nDemotrs of tbe nsuseum of Comparative Zoolofls AT HARVARD COLLEGE. Vol. XXXVIII. No. 2. REPORTS ON THE SCIENTIFIC RESULTS OF THE EXPEDITION TO THE EASTERN TROPICAL PACIFIC, IN CHARGE OF ALEXANDER A3A!iSi.Z, BY THE U. S. FISH COMMISSION STEAMER " ALBATEaSS."MrjH.OiM OCTOBER, 1904, to MARCH, 1905, LIEUT. COMMANDER L. :,I. G \RRETT, U. S. N., COMMANDING. XXIII. THE SIPHONOPHORAE. By henry B. BIGELOW. WITH THIRTY-TWO PLATES. (Published by permlssioa of Geobqs M. Bowbbs, U. S. Oomtnissioaer of Fish and Fisheries. 1 CAMBRIDGE, U. S. A.: lPrinte5 for tbe /Duseum. December, 1911. EASTERN TROPICAL PACIFIC. The following puhlkations of the Museum eoniain Reports on the Dredging operations, in charge of Alexander Agassiz, of the U. S. Fish Commission Steamer "Albatross," during 1904 and 1905, Lieut. Commander L. M. Garrett, U. S. N., Commanding. I. A. Agassiz. Three letters to the Hon. G. M. Bowers on the Cruise in the Eastern Tropical Pacific. Bull. M. ('. Z., April, 1905. Vol. 46, no. 4. 22 pp. II. H. Richardson. Description of a new genus of isopods, typical of a peculiar family. Bull. M. C. Z., July, 1005. Vol. 46, no. 6. 4 pp. 1 plate. in. C. A. KoFoiD. Craspedotella, a new genus of the Cystoflagellata, an example of cbrivergence. Bull. M. C. Z., September, 1905. Vol. 46, no. 9. 5 pp. 1 plate. IV. W. E. RiTTER. Octacnemus. Bull. M. C. Z., January, 1906. Vol. 46, no. 13. 22 pp. 3 plates. V. A. Agassiz. General report of the Expedition. Mem. M. C. Z., January, 1906. Vol. 33. 90 pp. 96 plates. VI. T. W. Vaughax. Madreporaria. Bull. M. C. Z., August, 1906. ^'ol. 50, no. 3. 14 pp. 10 plates. VII. C. R. Eastman. Sharks' teeth and cetacean bones. Bull. M. C. Z., November, 1906. Vol. 50, no. 4. 26 pp. 4 plates. VIII. S. F. Clarke. The hydroids. Mem. M. C. Z., February, 1907. Vol. 35, no. 1. 20 pp. 15 plates. IX. C. A. KoFoiD. New species of Dinoflagellates. Bull. M. C. Z., February, 1907. Vol. 50, no. 6. 48 pp. 18 plates. X. M. J. R.\THBUN. The Brachyura. Mem. M. C. Z., August, 1907. Vol. 35, no. 2. 54 pp. 9 plates. XI. F. E. ScHULZE. Die Xenophyophoren. Bull. M. C. Z., November, 1907. Vol. 51, no. 6. 22 pp. 1 plate. XII. S. Garman. The reptiles of Easter Island. Bull. M. C. Z., June, 1908. Vol. 52, no. 1. 14 pp. 1 plate. XIII. E. C. Starks. Atela.xia. Bull. M. C. Z., July, 1908. Vol. 52, no. 2. 8 pp. 5 plates. XIV. W. H. Dall. The MoUusca and Brachiopoda. Bull. M. C. Z., October, 1908. Vol. 43, no. 6. 285 pp. 22 plates. XV. J. Thiele. Bathysciadium, Lepetella, und Addisonia, Bull. M. C. Z., October, 1908. Vol. 52, no. 5. 11pp. 2 plates. XVI. H. B. BiGELOw. The Medusae. Mem. M. C. Z., February, 1909. Vol. 37. 243 pp. 48 plates. XVII. J. Murray and G. V. Lee. The depth and marine deposits of the Pacific. Mem. M. C. Z., June, 1909, Vol. 38, no. 1. 170 pp. 5 plates, 3 maps. XVIII. R. WoLTERECK. Ampliipoda. Bull. M. C. Z., June, 1909. Vol. 52, no. 9. 26 pp. 8 plates. XIX. L.J.Cole. Pycnogonidu. Bull. M. C. Z., August, 1909. Vol. 52, no. 11. 10 pp. 3 plates. XX. C. A. KoFOlD. Mutations in CeratiunL Bull. M. C. Z., September, 1909. Vol. 52, no. 13. 48 pp. 4 plates. XXI. R. VON Ledenfeld. The siliceous sponges. Mem. M. C. Z., August, September, 1910. Vol. 41. 323 pp. 56 plates. XXII. C. A. KoFoiD and J..R. Michener. New genera and species of Dinoflagellates. Bull. M. C. Z., August, 1911. Vol. 54, no. 7. pp. XXIII. H. B. BiGELow. The Siphonophores. Mem. M. C. Z., December, 1911. Vol. 38, no. 2. 231 pp. 32 plates. Memoirs of tbe riDuseum ot Comparative Zoology? AT HARVARD COLLEGE. Vol. XXXVIII. No. 2. REPORTS ON THE SCIENTIFIC RESULTS OF THE EXPEDITION TO THE E.\STERN TROPICAL PACIFIC, IN CHARGE OF ALEXANDER AGASSIZ, BY THE U. S. FISH COMMISSION STEAMER "ALBATROSS," FROM OCTOBER, 1904, to MARCH, 1905, LIEUT. COMMANDER L. M. GARRETT, U. S. N., COMMANDING. XXIII. THE SIPHONOPHOEAE. By henry B. BIGELOW. WITH THIRTY-TWO PLATES. [Published by permlssioQ of George M. Bowers, U. S. Coramissioaer of Fish aad Fisharies. 1 CAMBRIDGE, U. S. A.: prtnte& for tbe /Biuseum. December, 1911. CONTENTS. Page INTRODUCTION 175 Calycophorae 178 Sphaeronectidae 182 Sphaeronectinae 182 .Sphaeronectes Huxley 182 truncata (Will) . . .184 Muggiinae 185 Muggiaea Busch 185 atlantica Cunningham . . 187 kochii (Will) 188 Cuboides Quoy and Gaimard . . . 189 vitreus Quoy and Gaimard . 190 Nectopyramidinae 191 Neetopyramis Bigelow 191 diomt'deae sp. nov. . . 191 Prayidae 194 Amphicaryoninae 194 Araphicaryon Chun 195 acaule Chun .... 195 Prayi.nae 197 Praya BlainviUe 200 cymbiformi.s (Delle Chiajp) . . 200 Rosacea Quoy and Gaimard . . . .201 ?plicata Quoy and Gaimard . 201 medusa (Metschnikoff) . . 203 Nectodroma, gen. nov. 204 dubi a (Quoy and Gai mard ) 204 reticulata, sp. nov. . . 20(5 IIippopodiidae 207 Hippopodius Quoy and Gaimard . . 207 hippopu.s (Forskai) . . 208 Vogtia Kolliker 210 spinosa Keferstein and Ehlers . 210 DiPHYID.iE 213 Abylinae 213 Key to the polygastiic stale. 215 Abyla Quoy and Gaimard 21f) leuckartii Huxley 210 trigona Quoy and Gaimard . . 221 haeckeli Lens and Van Hiem.sdijk 222 Abylopsis Chun 224 tetragona (Otto) .... 224 eschscholtzii (Huxley) . . . 226 Bassia L. Agassiz 229 bassensis (Quoy and Gaimard) . 229 Page Diphyabyla Lens and Van Uiem.sdijk . 231 hubrechti Lens and \im Riera.sdijk 231 Galeolariin.ae 233 Galeolaria BlainviUe 233 Key to the species 236 Galeolaria quadrivalvis (BlainviUe) . 237 australis Quoj' and Gaimard 238 monoica Chun 239 DiPHYOPSIINAE 240 Key to the species 246 Diphyes Cuvier 248 appendiculata Esehsfholtz . . 248 spiralis, sp. nov 249 bojani (Chun) 251 contorta Lens and ^"an Riems- dijk 254 fowleri Bigelow 255 Diphyopsis Haeckel 257 dispar (Chamisso and Eysen- hardt) 257 mitra (Huxley) .... 258 Chuniphj-es Lens and Van Riemsdijk . 261 multidentata Lens and ^'an Riemsdijk 262 Ersaea bojani (Eschseholtz) .... 264 Archisoma, gen. nov 266 natans, sp. nov 266 Physophorae 267 forskaliidae 269 Forskalia Kolliker 270 sp 271 Erenna Bedot 271 richardi Bedot 271 Agalmidae 272 Agalma Eschscholtz 274 haeckeli, nom. nov 277 okeni Eschscholtz 277 elegans (Sars) 2S1 Stoph.anomia Peron and I.esueur . . 283 bijuga (Delle Chiaje) . . 284 amphitridis Peron and Le.sue\u- 2,s7 Nectaliinae 2S9 Nect alia Haeokcl 290 174 CONTENTS. Page Neotalia loligo Hapckcl 290 PHYSOPHOniDAB 291 Physophora Forskai 292 hydrostatica Forsk&l . . 293 Anthophysidae 294 Anthophysa Brandt 295 rosea Brandt 296 Rhodaliidae 300 Uromalia, gen. nov. 303 alexandri, sp. nov. . . . 303 Angelopsis Fewkes 309 dilata, s]). nov 310 .•VUROPHORE AND ZONE OK PROLIFERATION IN THE Rhodaliidae 313 Distribution of the Rhodaliidae . . . 316 Rhizophysall^e 317 Rhizophysidae 317 Rhizophysinae 317 Rhizophysa Poron and Losucur . . . 318 filiformis (For.skai) . . .319 eysenhardtii Gegenbaur . 320 Epibulinae 320 Bathyphysinae 320 Bathyphysa sp.? 321 Physaliidae 321 Physalia Lamarck 322 utrioulus (La Martiniere) . . 323 Chondrophorae 323 Porpitidae 323 Porpema Haeckel 324 prunella (Haeckel) .... 325 Page Porpita Lamarck 329 pacifica Lesson 33:{ Velellidae 341 Velella Lamarck 341 lata Chamisso and Eysenhardt . 343 SYNOMYMICAL LLST OF SPECIES NOT COLLECTED BY THE "ALBA- TROSS " 346 DOUBTFUL SPECIES 354 EUDOXIDS NOT CONNECTED WITH A PARENT SPECIES 356 GEOGRAPHICAL DISTRIBUTION . . 357 The tropical Pacific 357 Comparison between Pacific, Malaysian, and Indian species 362 Comparison between the species of the Indo-Pacific and Atlantic regions . 364 Oceanic temperatures and their rela- tion to distribution 309 The eastern and western sides of the tropical and subtropical Atlantic . .371 Seasonal fluctuations in horizontal dis- tribution . . . 376 Bathymetric range 376 Seasonal fluctuations in vertical distri- bution 3S0 Sahnity in its relation to distribution . 380 TABLE OF DISTRIBUTION .... 381 GENERAL CONSIDERATIONS . . . 380 BIBLIOGRAPHY 390 EXPLANATION OF PLATES THE SIPHON OPHOliAE. INTRODUCTION. The collection of Siphonophores obtained by the "Albatross" in the Eastern Tropical Pacific in 1904-1905, together with the few specimens pre- viously collected by her in other parts of the Pacific, is one of the most exten- sive series which has been made. Out of a total of forty-six genera and about ninetj^ species which deserve recognition, it contains no less than thirty-five genera and fifty-two species. Since formalin has come into use, the preservation of the Siphonophores is no longer attended with any great difficulty, and the collection, as a whole, is in excellent condition. I have already (:09a, p. 11) called attention to the value of chloretone as a stupefying reagent and given short directions for using it. Throughout the Cruise I had the opportunity of studying the Siphonophores in life; and of making numerous drawings and these have been of great assistance. Two new genera and six new species are described. That no more no\-cl- ties were obtained is, of course, a corollary of the holoplanktonic habit of the group. Especially noteworthy, from the standpoint of morphologj' and classi- fication are: — the discovery of a new Nectopyramis with its Eudoxid, a genus previously known from one specimen; the capture of a large series of Amphi- caryon, previously unfigured and known from one record only; the rediscovery of the Diphyes dubia of Quoy and Gaimard, known only from the original record, and for which a new genus is required, and the discovery of a new species of the same genus; the discovery of a new Rhodalid, represented by a large and excellently preserved series allowing anatomic study; the capture of a large series of the little-known genus Porpema, and of Porpita pacifica. On these two I was able to make a study of the "central organ," as well as of the anatomy in general. 176 INTRODUCTION. I have studied the extensive collection in the Museum of Comparative Zoology, rich in West Indian material, and also the collections of the U. S. National Museum, including a valuable series of Velella and Physalia from the Pacific. With such a wealth of material the time seemed ripe for a more adequate presentation of oui- knowledge of the group than would be associated with the mere description of the "Albatross" specimens. Haeckel's monograph, loaded down as it is with no less than twenty-three nomena nuda of his own making, and with many new species, beautifull.y figured, but none of them critically studied from the systematic standpoint, can not be used as a manual of the group. The list of Atlantic species given by Chun in his report of the col- lections made by the "Plankton" Expedition, is a great advance; but this takes no account of the Indo-Pacific species, and, besides, during the last twelve years our knowledge of the group has grown along many lines. A revision has been attempted by Schneider; but the reductions which he proposed are so sweeping and in many cases so unnatural, that they have not been generally adopted. I have sought less for a well-balanced scheme of classification, than to present the actual state of our knowledge. The lacunae are still far too great to allow a systematic revision of the group in the sense in which such is possible for birds, or for mammals. By emphasizing these gaps, other researches may be stimulated, and thus the desirable end be obtained. Among Siphonophores we constantly encounter doubtful species, which inay or may not be distinct from their nearest allies. To justifj' their union with other forms we must have something more than a fair probability. Other- wise we are likeh^ to mask existing and important differences. In several such cases I have been able to base vuiions on the actual comparison of speci- mens of the forms concerned, and whenever unable to do this, it is so noted. In cases where direct comparisons have not been made, and where the published descriptions are not conclusive, it is better to allow both species to stand. The nomenclature of the Siphonophores has long been a bete noire. The labors of Bedot and of Chun, have brought some improvement, but there is still much confusion. In such a group as the present, uniformity can only be hoped for through a strict application of the law of priority; and especially must we follow the rule of applying to a species as a whole the name first applied to any part of it or its larva. ' But what should be done with the older names INTRODUCTION. 177 applied by some modern authors to one species, by others to another, especially when, as is often the case, the original figures do not agree very well with any actual form? If we abandon them altogether, they remain as constant sources of confusion, for they cannot be considered nomena nuda. If used there is the danger of applying them to wrong species, their true identity being discovered later. More than one such case has occurred. In the present Memoir I have used an old name whenever the figures allow. Otherwise they are given in the doubtful list (p. 354-357). Many nomena nuda have been used, espe- cially by the older writers; these are omitted. The classification employed is based on that outlined by Chun ('97b), because of the various schemes which have been proposed, this most nearly represents the natural relationships of the several groups. But I have not hesitated to make various changes which more recent studies have shown to be necessary. The family relationships of the Calycophorae form such a case, to which attention is called. It is a pleasure to acknowledge my indebtedness to Alexander Agassiz, the lamented leader of the Expedition, not only for the opportunity to accompany him on the Cruise, but for encouragement without which the present Memoir could never have been prepared. CALYCOPHORAE Leuckart, 1854. The classifications proposed by the two authors who have most recently attempted the revision of the Calycophorae are essentially different both in premise and in conclusion. Chun ('97b) has adopted the number of nectophores as the most important character, and as a result, divides the order into three families, Monophyidae with one, Diphyidae with two (rarely more), and Poly- phyidae with several nectophores. This is essentially the system used by Haeckel in his "Challenger" report. Schneider ('96, '98) on the other hand, has maintained that the number of the nectophores is not an important systema- tic character, but that the Calycophorae are divisible into two families, Prayi- dae and Diphyidae, according as the older and the younger definitive necto- phores are structurally similar or dissimilar. Schneider's explanation of the well-known dissimilarity of the nectophores in Diphyids and Abylids is that while the posterior bells in these groups are true nectophores, the anterior ones and all the swimming bells of Hippopodius, of the Prayids, and of Sphaeronectes, are combinations of nectophore and bract. The homologi es thus outlined by Schneider have been criticised severely by Chun ('97b, '98a). According to Schneider the chief evidence that the swimming bells are partly bract is the presence of the somatocyst, which according to him is never found in a true nectophore; but while it is true that in some Calycophorae the somatocyst is a highly specialized organ deeply embedded in the gelatinous substance, I cannot find any evidence either in anatomy or development suffi- ciently strong to invalidate the homology between the somatocyst and the so-called " Oelbehalter " in the nectophores of Agalmids, drawn by Leuckart ('53), and recently denied by Schneider ('98). The mere statement by the latter author ('96, p. 581) that "Es ist nun aus mehreren Griinden unmoglich den Saftbehalter mit sammt seiner Gallert umgebung als blossen Anhang des Glockentheiles zu betrachen" is insufficient to prove his theory; nor has he supported with sufficient facts, his view that the degenerate oldest nectophore CALYCOPHORAE. ' 179 of Ainphicaryon is a bract. Indeed the actual course of development in that genus seems quite opposed to such a conclusion (p. 195). The other arguments adduced in favor of a double origin of the nectophores of the Prayids seem of no more weight. Chun ('98a) has so thoroughly discussed this question, that it is unnecessary to do more here than state my agreement with his general conclusion that the two bells of Diphyids and others are homologous — both are pure nectophores. The very significant fact remains however, that in Diphyids and Abylids the anterior and posterior bells are structurally dissimilar, while in Prayids, Stephan- ophyids, and Hippopodids the two or more bells are all structurally alike. Chun ('97b, p. 13) maintains that the "Diphyes ornata" of Kefferstein and Ehlers ('61) is a connecting link between these two types. But no one since Kefferstein and Ehlers has ever seen a Siphonophore answering to their description of this species, and apart from this doubtful form, the distinction between the posterior bells of Diphyids and Abylids on the one hand, and those of Prayids and Hippopodids on the other is perfectly clear cut. It therefore seems more important as a systematic character than Chun ('97b) supposed. On the other hand the number of nectophores, as most students now agree, whether two or more, is of comparatively little importance, because while the Hippopodiidae, with several, are undoubtedly a natural group, Prayids and some Diphyids normally develop a succession of bells, though they successively cast off the older ones. This is especially true of Praya cymbiformis (Chun, '97a, p. 66, fig. 8), and of Galeolaria. Since therefore, there is no question but that the bells of Prayids and of Hippopodids are budded in the same fundamental manner (Chun, '97a, p. 66), the only essential difference, so far as their number is concerned, is that they are retained longer in one group than in the other. This fact, together with the structural unity of all the bells in the Hippopodids as well as in the Prayids points to a closer relationship between the two, than between either of them and the Diphyids or Abylids. The absence of bracts in Hippopodids demarks them so definitely from their allies, that it undoubtedly justifies the distinct family recognized by Chun. We have now to consider the most puzzling Calycophorids of all, namely the forms usually grouped together as Monophyidae (Haeckel, '88b, Chun, '97b, Lens and Van Riemsdijk, :08). These animals agree in that neither second nectophores nor "reserve buds" are ever formed, and that, so far as known, their groups of appendages are detached to become free-swimming Eudoxids; but they differ widely from one another in form, and although as a rule external 180 CALYCOPHORAE. form is only of minor significance in phylogeny, in the present case it assumes unusual importance because there is a remarkable parallelism in this respect between the various Monophjads and the other more complex Calycophorae. Thus, one group of Monophyids, the Sphaeronectids, resembles the Prayids both in nectophore and Eudoxid, a second, represented by Cuboides, is, in both these respects, of the Abylid type, while the components of a third, Muggiaea and Doromasia, parallel Diphyes and Diphyopsis to such a remark- able degree that they might readily be mistaken for each other; and finally there is a recently discovered genus, Nectopyramis (p. 191), where the somato- cyst, represented by a series of branching canals, recalls that of Stephanophyes and of Nectodroma (p. 205). Of course the important question is, are all these Monophyids primitive types, as the simplicity of their organization suggests, or are some of them primitive, others degenerate. The first view is the one which has generally been held (Haeckel, '88b, Chun, '97b). Schneider has recently maintained how- ever, that while the Sphaeronectids are primitive, Muggiaea is merely a Diphyes with the second nectophore aborted. Sphaeronectes, judging from the adult, has an excellent claim to be regarded, as ancestral, because its definitive necto- phore so closely resembles the transitory primary nectophore of Hippopodius that it may reasonably be considered homologous with that structure, though whether or not correctly, can be determined only when the development of Sphaeronectes is studied. The case of Muggiaea is not so easily settled. In the first place the definitive bell of Muggiaea is not the primary bell; the latter is early lost just as it is in Hippopodius and in Galeolaria. Then too, we must consider the parallelism between Muggiaea and Doromasia on the one hand, and Diphyes and Diphyopsis on the other, which is complete even to the most trivial details of nectophore and of Eudoxid. The resemblance is too close to be accidental ; the only reasonable conclusion is that either Diphyes has been derived from Muggiaea, or Muggiaea from Diphyes. Schneider's conclusion that Diphyes is the parent, Muggiaea the derivative, can be justi- fied only on the assumption that Muggiaea becomes mature before the appear- ance of the second bell, which fails to develop, and of course, precisely the same ground might be taken from which to argue that Cuboides, of which the develop- ment is unknown, is an Abylid with the second bell aborted, though in this case the parallelism in the form of nectophore and Eudoxid is much less close than it is between Muggiaea and Dyphyes. The entire absence of even the trace of a bud for a second nectophore in all the many specimens of Muggiaea which CALYCOPHORAE. 181 have now been examined (p. 185) is a strong argument against this view, and, furthermore, the essential difference between Prayids and Hippopodids on the one hand, and Diphyids and AbyUds on the other with respect to the second nectophores indicates clearly that the two groups have originated from different Monophyid ancestors: i. e., the former from Sphaeronectids, the latter from Muggiaea- and Halopyramis-like forms. Thus there are both structural and phylogenetic reasons for adopting the Muggiaea-Diphyes, rather than the Diphyes-Muggiaea sequence. For the case of Doromasia, and its relation- ships to Diphyopsis, see p. 205. For this reason I have recognized Chun's Monophyidae, but since Monophyes is undoubtedly a synonym of Sphaero- nectes, the name of the family must be changed to Sphaeronectidae. The accompanying diagram will represent the probable relationships of Sphaeronectidae Diphyidae /\ \ / Amphicary- Stephanoph- V Abylinae oninae yinae / ' / Hippopodiidae / Galeolariinae Prayinae Diphyopsiinae the Calycophorae better than a linear arrangement. The various families and subfamilies may be defined as follows : — (the definitions of the subfamilies are practically those of Chun, '97b, p. 12). 1. Sphaeronectidae — only one nectophore. 1. Sphaeronectinae. With rounded nectophore probably representing the ''primary" bell of the non complex Calycophorae. 2. Muggiinae. With pyramidal nectophore of Diphyid or Abylid outline. The definitive nectophore is a secondary bell. 3. Nectopyramidiinae. With rounded nectophore : the somatocyst repre- sented by a system of branching canals. Diphyidae Eschscholtz. With 2 (or temporarily 3 or 4 nectophores: the oldest definitive nectophore differs from the one (s) subsequently formed in the presence of a somatocyst. 1. Abylinae L. Agassiz. Superior nectophore prismatic and much smaller than the inferior one. Free Eudoxids have prismatic bracts. 182 SPHAERONECTES. 2. Galeolariinae Chun. Nectophores of about the same size; rounded, mostly without sharp ridges. Groups of appendages permanently sessile. 3. Diphyopsiinae Haeckel. Nectophores pyramidal, with strong ridges. Groups of appendages detached as free Eudoxids, with rounded bracts. Prayidae Kolliker. With 2 (or temporarily 3-4) nectophores, all structurally alike. 1. Amphicaryoninne Chun. Oldest nectophore with its nectosac degen- erating into a bract-like shield partially enclosed bj^ the younger one. No "reserve bells." Has free Eudoxids. 2. Prayinae Haeckel. The two rounded nectophores are replaced suc- cessively by the formation of new ones. Groups of appendages remain sessile (?). 3. Stephanophyinae Chun. Several nectophores arranged in a ring. Somatocyst replaced by a system of branching canals. Groups of appendages sessile. Hippopodiidae Kolliker. With many nectophores, all structurally alike. Groups of appendages sessile. Without bracts. Sphaeronectidae Huxley, 1859. Sphaeronectinae Haeckel, ISSS. The two genera of this subfamily, Sphaeronectes and Monophyes, recog- nized by Haeckel ('88b) and by Chun ('92, '97b) are separated only by differences in the form of the hydroecium and of the somatocyst, so slight that they are only of specific importance. I therefore follow Schneider ('98) in uniting them under the older name, Sphaeronectes. The recently discovered genus Necto- pyramis is also included here, provisionally, because its affinities are evidently closer with this subfamily than with the Muggiinae. But until its devel- opment is known its position cannot be determined. SPHAERONECTES Huxley, 1859. The structure of this interesting compound genus has been so thoroughly studied by Claus ('74) and by Chun ('92) that it is necessary to examine only the validity of the five species S. {Monophyes) gracilis Claus, S. kollikeri Huxley, (S. {Monophyes) irregularis Claus, 8. {Monophyes) brevitruncata Chun, and S. SPHAERONECTES. 183 (Monophyes) princeps Haeckel, which share the generic characters. According to Schneider ('98) all but princeps are merely members of one varietal series. I very much regret that I have been unable to study actual specimens referable either to irregularis or to brevitruncata, but judging from my examination of kollikeri, and from the various pubUshed descriptions, I am convinced that though a reduction of species is called for, Schneider has gone too far. The most cursory study shows that gracilis and kollikeri are very closely related to each other. Chun who believes that they are distinct, gracilis being an Atlantic, kollikeri a Pacific form, maintains ('92, p. 86) that they can be separated by the somatocyst, which turns downward (toward the bell opening) in kollikeri, upward in gracilis. To this Schneider has replied that he has observed the ''kollikeri" form at Naples, while Agassiz and Mayer ('99) have figured a specimen from the Fiji Islands with the typical "gracilis" somatocyst, and Mayer (:00, p. 74) states that "there appears to be much individual varia- bility in respect to the curvature of the phyllocyst in the Pacific species." I have studied this character in the series listed below, finding, witli Schneider, that it is variable. In general, small specimens are of the "gracilis," larger ones of the "kollikeri", type. In many of intermediate size the somato- cyst is horizontal but in one of the largest individuals it turns sharply upward. It is evident from these facts that this character cannot serve as the basis for specific separation; and therefore gracilis and kollikeri must be united. As Chun ('92) pointed out, the Eudoxids of this compound species had been de- scribed by Will as Ersaea truncata long before the discovery of the polygastric state, and Will's figure ('44, pi. 2), is so satisfactory that this conclusion may safely be adopted. Chun relegated this early name to the synonymy of S. gracilis, but, as Schneider has more recently remarked, the rules of zoological nomenclature require that it be applied to the species as a whole. S. irregularis and brevitruncata are another pair of closely allied forms. According to Chun they are separated from each other by the very much reduced somatocyst of the former, and the very short stem and small number of groups of appendages in the latter. But Schneider has pointed out that the last character is of very doubtful importance, in view of its variability in various Diphyids; a varia- bility probably connected with the setting free of the groups of appendages. As to the size of the somatocyst, the importance of this character depends wholly on its constancy. Unfortunately this has never been tested; but the difference in this respect between irregularis and brevitruncata is so slight that it suggests varietal, rather than specific separation. On the whole, then, the 184 SPHAERONECTES TRUNCATA. two are so closely allied that it is better to unite them under the older name, irregularis Claus. The characters by which irregularis is separated from truncata are its pro- portionately much larger nectosac, its thinner gelatinous substance, short hydroecium, more upright somatocyst, and especially the bowed course of its dorsal and lateral subumbral canals. I have not observed any specimen of truncata, either large or small, which approaches irregularis in any of these respects. Schneider ('98, p. 78), it is true, states that "von der irregularis Form giebt es Ubergange zur gracilis Form," but he has not described these supposed intermediates, nor has he analyzed the value of the diagnostic char- acters. In view of the constancy of the course of the subumbral canals in other Calycophorae, and the very marked difference in this respect between the two species under consideration, this character alone would suffice to separate them, and when we add to this the difference in form, irregularis certainly deserves recognition as a good species. The form from the Indian Ocean recorded by Haeckel as Sphaeronectes princeps ('88a, p. 34), and later described by him ('88b, p. 129), as Monophyes princeps has not been discussed either by Chun or bj^ Schneider. Its subumbral canals resemble those of irregularis, but the nectosac is proportionately even higher, and the hydroecium is a mere groove, much as in certain Prayids. Should it prove that these characters are constant, and that the specimen was in fact a Monophyid, princeps would deserve recognition. But to determine whether this is the case will require renewed examination of material agreeing with Haeckel's account. A knowledge of its appendages would be particularly valuable. The other species of Monophyes mentioned by Haeckel ('88b, p. 128) are M. diptera and M. hydrorrhoa. The first of these is applied to the posterior nectophore of Diphyes subtilis (p. 347), first described by Chun ('85) as the "primary bell" of S. truncata {"gracilis"); the second, described merely as being similar to the former, is no doubt the same. M. primordialis Chun ('82) is a synonym of Muggiaea kochii Will, to the "primary" nectophore of which it was applied. Sphaeronectes truncata (Will) Schneider. Ersaea truncata Will, '44, p. 82, taf. 2, fig. 2S. Eudoxid. Diphiphijm incrmU Gegenbaur, '53, p. 9, taf. 16, fig. 3; Clacs, '74, p. 27, taf. 4, figs. 1-4; Fewkes, '81, p. lG(i, pi. 6, fig. 12; Haeckel, '88b, p. 107; Chun, '92, p. 8.5. Eudoxid. Sphaeroiwdes l^oUikeri Huxley, '59, p. 50, pi. 3, fig. 4; Haeckel, '88b, p. 130; Chun, '92, p. 84; Agassiz anil Mayer, '99, p. 177, pi. 17, fig. .53. MUGGIAEA. 185 Monophyes gracilis Claus, 73, p. 258; 74, p. 30, taf. 4, figs. 8-10; Chun, '85, p. 265, taf. 2, figs. 1, 2. Praya inermis Metschnikoff, 74, p. 46. Sphaeronecles (Monophyes) inermis Fewkes, '80a, pi. 3, fig. 6. Sphaeronectes gracilis Chun, '88, p. 1154; Haeckel, '88b, p. 130; Mayer, :00, p. 73, pi. 27, fig. 89. Monophyes kollikeri Haeckel, '88a, p. 34. Diplophysa Iruncala Haeckel, '88a, p. 32. Eudoxid. Diplophysa kollikeri Haeckel, '88a, p. 32, 'S8b, p. 108. Eudoxid. Sphaeronectes gigantea Fewkes, '89b, p. 119. Sphaeronectes truncata Schneider, '98, p. 75, (partim). Station 4583 300 fathoms to surface 2 specimens " 4659 " " " " 2 " 4680 " " " " 4 " 4696 " 1 Acapulco Harbor " 32 " The forty-one specimens range in diameter from 1-8 mm.; and are all fairly well preserved. The variability in the form of the somatocyst has already been noted. In several examples the groups of appendages were sufficiently far advanced to show the typical "Diplophysa" form of bract so often de- scribed, and so far as these young stages show there is no visible difference in this structure between Atlantic and Pacific specimens. The various records show that S. truncata occurs generally over the tropical and subtropical regions of all three great oceans. Muggiinae, nom. nov. Cymhonedidae Haeckel, '88a, '88b; Chun, '88, '92. The name Cymboncetidae must be abandoned because as Chun ('92) and Schneider ('98) point out Cymbonectes Haeckel is undoubtedly identical with Muggiaea Busch. To replace it I suggest Muggiinae. At present three genera can be distinguished: Muggiaea and Doromasia, both of Diphyid outline, but separated by the presence of a special nectophore in the latter, contrasted with its absence in the former, and Cuboides ( = Halopyramis) easily distinguished by its peculiar pyramidal shape (p. 189). Schneider unites Doromasia and Muggiaea, but the difference above mentioned seems as worthy of generic recognition here as among the Diphyidae. It is possible, however, that Doro- masia will finally be abandoned on another ground, namely that it is not a Sphaeronectid but a Diphyid (p. 265). MUGGIAEA Busch 1851. Four species have been described which must be referred to Muggiaea, as above defined, viz. M. kochii (Will) Chun ( = M. pyramidalis, Busch = Monophyes primordialis Chun), M. pyramidalis Haeckel, M. (Cybonectes) 186 MUGGIAEA. huxleyi (Haeckel), and M. atlantica Cunningham. The Diphyes chamissonis of Huxley, referred to this genus by Haeckel, proves to be a true Diphyid (p. 244). Diphyes arctica Chun, is likewise classed here by Schneider ('98, p. 89) on the ground that the "einmal beobachtete Schwimmglocken-anlage diirfte eher einem Rudiment als einer Ersatzglocke entsprechen." But so far as we know, neither rudimentary nor reserve bells occur among the Monophyidae; and it is there- fore better to retain arctica among the Diphyidae, at least until it is known whether or not a posterior nectophore is normally pret-ent. Neither Chun ('92) nor Schneider ('98) recognize M. pyramidalis Haeckel as distinct from M. kochii. According to Haeckel pyramidalis "differs from the former [kochii] mainly in the size of the conical hydroecium, the top of which attains half the length of the nectosac" ('88b, p. 137). This particular feature i. e. length of the hydroecium, is so important among Diphyids, that it might be expected to be significant in the case of Muggiaea. And Cunningham's ('92, p. 214) studies of large series of this genus from Plymouth, England, have proved that such is the case. HisM. atlantica is easily separated from M. kochii by the great length of the hydroecium, and by the fact that the somatocyst, reaching barely to the mid-level of the nectosac in kochii, reaches to its apex, or even beyond it in atlantica. I have myself been able to test these characters in series of the former both from the Atlantic ( :11b, p. .340) and the Pacific, and of the latter from the Pacific, with the result that they prove so constant as to be valuable for diagnosis. Cunningham thought it extremely probable that the form observed by Haeckel at the Canary Islands was the same species as that which he obtained at Plymouth, and no doubt this view is correct. Haeckel's name, however, cannot be used, because preoccupied by Busch for M. kochii; and atlantica must therefore be applied to the compound species characterized by deep hydroecium and long somatocyst. The status of M. huxleyi, known from one record only, is doubtful. Chun ('86) has worked out the development of M. kochii, finding that the primitive bell is soon lost, and that the definitive nectophore is a secondary structure. M. kochii is known from the Mediterranean, the Canaries (Chun '86), and the Bay of Biscay (Bige- low :11b), M. atlantica from the Canaries (Haeckel) from the English Channel and the Irish Sea (p. 376). It has also been recorded from Skagerak, but this record probably belongs to Diphtjes arctica (p. 188) ; and the capture of both in the Eastern Tropical Pacific, shows that their distribution is parallel in the warmer parts of both oceans. MUGGIAEA ATLANTICA. 187 Muggiaea atlantica Cunningham. Muggiaea pyramidalis Haeckel, '88b, p. 137 (non Busch '51). Cucubalus pyramidalis Haeckel, '88b, p. 109. Eudoxid. Muggiaea allanlica Cunningham, '92, p. 214; Gough, :0.5, p. 1; Vanhoffen, :06, p. 13. (Non Eudoxia eschschoUzi Johannsen and Levinsen, :03). Plate 7, Fig. 1; Plate 9, Figs. 7, 8. Station 4571 surface 1 specimen 8 mm. long. " 4598 300 fathoms to surface 1 " 7 " " " 4611 " " " " 68sppfimcns 3-5 " " " 4655 " " " " 25 " 6-7 " " " 4673 " " " " 2 " 6,7 " " The specimen,s agree even to minor details with Cunningham's account and figure. Although at least the basal part of the stem was well preserved in most cases, in none could I find any bud which might be identified as a reserve bud for a future posterior nectophore. The diagnostic features of M. atlantica are as follows : — There are five ridges at the apex, and these run to the base without branching; there are no basal teeth, and the only suggestion of such structures is a slight prominence of the angles at the basal terminations of the ridges (Plate 7, fig. 1). The degree of serration of the ridges is variable, some specimens showing it strongly from apex to base, others, hardly at all; and there are various intermediates between these two extremes. The hydroecium, which varies very little, reaches to slightly less than one third the length of the nectosac, as Cunningham shows it; but it extends basally some distance below the bell opening, so that its entire length is nearly one half that of the nectosac. In no example does it reach the mid-level of the nectosac, as Haeckel describes it; but his account is altogether insufficient. Apically the hydroecium is conical. The dorsal hydroecial wall, below the level of the bell opening, is divided longitudinally, forming two sym- metrical lateral wings (Plate 9, fig. 8), a character not mentioned by Cunning- ham. The lateral basal margins of the hydroecium are nearly straight. (Plate 9, fig. 7.) Somatocyst. This structure is nearly cylindrical, very slender, and as a rule terminally dilated with a large oil bubble. It is closely apposed to the ventral wall of the nectosac. In the smaller specimens (3-4 mm.) it considerably surpasses the apex of the nectosac (Plate 7, fig. 1); but with increasing growth it becomes proportionately shorter and shorter. In specimens 6 mm. long. 188 MUGGIAEA KOCHII. it about equals the apex of the nectosac, as Cunningham shows it, and in one example of 7 mm. it falls somewhat short of that level. Stem and appendages. In none of the examples were any of the appendages sufficiently advanced to show the final shape of the bract; they consist simply of siphon, tentacle, very young bract, and the bud for the future gonophore. Cunningham who observed "detached eudoxomes " ('92, p. 215) has not described them. VanhofTen's provisional identification of the Eudoxids recorded by Johannsen and Levinsen under the name Eudoxia esckscholtzi as belonging to this species rests only on the ground that "Die Eudoxien sind unbekannt, werden aber jedenfalls der Eudoxia eschscholtzi Busch nahe stehen." (:06, p. 14). Muggiaea kochii (Will) Chun. Plate 12, Figs. 2-4. Diphyes kochii Will, '44, p. 77, taf. 2, fig. 22; Busch, '51, p. 46, taf. 4, figs. 3-5. Ersaea pyramidalis Will, '44, p. 81, taf. 2, fig. 17. ■ Eudo.kid. Muggiaea pyramidalis Busch, '51, p. 48, taf. 4, fig. 6. Eudoxia eschscholtzi Busch, '51, p. 33, taf. 4, figs. 7-10, taf. 5, figs. 1-9; Chun, '92, p. 90 (non Johannsen and Levinsen :03). Eudoxid. Monophyes primordialis Chun, '82, p. 677, taf. 12, fig. 1. Muggiaea kochii Chun, '82, p. 679, taf. 17, figs. 2; '88, p. 15; '92, p. 89 (partim); Haeckel, '88b, p. 137; Schneider, '98, p. 88 (partim); Bigelow, :11b, p. 340. Cucubalus eschscholtzi Haeckel, '88b, p. 109. Eudoxid. Stations 4679, 4681, 4691; all 300 fathoms to surface. At each, 1 necto- phore. All about 12 mm. long. The identification of these three nectophores, none of which were in verj^ good condition, rests on an actual comparison between them and the Biscayan specimens already mentioned. Apart from the absence of a posterior necto- phore, or of reserve buds for such structures, the diagnostic features of M. kochii are as follows: — There are five ridges, running undivided from apex to base, but the lateral ones terminate a short distance above the basal margin. This fact, easily demonstrable in specimens as relaxed as the present ones, is often concealed in better preserved and more contracted examples, as was the case in the Biscayan series (Bigelow :11b, p. .340). The somatocyst is cylindrical and reaches onl}^ from one third to one half the length of the nectosac, instead of reaching or surpassing the apex of the latter as in M. atlantica. The hydroecium, as already noted (:11b), lies wholly below the opening of the nectosac, and its shortness together with the form of the somatocyst is one of the most valuable field marks to separate this species from M. atlantica. CUBOIDES. 189 M. kochii was previously known only from the warmer parts of the Atlantic, as far north as the Bay of Biscay (Bigelow, :11b). The record by Murbach and Shearer of this species from the North Pacific probably belongs to Diphyop- sis chamissonis Huxley. CUBOIDES QtJOY AND Gaimard, 1827. In 1888 Chun described, from the Canary Islands, a very well-marked Cymbonectid under the name Halopyramis adamantina. Almost simultaneously it was described and figured by Haeckel ('88b) as Cymha crystallus. In 1892 Chun published a second, very detailed account, with beautiful figures; and he then recognized that instead of being unknown to the early students, it was in fact the polygastric state of the Eudoxid described by Quoy and Gaimard in 1827 as Cuboides vitreus. Chun also recognized the possibility that his Halo- pyramis might be identical with the Enneagonum hyalinum of the latter authors, though, owing to the unsatisfactory nature of the figures and description of Enneagonum, he retained the name Halopyramis. Since that time Halo- pyramis has been adopted by Bedot ('96) and by Lens and Van Riemsdijk (:08), but Schneider argues that the form studied by Chun was in reality the Enneagonum of Quoy and Gaimard. The figures of Enneagonum (Quoy and Gaimard, '27) are so indefinite that after studying them together with the original description I feel as uncertain as did Chun ('92) whether or not Enneagonum and Halopyramis are identical or distinct. However, whatever may be the decision on this point, the use of the generic term Halopyramis is contrary to the International code of zoological nomenclature, because all recent authors, Chun himself included, agree that the Eudoxid of Halopyramis was long ago described by Quoy and Gaimard as Cuboides vitreus. The principle that a name, generic or specific, applied to any part of an animal, or to the larva, or to any one generation, before the animal itself is named, is to be retained, is now well established and generally accepted. And this principle, of course, gives Cuboides precedence over Halopyramis; and inasmuch as Cuboides is recognizable, whereas Enneagonum is at best dubious, and both were proposed in the same publication, and figured on the same plate, there is good reason for accepting the former definitely. For the history of Enneagonum hyalinum, and the various names under which it has been quoted, see Chun, '92, p. 113. Leaving out of the question the problematical Enneagonum hyalinum it is probable that all the members of Cuboides ("Halopyramis") yet described belong to a single species. This is certainly true of the forms studied by Chun and by Haeckel; and though Chun ('92) believed that Abyla vogtii Huxley, 190 CUBOIDES VITREUS. from the Indian Ocean represented an Indian, distinct from the Atlantic, species, the capture, by Bedot ('96), by the "Siboga" (Lens and Van Riemsdijk, :08), and by the "Albatross" of Indo-Pacific specimens indistinguishable from material from the Tropical Atlantic, shows Chun's view to be ill founded. Chun, '92, p. 112, though expressly stating that C. vitreus is the Eudoxid of his Halopyramis adamantina, calls "Die freien Eudoxiengruppen" Cuboides adamantina. But this is contrary to usage. Cuboides vitreus Quot and Gaimard. Cuboides vitreus Qdoy and Gaimard, '27, p. 19, pi. 2E, figs. 1-3. Eudoxid. Cymba cuboides Eschscholtz, '29, p. 135. Abyla vogtii Huxley, '59, p. 46, pi. 2, fig. 3. Cuboides vitreus Huxley, '59, p. 63, pi. 4, fig. 5. Eudoxid. Halopyramis adamantina Chun, '88, p. 1155; '92, p. Ill, taf. 10, fig. 10, taf. 12; Bedot, '96, p. 369; Lens and Van Riemsdijk, :08, p. 7. Cuboides adamantina Chun, '88, p. 11.56; '92, p. 112; Bedot, '96, p. 369; Lens and Van Riemsdijk, :08, p. 8. Eudoxid. Cuboides crystallus Haeckel, '88a, p. 53; '88b, p. Ill, pi. 42. Eudoxid. Cuboides vogtii Haeckel, '88b, p. 111. Cymba vogtii Haeckel, '88a, p. 34; '88b, p. 138. Cymba crystallus Haeckel, '88a, p. 34; '88b, p. 138, pi. 41, 42. Enneagonum hyalinum Schneider, '98, p. 91 (non Quoy and Gaimard, '27). The following names may perhaps belong to this species; they are all founded on the description of Enneagonum bj^ Quoy and Gaimard: ? Enneagonum hyalina Quoy and Gaimard, '27, p. 18, pi. 2D, fig. 1-6; Blainville, '34, p. 133, pi. 4, fig. 5b; Lesson, '43, p. 455. ? Diphyes enneagonum Quoy and Gaimard, '34, p. 100, pi. 5, fig. 1-6. ? Cymba enneagonum Eschscholtz, '29, p. 134. The polygastric generation was taken at Stations 4613, 4617, 4619, 4634, 4646, 4652, 4663, 4667, 4669, 4673, both on the surface and in hauls from 300 fathoms to surface. The series consists of thirty-four well-preserved specimens ranging in height from 3-10 mm. The Eudoxid was taken at Stations 4661, 4663, 4667, 4669, 4673, 4676, 4699, 4743, both in surface and in 300 fathom hauls. There are fifty-six well- preserved specimens, from 3-5 mm. high. This species has been figured and described in such detail by Chun ('92) that no account is necessary here. The present series is indistinguishable from his specimens from the Canary Islands, and from West Indian examples which I have studied. The largest example of the polygastric stage, measuring 10 mm. in height by 8 mm. in breadth, is rather larger than the "Siboga" specimens (7x5 mm.), and approaches the specimens recorded by Chun (10 mm.). It is evident, then, that there is no distinction in size between Cuboides from the NECTOPYRAMIS DIOMEDEAE. 191 Atlantic and from the Indo-Pacific region. Enough captures of C. intreus have been recorded to show that it is widely distributed over the tropical Atlantic, the Indian Ocean (Huxley), the Malaysian region (Lens and Van Rienisdijk), and that it occurs rather commonly in the Eastern Tropical Pacific. Nectopyramidinae, nom. nov. NECTOPYRAMIS Biqelow. Nectopyramidinae with rounded nectophore; somatocyst represented by a series of diverging canals. Nectopyramis was founded (Bigelow, :11b) for a Monophj'id distinguished from all other members of the family by the above characters. To the type species A'', thetis, the present collection has added a second, of which the Eudoxid as well as the polygastric state is represented. As stated in the original descrip- tion, this has no special nectophore, thus resembling the Eudoxids of the Sphaeronectinae. The new species, N. diomedeae, is distinguished from the type species not only by a very differently shaped nectophore and hydroecium, but by an even more complex system of somatic canals. It was particularly fortunate that in one of the specimens there was a group of appendages old enough to show their identity with a very large Eudoxid, differing in many important features from any previously described. It is possible that the problematical Clausophyes galatea of Lens and Van Riemsdijk may belong in this subfamily. If it is a Monophyid as Lens and Van Riemsdijk suggest, the large size of the nectophore points to this location, but the single specimen was so fragmentary that it is impossible to get a correct idea of its structure. Nectopyramis diomedeae, sp. nov. Plate 1, figs. 1-6. Station 4652 400 fathoms to surface 2 excellent examples of the poly- gastric state. Types. " 4661 300 " " " 2 Eudoxids. " 4669 " " " " 1 Eudoxid. " 4711 " " " " 1 Eudoxid. " 4732 2012 " " " 1 Eudoxid. All the specimens, with the exception of one Eudoxid, were in excellent condition. 192 NECTOPYRAMIS DIOMEDEAE. Nectophore. The nectophore, in the better of the two examples, reaches the unusual dimensions of 38 mm. in length bj'^ 26 mm. broad. It is roughlj' rectangular as seen in side view (Plate 1, fig. 1), laterally compressed (Plate 1, fig. 2) with a ridge extending from the level of the hydroecium to the dorsoapical corner, and with the two lateral faces meeting along the dorsal edge in a rounded subacute angle. In cross-section the nectophore is roughly triangular. At the base the gelatinous substance projects below the level of the opening of the nectosac in a triangular, but rounded, ventral, and a wedge-shaped dorsal promi- nence (Plate 1, fig. 1). The nectosac is shallow, rounded; the hyroecium lies transverse to the main axis of the nectophore, reaching dorsad nearly as far as the dorsal face of the nectosac; it is deeper than broad, and opens on the ventral edge by a narrow slit. Dorsally it is rounded, and sac-like, and it is asymmetrical in form, as is seen in ventral view (Plate 1, fig. 2). Somatic canal system. The system of canals which replaces the somatocyst is more complex than in N. thetis. Commencing with the point at which the pedicular canal reaches the hydroecium, we can recognize a descending and an ascending branch, as in the Prayinae. The former is very short and soon turns apically, to run over the left-hand face of the hydroecium, where it branches once (Plate 1, fig. 4), or twice (Plate 1, fig. 3). The ascending system is much more extensive. In its passage over the dorsal sm-face of the hydroecium it gives off two large branches, one subdividing twice, and running to the dorso- basal angle (Plate 1, fig. 1, C. Pa ) the other branching four or five times, and running to the apicodorsal angle (Plate 1, fig. 1, C. Pa ). The ascending canal does not follow the upper wall of the hydroecium, but turns and runs to the apico- ventral corner of the nectophore (Plate 1, fig. 1, C. Pa ). At the point at which it bends apically it gives off a branch which runs over the left-hand face of the hydroecium, and a short distance further on gives off a second trunk which passes over its right-hand face. These two canals of the hydroecium are asymmetrical, the right-hand one branching one and three, and the left-hand one five and seven times respectively in our two specimens. {Cf. Plate 1, fig. 3 and fig. 4). In both A'', thetis and N. diomedeae, ascending and descending branches can be distinguished, the former giving off the more or less complex hydroecial canals. But, whereas it is the latter which are the parents of the two canals running to the distal portions of the nectophore in N. thetis, in A'', diomedeae these arise from the ascending trunk. The relation of the sub- umbral canals to the somatic system is likewise different; for while in A^. dio- medeae there is a single pedicular canal, in N. thetis all four subumbral canals NECTOPYRAMIS DIOMEDEAE. 193 extend beyond the nectosac to the hydroecium; but although the canal system of N. diomedeae is much the more complex, the difference is not an essential one, being of degree only. The difference is therefore better regarded as of specific than of generic significance. The subumbral canals are direct, not bowed. Stem and appendages. These, though much contracted, were well pre- served. An important feature is the absence of any signs of the previous attach- ment of a posterior nectophore, or of any reserve buds which might suggest the future development of such an organ. The appendages consist, for the most part, of very young siphons and tentacles and of the buds for gonophores and bracts; but near the extremity of the stem in one example all three organs are much further advanced. Most important is the bract because it links this species with the Eudoxid described below. The largest bract is about 1.5 mm. long; in outline it is triangular, laterally compressed, with prominent antero- and posterobasal angles. There is a deep basal concavity enclosing the proximal portion of its pedicular canal, and foreshadowing, not only in situation but in form, its future hydroecial cavity. Its somato- cyst is represented by four canals arising together from the apex of the basal concavity, one running to the apex, one to the anterior basal angle, the other two toward the posterior basal angle, but over the faces of the future hydroe- cium. The apical trunk already shows the beginning of a branch, and each of the two hydroecial canals bears a branch of considerable length (fig. A). The siphons, each of which shows a well-marked basigaster, are of the usual type. The tentilla are of the usual Calycophorid type, but are unusually large, and differ in form from those of other Monophyids (e. g. Cuboides Chun, '92, pi. 12, fig. 14). Their most distinctive features are the thickening, marking the beginning of the contractile portion of the stalk, and the arrangement of the nematocysts as the walls of a cylinder, which in young stages is compara- tively long, in older ones shorter and more knob-like. It likewise appears to be very contractile. The young gonophores, among which both 9 and d' could be distinguished, already show the deep ventral furrow noticeable in their ripe state. Fifi. A. — Nectopyramis diomedeae. Bract. 194 AMPHICARYONINAE. The Eudoxid. The Eudoxids of N. diomedeae (Plate 1, fig. 5) rival in size the " Ceratocymba " of Abyla leuckartii, the bract of the largest specimen being 33 mm. long. But these enormous bracts, except for size, and for minor details as to the branching of their canals, resemble so closely the bract described above that there is no doubt that they belong to the N. diomedeae. Thus they are of the same triangular, laterally flattened form, show the same basal hydroecial cavity, and similar basal gelatinous prominences. The canal system consists of the same four main trunks. The odd basal one now gives off three or four short transverse branches, the apical trunk from four to six, already foreshadowed in the young bract. The branching of the paired hydroecial trunks is now more complex than it was in the young stages already described. Furthermore it is asymmetrical as in the adult nectophore. Here, as in the latter, the branch- ing of the canals shows a good deal of individual variation. It is easily derived from the condition in the young bract as the result of growth, a conclusion sup- ported by the fact that its branching is progressively more and more complex in larger and larger specimens. The gonophores show little change except for the much greater size, from the form described above for their earlier stages. In each of the Eudoxids there is one large gonophore, either male or female, and one or two buds for future ones. The siphon, which has a well-marked basigaster (Plate 1, fig. 6), is of the usual type. The tentilla are of the form described above. The agreement between their structure, and those of the cormidia of N. diomedeae while still attached to the stem is a further reason for uniting these Eudoxids with that species. Prayidae Kolliker, 1853. Diphyidae Chun partim. Amphicaryoninae Chun, 1888. This subfamily is treated first of the Prayidae because the failure to develop more than two nectophores or even additional reserve buds, clearly shows that it has departed but little from its Monophyid ancestors. In the more highly specialized members of the family the older nectophores are successively dropped as new ones develop, the number thus remaining approximately constant. In the Amphicaryoninae, however, the older of the two nectophores is retained permanently, but decreases both in relative size and in function. AMPHICARYON ACAULE. 195 The type of the subfamily, and indeed its only undoubted representative, is Amphicaryon, described by Chun ('88) from the Canary Islands. As a second member Chun ('97b) lists Mitrophyes Haeckel. Schneider ('98) has made the latter a sjTionym of Amphicaryon; and although Haeckel's figure shows a long stem and a very remarkable hydroecium, the undoubted resemblance between the two, and the fact that both were taken at the same locality, supports Schneider's view. AMPHICARYON Chun, 1888. So far as I can learn, Amphicaryon has never been definitely recorded since described by Chun ('88, p. 1162). The several specimens in the "Albatross" collection and two examples from the West Indies are therefore of unusual interest. The genus may be defined as Prayidae with two nectophores of very unequal size, the older one degenerating, so that in the adult, at least, the younger is much the larger; nectosac of the older nectophore much reduced; stem very short. Chun's ('88) description of A. acaule, unfortunately not figured, is so brief that I should have been in some doubt whether or not the present Pacific speci- mens are identical with it, were it not that they agree very closely with a West Indian specimen which I have studied. Amphicaryon acaule Chun. Plate 4, figs. 1-8. Amphicaryon acaule Chun, '88, p. 1162. ? Mitrophyes peliifera Haeckel, '88a, p. 34; '88b, p. 131, pi. 28; Chun, '97b, p. 102. Station 4613 300 fathoms to surface 1 specimen. 4638 4676 4683 4701 4705 4732 The largest specimen is 9 mm., the smallest 3 mm. in le^igth. All are well preserved. In the larger specimens the two nectophores are very unequal in size. The larger are rounded, higher than broad, ventrally concave, its ventro- lateral edges partly enclosing the other much smaller flattened bract-like necto- phore. In the largest specimens of A. acaule, 15 mm. in height, according to 196 AMPHICARYON ACAULE. Chun, the larger nectophore entirely encloses the smaller, and there is no reason to suppose that with further growth this condition may not be attained in the Pacific specimens. In earlier stages in growth the smaller nectophore, as Chun observed, is proportionately much larger. In our smallest individual it is plano- convex, nearly circular, and considerably overlaps the larger nearly spherical nectophore. At this stage there is no distinct hydroecium, but with advancing growth the larger nectophore becomes deeply, the smaller one slightly concave along the ventral surface, so that in the older stages (Plate 4, fig. 1) there is a well-developed hydroecial tube extending from end to end of the smaller necto- phore. The nectosac of the larger nectophore is of the usual type; it reaches to about the mid-level of the nectophore, is narrow and cylindrical in form, and its canals pursue a direct course suggesting the condition among Diphyids rather than the convolutions which they follow in the Prayinae. But, as noted above (p. 195), the corresponding structure in the smaller nectophore is very much reduced. In large specimens it is extremely small (Chun, '88, p. 1163); but even here the four radial canals can easily be traced (Plate 4, fig. 4). Appar- ently the bell-mouth is permanently closed; at least I have seen no evidence, other than a slight indentation of the surface of the nectophore, to indicate that it could be opened in life. In the younger stages the nectosac is relatively larger (Plate 4, fig. 8), but its opening is as tightly closed. Indeed so degenerate is it even at this stage that it is doubtful whether it ever functions as a swimming bell. If we judged from the adult only, and from analogy with the other Prayinae, we should expect the enclosed nectophore to be the younger; but its relatively larger size in younger stages, when it overlaps the nectophore which later encloses it, and its subsequent relative degeneration, shows that it is in reality the older, and that the younger overtakes it by its much more rapid growth. Stem and appendages. The stem is so short that Chun ('88, p. 1162) speaks of it as "zu einer Scheibe umgebildet." In none of the specimens studied is it extended any further than in the figure (Plate 4, fig. 1, 3). The character- istic form of the bracts (Plate 4, fig. 7), each with two long lateral canals, was likewise observed by Chun. In the two specimens in the series which are sexually mature all the gono- phores are 9 , a fact suggesting that like " Amphicaryon", (Haeckel '88b, p. 193) Mitrophyes may be dioecious; but the material studied is insufliicient to estab- lish the point. The gonophores bear small swellings, or tentacular rudiments on the bell margins opposite the terminations of the foin- radial canals, as in various other Siphonophores. PRAYINAE. 197 The previous records for Amphicaryon are the Canary Islands (Chun, '88), where "Mitrophyes" likewise was found (Haeckel, '88b), and possibly also Bermuda (Chun, '97b, p. 16). Prayinae Hafxkel, ISSS. Considering that the published accounts justify the recognition of only seven species, two of which are insufficiently known, the synonymy of this subfamily is remarkably confused. The earliest descriptions of any Prayids are probably those of Rosacea plicata and of R. ceutensis (Quoy and Gaimard, '27). The figure of R. ceutensis is so insufficient that it is impossible to identify it beyond the mere fact that it was taken from a single nectophore belonging to this subfamily. But the figure of R. plicata (Quoy and Gaimard, '27, pi. 4B), shows clearly the short broad outline, and the terminal dilation of the ascending branch of the somatocyst which are characteristic of the animal since described by Kolliker ('53) and by Vogt ('54) as Praya diphyes. Chun ('85) has founded Lilyopsis for species with special nectophores, such as Lilyopsis diphyes. Of course the identification of figures so lacking in detail as the original ones of Rosacea plicata, can never be absolutely certain; but for the sake of stability it is most desirable to give old names a final resting place; and since Quoy and Gaimard's figure of R. plicata shows the two trivial characters, i. e. form of the nectophores and dilation of the somatocyst, which must readily serve to distinguish L. diphyes from P. cymbiformis which strongly resembles it in external appearance, and when, furthermore, the figure certainly belongs to one or to the other, as Leuckart ('53) and Huxley ('59) long ago pointed out, no course is open but to follow Schneider ('98) in identifying it with L. diphyes. Lilyopsis then becomes a synonym of Rosacea, L. diphyes of R. plicata. The following also belong to Rosacea, because of the presence of special nectophores: — Praya diphyes Graeffe ('60), Praya medusa Metschnikoff ('70), Lilyopsis rosea (Chun, '85). These agree with one another so closely, especially in the form of the definitive nectophores, and in the structure of bract, gono- phore, and special nectophore, that there is every reason to unite them. Praya blaino Fewkes ('83a) and P. gracilis Fewkes ('83a) also belong here, so far as the rather unsatisfactory descriptions indicate. The same is true of Haeckel's Lilyopsis catena, from the Canary Islands, all we know of which being that it is similar to rosea (Haeckel, '88b, p. 150). The resultant compound species is easily distinguished from R. plicata by the triangular shape of the definitive nectophores, the relatively large nectosacs, and the presence of tentacular rudi- 198 PRAYINAE. ments on the special nectophores. Schneider ('98) has retained the specific name diphyes, but this is preoccupied by Kolliker ('53) and by Vogt ('54), and the next available name, medusa Metschnikoff, must be used. A member of the subfamily, without special nectophores, well known from the Mediterranean, seems to have been described by Delle Chiaje ('42) as Physalia cymbiformis. And since the middle of the last century it has been known almost universallj^ as Praya cymbiformis Delle Chiaje, or Praya maxima Gegenbaur. The genus Praya was proposed in 1834 by Blainville for a species which he called Praya dubia. In his description he states that it is the same as the Diphyes dubia of Quoy and Gaimard ('34) whose unfinished manuscript he had examined, and his brief account agrees fairly well with that species. But his figure shows no resemblance whatever to Quoy and Gaimard's figures of D. dubia. On the contrary it much more nearly resembles their D. prayensis. The latter has usually been taken to be Rosacea plicata, but the figures agree with the well-known cymbiformis much more closely than with prayensis. By identifying them with the latter Blainville's dubia becomes a synonym of cymbiformis (it is the figures which must be used as the clue, rather than the insufficient account), and cymbiformis thus the type of Praya. This is very desirable, for it gives assured standing to a name which has long been in use. Praya calif ornica Gravier ('99) very closely resembles cymbiformis in its general form. It is separated from it, according to Gravier ('99), by the form of its bracts and by the structure of the tentilla. . But, as I have observed, preserved and distorted bracts of cymbiformis often agree very well with Gravier' s figure. The swelling which he observed at the base of the tentilla is of no more importance as a diagnostic character, because a similar appearance has been figured for contracted tentilla in cymbiformis by Haeckel ('88b, pi. 32, fig. 14), and I may add that I have observed it both in Mediterranean and in Pacific specimens. It is merely an evidence of the contraction of the stalk immediately proximal to the nematocyst-band. As to Gravier's supposition that his species might perhaps have only one nectophore normally, I may point out that the older nectophore is so easily detached that its absence in one specimen can have no weight. Therefore I have no hesitation in uniting californica with cymbi- formis, especially since the present collection shows that the latter occurs in the Pacific. i Praya and Rosacea are united by Schneider ('98) in one genus, Rosacea. But I agree with Chun and with most other authors that the presence or absence of special nectophores in the groups of appendages is of generic importance both PRAYINAE. 199 here and among the Diphyopsiinae. So striking a paralleHsm between the two subfamiUes surely deserves more than specific recognition. It may well be that more detailed study of Rosacea will reveal other important differences. Thus in Praya the nectophores are similar in form; but in the only species of Rosacea of which we can speak with confidence, i. e. R. plicaia, they differ from each other in form and in the extent of the hydroecium. Furthermore, it is not unlikely that the succession of nectophores may differ in the two species, for while new ones seem to be formed continuously, or at least frequently in cynibiformis, with the concomitant dropping of the oldest, as described and figured in detail by Chun ('97a), such a process seems never to have been observed in R. plicata. Quoy and Gaimard's Diphyes dubia has never been recorded since first described. Schneider ('98) has identified it with the Stephanophyes superba of Chun ('88, '91), but an excellent specimen of dubia in the present collection (p. 204) agreeing in all its essentials with Quoy and Gaimard's figures, proves to be so different not only from Stephanophyes, but also from all known Prayinae in the arrangement and number of the subumbral canals, as to warrant a new generic name, Nectrodroma. For the present it is retained in this subfamily, but when we know the number and arrangement of its definitive nectophores it may be necessary to locate it elsewhere. Finally, Haeckel's ('88b) genera Desmalia and Desmophyes are undoubtedly Prayids, the former without, the latter with special nectophores in the groups of appendages. But instead of only two chief nectophores, Desmalia has four, Desmophyes six, i. e. three pairs. Schneider ('98, p. 82) has identified Des- mophyes with R. viedusa (= "diphyes" Graeffe). But though it is true that there is a succession of nectophores in that species (Chun, '88), it is equally certain that the normal number of well-developed bells retained at one time in that genus, and in Praya, is two only. Should further study prove that the number of definitive nectophores retained simultaneously in Haeckel's species is six, as in his single example, it would deserve generic separation. I therefore retain Desmophyes and Desmalia, at least provisionally. The former was described, and beautifully figured — but we know the latter only from an in- sufficient notice. 200 PRAYA CYMBIFORMIS. PRAYA Blainville, 1834. Praya cymbiformis (Delle Chiaje) Leuckart. Plate 2, figs. 1-6. Physalia cymbiformis Delle Chiaje, '42, tab. 33, fig. 1. Praya dubia Blainville, '34, p. 137, pi. 6, fig. 4 (non Diphyes dubia Quoy and Gaimard, '34). Diphyes prayensis Quot and Gaimard, '34, p. 106, pi. 3, fig. 37, 38. Praya diphyes Lesson, '43, p. 144 (non Kolliker, '53). Praya cymbiformis Leuckart, '53, p. 2, taf. 1, fig. 4; '54, p. 286, pi. 11, fig. 18-24; Hcxley, '59, p. 30; Keferstein and Ehlers, '61, p. 20, pi. 1, fig. 28; Haeckel, '88b, p. 146; Chun, '97b, p. 66, fig. 8; '97b, p. 102. Praya maxima Gegenbaur, '54a, p. 19, pi. 17, fig. 1-6; Haeckel, '88b, p. 146; Lens and Van Riemsdijk, :08, p. 17. Praya diphyes ? Huxley, '59, p. 52, pi. 3. Praya galea Haeckel, '88a, p. 35; '88b, p. 146, pi. 31, 32, Eudoxella galea Haeckel, '88b, p. 108, pi. 32. Praya (Huxleya) californica Gravier, '99, p. 87, fig. 1-4. Station 4574 surface 2 entire colonies and 1 detached nectophore. 4648 300 fathoms to surface 1 superior nectophore, 20 mm. long. " 4687 " " " " 1 nectophore, with basal part of stem and 1 reserve nectophore. 4703 " " " " 1 fragmentary nectophore. This species is so well known, and has been so well described and figured by Leuckart ('54), Gegenbaur ('54), and Haeckel ('88b) that no detailed account is necessary. The identification of the material has been made more certain by comparison with two excellently preserved colonies from the Naples Zoo- logical Station than could otherwise have been possible, and I have not found a single character, either in the chief nectophores, or in the groups of appendages, to separate Pacific from Mediterranean specimens. As elsewhere stated (Bigelow :11b, p. 342) one of the most serviceable field characteristics for distinguishing this species from Rosacea plicata which it resembles closely in general aspect, is the form of the hydroecium of the younger of its two chief nectophores. That this extends nearly or quite the entire length of the ventral surface of the younger (Plate 2, fig. 2), just as it does of the older nectophores in P. cijmbiformis, has long been known; but its importance as a diagnostic character seems to have been overlooked. Com- parison of the figures of the nectophores of the two species (Plate 2, fig. 1, 7) will show how evident the difference is. Furthermore no specimen shows the terminal dilation of the somatocyst, so characteristic of Rosacea plicata. In the colony figured (Plate 2, fig. 1), in which the chief nectophores were about 11 and ROSACEA PLICATA. 201 14 mm. long, only one very small bud for a reserve nectophore is to be seen (Plate 2, fig. 3) but in another specimen in which only one full grown nectophore is present, there is a reserve bell of considerable size. The single nectophore observed by Huxley, evidently the younger of the two definitive ones because part of the stem was attached, is included in the present species, because it has the long hydroecium characteristic of P. cymbiforviis. The only records of P. cymbiformis from the Indo-Pacific region are from the Indian Ocean and from Torres Straits (Huxley), from the Malay- sian region (Lens and Van Riemsdijk) from the coast of Lower California (Gravier), besides the present series from the Eastern Tropical Pacific. These few, however, are sufficient to show its wide distribution, and taken in connec- tion with its known occurrence in the Mediterranean and in the Atlantic indi- cate that it may be expected to occur throughout the warmer regions of the three great oceans. ROSACEA QioY and Gaimard, 1827. Lilyopsis Chun, '85. ? Rosacea plicata Quoy and Gaimard. Plate 2, figs. 7-9. Rosacea plicata Quoy and Gaimard, '27, p. 177, pi. 4B, fig. 4; Schneider, '98, p. 78. Rosacea ceutensis Blainville, '3-t, p. 140 (partim), p!. 6. Pmya diphyes Kolliker, '53, p. 33 taf. 9; Vogt, '54, p. 99, pi. 16, 17; Bedot, '82, p. 122 (non Lesson, '43, p. 144). Diphyes bragae VoGT, '51, p. 140. Praya filiformis Keferstein and Ehlers, '61, p. 20, taf. 5, fig. 8-11. Lilyopsis diphyes Chun, '85, p. 280; '97b, p. 102; Haeckel, '88b, p. 150. ? Rosacea ceute7isis Quoy and Gaimard, '27, p. 176, pi. 4B, fig. 2, 3. ? Rhizophysa filiformis Delle Chiaje, '29, tav. 50, fig. 3, '42, p. 135, pi. 149, fig. 3. Station 4661 300 fathoms to surface 2 fragmentary nectophores. " 4684 " " " " 1 .specimen with both nectophores. " 4685 surface 1 " 4705 300 fathoms " " 1 fragmentary nectophore. " 4740 " " " " 1 specimen, with both nectophores. In none of the specimens was anything but the basal end of the stem with a few small buds preserved. The nectophores were all separated. Those listed above as belonging together are united on the strength of being taken together, and since this species was comparatively rare throughout the area traversed, it is probable that the association is natural. Thej^ are easily dis- 202 ROSACEA PLICATA. tinguishcd from R. medusa (p. 203) by the depth of the hydroecium and the small nectosac. The provisional identification as plicata rests on their general resemblance to the Biscayan specimens of that species (Bigelow, : lib), especially in the shortness of the hydroecium of the younger nectophores. There is, however, a difference in the somatocyst. In all the Biscayan examples of plicata the upper end of the somatocyst turns dorsally, away from the dorsal face of the hydroecium which it follows for the rest of its length, and its terminal region is slightly thickened ; in some specimens it forms a definite egg-shaped dilation, and a more or less pronounced terminal swelling has usually been described. But in the Eastern Pacific speci- mens, the ascending branch of the somatocyst lies in the hydroecial wall to its very tip, and there is no terminal dilation. At first sight this difference sug- gested that the Pacific specimens might be specifically separate from the Atlan- tic ones. But the conditions in the latter are so variable that I doubt whether there is any actual discontinuity between the two; if not, the extremes would at the most represent varieties of the one species. To settle the question will require better preserved, and more extensive material from the Pacific. And until such is forthcoming the question may be left open. The hydroecium in the younger nectophores (Plate 2, fig. 7) is much shorter and deeper than it is in Praya cijmbiformis; as I have already noted (:11b), the difference affords a good field mark, even in the case of battered specimens, for the separation of the two. None of the older figures show the extent of the hydroecium in the younger nectophore, or even whether there is one, though Vogt ('54, pi. 17, fig. 3), has given a good representation of it in the older of the two chief nectophores. But neither Kolliker nor Vogt gave detailed figures of this portion of the colony, though they described the appendages fully. The older nectophores (Plate 2, fig. 9) are proportionately shorter and broader than those of P. cijinbiformis (Plate 2, fig. 2), and their hydroecial furrows much shallower, a feature probably connected with the loose associa- tion of the two nectophores, shown by Kolliker and by Vogt. But this feature is so often masked by distortion in preserved material that identification of the separate nectophores would be difficult or even impossible unless they were captured side by side with the better characterized younger nectophores to which they are normally attached. In none of the specimens was there a reserve nectophore, nor could I certainly identify the bud for such a structure. On account of the condition of the material, no description of the appendages is possible. ROSACEA MEDUSA. 203 The only previous records from the Indo-Pacific, which could belong to Rosacea plicata are the specimens from the Malaysian region, described by Lens and Van Riemsdijk (:08) as '?Lilyopsis diphyes Vogt. Rosacea medusa (Metschnikoff.) Praya diphyes Graeffe, 'GO, p. 11, taf. 1, figs. 1-3 (non Kolliker, '53; Vogt, '54). Praya medusa Metschnikoff, '70, p. 925, pi. 1. Lilyopsis medusa Chun, '85, p. 280. Lityopsis rosacea Chun, '85, p. 280; Bedot, '96, p. 309, pi. 12, fig. 1. Praya sp. ? Fewkes, '80a, pi. 3, fig. 2. Praya blaino Fewkes, '83a, p. 845. Praya gracilis Fewkes, p. '83a, p. 841. Rosacea diphyes Schneider, '98, p. 81. ? Lilyopsis catena Haeckel, '88b, p. 150. Station 4665, 300 fathoms to surface, one specimen. In the single specimen the two chief nectophores were still attached to each other, but both were somewhat battered. Only a very much contracted portion of the stem and appendages remains intact. So fragmentary is the latter that I can give no account either of bracts or special nectophores, both of which according to Graeffe ('60), Metschnikoff (70), and Chun ('85) are characteristic; the latter especially so in the presence, on the margin, of the tentacular rudiments. The nectophores are of equal size (11 mm. long), and similar in shape, both being somewhat triangular, and obliquely truncate basally with proportionately large nectosacs. So characteristic are these features, according to the figures and accounts of all previous authors, that they serve as excellent field marks to dis- tinguish this species either from R. plicata or from Praya cymbiformis (p. 200). As indicated by Metschnikoff ('70) and by Bedot ('96, pi. 12, fig. 1), neither nectophore encloses the other, but the two are merely closely opposed. The hydroecial grooves are broad but very shallow, and extend the entire length of the ventral surface, but, apparently, in life they do not form a closed tube except near the anterior end. None of the older figures show these ventral furrows clearly, but on the specimen studied they are plainly seen. The sub- umbral canals, though fragmentary, are sufficiently preserved to show that their course is a complex one, as observed by Chun and by Bedot, not straight as Fewkes ('80a, pi. 3, fig. 2) represented them. In neither nectophore is there a distinct terminal dilation of the nemato- cyst, such as has been figured by both Metschnikoff and Bedot; but the .shrivelled condition of these organs has no doubt obscured their normal form. The records of the occurrence of this species: — Mediterranean (Graeffe, Metschnikoff, Chun), Western Atlantic (Fewkes), Malaysian region (Bedot) 204 NECTODROMA DUBIA. and Eastern Tropical Pacific, suggest that it will be found generally distributed over the warmer regions of all three great oceans. So far as our present knowl- edge goes, it is a much less common form than either R. plicaia or P. cymbi- formis. NECTODROMA, gen. nov. Prayinae with the somatocj'st represented by a system of branching canals. Subumbral canals numerous (more than four) ; they may branch or anastomose. The only described species referable to the genus is the type, Di-phyes dubia Quoy and Gaimard. But the present collection contributes a second, N. reticulata, sp. nov. (p. 206) equally well defined. The branching somatocyst recalls the condition in Nectopyramis among Monophyids, and in Stephanophyes among Prayids. But the arrangement of the subumbral canals sharply distinguishes Nectodroma from the latter. The genus is included in the Prayinae rather than in the Stephanophyinae because the presence of a well-developed hydroecial groove in each nectophore suggests a biserial rather than a coronal arrangement of the bells. But the exact plan of architecture can not be determined until complete specimens are studied. Nectodroma dubia (Quoy and Gaimard). Plate 3, fig. 8, 9. Diphyes dubia Quoy and Gaimard, '34, p. 104, pi. 5, fig. 34-36. Praya dubia Lesson, '43, p. 143; (non Blainville, '34, p. 137, pi. 6, fig. 4). Rosacea dubia Schneider, '98, p. 79 (partini). Station 4652, 100 fathoms to surface; 2 nectophores, each about 40 mm. long. The rediscovery of a species so long unrecorded as A^. dubia is not the least interesting find in the present collection. And before proceeding with the description, I must observe that comparison between the "Albatross" speci- mens and Quoy and Gaimard's figures show that the latter, far from being founded on an "apokryphen Art," as Chun ('97b, p. 115) believed, were in reality extremely accurate representations of an important species. Unfortunately both of the "Albatross" nectophores are somewhat battered, but they are sufficiently well preserved to allow me to give an account of their more important anatomic features. Younger nectophore. It is probably correct to identifj^ as the younger nectophore the one which is still attached to the stem (Plate 3, fig. 8), for among the Prayinae it is usually the older one which is most easily detached. The NECTODROMA DUBIA. 205 general form of the nectophore is nearly cylindrical, truncate so obliquely at the base that the ventral wall extends below the level of the opening of the nectosac. Our example is proportionately longer and narrower than Quoy and Gaimard's figure; but as these authors expressly state that the gelatinous substance is very soft, this difference is merelj' an evidence of contraction or of preservation. The hydroecial groove is deep, and runs the entire length of the nectophore, though it is partially closed over anteriorly by a small gelatinous flap, and is enclosed by two lateral flaps, as Quoy and Gaimard observed. The somatocyst, as noted above, strongly suggests the corresponding struc- ture in Stephanophyes superba ; indeed, it was on the strength of this resemblance that Schneider believed that the two species were identical, a possibility negatived by the subumbral canals. Below the point of origin of the pedicular canal it runs as a single unbranched tube, along the dorsal surface of the hydroecium, to a point slightly below the bell opening. Its ascending trunk, however, splits into three branches near the anterior end of the nectophore, the median branch running directly dorsad (Plate 3, fig. 8) and the two laterals (Plate 3, fig. 9) curving posteriorly, with several minor lateral branches, to terminate slightly above the apex of the nectosac. Except for the exact positions and lengths of the minor branches, this agrees very well with the original account of the species. The most interesting feature of N. diibia is afforded by the subumbral canals. These were described by Quoy and Gaimard as being numerous, and running radially, as they do in various Medusae. And in the present specimens the subumbrella surface is ribbed radially (Plate 3, figs. 8, 9), precisely as they represented it. To determine whether these ridges do actually represent canals, I cut transverse serial sections of three, and on examination found that each was provided with an open lumen surrounded by a distinct laj'er of entoderm. The precise number of canals could not be determined because in each case one side of the nectosac was torn. Apparently there are twelve at the apex of the bell; and these branch so that there are about thirtj'-five at the margin. The number and arrangement of the canals distinguishes Nectodroma from all other Siphono- phores as yet known. Stem and appendages. Though a considerable length of spirally coiled stem is still intact, all of the appendages except a large number of proximal buds have been stripped off. It is important to note that in addition to the large and well-preserved muscular lamella to which the older nectophore was attached, there is a third much smaller lamella which probably bore a "reserve-bell " in life. Of course from the present material it is quite impossible to make out whether 206 NECTODROMA RETICULATA. more than two developed nectophores were normally present at one time; but the conditions outlined suggest three as the maximum. The older posterior nectophore, though much battered, is proportionately shorter and somewhat broader than the younger one. The structure of the somatocyst, with three branching ascending limbs, is the same, and there are numerous radial subumbral canals. The original record for this species was from the neighborhood of Kangaroo Island, off Adelaide, South Australia. Nectodroma reticulata, sp. nov. Plate 1, tigs. 7, 8; Plate 3, tigs. 1-7. Station 4681 300 fathoms to surface; 2 nectophores, and 3 bracts. Type. " 4709 " " " " 1 nectophore. " 4709 " " " " " " young, 15 mm. long. The nectophores and bracts taken at Station 4681 apparently all belong to one colony; and they are therefore made the basis of the description and figures. Both nectophores are about 55 mm. long, by 20 mm. in greatest diameter; they are similar in shape, and neither has the base of the stem still attached. In general form they are subcylindrical; truncate transversely at the anterior, obliquely at the posterior end. The hydroecial canal is deep (Plate 3, fig. 2) and extends the entire length of the ventral surface. In one nectophore it is entirely covered over by the lateral flaps, but in the other, the flaps are widely separate. Probably the latter was the older and partially enclosed the other, the younger. The nectosac is proportionately smaller than in N. dubia. The somatocj^st alone is sufficient to distinguish this species from P. dubia. Its descending branch, which extends below the level of the bell-opening (Plate 3, fig. 1), bears several short lateral branches. Its ascending branch runs along the surface of the hydroecium nearly to the anterior end of the nectophore, and then turns abruptly dorsad (Plate 3, fig. 2). Throughout its ascending course it gives off short transverse lateral trunks, which are themselves often divided at their extremities, and in its ventrodorsal extension there are numerous very much smaller lateral branches. In all the three large nectophores the general type of branching is the same, though the precise number, length, and arrange- ment of the lateral trunks varies slightly. The subumbral canals are numerous, as in P. dubia, and fundamentally radial, but their primitive arrangement is masked by branching and anastomosis. HIPPOPODIUS. 207 At the apex in the younger nectophore there are eight radial canals (Plate 3, fig. 4) ; but these all branch dichotomously at different distances from their points of origin ; and the resultant canals anatomose by means of short transverse trunks until they form an irregular reticulum covering the subumbrella surface (Plate 3, fig. 2). Fortunately in this one example the nectosac was in such good condition that the canals could be traced over most of its surface with ease. To make certain that the ridges actually represent canals, serial transverse sec- tions were cut of two adjacent ones, and in each the open lumen, surrounded by entoderm, was visible. Bract. Of course, in the entire absence of the stem, the identity, with P. reticulata, of the bracts (Plate 3, fig. 6) is rather doubtful. They are referred to it because of their occurrence in the same haul, and because they differ from the corresponding structures yet described for any other Praj'id, in their large size (20 mm. in length), and lateral flattening. The condition of the somatocyst and of the subumbral canals in the j'oung nectophore (Plate 1, figs. 7, 8) suggest that it is a young stage of P. reticulata. The somatocyst is thicker, its lateral branches proportionately stouter, and its ventrodorsal arm bends posteriorly corresponding to a curving of the nectophore as a whole. The subumbral canals are evidently radial, and the development of cross-trunks has not proceeded so far as in the older nectophores. But the condition in the latter may be easily derived from the former by progressively increasing anastomosis. Indeed the beginnings of the process are clearly fore- shadowed by the few transverse canals which already connect several of the radial canals. The general form, and the well-developed hydroecium extending from end to end, also suggest that the specimen is a young nectophore of N. reticulata. Hippopodiidae Kolliker, 1853. Following (Chun, '97bj two genera, Hippopodius and Vogtia, are recognized. Schneider ('98) has united these. But though they are no doubt closely allied, the difference in the structure of the nectophores seems of more than specific importance. Were subgenera recognized, Vogtia would be considered one. HIPPOPODIUS QuoY and Gaimard, 1827. For the reasons for the use of this name rather than Gleba, see Chun ('97b) and Schneider ('98). Chun recognizes two species of Hippopodius, the well- known Atlantic and Mediterranean form so often described under the names 208 HIPPOPODIUS HIPPOPUS. H. luieus and H. gleba, and the H. (Polyphyes) ungulata of Haeckel. The H. neapolitanus of KoUiker and Weismann, was retained as distinct by Haeckel ('88b) on the grounds that in it cf and 9 gonophores are associated with each other, whereas in luteus they are all separate. The structure and arrange- ment of the gonophores in this genus has been examined in detail by Richter ( : 07) . He has shown that normally male and female gonophores are associated together, but not with the numerical regularity ascribed to them by Weismann ('83). I may add that all the specimens studied, both Atlantic and Pacific, which were well enough preserved to show the gonophores at all, agreed with his account. I therefore follow Chun ('97), Schneider ('98), and Lens and Van Riemsdijk (:08) in uniting neapolitanus and luteus under H. hippopus Forskal. The status of the Polyphyes ungulata of Haeckel which is undoubtedly a Hippopodius, is doubtful. It is retained by Chun as distinct, but united with H. hippopus by Schneider. Leaving out of account the question of unisexual or bisexual cormidia, ungulata is supposed to differ from hippopus only in the presence of six prominent irregular teeth, four dorsal and two ventral, on the margin of its nectophores. According to Schneider the presence or absence of these teeth is merely an evidence of individual variation. And several of the many nectophores of H. hippopus which I have examined approach Haeckel's figures in this respect. It is of course the constancy of the difference which must determine its importance in classification. Under the circumstances it seems best to class H. ungulatus as a doubtful synonym of hippopus. I believe that Schneider was justified in substituting Forskal's name hippo- pus for luteus as the specific designation of the one well-known member of the genus, because, though Forskal's figures are not sufficiently detailed for absolute determination, the probability of their identity with H. luteus is very strong. That they do belong to some Hippopodius has generally been accepted; indeed Chun, who uses the name luteus, includes hippopus as a doubtful synonym of it; and since they can hardly be identified with H. ungulatus for the want of promi- nent teeth, there seems no course open but to refer them to the only other species of the genus. On general principles it is always desirable, for the sake of sta- bility, to identify the older figures and accounts with actual species; and it seems entirely justifiable in the present instance. Hippopodius hippopus (Forskal) Schneider. Gleba hippopus ForskAl, 1775, p. 14, 1776, taf. 43, fig. E; F'ewkes, '82b, p. 304, pi. 1, figs. 31-33. Gleba excim Otto, "23, p. 309, taf. 42, fig. 3 a-d. Hippopodius luteus QuoY and G.\imard, '27, p. 172, pi. 4A, fig. 1-12; Eschscholtz, '29, p. 146; Delle HIPPOPODIUS HIPPOPUS. 209 Chiaje, '42, tav. 92, fig. 7, tav. 149, fig. 1, 2; Lesson, '43, p. 473; Vogt, '54, p. 93, taf. 14, fig. 7-12, taf. 15, fig. 1, 2; Muller '70-'71, taf. 11, fig. 8, taf. 13, fig. 1-8; Chdn, '88, p. 1165; '97b, p. 34; Lens and Van Riemsduk, :08, p. 62, Hippopus excisiis Delle Chiaje, '29, p. 64; '42, pi. 149, fig. 1, 2. Stephanomia hippopoda QuoY and Gaimard, '34, p. 67, taf. 2, fig. 13-21. Protomedea lutea Blainville, '30, p. 110; '34, p. 121, pi. 2, fig. 4. Protomedea uniformis Blainville, '30, p. 110. Protomedea calcearia Blainville, '30, p. 110. Protomedea notata Blainville, '30, p. 110. Hippopodius mediterranaeus Costa, '36, p. 3, taf. 2. Elaphanlopes neapolitanus Lesson, '43, p. 473. Hippopodius neapolitanus Kolliker, '53, p. 28, taf. 6, fig. 1-5; Weismann, '83, p. 194, taf. 20, taf. 21, fig. 9-13. Hippopodius gleba Ledckaht, '54, p. 299, taf. 12, fig. 1-4; Keferstein and Ehlers, '61, p. 22, taf. 5, fig. 18-21; Haeckel, '88b, p. 178. Polyphyes luteus Haeckel, '88a, p. 36. Polyphyes elephantopus Haeckel, '88b, p. 364. Hippopodius hippopus Schneider, '98, p. 82, Richter, : 07, p. 589, taf. 28, figs. 27-34, taf. 29. ? Polyphyes ungulala Haeckel, 'S8b, p. 179, ])!. 29, fig. 1-8. ? Hippopodius ungulatus Chdn, '97b, p. 103. Station 4644 surface 4 loose nectophores. " 4646 300 fathoms to surface 2 " " 4652 400 " " " 4 specimens with 3, 1 with 5, and 1 with 2 nectophores, and 4 larger detached nectophores. 4655 400 fathoms to surface 2 excellent specimens, with 4 and 5 nectophores respectively. 4659 300 fathoms to surface 1 large detached nectophore. " 4704 surface 2 excellent specimens, with 3 and 7 nectophores respectively. " 4734 300 fathoms to surface 3 detached nectophores. The largest nectophore is 15 mm. long. The identification of the very well-preserved material listed as belonging to the well-known Atlantic species rests upon actual comparison between it and a number of good specimens from the West Indies and from the Mediter- ranean. I have not been able to find a single character to separate the two; this same conclusion was reached by Lens and Van Riemsdijk for the Malaysian specimens collected by the "Siboga." H. hippopus has so often been described and figured that no account is needed here, further than to note that while the younger nectophores have the basoventral margin more sharply concave and the dorsolateral prominences more tooth-like than do older ones, the two dorsal prominences though somewhat variable in size, are merely small, rounded knobs, in all that I have examined, both young and old. They are never triangular and pointed as Haeckel has described and figured them 210 VOGTIA SPINOSA. for his H. ungulata. So far as the outUne of the basoventral margin is concerned ■ there is very Uttle variation in the form of the older nectophores except such as is due to violent contraction. With regard to the coloration of this species I may note that while most of the specimens were entirely colorless except for the yellow tentilla, the nectophores in the two examples from Station 4707 were pale emerald-green, the tentacles bright yellow, and the siphons a brilliant carmine. This color difference, certainly not of any systematic value since the brilliant specimens were anatomically indistinguishable from the others, is probably the external indication of different physiological states, perhaps of nutrition. So far as I can learn, Hippopodius has only once been recorded from the Indo-Pacific region (Lens and Van Riemsdijk). The present captures show that it is generally distributed over the Eastern Tropical Pacific. VOGTIA KoLLiKER, 1853. At most only two species of Vogtia can be recognized, V. pentacantha Kolliker, and V. spinosa Keferstein and Ehlers ( = V. kollikeri Haeckel) ; neither of which has been thoroughly studied. Indeed the latter is known from detached nectophores only. Fortunately the "Albatross" collection contains a well- preserved series which agree so closely with the figures of V. spinosa by Keferstein and Ehlers and Haeckel, that I have no hesitation in uniting them. The question whether spinosa is actually distinct from pentacantha, with which it is united by Schneider, is still an open one. The evidence afforded by the single specimen of the latter which I have had the opportunity to study (:11b, p. 35), together with the various figures of it which have been published (Kolliker, '53, KefTerstein and Ehlers, '61, Chun, '97b), seem to show that the differences in the form of the nectophores, and especially in the location of the gelatinous spines, are sufficient to separate the two species. However, a final decision is impossible until the constancy of the two characters in question has been tested on a considerable series of pentacantha. The union of Haeckel's V. kollikeri with spinosa, proposed by Chun ('97b, p. 35) is undoubtedly necessary. Vogtia spinosa Keferstein and Ehlers. Plate 15, fig. 5-12. Voglia spinosa Keferstein and Ehlers, '61, p. 24, pi. 5, fig. 16; Haeckel, '88b, p. 364; Chun, '97b, p. 103. Vogtia kollikeri Haeckel, '88b, p. 182, pi. 29, fig. 9-14. Station 4646 tc 4652 ii 4671 (I 4673 ii 4679 a 4681 li 4705 ii 4740 VOGTIA SPINOSA. 211 300 fathoms to surface 1 specimen with 4 nectophores and 6 detached nectophores. surface 1 specimen with 6 definitive nectophores. loose nectophores. 300 fathoms to surface. " " " "1 specimen with 10 nectophores, and 7 detached nectophores. " " " " 1 specimen with 13 nectophores. " " " " 1 specimen with 11 nectophores. " " " " 3 large detached nectophores, in poor condition. The arrangement of tlie nectophores follows exactly the same plan as it does in the better known genus Hippopodius. As in that genus the nectosome is composed of two series of obliquely placed alternating nectophores, the oldest at the bottom. Their concave ventral surfaces form a typical hydroecial canal, within which the stem with its appendages is entirely retracted in all the speci- mens studied (Plate 15, fig. 5). Observations on the living colonies showed that the nectosome is no more effective as a swimming organ in Vogtia than it is in Hippopodius. Indeed the arrangement of the nectophores precludes the possibility of any but the oldest two so serving. In all the others the opening of the nectosac is closed by the anterior surface of the neighboring nectophore. As in Hippopodius the necto- phores are attached to a zigzag muscle band, which, as Chun has shown ('97a), is nothing more than the very much prolonged "Knospungszone." So close is the resemblance in this particular between the two genera that except for the form of the nectophores Chun's figure ('97a, fig. 11) of a longitudinal section of the siphosome of Hippopodius might equally well apply to Vogtia. Nectophores. The older nectophores, as shown by Haeckel ('88b, pi. 29, fig. 12) may be likened in their outlines to short pentagonal prisms (Plate 15, fig. 9). The largest are about 20 mm. broad. The arrangement of the char- acteristic gelatinous tubercles or spines can be better shown in the figure than in the description; but I may call attention to the fact that they occur closely crowded not only on the margins of the facets, but on the lateral and dorsal facets themselves. In V. penlagona, so far as we yet know, they are entirely restricted to the angles. The ventral facet, which is deeply concave, is without spines. The youngest nectophore in one colony, 3 mm. broad, is more nearly rectangular, when seen from the basal side, and it has spines only on the dorsal 212 VOGTIA SPINOSA. facets, as yet hardly divided by the dorsal angle (Plate 15, fig. 11). In a slightly older example (Plate 15, fig. 12), the dorsal angle is so much more prominent, that the form is now clearly pentagonal. All the specimens were examined to test the constancy of the occurrence and arrangement of spines, and in all but one they showed the typical condition outlined above, though with some minor individual variation in the number and precise location of the spines, a variation which might have been expected. In a single example, however, while the youngest nectophores wore spinous on their dorsal and dorsolateral facets, the oldest three have no spines on either angles or facets, although they are of the usual pentagonal form. The colony is in such good condition as a whole that the absence of spines can not be charged to poor preservation. So constant in occurrence and location are these structures in all the other specimens and so typical are they in the young nectophores of the aberrant example, that their absence in the older nectophores is difficult to account for. But a sporadic variation of this kind does not point to a connec- tion between the "spinosa" and " pentacantha" types of spination. On the contrary, in this specimen there is an entire abortion of spines which are well developed at a younger stage, whereas in V. pentacantha (Bigelow, : lib, p. 351) there are no spines on the facets at any stage in growth. The nectosac is broad and shallow as in Hippopodius, and its four radial canals (Plate 15, fig. 9-12) follow a nearly direct course, as in that genus. Haeckel ('88b) has already observed that there is a crescent-shaped ventral sinus connected with the ventral radial canal. In young nectophores this sinus, walled with flat tile-shaped cells, covers nearly the entire upper surface of the nectosac (Plate 15, fig. 11), but with the increasing development of the nectophore, it becomes proportionately much smaller. The pedicular canal, of course, con- nects with the axial canal of the "Knospungszone." Stem and appendages. In life the stem was extensible to a considerable length. The individual appendages so closely resemble those of Hippopodius that no extended account is necessary here. I may, however, call attention to the fact that, as Kolliker observed for V. pentacantha, each cormidium has both d' and 9 gonophores (Plate 15, fig. 8). The tentilla (Plate 15, figs. 6, 7) very closely resemble those of Hippopodius. In V. pentacantha, according to Kolliker ('53), Keferstein and Ehlers ('61), and Claus ('63), the tentilla are bright yellow, but in the present specimens they were brick-red in life. Should this color difference prove constant it might be considered a specific character. But color among Siphonophores is so often variable that it is unsafe to lay stress upon it until it has been tested. ABYLINAE. 213 The only previous records for F. spinosa are from off the coast of Brazil (Keferstein and Ehlers), from the South Atlantic 37° 3' S., 44° 17' W. (Haeckel), and probably from the Bay of Biscay (Bigelow, 'lib, p. 351). The present cap- tures, from widely separated localities in the Eastern Pacific suggest that, like so many other Siphonophores, it is distributed generally over the warmer regions of all three great oceans. V. pentacantha is known from the Mediter- ranean and from the Atlantic (Bay of Biscay, Bigelow, :11b, p. 351; Equatorial current, Chun, '97b, p. 35). The genus is also credited by Delage and Herouard (:01, p. 272) to the Pacific. Diphyidae Eschscholtz, 1829.' Abylinae L. Agas.siz, 1862. As Chun ('97b) has pointed out, it is much more difficult to separate the Abylinae into several natural genera than the other Diphyidae. Since the appendages of all species of the subfamily are set free as Eudoxids, and since none have special nectophores in the Cormidia, the genera or subgenera as yet proposed rests on such characters as the structure of the bracts, and the external sculpture of the nectophores. Haeckel ('88b) recognized three genera of Abylinae: — Abyla, Bassia, and Calpe, basing the distinction on the form of the bracts and of the posterior nectophore. Chun ('97b) has adopted the same classification, with the excep- tion that he reduces the divisions to the rank of subgenera, and substitutes Abylopsis for Calpe, because the latter is preoccupied for a genus of Lepi- doptera. A rather different scheme is used by Lens and Van Riemsdijk (:08), who list two genera, Abyla and Abylopsis, though without defining them, (leaving out of account, for the moment, their new genus Diphyabyla) ; while Schneider ('98) recognizes only one genus, Abyla. The present collection, embracing as it does all the well-founded species of the subfamily, including both nectophores of the little known leuckartii, together with the various Eudoxids, gives an opportunity to test the importance of the characters on which the schemes of Haeckel and of Chun rest. When we analyze the structure of the posterior nectophore, we find that its form is best expressed, not as trigonal, tetragonal, or pentagonal as Haeckel characterized it, but in terms of the number of ridges, which are the basis for its external outlines. In three species, i. e. telragona, eschschoUzii ("quincunx" Chun), and leuckartii, there is a dorsal, and on either side a well-developed 214 ABYLINAE. lateral ridge, in addition to the ventral angles. In one species, trigona, in which the nectophore has been described as trigonal, the right lateral ridge is nearh- but not altogether, suppressed. In one, bassensis, the dorsal ridge is entirely lacking, and in the latter alone is the hydroecium a closed tube. Thus, although the nectophore of bassensis is truly tetragonal as Haeckel supposed, we can not draw any sharp line between the "pentagonal" nectophore, e. g. of tetragona, and the "trigonal" one of trigona; therefore the structure of this nectophore alone would justify only two groups, bassensis being opposed to all the other species. When we study the anterior nectophore, we find that so far as it is concerned, the Abylinae fall into two main groups. In the one are leuckartii, trigona, and haeckeli, which agree in that the nectophore has a rectangular apical facet, and in the general arrangement of facets and ridges, the only difference of much importance between them being that the simple ventrolateral facet of leuckartii is subdivided in the other two species by a transverse ridge. This may be called the "trigona" tj'pe. In the other group are tetragona, eschschoUzii, and bassensis in which the nectophores, distinguishable from one another only by minutiae of form, have no apical facets, the lateral ones of the two sides joining apically in a ridge. It is evident that while the use either of the anterior or of the posterior nectophore as the prime factor in generic subdivision results in two groups of AbyUnae, the hne of demarcation between the two differs, according as we choose one or the other nectophore as our guide. On a priori grounds we might expect that the anterior one, being phylogenetically the older, might be the more important, and this view is supported by the structure of the bract. It appears that Haeckel was in error in drawing a parallel between the bract and the posterior nectophore in all cases, because the "Amphiroa" type, instead of being restricted to species with apparently trigonal lower nectophore as he supposed, is also found in one species, leuckartii, in which both dorsal and lateral ridges are well developed in the posterior bell. But the two other species which agree with the latter in the pentagonal form of the posterior nectophore, have very different bracts, namely the "Aglaisma" type. Bassia bassensis alone is distinguished from all other Abylinae by the structure of both posterior nectophore and bract. In comparing the bract with the anterior nectophore, we find a close correspondence in place of the confusion just outlined. Thus in all species with the "trigona" type of anterior nectophore (including leuc- kartii, as I have determined, p. 218), the bract is an "Amphiroa." And of the ABYLINAE. 215 three species with "tetragona" type of anterior nectophore in two, tetragonn and eschscholtzii, the bract is an "Aglaisma." In brief, then, Haeckel's three genera, as he defined them, rest on a mis- interpretation of the structure of trigona, and an ignorance of A. leuckartii. But the combined evidence of the anterior nectophore and bract shows that the three divisions recognized by Haeckel and Chun are vahd, though on grounds other than those employed by Haeckel. To these must be added Diphyabyla hubrechti Lens and Van Riemsdijk, a form as yet known from the anterior nectophore only. In its essential features it agrees with the corresponding structure in ^4. leuckartii; but its pyramidal external outline, and the form of the nectosac, are so aberrant that it is best retained as a separate genus, at least until its posterior nectophore and Eudoxid are known. This is the only Abylid which can not be connected, even provi- sionally, with any known Eudoxid. Most students agree that the species listed by Chun ('97b) are all worthy of recognition; and to them must be added Abijla haeckeli Lens and Van Riemsdijk, closely allied to — A. trigona, hut separated from it by a constant, if minor character. I regret that in the following description two nomenclatural changes have been found necessary: — .4. pentagona Quoy and Gaimard, a name long used, must be supplanted by tetragona Otto (p. 224) ; and quincunx Chun, by eschscholtzii Huxley (p. 227). There are three Eudoxids, probably belonging to this subfamily, as yet unconnected with their respective polygastric stages; these are Ceratocymha sagittata (Quoy and Gaimard) Chun, Enneagonoides quoyi Huxle}^ and E. picteti Bedot. Key to the polygastric state. I. Anterior nectophore with rectangular apical facet; posterior nectophore essentially pentagonal, its hydroecium open; bract of "Amphiroa" tj-pe. Abyla. a. Anterior nectophore with one ventrolateral facet on each side; not divided transverse!}'. a'. Posterior nectophore with a well-developed ridge on either side; somatocyst of the bract recurved at its tip ("Ceratocymba"). A. leuckartii. h. Two ventrolateral facets, apical and basal, on either side of the anterior nectophore. Posterior nectophore with lateral ridge almost suppressed, strongly asymmetrical. 216 ABYLA LEUCKARTII. b'. Anterior nectophore with simple ventral facet, contracted near the middle. A. trigona. c. Anterior nectophore with the ventral facet divided into two by a transverse ridge. A. haeckeli. 2. Anterior nectophore without apical facet, the lateral facets on the two sides meeting at apex in a ridge. Posterior nectophore with both dorsal and lateral ridges well developed. Its hydroecium open. Abylopsis. a. Basal portion of posterior nectophore strongly asymmetrical; the canals of its nectosac with basal dilations, and following an aberrant course (Plate 14, fig. 7). A. tetragona. h. Basal portion of posterior nectophore subsymmetrical ; canals of its nectosac of ordinary type. A. eschscholtzii. 3. Anterior nectophore as in Abylopsis; posterior nectophore with dorsal ridge entirely absent; its hydroecium a closed tube. Bract of "Sphenoides" type. Bassia B. bassensis. 4. Anterior nectophore pyramidal; pointed apically: resembling externally the Diphyids; its facets agreeing in their essentials with those of A. leuckartii. Nectosac reaching high above the level of its pedicular canal. DiPHYABYLA. Diphyabyla hubrechti. ABYLA QnoY and Gaimard, 1827. Abyla leuckartii Huxley. Plate 1.3, fig, 5-8; Plate 15, fig. 3, 4 Eudoxid. Abyla leuckartii Huxley, '59, p. 49, pi. 3, fig. 2; Agassiz and INIayer, :02, p. 165 (partim); Lens and Van Riemsdijk, : 08, p. 34, pi. 5, fig. 42-46. Enneagonum leuckarlii Schneider, '98, p. 93. ? Ahyla trigona Chun, '97b, p. 31 (partim). Station 4592 surface 1 anterior nectophore. " 4661 " " " " 4667 300 fathoms to " " " ABYLA LEUCKARTII. 217 Station 4671 300 fathoms to surface 1 anterior nectophore " 4fi7fi " " " " " " " " 4707 " " " " " " " " 4708 surface; 2 specimens with both anterior and posterior nectophore. The largest anterior nectophore is 9, the smallest 4 mm. long. The pos- terior nectophore is 4.5 mm. long. Abyla leuckartii has been recorded twice since it was described by Huxley with a total of eleven specimens; and of the two described by Agassiz and Mayer (:02, p. 165) one, from its "narrow elongated, five sided" pyramidal form, certainly does not belong here. The description of the nectosac as long and tapering to a point near the apex of the bell, as well as a sketch from life sub- mitted to me by Dr. Mayer, shows that the individual in question was in reality a Diphyabyla. The external form of the anterior nectophore of this species, which is so characteristic that there is no danger of confusing it with any other Siphono- phore, has been well figured by Lens and Van Riemsdijk, and its ridges and facets described by them in great detail. As a guide to identification the following brief account is given. The nectophore is pentagonal in side view; the upper portion rectangular; slightly longer than broad, and laterally compressed. The ridges are 2 dorsals, 2 laterals, 2 ventrals, and two which bound the roughly rectangular apical facet. The two ventral ridges come together basally to form a single tooth, and each of the two dorsal ridges ends in a large basal tooth. There is also a prominent triangular tooth on each side interrupting the basal margin of the nectophore opposite the dorsal face of the hydroecium. But the lateral ridges instead of reaching these teeth terminate some distance above them. These lateral ridges follow a characteristically curved course. The basal parts of all the ridges are strongly serrate in the present specimens, but apparently less so in the "Siboga" material. The nectosac is cylindrical, and reaches nearly to the apex, as does the hydroecium (Plate 13, fig. 5). The somatocyst is very large, ovoid, its long axis lying nearly apicobasal. At its upper end it connects with the stem by a narrow canal. Up to the present time the species has been known from anterior nectophores only, and Schneider has referred it to Enneagonum ( = Cuboides) on the assumption that no posterior nectophore occurs. Two specimens in the present series (Plate 13, fig. 5) with small posterior necto- phores still attached, and others with easily distinguishable reserve buds were 218 ABYLA LEUCKARTII. therefore especially valuable. The posterior nectophore in both instances was still entirely enclosed in the hydroecium, being attached to the base of the stem by a long pedicular canal. But when detached and studied each proved to be far enough advanced in development to show the general characters, (Plate 13, fig. 5). The posterior nectophore is comparatively long and narrow (Plate 13, fig. 6) and laterally compressed; its general appearance suggests the correspond- ing structure in Diphyes bojani (p. 253). There is a well-marked dorsal ridge extending from apex to base, and on each side a lateral ridge arising at about the level of the top of the nectosac. Each of these ridges terminates in a large triangular serrate tooth, and there is also on either side a tooth at the dorsobasal margin of the hydroecium, the left hand one being much the larger. The hydroecial groove, as in D. bojani, is open throughout its length, but it is covered over by two lateral wings. A characteristic feature is that the left wing bears a secondary flap with undulating margin, on its inner face near the base, while the right wing bears two such flaps (Plate 13, fig. 7). The nectosac is of the usual form, nor do its canals present any features of special interest. The discovery of a group of appendages, rather far advanced in development, is likewise important, not only because the structiu'e of the cormidia was pre- viously entirely unknown, but especially because the structure of the somato- cyst of the bract suggests that it may be an early stage of the interesting Eudoxid known as "Ceratocymba." In the present example the somatocyst is of the "Amphiroa" type, consisting of a descending sac, and two more slender diverging canals; and the former, seen in side view, is curved upward sharply near its free end. A comparison between it and the various figures of Cerato- cymba (Bedot, :04, Lens and Van Riemsdijk, :08) as well as with the "Alba- tross" specimens of the latter (Plate 15, fig. 3, 4) shows that the resemblance between the two, in so far as this character is concerned, is an extremely close one. The general form of the bract is not yet sufficiently advanced to show its final outline, but its large descending scale-like portion resembles in its general form and proportions the corresponding region in Ceratocymba. It is already divided into three facets, a dorsal, and two laterals, and of the latter the right hand one is already the larger, a character which foreshadows the asymmetry of the bract in the free "Ceratocymba" Eudoxid. The apical portion of the bract, still divided for the passage of the stem, corresponds to the dorsal facet of the latter. As to the arrangement of its ridges nothing can yet be said. There are two gonophores, one well developed (apparently cf), one still merelj- a bud. The ABYLA LEUCKARTII. 219 larger is proportionately very broad; but the basal tooth and particularly the pronounced serrations of the hydroecial wings suggest the conditions in the corresponding regions in Ceratocymba (Bedot, :04, pi. 1, fig. 1). The siphon has a well-developed basigaster, but neither it, nor the tentacle, shows any features of special interest. The tentilla are of the ordinary Abylid type. On the whole, the resemblance of the cormidium to Ceratocymba is so close that I have no hesitation in identifying the latter as the free Eudoxid of Abyla leuckartii. Chun ('88, '97b) has already suggested that Iho polygastric stage of the "Ceratocymba" Eudoxid would prove to be an Abylid, basing this view on the remarkably close resemblance between the bracteal canals in Ceratocymba and in the Eudoxid of Abyla irigona, though admitting ("97b) the possibility that it might be derived from a Monophyid. Schneider ('98) as noted above, united it previously with Abyla leuckartii, though he believed that the latter was a Monophyid. Two species of Ceratocymba, C. sagittata (Quoy and Gaimard) Chun, from the Atlantic, and C. asymmetrica Lens and Van Riemsdijk, from the Malay- sian region, have been described. Lens and Van Riemsdijk (:08) refer the specimens from between the Azores and Portugal, described by Bedot ( : 04) as C. sagittata to their asymmetrica. 1\\ as much as they have had the opportunity of examining well-preserved material of C sagittata, identified by Chun, I accept their identification. The slight asymmetry of the descending posterior portion of the bract which is already visible in the early stage described above, suggests that it is asymmetrica. The facts that asymmetrica occurs side by side with ^4. leuckartii in the Indo-Pacific region, that it was taken by the "Albatross," and that both it and A. leuckartii are known from the Atlantic as well, is good evidence that it is asymetrica which is the Eudoxid of leuckartii. The synonymy of the Eudoxid is : — Ceratocymba asymetrica Lens and Van Riemsdijk. Ceratocymba asymmelrica Lens and Van Riemsdijk, : 08, p. 9, pL 1, fig. 2-5. Ceratocymba sagittata Bedot, :04, p. 1, pi. 1, fig. 1, (non Chun, '88). It was taken at Stations 4667, 4669, 4671, 4673, 4708, 4715, 4723, 4725, both in surface and in 300 fathom hauls. The total number of specimens is fifteen. All the bracts, of which the largest was 19 mm., the smallest, 6 mm. long, were in good condition. The large gonophores were all badly crushed and distorted; but most of the smaller ones, 6-10 mm. long, were well preserved. The form of the bract is characteristic, and shows the most important feature 220 ABYLA LEUCKARTII. distinguishing the species from the Eudoxid described by Chun as C. sagittata. Even in the smallest examples it already shows the characteristic form and asymmetry. Its various angles and facets have been described by Lens and Van Riemsdijk; but their account is so complex that a more simple summarj', with the accompanj'ing figures, may be useful for identification. The bract is composed of five distinct facets (six if we follow Lens and Van Riemsdijk in applying this term to the hydroecial cavity). These are a ventral, an apical, and three which together compose the arched dorsal surface. The apical (anterior) is an irregular tetrahedron, placed obliquely. The three dorsal facets are separated from each other by two dorsal ridges, running to the base from the two dorsal angles of the apical facet. These ridges are not symmetri- cally placed, for the right hand one lies nearly in the main longitudinal axis of the nectophore, whereas the left hand one is far to the left of it (Plate 15, fig. 4). Consequent on the positions of the ridges the three dorsal facets are asymmetrical, the left hand one very short, the central and right hand ones much longer and broader. Lens and Van Riemsdijk suggest that the asym- metry is due to the absence of a ridge which may be supposed to have primitively been present on the right hand side, subdividing the right dorsal facet longi- tudinally. But it seems to me that no such assumption is required. If we compare the bract of this form with that of Abyla trigona ("Amphiroa alata") we find that its apical facet corresponds in position to that of the latter, and that it would require only a slight distortion to make its mid-dorsal facet corre- spond to the dorsal, its right and left dorsal facets to the right and left laterals of "Amphiroa." In other words were the apical facet of Ceratocymba a true rectangle as it is in Amphiroa, instead of a rhomboid with unequal angles, and were the basal outline transversely truncate instead of angular, the asym- metry characteristic of the former would disappear, and the two would agree. If we accept this explanation it is easy to derive the form of the adult bract from that of the younger one described above. The two laterals of the latter would correspond to the right and left dorsals, the dorsal to the mid-dorsal of the former. The only facet of the "Amphiroa" which is not represented in "Ceratocymba" is the basal one. This is suppressed by the form and large size of the ' hydroecial cavity. A diagnostic character only second in importance to the asymmetry of the bract is afforded by the somatocyst, the stout single median descending branch of which is curved dorsad near its tip in an extremely characteristic manner. So far as I know, no other Amphiroa-like Eudoxid possess this character; and it therefore assumes greater systematic importance ABYLA TRIGONA. 221 than its slight anatomical significance would suggest. It is, as noted above, largely on account of the curved somatocyst in the bracts of Abyla leuckartii that I have identified the latter as the young stage of the "Ceratocymba." In several examples there are two gonophores. A. leuckartii has so far been recorded, in its polygastric state, only from the Indo-Pacific region, where it is widely distributed in warm waters. But that it also occurs in the Atlantic, where it has been generally overlooked, is proved by an excellent and altogether typical specimen which I collected in the West Indies, and which is now in the collection of the Museum of Comparative Zoology. Its occurrence in the West Indies has also been reported to me by Dr. A. G. Mayer. Abyla trigona Quoy and Gaimard. Plate 13, figs. 3, 4. Abyla trigona Quoy and Gaimard, '27, p. 14, pi. 2B, fig. 1-8; Eschscholtz, '29, p. 131; Blainville, '30, p. 123; '34, p. 135, pi. 4, fig. 4; Gegenbaur, '60, p. 337, taf. 26, taf. 27, fig. 9-12; Chun, '88, p. 1160; 97b, p. 31; Schneider, '98, p. 90; Lens and Van Riemsdijk, .-08, p. 28, pi. 4, fig. 34-36 (non Huxley, '59, p. 47, pi. 3, fig. 1). Amphiroa alata Blainville, '30, p. 121; '34, p.'133, pi. 4, fig. 1 (Lesueur, Manuscr.); Huxley, '59, p. 64, pi. 5, fig. 1; Chun, '88, p. 1160; '97b,p.31; Lens and Van Riemsdijk, : 08, p. 28, pi. 4, fig. 37, 38. EUDOXID. Diphyes abyla Quoy and Gaimard, '34, p. 87, pi. 4, fig. 12-17. Eudoxia trigonae Gegenbaur, '60, p. 349, taf. 27, fig. 10-12. Eudoxid. Abyla carina Haeckel, '88b, p. 156, pi. 35. Amphiroa carina Haeckel, '88a, p. 33; '88b, p. 114, pi. 36. Eudoxid. Amphiroa trigona Haeckel, '88a, p. 33; '88b, p. 113. Eudoxid. The polygastric stage was taken at Stations 4646, 4673, 4684, 4713, 4715; seven entire specimens and two loose anterior nectophores, in both surface and 300 fathom hauls. The largest anterior nectophores are about 6 mm. long, the posterior ones 7-13 mm. I have been able to compare these very well-preserved specimens with an Atlantic series, with which they agree so closely that I have no doubt of their specific identity. The same conclusion was reached by Lens and Van Riems- dijk for the "Siboga" collection. A. trigona has been so well described by the various authors listed in its synonymy that no detailed account is called for. The only species of the genus with which it might be confused is ^4. haeckeli Lens and Van Riemsdijk, and the presence of a single ventral facet in the superior nectophore of trigona (Plate 13, fig. 4) instead of two ventral facets as in haeckeli (Plate 13, fig. 2) readily separates the two. For a detailed account of the facets and ridges, see Lens and Van Riemsdijk, : 08, p. 29. The posterior nectophores agree very well with the accounts by Gegenbaur ('60) and by Haeckel ('88b). 222 ABYLA HAECKELI. Their apparently trigonal form is diagnostic, but, as Haeckel observed, this form is apparent rather than real, because the right lateral ridge, though insignificant, can be traced at least for the lower one third of its course. The importance of the posterior nectophore in classification, has already been discussed (p. 214). The identity of the Amphiroa alata of Huxley, from Torres Straits with the corresponding Eudoxid from the Atlantic described by Blainville, Gegenbaur, and Haeckel has been maintained recently by Lens and Van Riemsdijk; and comparison of the present series with a collection from the West Indies shows that they were correct. Gegenbaur, who traced the development of Amphiroa alata proved that it is the Eudoxid of A. trigona. The bracts, even before their detachment, show the characteristic "Amphiroa" structure, (Haeckel, '88b). A. trigona is widely distributed over the Mediterranean and the warmer portions of the Atlantic, as well as the Eastern Tropical Pacific, and the Malaysian region. Apparently it has not been recorded from the Indian Ocean; but in view of its known distribution it may be expected to occur there. Abyla haeckeli Lens and Van Riemsdijk. Plate 13, fig. 1, 2. Abyla haeckeli Lens and Van Riemsdijk, :08, p. 32, pi. 5, fig. 39— iL Abyla trigona Huxley, '59, p. 47, pi. 3, fig. 1 (non Qdoy and Gaimard, '27). ? Amphiroa angulala Huxley, '59, p. 64, pi. 5, fig. 2. Eudoxid. 1 Abyla alata Haeckel, '88b, p. 156 (non Amphiroa alata, BLArN\aLLE, '30). ? Amphiroa dispar Bedot, '96, p. 373, pi. 12, fig. 5, 6. Eudoxid. Station 4634 300 fathoms to surface 1 anterior nectophore. " 4646 " " " " " " " " 4665 " " " " " " " " 4fifiS " " " " " " " 4729 " " " " " 4746 " " " " " " " These detached anterior nectophores, 5-6 mm. long, agree very well in their ridges and facets, with the detailed account of A. haeckeli given by Lens and Van Riemsdijk. The inclusion under this species of the specimen from Torres Straits described by Huxley ('59, p. 47) as A. trigona, rests upon his very clear account of the structure of the nectophore, from which it is evident that in his example there were two ventral facets separated by a transverse ridge, instead of the single ventral facet of the true ^4. trigona. The comparison between the anterior nectophores of the two species by Lens and Van Rienasdijk is so detailed that to go over the ground again here ABYLA HAECKELI. 223 would be a needless repetition. The one important point of difference is the nature of the ventral facet, whether simple and with concave lateral margins (.4. trigona), or divided into a lower pentagonal and an upper rectangular por- tion by a well-marked transverse ridge (.4. haeckeli). The upper lateral facet is likewise proportionately larger in haeckeli than it is in trigona (compare fig. 1 with fig. 3, Plate 13). The posterior nectophore of .4. haeckeli is so far known only from Huxley's description and figure ('59, pi. 3, fig. 1), from which it is clear that it closely resembles the corresponding structure in .4. trigona. Without a study of actual specimens of haeckeli it is impossible to state whether or not the posterior necto- phores of the two species show any constant differences in form or structure. EuDOXiD. Neither the "Siboga" nor the "Albatross" material throws any light on the Eudoxid of A. haeckeli. Huxley described and figured a bract, which, though detached, was taken together with his one specimen of A. haeckeli, as resembling the Eudoxid of A. trigona (" Amphiroa alata") except that the basoventral margin of the hydroecium is deeply concave, instead of being straight. And it is just this character which distinguished his Amphiroa angu- lata (taken once only), which he thought might prove to be a young stage of the Eudoxid of A. trigona. Recently Bedot ('96) has described, from Amboina, an "Amphiroa" which likewise has a deeply concave ventrobasal hydroecial margin, besides having asymmetrical lateral hydroecial walls with a prominent basal tooth on the right, and none on the left side, under the name Amphiroa dispar. On comparing Huxley's figure ('59, pi. 5, fig. 2) of angulata with the lateral view of dispar given by Bedot ('96, pi. 12, fig. 6) we see that angulata, like the latter, has a prominent basal tooth on the side of the hydroecium. And this, together with the concavity of the basoventral hydroecial margin present in both, and their generally close agreement in other respects, is sufficient ground for concluding that both are the Eudoxids of one species. In the basoventral concavity they agree so well with the bract figured by Huxley, that I have no doubt that they are specifically identical with it. And although it is not alto- gether certain that the bract in question belonged to ,4. haeckeli, there is every reason to suppose that such was the case. There is thus a strong probability that the Eudoxids Amphiroa angulata Huxley, and A. dispar Bedot, are the free cormidia of Abyla haeckeli; but to determine conclusively whether this view is correct will require an examination of specimens of that species with stem and appendages intact. So far, A. haeckeli is known only from the Malaysian region and from the 224 ABYLOPSIS TETRAGONA. Eastern Tropical Pacific. Considering, however, how closely it resembles A. trigona, and how long the very common, and easily distinguishable A. esch- schoUzii ( = quincunx) escaped notice, it is not unlikely that it may occur in the Tropical Atlantic. ABYLOPSIS Chun, 1888. Abylopsis tetragona (Otto). Plate 14, figs. 6, 7; Plate 15, fig. 2. Pyramis tetragona Otto, '23, p. 306, taf. 42, fig. 2a-2e. Aglaja baerii Eschscholtz, '2.5, p. 743, taf. 5, fig. 14. Plethosoma cryslalloides Lesson, '26, pi. 4, fig. 2 (partim), '30, p. 64. Calpe pentagona QuoY and Gaimard, '27, p. U, pi. 2A, fig. 1-7; Blainville, '30, p. 132; '34, p. 134, pi. 4, fig. 3; Lesson, '43, p. 449. Aglaisma baerii Eschscholtz, '29, p. 129, taf. 12, fig. 5. Abyla pentagona Eschscholtz, '29, p. 132; Leuckabt, '53, p. 56, taf. 3, fig. 1-6; '54, p. 11, taf. 11, fig. 1-10; KoLLiKER, '53, p. 41, taf. 10; Vogt, '54, p. 121, taf. 20, fig. 4r-7, taf. 21, fig. 3-6, 10-13; Huxley, '59, p. 40, pi. 2, fig. 2; Gegenbaur, '60, p. 349, taf. 28, fig. 17-19; Keferstein and Ehlers, '61, p. 14, taf. 3, fig. 5, 6; Spagnolini, '70, p. 21; Fewkes, '74, p. 318, pi. 3; Chun, '97b, p. 30; Lens and Van Riemsdijk, :08, p. 17, pi. 2, fig. 17-20. 'Diphyes calpe QuoY and Gaim.\rd, '34, p. 89, pi. 4, figs. 7-11. Aglaisma pentagonum Leuckart, '53, p. 150, taf. 3, figs. 2, 3. Eudoxia cuboides Leuckart, '53, p. 54, taf. 3, figs. 7-10; Muller, '70-'71, taf. 11, figs. 6, 7, taf. 13, fig. 9; Chun, '85, p. 525, taf. 2, fig. 11; Bedot, '96, p. 375. Eudoxid. Aglaismoides elongata Huxley, '59, p. 61, pi. 41, fig. 3. Eudoxid. Aglaisma gcgenbauri Haeckel, '88b, p. 119, taf. 40. Eudoxid. Calpe gegenbauri Haeckel, '88b, p. 164, pi. 39, 40. Calpe huxleyi Haeckel, 'S8a, p. 36; '88b, p. 164. Aglaisma cuboides Chun, '97b, p. 30; Lens and Van Riemsdijk, : 08, p. 19, pi. 2, fig. 21. Eudoxid. Abyla tetragona Schneider, '98, p. 89. Abyla huxleyi Agassiz and May'ER, :02, p. 166, pi. 11, figs. 48. Abylopsis tetragona was taken from the following Stations: 4642,4646,4652, 4655, 4657, 4659, 4669, 4671, 4676, 4701, 4702, 4708, 4715, 4716, 4722, 4724, 4731, 4732, 4734, 4737, 4740. The material consists of 4 specimens from 3 surface, 93 from 20 intermediate, hawls with open nets, chiefly 300-0 fathoms. Its Eudoxid was taken at Stations 4655, 4657, 4676, 4679, 4681, 4715, 4724, 4673. 25 specimens in one surface, 18 in 7 intermediate, hawls with open nets. The largest anterior nectophore is 8 mm., the largest posterior one 35 mm., the largest Eudoxid 7 mm. long. My choice of Otto's name tetragona for this species, in place of the commonly accepted pentagona, rests on Chun's statement that he has examined Otto's type specimen (specimens?) which is still in good condition, in the Museum at Breslau, and that he "erkannte sofort, dass thatsachlich die Abyla pentagona vorliegt." ('97b, p. 31.) In the face of the statement, by one of the most experienced students of coelenterates, that the type specimen of tetragona is identical with pentagona, the more recent name must, of course, become a syno- ABYLOPSIS TETRAGONA. 225 nym, no matter how incorrect the description and figure on which the older name rests. That this course must be followed, to accord with the International rules of zoological nomenclature, has already been pointed out by Schneider ('98). Inclusion in the above synonym of the Aglaja baerii of Eschscholtz ('25) is necessary, because the figure of that form, especially of the posterior nectophore, shows clearly that it was in reality A. tetragona. Plethosoma crystalloides Lesson, is a combination of the siphosome of some Physophorid, with an Abylid; Huxley long ago pointed out that the latter was almost certainly A. tetragona, with which Lesson's figure agrees very well. Neither Chun ('97b) nor Lens and Van Riemsdijk (:08) have placed the Aglaisma peniagona of Leuckart ('53) here. Leuckart's figures show that his specimens were young Abylopsis, either .4. tetragona or A. eschscholtzii ( = quin- cunx). Unfortunately the one feature absolutely distinguishing the two, i. e., the canal-course of the posterior nectosac, is not shown. But the shape of the posterior nectophore suggests identity with the former rather than with the latter. In including here the .4. pentagona of Huxley, which Haeckel ('88b) and Chun ('97b) considered a separate species, I follow Lens and Van Riemsdijk, and I need only add that examination of Huxley's figures has convinced me that they were correct in thinking that Huxley's specimens were merely small examples of A. tetragona. Aglaismoides elongata Huxley, agrees according to the figures, with the many accounts of the "cuboides" Eudoxid of A. tetragona, and differs correspondingly from the Eudoxid of A. quincunx. It is probable that the A. huxleyi of Agassiz and Mayer (:02) also belongs here, especially since I have found specimens of ^4. tetragona in the material on which their report was based. But in as much as their figure shows canals of the ordinary Abylid type in a specimen otherwise resembling A. tetragona, the identification remains doubtful. The present large and excellently preserved series allowed me to make a thorough comparison between this species and A. eschscholtzii, with the result that I am convinced the two species are entirely distinct. Several adequate accounts of ^4. tetragona have been published. It is not likely to be confused with any species except A. eschscholtzii, and from the latter it can readily be distinguished by its very large size; its relatively much longer posterior nectophore (between four and five times as long as the anterior one), and especially by the structure of that organ. The asymmetry of the nectophore, and the diagnostic features of the hydroecium are mentioned in the account of A. eschscholtzii (p. 228). The pecuUar arrangement of the canals of the pos- 226 ABYLOPSIS ESCHSCHOLTZII. terior nectosac has been well described and figured by Gegenbaur ('60), and the importance of this character has recently been emphasized by Lens and Van Riemsdijk. The present series show it very well (Plate 14, fig. 7). There is no variation from the typical arrangement in anj- of the specimens. The free Eudoxids have often been described, and Lens and Van Riemsdijk have pointed out the differences between them and those of .4. eschscholtzii. These consist, it is true, chieflj' of minor particulars in the form of the bract; but they are so constant that it is easy to distinguish the two species. The most diagnostic feature is the outline of the dorsal facet, which is a regular pentagon in eschscholtzii, but subrectangular in tetragona. The ventral facet is basally deeply convex in the former, straight in the latter; and the basolateral facets also differ in proportions. (Compare Plate 15, fig. 7 with fig. 2.) Abylopsis tetragona is common in the Mediterranean, in the Tropical Atlantic, where I have taken it among the West Indies, in the Malaysian region, and over the entire region covered by the present cruise of the "Alba- tross." It is also known from the Indian Ocean (Huxley). Abylopsis eschscholtzii (Huxley). Plate 14, Figs. 1-5; Plate 15, Fig. 1. Aglaisinoides eschscholtzii Huxley, '59, p. 60, pi. 4, fig. 2; Chun, 'SS, p. UGO; Lens and A'an Riems- dijk, :08, p. 25, pi. 3, fig. 18-31. Eudoxid. Abylopsis quincunx Chun, '88, p. 1160; Bedot, '96, p. 375. Abyla (Abylopsis) quincunx Chun, '97b, p. 29. Aglaisinoides quincunx Chun, '97b, p. 29. Eudoxid. Aglaisma quincunx Aoassiz and Mayer, '99, p. 180; Mayeu, : 00, p. 78; (non Agas.siz and Mayer, :02, p. 164, pi. 10, fig. 45). Eudoxid. Aglaisma cuboides May'Er, :00, p. 77, pi. 30, fig. 104 (non Leuckart). Eudo.xid. Abyla quincunx Mayer, :00, p. 78, pi. 34, fig. 115-117, .\gassiz and Mayer, :02, p. 163, pi. 11, fig. 46, 47; Lens and Van Riemsdijk, :08, p. 21, pi. 3, fig. 22-27. Abyla tetragona Schneider, '98, p. 89 (partim). Abyla peniagona May'er, :00, p. 77, pi. 30, fig. 101-103 (non Eschscholtz, Chun). Chunia capillaria Mayer, :00, p. 78, pi. 27, fig. 90. The polygastric state of this species was captured at Stations 4592, 4594, 4613, 4637, 4646, 4659, 4665, 4673, 4687, 4707, 4715, 4732, 4734, 4737; the total number of specimens being 25. The largest anterior nectophore is 5 mm., the largest posterior one 8 mm., and the largest Eudoxid 5 mm. long. The records are both from the surface and from open hauls between 300 fathoms and the surface. The free Eudoxid was taken only at Stations 4671, 4673, and in Acapulco Harbor, a total of four specimens. The union of this Pacific series with the Atlantic species, rests not only on the similar identification by Lens and Van Riemsdijk (:08), but on actual comparison of specimens from both oceans. ABYLOPSIS ESCHSCHOLTZII. 227 When Chun ('88) first described the polygastric state of this species he beUeved that the Eudoxid which he observed in connection with it was identical with the Aglaismoides eschscholtzii, of Huxley, but in his later work he abandoned this %'iew. More recent authors, who have described Eudoxids as ^4. esch- scholtzii, or as ^. quincunx, have not been able to trace the actual development of the cormidia of the polygastric stage into the free Eudoxid. Fortunately in several of the present specimens the stems bear groups of appendages suffi- ciently far advanced for comparison with the few examples of Aglaismoides eschscholtzii, as well as with the figures of the latter given by Huxley and by Lens and Van Riemsdijk. As I shall show below (p. 229), there is every reason to conclude that Aglaismoides eschscholtzii, is actually the Eudoxid of A. quincunx; Haeckel ('88b), confused it with the Iilucioxid of ^4. tetragona. This being the case, Huxley's name must be substituted for the more recent quin- cunx. That the species recorded by Mayer ( : 00) as A . pentagona in reality belongs to A. eschscholtzii, has already been pointed out by Lens and Van Riemsdijk (:08, p. 25), and an examination of Mayer's figure confirms this conclusion. As for Chunia capillaria Mayer, though Lens and Van Riemsdijk retain this specific name, it seems to be absolutely indistinguishable from A. eschscholtzii; the "long slightly curved, bristle-like spine" (Mayer, :00. p. 79) is evidently nothing but the denuded stem. Anterior nectophore. Structurally the anterior nectophore closely resembles that of A. tetragona, with which it agrees in the number and arrangement of ridges and facets. It has been described and figured in great detail by Lens and Van Riemsdijk. I may point out, however, that an examination of very considerable numbers of each species, from both Atlantic and Pacific, shows that the minor characters which they mention as distinguishing the two, e. g., acute angles in eschscholtzii, blunt ones in tetragona, and the exact outline and degree of curvature of the ridges, is so variable that identification from these features alone is often impossible. But there is one character in the anterior nectophore which appears to be diagnostic, i. e. the course of the subumbral canals (c/. Plate 14, fig. 6 with fig. 1). Posterior nectophore. Both Chun and Lens and Van Riemsdijk, have pointed out the striking differences in this structure in A . eschscholtzii and in A. tetragona. Briefly stated they are as follows : — In the former the posterior nectophore is much smaller, in proportion to the anterior one; and the gelatinous substance much thicker. Important features are afforded by the structure of the base. 228 ABYLOPSIS ESCHSCHOLTZIl. and the subumbral canals of the nectosac. In each species there are five well- developed basal teeth, one dorsal, two lateral, and two marking the dorsal wall of the hydroecium. But while in A. eschschoUzii these are symmetrical, except that the right hydroecial tooth is somewhat larger than the left one (Plate 14, fig. 3), in A. tetragona they are so asymmetrical that it is only by tracing out the ridges with which they are connected that their essential orientation can be determined (Plate 14, fig. 8). The hydroecium also is diagnostic. In both it is covered over by two lateral wings, but whereas in A. eschschoUzii the right hand wing bears three prominent teeth near its base, and the margin of the left hand wing is entire (Plate 14, fig. 2), in tetragona the right wing is only slightly serrate on its transverse basal margin, while the left hand wing is toothed throughout its length (Plate 14, fig. 7) instead of being entire. The most important diagnostic feature of the posterior nectophore is afforded by the canals of its nectosac, for while these are of the usual radial type in A. esch- schoUzii, in A. tetragona they follow a very peculiar course (Plate 14, fig. 7). Stem and appendages, and free Eudoxids. In the oldest cormidia which are still attached to the stem the bract (Plate 14, fig. 4) has already assumed its characteristic pentagonal outlines; and though it still shows evidences of im- maturity, it already agrees with the free Eudoxids (Plate 15, fig. 1) not only in the essentials of facets and ridges, but even in such a trivial feature as the presence of a tooth on the basal hydroecial margin on either side. The dorsal facet is already of the regular pentagonal form, so characteristic of the free Eudoxid. The serration of the ridges, prominent at this early stage, is pro- gressively lost, a fact I have been able to observe on several specimens of slightly different ages. The somatocyst has already assumed its final form; and the gonophore, except for its small size, shows the structure characteristic of its later stages. Indeed, the re.semblance between these cormidia and the free Eudoxids is so close that there is no doubt of their genetic connection. The latter agree so well with the account given by Lens and Van Riemsdijk that no account of them is necessary here, further than to point out that they are easily distinguished from the Eudoxids of A. tetragona by the regular pentagonal outlines of the dorsal facet, by the proportionately shorter anterolateral and the proportion- ately longer posterolateral facets. (Compare Plate 15, fig. 1, 2.) The form of the hydroecium is likewise different in the two, and connected with it, the ventral facet is basally deeply concave in eschschoUzii instead of entire as in tetrago7ia. BASSIA BASSENSIS. 229 Huxley's figures of his Aglaismoides eschscholtzii ('59, pi. 4, fig. 2-2a, 2b) show the same characteristic form of the bract, and of its somatocyst; and I am therefore convinced that the original diagnosis by Chun ('88) of the Eudoxid of his Abyla quincunx, and by Lens and Van Riemsdijk of the "Siboga" speci- mens, as identical with Huxley's species, was correct. Distribution. Abylopsis eschscholtzii, as shown by the records by Bedot ('96), and by those of the "Siboga" and "Albatross," is very generally dis- tributed over the Tropical Pacific and the Malaysian region. It was previously known to be very common in the Tropical Atlantic (Chun, '88, '97b); and I have examined a considerable series from the West Indies. So far as known it is restricted to tropical and subtropical regions. BASSIA L. Agassiz, 1862. The genus Bassia has usually, but erroneously, been credited to Quoy and Gaimard. It was first mentioned by Blainville ('30) who quoted Bassia quad- rilatera, a manuscript name proposed by Quoy and Gaimard without descrip- tion or figure. Since the latter do not give this name in their published work ('34) it is necessarily a nomen nudum. L. Agassiz in 1862 considered that Abyla perforata Gegenbaur ( = Diphyes bassensis Quoy and Gaimard) belonged to Bassia, hence bassensis is the type and as yet the only known species of the genus. Bassia bassensis (Quoy and Gaim.^rd). Plate 12, fig. 8; Plate 14, fig. 9. Diphyes bassensis Quoy and Gaimard, '34, p. 91, pi. 7, fig. 18-20. Calpe bassensis Lesson, '43, p. 451. Abyla bassensis Huxley, '59, p. 45, pi. 2, fig. 1 ; Sch.neider, '98, p. 91 ; Lens .and Van Riemsdijk, : OS, p. 26, pi. 4, fig. 32. Spheiioides aiistralis Huxley, '59, p. 62, pi. 4, fig. 4, Chun, '88, p. 1160; Haeckel, '88b, p. 360; Bedot, '96, p. 375; Lens and Van Riemsdijk, :0S, p. 26, pi. 4, fig. 33. Eudoxid. Abyla perforata Gegenbaur, '60, p. 356, taf. 29, fig. 20, 21; Chun, '97b, p. 32. Bassia perforata L. Agassiz, '62, p. 372; Chun, '88, p. 1190; Haeckel, '88b, p. 160; Bedot, '96, p. 374. Bassia obeliscus Haeckel, '88a, p. 36; '88b, p. 160, pi. 37. SphenoiJes obeliscus, Haeckel, '88a, p. 33; '88b, p. 116, pi. .38. Eudoxid. Sphenoides perforata, Haeckel, '88a, p. 33; '88b, p. 116; Chun, '97b, p. 32. Eudoxid. ? Parasphenoides amboinensis Bedot, '96, p. 376, pi. 12, fig. 2, 3. The polygastric state was taken at Stations 4598, 4611, 4617, 4659, 4661, 4667, 4673, 4679, 4699, 4716, 4724, in both surface and 300 fathom hauls. The total number of specimens is 113; at Station 4617 a swarm was encountered. The Eudoxid was taken at Stations 4588, 4611, 4639, 4646, 4654, 4661, 230 BASSIA BASSENSIS. 46G3, 4665, 4667, 4669, 4671, 4673, 4714, 4715, 4716, 4743, and in Acapulco Harbor; both surface and 300 fathom hauls; about 180 specimens. In the largest specimen the superior nectophore is 5 mm. long, the inferior one 8 mm. long. The material as a whole is in very good condition. After comparing it with numerous Atlantic specimens, as well as with the descriptions and figures of Gegenbaur and Haeckel, I have been unable to find a single difference suffi- ciently constant to warrant the recognition of but one species. The same con- clusion was reached by Bedot ('96) for specimens from Amboina, and I can bear out his observations as to the variability of the outlines of the two nectophores and their proportions, and of the inclination of the anterior one. Lens and Van Riemsdijk have summarized the historj^ of the species; but as their material was too fragmentary for satisfactory identification they retain a Pacific and an Atlantic species. B. basscnsis has been well described and figured by Huxley, Gegenbaur, and Haeckel. Its most diagnostic features are the form of the posterior necto- phore which is quadrilateral, the right lateral ridge entirely suppressed except at its basal extremity, and especially the coalescence of the two ventral wings, by which the hydroecium is closed for the upper two thirds of its length. This feature alone is sufficient to distinguish B. bossensis from all species of Abyla and Abylopsis. The anterior nectophore resembles that of A . pentagona and A . eschscholtzii, in the general arrangement of its facets and ridges. But it is easily distinguished from them, because in it the base of the hydroecium does not project as it does in those species. This difference is more readily illustrated by figures than by description (Plate 14, fig. 1, 6, 9). Huxley long ago suggested that his Sphen- oides australis was the free Eudoxid of B. bassensis, and both Chun ('88) and Haeckel ('88b) have observed the actual development of the cormidia of this species into "Sphenoides." In many of the "Albatross" specimens the bracts are sufficiently developed to show that they are undoubtedly the younger stages of S. australis; and the same was true of Haeckel's material ('88b, pi. 38). There- fore there is no longer any excuse for retaining the name Sphenoides australis. The young bracts, as shown in Haeckel's figures ('88b, pi. 38, fig. 13, 14), have more prominent angles and ridges than the older ones, and the same is true of the gonophores. The bract in the largest "Sphenoides" is 9 mm. long. The Eudoxid described by Bedot as Parasphenoides amboinensis, in the extreme development of its ridges and angles, suggests the bracts of B. bassensis while DIPHYABYLA HUBRECHTI. 231 still attached, and for this reason is included here as probably belonging to the latter species. Most likely it represents a case where the changes in form, out- lined above, have been delayed. Bedot does not state whether he observed more than one such specimen. B. bassensis is known to occur very generally throughout the Mediterranean and Tropical Atlantic, the Malaysian region, the Eastern Tropical Pacific, and it is recorded from off the southeast coast of Australia (Bass Straits) and from south of Tasmania. I can find no record of it from the Indian Ocean, but it may be expected to occur there, and thus to parallel Abylopsis tetragona (p. 220) in its distribution. DIPHYABYLA Lens and Van Riemsdijk, 1908. This interesting genus is so far known from only one species, D. huhrechti Lens and Van Riemsdijk, founded for a single specimen in the "Siboga" col- lection, and represented by a second rather better preserved example in the present series. Diphyabyla hubrechti Lens and Van Riemsdijk. Plate 12, fig. 7. Diphyabyla hubrechti Lens and Van Riemsdijk, : OS, p. 36, p\. 6, fig, 47. Station 4683, 300 fathoms to surface; 1 anterior nectophore, 7 mm. long. The nectophore agrees in shape with the account by Lens and Van Riems- dijk, who have called attention to the essential similarity in external form between this species and Abyla leuckarti. The most interesting feature of Dyphyabyla is the apical projection of the nectophore in a narrow pyramidal form. And it was the consequent external resemblance to the Diphyids which suggested the generic name. This external modification obscures its close rela- tionship to A. leuckartii; but when the ridges and facets are analyzed their fundamental unity is at once apparent. Lens and Van Riemsdijk have given such an extended and complex discussion of the two that the following summary of the superior nectophore will suffice here. In Diphyabyla there are four ridges at the pointed apex, two dorsal, and two ventral. The two dorsals run direct to the base, enclosing a triangular dorsalfaeet. Each of the two ventrals branches dichotomously at the level of the apex of the nectosac, so that from this point downward, there are two ventrals, and a lateral on each side running without further subdivision to the base, though the ventrals reach the base together, 232 DIPHYABYLA HUBRECHTI. forming a single tooth. The facets are thus a triangular dorsal, a dorsolateral, and a ventrolateral on each side, and a fusiform ventral. The ridges all termi- nate in prominent triangular teeth at the base. The hydroecial opening lies high above the opening of the nectosac (Plate 12, fig. 7). The nectosac extends apically far beyond the level at which the pedicular canal joins it, and conse- quent on this prolongation its dorsoradial canal follows a Diphyid rather than an Abylid course (Plate 12, fig. 7). The other canals present no features of special interest. In the "Siboga" example the nectosac was narrow and tubular for the last part of its course. But in our example it terminates bluntly slightly above the level at which the ventral ridges branch. This apparent difference is probably due to the distortion of that region mentioned by Lens and Van Riemsdijk (:08). This same level marks the beginning of the apical projection (Plate 12, fig. 7). This is bent; but as the bending is dorsad in the "Siboga," ventrad in the "Albatross" specimen, it is probably an accidental distortion. To derive the pyramidal form of Diphyabyla from the rectangular necto- phore of Abyla leuckartii, all that is necessary is to imagine the apicodorsal angle of the latter, with the apex of the nectosac, drawn out into a triangular point. The dorsal facets of the two correspond ; but the ventral of the Diphya- byla represents both the ve ntral and the rectangular apical facets of A . leuckartii. It is true that the transverse ridge separating the two in the latter is unrepre- sented in the former, but the presence or absence of the ridge is a very minor matter, depending on whether the ventral facet is straight as in Diphyabyla or bent at a right angle as in A. leuckartii. It is entirely comparable to the transverse ridge which subdivides the ventral facet in A. haeckeli, but is absent in the closely related A. trigona. The somatocyst is large, oval, and extends basally from its connection with the hydroecium, as in Abyla leuckartii. The ventral ridges in the two follow the same course, particularly in their basal junction, as do the lateral ridges except for the fact that in A. leuckartii they terminate a short distance above the lateral teeth (Plate 13, fig. 5) instead of reaching the basal margin as in Diphyabyla. The basal teeth likewise correspond in both species. The corre- spondence in such minor details as the basal teeth and in the degree of serration is of great interest from the phylogenetic standpoint for it points in an unmis- takable manner not only to the genus, Abyla, but even to the particular species, {. e. leuckartii, from which Diphyabyla is descended. The Abylid affinities of Diphyabyla are so close that the subfamily Diphyabylinae of Lens and Van Riemsdijk is unnecessary (p. 215). To preserve it would only obscure the rela- OALEOLARIA. 233 tionship of the genus. The Diphyid appearance of the pyramidal nectophore is nothing more than an instance of parallehsm. And the same is true of the Diphyid form of the nectosac. The apical prolongation of the latter above the level of the pedicular canal is a concomitant of the alterations of the general external form, not an indication of relationship to Diphyinae. There is no trace of an inferior nectophore, nor of any reserve bud which might foreshadow such a structure. The appendages are represented by several small buds, and a single definitive siphon with tentacles and very immature bract. The latter structure has been described by Lens and Van Riemsdijk as scale-like. Galeolariinae Chun, 1,897. GALEOLARIA Blaixville, 1834. Galeolaria, the only kn nvn genus of the Galeolariinae, sometimes, though wrongly, credited to Lesueur, was proposed by Blainville in 1S30, but must date from 1834, when one of its species was first described. In the same year, 1834, Quoy and Gaimard described two species, one of them being described also and figured by Blainville. The genus is usuallj' credited to Bla'nville and the two species to Quoy and Gaimard, and nothing would be gained by changing this arrangement. We must first consider the species listed by Blainville in his second diag- nosis ('34) of the genus, since it is one of these which must be taken as the type. They are G. australis Quoy and Gaimard, G. quadridentata Quoy and Gaimard, G. rissoi, and G. bilobaia, but the last two are manuscript names of Lesueur, and have no standing. Chun ('97b, p. 16) mentions australis and quadridentata merely as "zwei obere Schwimmglocken aus dem Indischen Ocean," but Haeckel ('88b) recognized their importance. G. quadridentata was figured by Quoy and Gaimard ('34); and their Diphyes quinquedentata was probably its posterior nectophore. The conformation of the base of both nectophores approaches in complexity that of G. monoica Chun. But it differs so much from the latter in the number and arrangement of the basal teeth that it can not be identified with it, or with any other actual species. G. quadridentata must still, and perhaps always, remain a doubtful form. Galeolaria australis (Quoy and Gaimard, '34, pi. ;3, fig. 29,' 30, 31) was very ' Fig. 29 is given by Quoy and Gaimard as " Diphyes quiitquedeiUiUa," but there are two figures numbered 29, and tlie internal evidence of the figures themselves shows tliat one is auslralis, the other Diphyes quinquedentata. 234 GALEOLARIA. well figured. As is shown both in side and basal views of the anterior necto- phore, there are two basoventral wings, but no basal teeth, either lateral or dorsal. This conformation of the base agrees perfectly with the Malaysian species de- scribed by Lens and Van Riemsdijk (:08) as G. biloba Sars, as well as with a considerable series in the present collection. Since australis can now be identi- fied with actual specimens, it must be chosen as the type of the genus. The question whether Sars's Norwegian biloba is actually identical with the Malay- sian form, as Lens and Van Riemsdijk suppose, is important from the standpoint of distribution. It is certainly true that Sars's ('46) figures afford no basis for separating the two. Unfortunately, however, they are not sufficiently diagnos- tic, and no recent author has studied the North Atlantic form for the purpose of testing its specific characters. Until this is done, the onlj' course to follow is to consider biloba as a doubtful synonym of australis. In the Atlantic, G. biloba is so far known certainly from northern regions only, doubtfully from the Mediterranean. In the Indo-Pacific region, on the contrary, australis is a common surface form in regions of very high tempera- tures. At present it is impossible to say whether the two are identical, having been overlooked in the warmer parts of the Atlantic, or whether they are dis- tinct, but closely allied species, one peculiar to cold, the other to warm waters. But they are so closely related that the former is probably correct ; biloba is therefore listed as a doubtful synonym of australis. Lens and Van Riemsdijk (:08), who have attempted a much needed revision of the genus, recognize four well-founded species in addition to biloba, viz. G. truncata Sars, '46 {= G. inflata Chun), G. monoica Chun, G. quadrivalvis Blainville, G. chuni Lens and Van Riemsdijk, and two problematical forms, Diphyes turgida Gegenbaur and Diphyes ovata Kefferstein und Ehlers ('61). Diphyes ovata, if the description be correct, is a very remarkable Diphyid. But as it has never been observed since 1861, its existence is problematical. At any rate it is idle to speculate on its affinities until it is reexamined. Diphyes turgida, according to the original account (Gegenbaur, '54), has no somatocyst. But such a peculiarity would be so remarkable among Calyco- phorae, that probably this structure was overlooked, as Lens and Van Riemsdijk suggest (:08, p. 57) or the species was founded on abnormal material. In all other respects, i. e., sculpture of the base of the nectophore, general form, and outline of the bracts, turgida resembles biloba, with which Schneider has united it and the same course is followed provisionally here. G. chuni Lens and Van Riemsdijk, known from three superior nectophores only, is closely GALEOLARIA. 235 related to G. australis, with which it agrees in the possession of two small basal- ventral wings, and the absence of either dorsal or lateral teeth. It is distin- guished from the latter only by its small size (3.5-4 mm. long), and "in the course of the canals which is as in Diphyopsiinae, the lateral canals not standing in any connection with the ventral one " ( : 08, p. 61), as well as by a longer somato- cyst. But size can not be made the basis of specific separation in the case of so small a series, for of course every specimen of G. australis must at one time be no longer than 3 mm. And in spite of the statement that the canals are of the Diphyopsid type, the figure (Lens and Van Riemsdijk, :08, pi. 9, fig. 7) clearly shows the transverse trunk connecting lateral and ventral subumbral canals characteristic of other Galeolariinae. As to the length of the somatocj^st, Lens and Van Riemsdijk have themselves found that this character is variable in otherwise typical australis, an observation I have been able to verify in the "Albatross" collection. None of the supposed diagnostic characters of chuni are, then, sufficient to separate it from australis, and there is every reason to think that it is the young of the latter. The union by Lens and Van Riemsdijk of G. inflata Chun with G. truncata Sars, is probably justified though it can not be more than provisional, owing to the briefness of Chun's account. With G. truncata they likewise unite the Diphyes conoidea of Kefferstein and Ehlers. But although according to their figure conoidea agrees well enough with truncata in the conformation of the base of the anterior nectophore, its general resemblance to Diphyes appendiculata is so close, that it is hard to believe that it is accidental. Finally I must mention Diphyes stephanomia Brandt, described from Mertens's unpublished drawing. Haeckel, who was able to examine the original figure, assures us that the species is a Galeolaria; but Brandt's ('35) description, which is the only published account, is insufficient to establish its position in the genus. The characters by which the nectophores of the various species of Galeolaria, both anterior and posterior, may be most readily distinguished are the conforma- tion of the base, i. e. number and arrangement of basal wings and teeth. There are also differences in the arrangement of the subu mbral canals, though in all species the lateral canal on either side is connected with the ventral one by an oblique transverse trunk. 236 GALEOLARIA. Key to the species. Anterior nectophore. 1. Without any basal teeth, or wings. G. truncata Sars, = G. inflata Chun? = G. conoidea Kefferstein and Ehlers? 2. With basal teeth or wings. a. With 2 large ventral wings only. G. australis Quoy and Gaimard = ? G. biloba Sars = G. chuni Lens and Van Riemsdijk. b. With 2 large ventral wings, and 2 small dorsal teeth. G. quadrivalvis Blainville. c. With 2 large ventral wings, 3 small dorsal teeth, and on each side a small triangular lateral angle. G. monoica Chun. Posterior nectophores. 1. Basoventral wing, single, undivided. a. No dorsal or lateral teeth. a'. With prominent longitudinal lateral wing-like enlargements, termi- nating above the basal margin. G. australis Quoy and Gaimard. = ? G. biloba Sars. a^. Without prominent lateral wing-like enlargements. G. truncata Sars. b. With 3 dorsal teeth, and 2 lateral triangular lateral angles. G. monoica Chun. 2. Two basoventral wings. a. With 2 large lateral and 2 dorsal teeth. Nectosac with circular trans- verse constrictions. G. quadrivalvis Blainville. G. truncata is so far known from the Atlantic alone; and its distribution is considered later (p. 369); The records of the occurrence of the remaining species of the genus show that they are widely distributed over the Indo-Pacific region as well as the Atlantic. Until recently G. biloba ( = australis) was supposed to be a northern species but the captures by the "Siboga" and by the "Albatross" show that this is doubtful. GALEOLARIA QUADRI^■AL^"]y. 237 Galeolaria quadrivalvis (Blainville) Chun. Plate 5, fig. 1-7. Sulcidcolaria qumlrimh'iti Blainville, '30, p. 120; '34, p. 138, pi. 6, fig. G. (Lbsueur, Ms.) Epibtdia aurianlaca Vogt, '52, p. 524, taf. 14, fig. 1, 2. Epibulia filiformis Leuckart, '53, p. 2. Galeolaria auriantiaca Vogt, '54, p. 110, taf. 18, 19, 20; Weismann, '83, p. 199, taf. 21, fig. 1-8; Haeckel, 'SSb, p. 151; Bedot, '96, p. 370. Diphyes quadrivalvis Gegenbaur, '53, p. 315, taf. 16, fig. 8-11; Kefferstein and Ehlers, '61, p. 18; Schneider, '98, p. 87. Galeolaria filiformis Leuckart, '54, p. 2.S0, taf. 11, fig. 14-17; Huxley, '59, pi. 12, fig. 1 (non Huxley, '59, p. 38, pi. 3, fig. 5). Diphyes (Galeolaria) quadrivalvis Costa, '62, p. 90, pi. 3. Epibidia anrianlaca var. canariensis Chun, '88, p. 1158. Galeolaria quadrivalvis Chun, '97b, p. 17; Lens and Van Riemsduk, :08, p. 58, pi. 9, fig. 74. This species was taken at Stations 4635, 4651, 4657, 4659, 4663, 4665, 4667, 4676, 4743, 4841, both at the surface and in open hauls from 300 fathoms to the surface. It is represented by three very well-preserved entire colonies, fourteen loose anterior, and six loose posterior nectophores. The largest an- terior bell is 18 mm. the largest posterior one 19 mm. long. The three entire specimens were captured while floating fully extended on the surface; and are in an excellent state of preservation; and I have been able to compare them with excellent material from the Bay of Naples. The canals of both nectophores follow the course described for them by Gegenbaur, differing correspondingly from those of the Diphyopsiinae. G. quadrivalvis has been so well described and figured by Vogt ('54) and by Gegenbaur ('54) that a detailed account is unnecessary. I need only note that in the conformation of the ba.se of the nectophores, and in the double constric- tion of the posterior one, the present specimens are entirely typical. The diag- nostic features of the species are enumerated in the key (p. 236); and this, together with the photographs (Plate 6, figs. 1-3) may serve for identification. The only previous records of G. quadrivalvis from the Indo-Pacific region are those of the "Siboga" specimens (Lens and Van Riemsdijk, :08), which agreed perfectly with Mediterranean specimens; and Bedot's ('96, p. 370) statement that it is ''abondante a Amboine, et les exemplaires que nous avons observes etaient absolument semblables a ceux de la Mediterrannee." Huxley's G. filiformis is doubtfully classed here by Lens and Van Riemsdijk, but it probably belongs to G. australis. 238 GALEOLARIA AUSTRALIS. Galeolaria australis Qdoy and Gaimard. Plate 5, figs. 8, 9, Plate 6, figs. 1, 2, 3. Gulculurki ausiralin Qdoy and Gaimard, '34, p. 42, pi. 5, fig. 29-31; ' Bl.unville, '34, p. 139, pi. (i, fig. 6; Lesson, '43, p. 140; Habckel, '88b, p. 151. Galeolaria filiformis Huxi.Er, '59, p. 38, pi. 3, fig. 5 (non Leuck.^rt, '54). Galeolaria chuni Lens and Van Riemsdijk, :08, p. 61, pi. 9, fig. 78, 79, pi. 5, fig. 8-10, pi. 6, fig. 1-3. ? Diphyes biloba Sars, '46, p. 45, taf. 7, fig. 16-21 , Schneider, '98, p. 86. ? Diphyes siebohtii Gegenhai'R, '53, p. 340 (non Kolliker, '53). ? Diphyes turgida Gegenbaur, '53, p. 344; '.54, p. 442, taf. 23. ? Diphyes sarsii Gegenbaur, '60, p. 372, taf. 29, fig. 30, 31. ? Epibulia hirgida Haeckel, '88a, p. 35. ? Galeolaria turgida Haeckel, '88b, p. 151, 362; Lens and Van Riemsdijk, :08, p. 57. ? Galeolaria biloba H.4ECKEL, '88b, p. 151; Chin, '97b, p. 17; Vanhoffen, :06, p. 16; Ro.mkr, :02, p. 173. This species was taken at Stations 4592, 4600, 4605, 4607, 4611, 4635, 4657, 4659, 4661, 4663, 4671, 4680, 4684, 4686, 4696, 4698, 4700, 4702, 4704, 4707, 4708, 4720, 4723, 4725, 4729, 2731, 4733, 4741, 4743, both on the surface and in hauls from 300 fathoms to the surface. The material consists of two entire colonies, 55 loose anterior, and 42 loose posterior nectophores. The former are from 5-17 mm., the latter from 5-23 mm. in length. For my reasons for considering biloba Sars as a doubtful synonym of australis, see p. 234. Haeckel ('88b, p. 151) lias ah-eady suggested that Huxley's G. filiformis from the Indian ocean is australis while Lens and Van Riemsdijk ( : 08) have identified it i)rovisionally with their biloba. Huxley's figure, with a single large ventral wing, and the total absence of dorsal or lateral teeth, show that both were correct. Lens and Van Riemsdijk have pointed out that the somatocyst in G. uuslralis varies in length, relatively to the size of the nectophore as a whole, and that the gelatinous substance varies in thickness. These observations are borne out by our material. The nectophores have been well described by these authors, by Sars, and by (legenbaur. The presence of a pair of ventral wings in the anterior, and of a single ventral wing in the posterior nectophore, in connection with the absence of either dorsal or lateral teeth in either, separates G. australis from all the other members of the genus. I may add that the lateral canals in the posterior necto- phore are looped, as in G. quadrivalvis, instead of being nearly straight as they are described by Sars ('46) for G. truncata. In the anterior nectophore the lateral canals arise, as usual, from the ring canal, not from the ventral one, as they do in G. monoica (p. 240). ' By a typographical error the reference in their text is to fig. 30-31. GALEOLARIA MONOICA. 239 Another distinctive feature is that the posterior nectophore has lateral ridges, or wings (Plate 6, fig. 3, R. L.). The specimens had lost all but the basal end of the stem when taken, so I can give no description of the various appendages. Galeolaria monoica Chun. Plate 6, figs. 4-9. Epibulia monoica Chun, '88, p. 1157. Galeolaria monoica Chun, '97b, p. 17; Lens and Van Riemsduk, ; 08, p. 60, pi. 9, fig. 76 77. Diphyes hiloba, Schneider, '98, p. 86 (partim). This species was taken at Stations 4592, 4617, 4634, 4635, 4640, 4644, 4646, 4681, 4691, 4700, 4702, 4716, 4718, both on the surface and in hauls from 300 fathoms to the surface. The material consists of twenty-seven loose anterior nectophores and thirty-one loose posterior nectophores. The identification of the latter rests partly, on their occurrence side by side with the anterior nectophores, often in pairs with them; but chiefly on the fact that they differ in several structural particulars from the posterior bells of any other known species of Galeolaria. These grounds taken together are sufficient demonstra- tion of identity with G. monoica. Although the original description of this species by Chun is very brief, Lens and Van Riemsdijk have pointed out that he mentions two important characters, namely, that the somatocyst is minute, and that the development of basal teeth is unusually complex. Unfortunatelj^ Chun ('88, p. 1158) does not describe the teeth further than to mention an "abweichende Bildung der sogen- annten Verschlussklappen am Schirmrande." Lens and Van Riemsdijk (:08, p. 60) identify two badly preserved nectophores taken by the "Siboga" as G. monoica, on account of the extraordinarily small size of the somatocyst and the complicated structure of the teeth. Fortunately the present series includes many excellent specimens both of anterior and of posterior nectophores, and these agree closely with the "Siboga" material. It is true that the basal teeth of the anterior nectophores (Plate 6, fig. 6) differ in dorsoventral orientation from I^ens and Van Riemsdijk's account, the single odd tooth being dorsal instead of ventral as they describe it. But their own figure of the lateral aspect (Plate 9, fig. 76) shows ventrally a pair of flaps, just as in the specimens studied. From this it appears that the terms "dorsal" and "ventral" were accidentally transposed in their description. In both "Siboga" and "Albatross" specimens, then, the anterior necto- phore has a pair of large ventral flaps or wings, which may or may not overlap. 240 DIPHYOPSIINAE. Opposite them is a single narrow dorsal tooth, flanked on either side by a much broader triangular tooth (Plate 6, fig. 6, To. L) ; and between each of the latter and the corresponding ventral flap is a second triangular tooth or wing. The latter vary greatly in apparent size with the condition of the specimens under examination. In contracted material, as the result of the incurving of the bell- margin, they are apparently very large. And it is thus that they were described for the "Siboga" specimens; but in expanded examples, it is evident that much of their bulk in reality belongs to the margin, not to the teeth (Plate 6, fig. 8). They are not such definite structures as the other basal prolongations. The ventral flaps, as seen in good specimens, are much the largest, and each bears a minor tooth on its dorsal surface. The small size of the somatocyst has proved a constant character for the entire series, and of itself would be sufficient to separate G. monoica from any other member of the genus except the somewhat problematical G. turgida Gegenbaur. Even when the margin is entirely destroyed anterior nectophores of monoica can be distinguished from those of australis, which they nearly resemble in form, by the course of the canals. ^Vhile in the latter the lateral canals arise from the ring canal as usual (Plate 6, fig. 3), in monoica they arise from the ventral vessel just above its union with the circular vessel (Plate 6, fig. 5). Posterior nectophores. The posterior nectophore of this species has not been described. Its basal teeth are complex, there being a single undivided median wing, bearing on its dorsal surface two secondary spines (Plate 6, fig. 7, X.), and an odd dorsal tooth, flanked on each side by a triangular lateral one as in the anterior nectophore. Of the last two, the dorsal is the larger. As is shown in the key (p. 2313) the structure of the base separates it from the corresponding nectophore of any other Galeolaria. The lateral canals are looped, as in G'. quadrivalvis and G. australis, instead of being nearly straight as in G. tnincotn. Unfortunately the stem was broken off short in all our specimens, so I can not give an account of the appendages. Diphyopsiinae Haeckel, 1888. Most students recognize the two genera Diphyes and Diphyopsis. Schnei- der ('98), it is true, doubts if the presence or absence of special nectophores in the Eudoxids is sufficient to warrant generic separation. But I agree with Haeckel ('88b), and Chun ('97b), that the occurrence in the Prayinae and in the DIPHYOPSIINAE. 241 present subfamily of series of species parallel in this respect fully deserves recog- nition. Such a difference is of much too great phylogenetic* significance to be classed as a mere specific character. Chuniphyes of Lens and Riemsdijk belongs here also. Although the authors who described it could give it no systematic position, the structure of a specimen in the present collection with both nectophores still connected, shows that it is certainly a Diphyid. Unfortunately all of the specimens yet taken lack the older groups of appendages, so it is impossible to state certainly whether special nectophores are developed. For that reason it is possible that the genus ought to be placed in the Galeolariinae ; but the pyramidal form of the nectophore and the strongly marked ridges support rather an affinity with the present subfamily. The species is so different in its general form from any known Diphyid that it is certainly entitled to generic rank. The excellent condition of the present series of Diphyes and of Diphyopsis together with the rich collection of both these genera in the Museum of Com- parative Zoology, warrant an attempt at a much needed revision of their species. The species described from the Pacific and Indian Oceans may be con- sidered first. They are : — Diphyes dispar Chamisso and Eysenhardt, since recorded by Brandt ('35), by Huxley ('59), and by Lens "and Van Riemsdijk (: 08) ; D. appendiculata Esch- scholtz, since recorded by Huxley ('59), Agassiz and ALayer (:02), and myself (:04); D. angustata Eschscholtz, since recorded by Agassiz and Mayer ('99, :02); D. mitra Huxley ; D. chamissonis Huxlej^ since recorded by Browne ( : 04) ; D. gracilis Gegenbaur, recorded by Bedot ('96), Diphyopsis campanulifera Eschscholtz, recorded by Browne ( :04) and by Lens and Van Riemsdijk (:08); D. co7npressa Haeckel, recorded by Bedot ('96) as var. picia. Also the following new species, described by Lens and Van Riemsdijk: — Diphyes contorta, D. nier- straszi, D. indica, D. malayana, D. gegenbauri, D. subtiloides, Diphyopsis diphy- oides, D. weberi, D. anomala, and Chuniphyes muUidentata, all from the"Siboga" collection. To these must be added an Eudoxid, indistinguishable, according to them, from the monogastric generation of the Atlantic D. bipartita Costa ( = D. sieboldii Kolliker), as well as their own Doromasia pictoides. Finally the "Albatross" specimens described below, show that the specimen described by Chun ('92) as Doromasia bojani on the supposition that no inferior nectophore was present, unquestionably belongs here. D. dispar Chamisso and Eysenhardt, D. campanulifera Eschscholtz, D. nierstraszi Lens and Van Riemsdijk, D. anomala Lens and Van Riemsdijk, and 242 DIPHYOPSIINAE. Diphyopsis compressa Haeckel, var. picta Bedot agree very closelj^ with each other, in the shape of the anterior nectophore. The first three were long ago united by Huxley ('59). This reduction is accepted by Schneider ('98), and Chun ('97b, p. 27), who has retained both dispar and campanulijera , the former for a Pacific, the latter for an Atlantic form, considers that they are " Ausserordent- liche nah" to each other. Lens and Van Riemsdijk again separate dispar and campanulifera. They record a large series as Diphyopsis campanulifera on the strength of the presence of special nectophores in the groups of appendages, and a single specimen which apparently lacked these structures as Diphycs dispar. Even if special nectophores were absent in this individual, it is not clear why they record it under the specific name dispar, when they themselves say that the description by Chamisso and Eysenhardt shows that the original specimens of dispar had such organs. But, apart from this criticism, the condition of their single specimen was such that it could not show whether it was a Diphyes or a Dyphyopsis. Although the stem bore fourteen "developed groups" of appendages, the fact that no gonophores but merely "some small buds" were present, shows that all the cormidia were very young, the older ones having been detached. In the one in which they figure that there was, in addition to bract, siphon, and tentacle, only one very small bud, which might develop equally well into gonophore, into nectophore, or into both, as in Doromasia picta (Chun, '92). The large size of the specimen has no bearing. It is a question of the state of development of the individual cormidia, not of the colony as a whole. In its general form it agreed perfectly with their specimens of Diphyopsis cam- panulifera, and was no doubt identical with them. On the grounds of priority dispar takes preference over campanulifera. The angustata of Agassiz and Mayer likewise belongs to Diphyopsis dispar as I am convinced from an examination of their specimens from the Fiji Islands, and of Mayer's (:06) material from the Hawaiian Islands. According to Lens and Van Riemsdijk, Diphyes nierstraszi is separated from Diphyopsis dispar ( = campanulifera) by the absence of special nectophores, by smaller size, slender form, and greater length of stem between the groups of appendages. The first of these statements is not well grounded. On the con- trary, the small size of the specimens (7-15 mm. long) indicates that the absence of special nectophores is evidence of immaturity of the cormidia, a conclusion supported by the fact that the authors observed only four groups of appendages in any specimen. So far as size and form are concerned, the former indicates nothing more than an early stage in growth ; and the latter is of no more value, DIPHYOPSIINAE. 243 because specimens in the present collection of the nierstraszi type are connected by an unbroken series with the broadest specimens of D. dispar. Finally, the length of stem between groups of appendages, especially in preserved material, is so variable that it is worthless as a specific character. There is no good reason for retaining D. nierstraszi as a distinct species. Diphyopsis anomala was founded for a specimen with abnormal canals. Lens and Van Riemsdijk themselves suggest (:08, p. 55) that it will "probably be struck out before long." From its form it no doubt belongs to D. dispar. With the latter we must also unite Bedot's var. picia of D. compressa Haeckel, which is nothing more than a local variety. (Chun, '97b, has shown that com- pressa is a synonym of D. canipanulifera Eschscholtz.) To settle whether or not this species is identical with the Atlantic D. cam- panulifera, I have compared Pacific specimens with a series taken at various localities in the Atlantic. Bearing in mind the well-known variability of D. campanulifera (Chun, '97b, p. 27) I have been unable to find any characters whatever to separate them. I therefore follow Huxley and Schneider in uniting them. From an examination of the figure by Bory de St. Vincent ('04) of his "Biphore biparti," I am convinced, as was Huxley, that it is identical with the species under consideration. But Bory's name, "Salpa (bipartita) lanceolata, bipartita," has never been considered a binomial, either by Huxley, by Chun, or by Schneider, nor, from the text of his description, would there be any grounds for so regarding it. Therefore, the next oldest name, disjmr, must be employed for the compound species. D. appendiculata Eschscholtz, is easily distinguished from the other Pacific species by the characters given below. It was thought by Huxley to be identical with the Atlantic D. bipartita Costa ( = D. seeboldii Kolliker), a union accepted by Schneider. Other authors, however, e. g. Chun ('97b), Vanhoffen (:06), Romer (:02), and Mayer (:00), have retained bipartita as a separate species. I have been able to test this question on large and very well-preserved series from all three great oceans, with the result that I can not find a single character to separate D. appendiculata from D. bipartita. I therefore unite them under the older name. From the standpoint of geographic distribution this result was to be expected, for this species is not restricted to warm waters, but attains high latitudes (Romer, :02). D. mitra Huxley. This species was classed by Haeckel among the Alono- phyidae, on the supposition that no inferior nectophore occurred ; but the pres- ence of a specimen in the " Albatross " collection, agreeing with Huxley's figures, 244 DIPHYOPSIIXAE. but with a small second nectophore still attached, s;hows that it is really a Diphyid. The figures of Diphyopsis diphyoides, by Lens and \'au Riemsdijk (:08), who also observed the bud for the inferior nectophore, agree so closely with D. mitra, even to trivial details, that there is no escaping the conclusion that the two arc identical. The specimens described from Amboina by Bedot ('96) as D. gracilis Gegenbaur also resemble D. mitra so closely in the form of both anterior and posterior nectophores that they too must be referred to it. They are discussed in the description below (p. 260). Diphyopsis mitra has not been recorded from the Atlantic, nor does it agree with any Atlantic species, unless perhaps D. hispaniana Mayer. It is true that it differs from the figure of the latter in having a shorter somatocyst and a more pronounced dorsobasal tooth; but the fact that the collection of this Museum contains a series of typical D. mitra from the West Indies suggests that the two may be identical. D. chamissonis Huxley, like D. mitra, has been classed by both Haeckel ('88b) and Chun ('92) as a Monophyid. But the remarkably close resemblance between Huxley's figures and the figures given by Lens and Van Riemsdijk of their Diphyopsis weheri, which is certainly a Diphyid, because it had the buds for the inferior nectophore, leaves little question that the two are identical. The "Albatross" collection contains no representatives of this species, but I have studied typical examples from the Philippines, \\liether or not the specimens described as Muggiaea kochii by Murbach and Shearer are the same as D. chamissonis, as they suppose, can not be determined from their brief descrip- tion (without figures). But the D. chamissonis of Browne (:04, pi. 54, fig. 6) from the Maldives no doubt belongs here. D. subtiloides Lens and Van Riemsdijk, though closely allied to the Atlantic D. subtilis Chun, is easily distinguished from the latter by the characters noted below (p. 247). In general form it closely resembles Muggiaea kochii, but Lens and Van Riemsdijk observed the bud for an inferior nectophore, which places it definitely among the Diphyopsiinae. Next we must consider a group of species which agree in their narrow- pyramidal form, long somatocyst, and prominently developed dorsobasal and laterobasal teeth; these are D. indica, D. malayana, and D. gegenbauri of Lens and Van Riemsdijk, the Doromasia pictoides of the same authors, and Diphijes {" Doromasia ") bojani Chun. The first three are separated only by such minor characters as size, degree of serration, shape of lateral teeth, number of ridges at the apex, and the presence DIPHYOPSIINAE. 245 or the absence of wing-like expansions of the ridges. To summarize Lens and Van Riemsdijk's account, D. gegenhauri is the smallest (65-82 mm.), it has four serrate ridges at the apex, the lateral teeth are small, and there are no "wings." D. indica is 9-11 mm. long; the dorsal ridge is not serrate; there are five ridges at the apex; lateral teeth are very large; "wings" are present. D. malayana is 9-10 mm. long; the dorsal ridge is slightlj' serrate in its distal part; the lateral teeth are large; there are four ridges at the apex, but no " wings." The present excellent series allows me to test these characters; and the condi- tion in fifty specimens of varying size, tabulated below (p. 252), shows that all of them are subject to so much individual variation as to be cjuite worthless for specific diagnosis. The .series shows every gradation between the three species, which must, therefore, be united in one. Lens and Van Riemsdijk have already noted that Doromasia picloides closely resembles their Diphyes gegenhauri, and though they class the latter among the Monophyidae, they admit that future study may prove it to be a Diphyid. That it is a Diphyid is shown bj' a specimen in our collection which, though agreeing with D. pictoides in form and in the presence of a single terminal group of appendages, is slightly larger and has an easily identified bud for an inferior nectophore (Plate 12, fig. 1). Lens and Van Riemsdijk have already noted the close resemblance between their several species, and the Doromasia bojani of Chun. The position of the latter (known from only one specimen lacking any trace of stem or appendages) among the Monophyidae rests merely on the supposition that it is the poly- gastric generation of Ersaea bojani. But the resemblance between Chun's ('92) figure and several of our specimens with "wings" which have inferior nectophores still attached, is too close to allow any conclusion other than that they are identical with the gegenbauri-indica-malayana group. On the grounds of priority bojani must be chosen for the compound species resulting from the union of D. gegenbauri, D. indica, D. malayana, Doromasia bojani, and D. pictoides. This name, it is true, has long been used for an Eudoxid; but the latter probably belongs either to the present species, or to another family (p. 265), and in either case the name bojani can be used for the Diphyes. D. bojani, as Lens and Van Riemsdijk point out, is closely allied to two Atlantic species, D. steenstrupii Gegenbaur and D. serrata Chun. The former, it is true, has been classed b> Schneider ('98) as a synonym of D. appendiculata ( = bipartita) but an examination of Gegenbaur's account convinces me that its true relationship is as here noted. Unfortunately, Chun's description (with- out figures), of sfrra/a, where he says that the outline of the hydroecium differs 246 DIPHYOPSIINAE. from that of steenstrupii, does not state what the difference is. But the fact that our collection of bojani shows that neither the number of rows at the apex, nor the relative size of the lateral teeth, mentioned by Chun as features in which the two differ, is as important as he thought, suggests that the two are identical. I should not be surprised if the Pacific bojani and the Atlantic steenstrupii and serrata eventually prove to belong to one species. But whether this is the case can only be determined by a fresh examination of Atlantic specimens, and unfortunately there have been none available. Diphyes coniorta Lens and Van Riemsdijk is a well-characterized species, easily distinguished from all other Diphyopsiinae by a peculiar asymmetry of the somatocyst. In addition to Diphyopsis dispar, Diphyes appendiculata, and the puzzling D. steenstrupi-serrata group, only three Atlantic species deserve definite recognition. These are Diphyes arctica Chun, D. suhtilis Chun, and D. fowleri Bigelow. The probable identity of Diphyopsis hispaniana Mayer and D. mitra is noted above. On the other hand there is a possibility that Doromasia pida Chun may belong here (p. 265). D. fowleri is here recorded from the Pacific and the collection contains one Diphyid, D. spiralis (p. 249), described as new on account of the remarkable spiral torsion of the entire superior nectophore. The corm, or the secondary nectophore, is so often destroyed in preserved specimens of Diphyes and Diph3'opsis that it would be a great convenience to find a set of characters, sufficient for specific identification in the anterior necto- phore alone. As it turns out, such are afforded by general form within certain limits, by the number of ridges at the apex, by whether their number is constant, by the presence or absence of basodorsal and basolateral teeth, and bj- the com- parative length of the hydroecium. Somewhat to my surprise the latter proves to be one of the most constant characters. The following kej^ to the species of Diphyopsiinae is based upon these features. Key to the Species. 1. With prominent basolateral and smaller dorsolateral teeth. A. 5 (or 4) ridges at the apex. a\ Somatocyst long; general form very broad; nectosac ending dis- tally in a tubular coecum. D. dispar Chamisso and Eysenhardt. a . Somatocyst long; general form, narrow; nectosac fusiform at the apex; ridges at the apex either 5 or 4; lateral teeth very long. DIPHYOPSIINAE. 247 D. bojani Chun (incl. serrata Chun and steenstrupi Gegenbaur). a . Somatocyst short, reaching only to the opening of the nectosac; hydroecium deep; general form narrow. D. chamissonis Huxley (= D. iveberi Lens and Van Riemsdijkj. B. 7 ridges from apex to base; very shallow hydroecium; nectosac short; somatocyst much longer. Chuniphyes multidentata Lens and \'an Riemsdijk. 2. Basolateral teeth absent; basodorsal tooth very small. A. Hydroecium short, truncate; somatocyst pear shaped, reaching only to mid-level of nectosac. D. mitra Huxley ( = D. diphyoides Lens and Van Riemsdijk, = hispaniana Mayer?) 3. With neither basodorsal nor basolateral teeth. A. 3 ridges only at the apex. a^. Somatocyst straight, median. D. appendiculata Eschscholtz ( = D. blpariita Costa). n^. Somatocyst curved to the right, ventral facet asymmetrical. D. contorta Lens and Van Riemsdijk. R. 4 ridges at the apex. rt\ Nectophore spirally twisted, fusiform; somatocyst straight. D. spiralis, sp. nov. a^. Nectophore not spirally twisted, somatocyst curved to the right. D. contorta Lens and Van Riemsdijk. C. Constantly 5 ridges at the apex. o\ Hydroecium very shallow. Somatocyst spherical or pear shaped, lying transverse to the main axis of the nectophore. D. fowler i Bigelow. a . Hydroecium almost entirely suppressed. 1. Somatocyst of the ordinary fusiform type, reaching to \ the length of the nectophore. Apex pointed. D. subtiloides Lens and Van Riemsdijk. 2. Somatocyst thread-like with a large spherical terminal dila- tion. Apex rounded. D. subtilis Chun. Diphyes arctica Chun is omitted as no details as to the number of ridges are given in Chun's description. It is easily distinguished from all other species 248 DIPHYES APPENDICULATA. of Diphyes and Diphyopsis by the fact that the rather deep hydroecium is open along its mid-ventral line, and from Chuniphyes by the smoothness of the external surface, the rounded apex, and the absence of basal teeth. DIPHYES CuviER, 1817. Diphyes appendiculata Eschscholtz. Plate?, figs, 5-6; Plate 8, figs. 7-S; Plate 9, fig. G; Plate 10, fig. G; Plate 11, fig. 1. Diphyes appendiculata Eschscholtz, '29, p. 138, pi. 12, fig. 7; Huxley, '59, p. 34, pi. 1, fig. 2; Schneider, '98, p. 85; BiGELOw, :04, p. 265. : 11, b, p. 344. DiphycsbipartitaCosTA, '36, p. 4, taf.4; Chun, '88, p. 11.58; '97b, p. 24; Mayer, :00, p. 74, pi. 34, fig. 114; RoMER, : 02, p. 175. Diphyes elongata Hyndman, '41, p. 165, fig. 1-4. Diphyes acuminata Leuckart, '53, p. 61, taf. 3, fig. 11-20; GEfiENBAUR, '00, p. 375. Diphyes siehoUii Kolliker, '53, p. 36, taf. 11, fig. 1-8; Gegenbaur, '54, p. 4.53; Kefferstein and Ehlers, '61, p. 15. Diphyes gracilis Gegenbaur, '53, p. 309, taf. 16, fig. 5-7 (non D. gracilis Bedot, '96). Eudoxia campanula Leuckart, '53, p. 43; Muller, '70-'71, taf. 11, fig. 1-4, taf. 13, fig. 10. Lens and Van Riemsdijk, :08, p. 48, pi. 7, fig. 62. Eudoxid. Eudoxia messanensis Gegenbaur, '53, p. 285. Eddoxid. Eudoxia alata McCrady', '57, p. 172, pi. 8, fig. 9, 10. Eudoxid. Eudoxoides sagittata Huxley, '59, p. 59, pi. 4, fig. 1. Eudoxid. Cucullus gegenbauri Haeckel, 'SSb, p. 110. Eudoxid. Cucullus eloiigalus Haeckel, '88b, p. 110. Eudoxid. Cucullus campanula Haeckel, '88b, p. 111. Eudoxid. ?Diphyes pusilla, McCrady, '57, p. 174. Non Ersaea appendiculata Agassiz and May'er, ; 02. The polygastric generation was taken at Stations 4571, 4574, 4575, 4641, 4644, 4646, 4650, 4661, 4676, 4679, 4681, 4683, 4699, 4701, 4704, 4705, 4707, 4710, 4713, 4715, 4716, 4717, 4720, 4724, 4725, 4734, 4740, 4742, and 4743, in twelve surface hauls, and in seventeen hauls from 300 fathoms to the surface. The material consists of three entire colonies (with the two nectophores still connected), one hundred and forty-six loose anterior and four loose posterior nectophores. The material was nearly evenly divided between the two classes of hauls. The Eudoxid was taken at Stations 4580, 4583, 4588, 4598, 4613, 4617, 4644, 4650, 4657, 4665, 4679, 4696, 4707. This material consists of twelve specimens from six surface, and twenty from seven 300 fathom hauls. Although this species has long been known and often figured, its most diagnostic characters deserve attention here. The most characteristic external feature is the conformation of the upper part of the anterior nectophore, the importance of which seems to have been generally overlooked, although it allows specimens of this species to be recognized at a glance. There are only three ridges at the apex; two of which enclose the ventral facet, while a third, at first lying in a dorsal position, tiu'ns to one side to become the right lateral ridge. DIPHYES SPIRALIS. 249 The left lateral ridge arises some distance below the apex, usuallj' at about the level of the upper end of the nectosac. In a series of one hundred Pacific and one hundred Atlantic specimens there is no variation except for very slight individual differences in the precise level at which the left lateral ridge arises. Such constancy is in marked contrast to the variability in the number of ridges at the apex in D. bojani (p. 252). As long ago pointed out by Gegenbaur ('60), the dorsal ridge, which extends upward from the basal margin, is very short (Plate 9, fig. 6). The serration of the lateral and ventral ridges, so often noticed, is chiefly restricted to the central two thirds of their length. They are smooth near the apex, and as a rule, though not always, close to the basal margin. Besides the ridges, the great length of the somatocyst, the absence of dorsal or lateral teeth, and the basal outline of the hydroecium (Plate 7, figs. 5, 6) are all characters of specific importance. The posterior nectophore has so often been figured that I may merely note for read}^ identification, that its hydroecial canal is closed, and that the basal teeth which are prominent, bear smaller teeth in their dorsal margins (Plate 10, fig. 6). The Eudoxid of D. nppendiculata is so well known, as to require no descrip- tion here. Agassiz and Mayer have described the Eudoxid of the Pacific D. appendiculata as an "Ersaea," not an "Eudoxia" as it is in the Atlantic form. But Lens and Van Riemsdijk found typical Eudoxia campanula in the " Siboga " material; and the figures of Agassiz and Mayer suggest that what they took for the monogastric generation of D. appendiculata was in reality the "Ersaea" of Diphyopsis dispar (cf. Agassiz and Mayer, :02, pi. 9, fig. 40, witli their own ])!. 10, fig. 41, and with Lens and Van Riemsdijk, pi. 7, fig. 62). Diphyes spiralis, sp. nov. Plate 7, fig. 4, Plate 8, fig. 1, 2, Plate 9, fig. 3, Plate 11, fig. 4. . Sta' ion 4583 surface 7 anterior nectophores. 4587 300-0 fms. 1 4663 300-0 fms. 1 4686 surface 59 4688 36 4690 4 4696 1 4700 10 4702 2 Types. 250 DIPHYES SPIRALIS. The largest is six, the smallest is two mm. long. These small nectophores differ so markedly in general from all previously known Diphyids that a new species is necessary to receive them. Their most remarkable feature is that the entire nectophore is spirally twisted, the tortion in all cases being in the same direction as the hands of a clock (Plate 7, fig. 4, Plate 8, fig. 1). This is so pronounced that the specimens, though very small, are recognizable at a glance. In contracted individuals (Plate 7, fig. 4) the tortion is so extreme as to render resolution of the facets and ridges extremely difficult, but on expanded material (Plate 8, fig. 1) these can be easily followed. There are four ridges at the apex (Plate 8, fig. 2), dorsal, ventral, and a lateral on either side. Owing to the general tortion the dorsal lies to the left, the ventral to the right of the mid-line. The dorsal and lateral ridges run to the basal margin without branching, following a spiral course, more easily represented in the drawing than by description. At the margin the dorsal ridge is nearly dorsal, but the left lateral lies dorsal, the right lateral ventral, to the mid-ventral line. The ventral ridge bends at first sharply to the right, and then divides into two, which enclose a ventral facet. The right hand one of the two resultant ridges runs obliquely to the left, so that it reaches the basal margin of the hydroecium near the mid-ventral plane. The left ventral ridge follows a corresponding parallel course, but at about the level of the opening of the nectosac it bends sharply toward the mid- ventral plane, and terminates (Plate 8, fig. 2), so that the ventral and left ventrolateral facets become confluent. All the ridges are strongly serrate, except near the apex. The arrangement of the ridges is con- stant in all the specimens examined, except for greater or less twisting, con- comitant with greater or less contraction. But even in specimens which had lost the musculature of the subumbrella, and were consequently fully expanded, the tortion is well marked. There are neither basolateral nor basodorsal teeth in this species. The hydroecium is rather short, and pointed at the apex; its base shows an asyrmnetry so characteristic that it is possible to identify the species from this region alone. Its basolateral margins are strongly concave (Plate 8, fig. 1) ; each ends dorsally in a pronounced tooth. The dorsal wall below the le\'el of the bell opening is divided so as to form two lanceolate wings of which the right hand one is much the larger in all our specimens. The ventrobasal wall of the hydroecium is deeply incised in the mid-line, where the right ventral ridge reaches it, and the entire basal margin of the hydroecium is strongly serrated. The somatocyst, which is cylindrical and rather more than half as long as DIPHYES BOJANI. ' 251 the nectosac, lies obliquely to the right of the main axis of the nectophore (Plate 8, fig. 2), it is not twisted itself. The very muscular nectosac shows a tortion corresponding to that of the nectophore as a whole. In none of the specimens was the subumbrella in good enough condition for me to trace the canals. Stevi and appendages. In two specimens the stem bore a very small bud which was apparently the forerunner of a posterior nectophore. It is the pres- ence of these buds which has caused me to refer the species to the Diphyidae rather than to the Sphaeronectidae. The stalk is much contracted in all the specimens, but in a few the groups of appendages are sufficiently loose for study. In these (Plate 11, fig. 4), there is, in addition to siphon, tentacle, and bract a single large bud, so far advanced as to be easily identified as the future gono- phore. In view of the conditions in Diphyopsis dispar (p. 258), where the special nectophores first appear at a late stage in development, at least in some individ- uals, it is possible that such organs might be developed later, in spiralis. Should this finally prove to take place, the species must be removed from Diphyes to Diphyopsis. The records of capture show that D. spiralis is a surface form. Diphyes bojani (Chun). Plate 7, fig. 2,3; Plate 8, fig. 6; Plate 9,fig. 1, 2; Plate 10, fig. 2, 3; Plate 11, fig. 5; Plate 12, fig. 1. Doromasia bojani Chu.n, '92, p. 108, 110, fig. 8. Diphyes indica Lens and V.4N Riemsdijk, :08, p. 44, pi. 7, fig. 54. Diphyes malayana Lens and Van Riemsdijk, :08, p. 4.5, pi. 7, figs. 55, 56. Diphyes gegenbauri Lens and Van Riemsdijk, : 08, p. 46, pi. 7, fig. 57, pi. 8, fig. 58. Doromasia picloides Lens and Van Riemsdijk, :08, p. 3, pi. 1, fig. 1. This species was taken at the following Stations:— 4587, 4588, 4592, 4605, 4644, 4665, 4673, 4676, 4684, 4687, 4695, 4704, 4707, 4708, 4710, 4721, 4722, 4724, 4727, 4734, 4735, 4740, and 4741. The records are from both surface and intermediate (300-0 fathom) hauls. The material consists of two entire col- onies, sixty-two anterior, and fifteen posterior nectophores. The largest anterior nectophore is 21 mm. long, the smallest, 6 mm. The largest posterior nectophore is 19 mm. The collection forms a continuous series between these extremes. As a test of the constancy of the characters of the anterior nectophore on which Lens and Van Riemsdijk separate their D. indica, malayana, and gegen- bauri, i. e., size and form of the basolateral teeth, number of ridges at the apex, and degree of serration of the ridges, I have tabulated them in fifty specimens, including the largest and the smallest, with the following results: — 252 DIPHYES BOJANI. Ridges at apex 3, 4, 5. Number of specimens 3, 15, 32. The ridges in the latter class are two ventrals, two laterals, and one dorsal. The individuals with four ridges at the apex, fall into two main divisions. 1. The original ridges are dorsal, two ventral and one lateral, and the second lateral results from the division of one of the ventrals, which is the left in eleven specimens, and the right hand one in two. This is the condition in D. malayana, and in D. gegenbauri (Lens and Van Riemsdijk, :08). 2. The four ridges at the apex are the dorsal, two laterals, and one ventral; the latter divides into two ventrals which enclose the ventral facet. This agrees with Gegenbaur's ('60) description of D. steenstrupi. In the three specimens with only three ridges at the apex, there are a dorsal and two ventrals, both of the latter branching, to form the two laterals. The level at which division of the ridges occurs is variable, and often so close to the apex that it is hard to say how many ridges there are at that point. Since the three classes intergrade it is clear that the number of ridges at the apex is not of specific importance, at least in D. bojani. On correlating this character with the presence or absence of wing-like enlarge- ments of the upper third of the ridges, it proved that of twenty-one specimens in which these were evident, twelve had five ridges, eight had four, and one had three at the apex. There is, then, no correspondence between the two charac- ters, and I may add that there is every gradation between individuals in which "wings" are prominent (Plate 7, fig. 2) and those in which no trace of them is to be seen (Plate 7, fig. 3). The size and form of the basolateral teeth also proves to be so variable that I can not follow Lens and Van Riemsdijk in making it the basis for specific determination. It can not be correlated either with presence or absence of "wings," or with the number of ridges at the apex. In a general way the pro- portional size of the lateral teeth increases with the growth of the colony. But this is irregular. In the larger individuals the margins of the teeth are strongly convex (Plate 9, fig. 1) in the small ones (7-10 mm.) concave. But there is every possible gradation between the extremes. In this respect "D. gegenbauri,'" " D. malayana," and " D. indica" show three successive stages, as they do in size. The degree of serration varies independently of the characters alread}- examined, and therefore is of no more importance. Small specimens are usually DIPHYES BOJANI. 253 more strongly serrate than large ones; such is the case in the small "D. gegen- bauri." From this evidence the only conclusion, it seems to me, is that D. gegen- bauri, D. tnalayana, and D. indica represent three successive stages in the devel- opment of a single species. My reasons for uniting them with Doromasia bojaui and D. pidoides are given above (p. 245). Diphyes bojani, though it varies in general form almost as much as Diphyop- sis dispar, is easily distinguished from other Pacific Diphyids by the following characters: — The anterior nectophore is slender, pointed at the apex, truncate at the base; there are five prominent ridges except at the apex in some indi- viduals, and as noted, these are often expanded to form "wings" in the upper one third of their course; the serrations of the ridges are everywhere variable, especially so at the apex; the nectosac reaches nearlj^ to the apex. The hydroecium is pointed at the top, and reaches nearly to one third the height of the nectosac. The somatocyst is fusiform, and its form and length very constant. Both dorsobasal and laterobasal teeth are large, though variable in form as already noted. The dorsobasal wall of the hydroecium, below the bell opening, is entire, its margin slightly concave, and the teeth serrate. The lateral basal margins are concave in small specimens (Plate 12, fig. 1) as described by Lens and Van Riemsdijk {" D. gegenbauri"), straight in large ones (Plate 7, fig. 3), and serrate in all. Posterior nectophore. The entire specimens afford an opportunity to describe the inferior nectophore. In general outline (Plate 10, fig. 2) it much resembles the corresponding nectophore in Diphyopsis dispar (Plate 10, fig. 1), and as in the latter the two lateral flaps which cover the hydroecium remain separate, instead of uniting to form a closed canal as they do in Diphyes appendiculata (Plate 10, fig. 6). It is easily distinguished from D. dispar by its more slender form, and by the pronounced serration of the two lateral basal edges and lateral teeth of the hydroecium, regions which are entirely smooth in dispar; in its basal region, and in its serration, it resembles the corresponding nectophore of D. steenstrupi (Gegenbaur, '60), a species with which bojani may finally be united (p. 246). The measurements of an entire colony are superior nectophore, length 12 mm., inferior nectophore, 9 mm. Cormidia. The most advanced groups of appendages (Plate 11, fig. 5). consist of siphon, tentacle, bract, and gonophore. As Lens and Van Riems- dijk ( : 08) have pointed out, there is no special nectophore. The bract with two prominent basal teeth, is of a characteristic form. 254 DIPHYES CONTORTA. The species was first encountered off Manzanilla; and thence occurred along the coast of Central America as far as Guatemala. It was not taken in the Panamic region. From the Galapagos, however, it was taken regularly on all our lines, both within and without the Humboldt Current. Chun's specimen was taken between Hawaii and the Carolines, and the "Siboga" col- lection was from the Malaysian region. Its close allies D. steenstrupi and D. serrata are known from various parts of the Tropical Atlantic. Diphyes contorta Lens and Van Riemsdijk. Plate 7, fig. 7, 8; Plate 8, fig. 3; Plate 11, fig. 2. Diphyes contorta Lens and Van Riemsdijk, :08, p. 39, pi. 6, fig. 48-50. Station 4580 300 fathoms — surface 1 specimen. " 4583 " 4587 " " 4594 " " 4598 " " 4605 " " 4634 " " 4644 " 4646 " " 4688 " " 4692 " 4694 " ■ 4696 Acapulco Harbor 3 5 1 1 1 1 7 3 2 1 1 7 4 Only anterior nectophores were taken; but as was the case in the "Siboga" collection, several show the bud for the inferior nectophore. The largest speci- men is 7 mm. long. This species was described in such detail by Lens and Van Riemsdijk that I will only emphasize such characters as are useful for specific identification. From this standpoint the most characteristic feature is the peculiar structure of the somatocyst, which arises from the hydroecium in the mid-ventral line, but turns sharply to the right, so that its upper end lies beside, and at the right of, the nectosac. Its form, with narrow stalk and distal dilation, so well figured by Lens and Van Riemsdijk, is likewise unusual. The ventral facet is twisted and asymmetrical, to correspond with the tor- tion of the somatocyst. The left lateral facet is broader than the right hand DIPHYES FOWLERI. 255 one; the dorsal facet is symmetrical, broadly oval, and bomided by the two prominent lateral ridges. The dorsal ridge is discernible only near the base of the nectophore. In the original account Lens and Van Riemsdijk state (:08) that there are four ridges at the apex. But in all of the specimens studied I find that the right- ventral ridge arises a short distance below the apex (Plate 8, fig. 3). Neither dorsobasal nor laterobasal teeth are present. The hydroecium is shal- low, its cavity hardly extending beyond the base of the nectosac (Plate 7, fig. 8). The dorsal wall of the hydroecium, below the bell opening, is not divided into separate wings, but is merely slightly concave.. In no case was the bud for the inferior nectophore sufficiently advanced to throw any light on its future form, nor was the "Siboga" series any more instructive in this respect. The apparent absence of a special nectophore in the groups of appendages has been noted by Lens and Van Riemsdijk, who have seen a gonophore in some specimens. In our most advanced cormidia only one bud, besides bract, tentacle, and siphon, was ever visible. This was probably the future gonophore (Plate 11, fig. 2, Go.). It must be confessed, however, that to establish the absence of a special nectophore, will require a study of material with the groups of appendages further developed. This species is entirely colorless in life. D. contorta is so far known only from the Malaj'sian region and from the Eastern Tropical Pacific. Diphyes fowleri Bigelow. Plate 8, fig. 4; Plate 9, fig. .5. Diphyes fowleri Bigelow, : lib, p. 346, PI. 28, fig. 5. Station 4587 300 fathoms to surface 2 anterior nectophores. " 4634 " " " " 1 " 4638 '■ " " " 1 " 4646 " " " '• 2 " 4657 " " " " 1 u 4(359 u u u u ^ The largest specimen is 12 mm. long. The identity of the series listed above with D. fowleri rests on an actual comparison between the Pacific and the Bis- cayan specimens. As I have elsewhere noted (:11b, p. 346) the anterior bell of D. fowleri very closely resembles D. subtiloides Lens and Van Riemsdijk in gen- eral form. As in subtiloides there are five ridges running from the pointed apex 256 DIPHYES FOWLERI. to the base; there are no laterobasal teeth and the dorsal tooth is represented merely by a slight prominence of the dorsal angle, while the very short conical hydroecium lies wholly below the level of the bell-opening. But it is separated from subtiloides by two characters which are sufficient basis for specific sepa- ration, since they have proved constant on the considerable series of the two species which have yet been studied (110 subtiloides, Q7 fowleri). In the first place, the dorsal wall of the hydroecium below the opening of the nectosac, is entire in subtiloides (Lens and Van Riemsdijk, : 08), but in Joideri it is divided into two wings of which the right hand one is the larger in those from the Pacific, as in those from the Atlantic (Bigelow, :11b, p. 347). In the second place the somatocyst in fowleri is pear-shaped or spherical, and occupies a position transverse to the long axis of the nectophore, reaching hardly, if at all, above the level of the mouth of the nectosac (Plate 8, fig. 4), instead of being of the ordinary fusiform type and of considerable length as it is in subti- loides. In the Biscayan specimens the point of attachment for the second necto- phore could usually be detected, but on the fragmentary stems in the present series neither this, nor any but the youngest appendages remain. My reference of this species to Diphyes rather than to Diphyopsis rests on the apparent absence of special nectophores in the only Atlantic specimen which still had a group of appendages in an advanced state of development attached to the stem. With- out knowing whether the groups of appendages remain attached permanently, or whether they are set free, it is, of course, impossible to determine finally whether the species belongs to the Diphyopsiinae or to the Galeolariinae. But the structure of the hydroecium and the pyramidal form of the anterior necto- phore indicate the former. The absence of basolateral teeth separates this species from Diphyopsis dispar, D. chamissonis, and Diphyes bojani among Pacific species, as it does from the Atlantic D. serrata Chun, and D. steenstrupi Gegenbaur. From Diphyes appendiculata , Diphyopsis mitra, and Muggiaea atlantica it is easily distinguished by the structure of hydroecium and somatocyst. The only Pacific Diphyid or Monophyid with which it might possibly be confused are Diphyes subtiloides Lens and Van Riemsdijk, and Muggiaea kochii Will, both of which resemble it in the shape of the hydroecium. But from both it is sepa- rated by the structure of the somatocyst, while between it and the latter there is the further distinction that while in D. fmvleri the lateral ridges extend to the basal margin, in M. kochii they end some little distance above that level (p. 188). DIPHYOPSIS DISPAR. 257 No species of Galeolaria as yet recorded from the Pacific could be confused with it. The locaHties from which the species is recorded, Eastern Tropical Pacific, Bay of Biscay, and West Indies, suggest that it will be found widely distributed over the warmer zones of all oceans. Though it has now been taken in twenty- four hauls (seventeen of which were in the Bay of Biscaj') , only once has it been found in a surface haul. On the other hand, the shallowness of most of the Atlantic captures (fifteen from 100 fathoms or less, one from 250, one from 300, all in open nets) shows that it belongs to the "epiplankton," though it is appar- ently uncommon immediately at the surface. DIPHYOPSIS Haeckel, 1888. Diphyopsis dispar (Chamisso and Eysenhardt) Haeckel. Plate 10, fig. 1; Plate 11, fig. 3. Salpa (hipartita) lanceolata bipartita Bory de St. Vincent, '04, 1, p. 134, taf. 6, fig. 3. Diphyes dispar Chamisso and Eysenhardt, '21, p. 365 pi. 33, fig. 4; Eschscholtz,' 29, p. 137; Huxley, '59, p. 30, pi. 1, fig. 1; Schneider, '9S, p. 197; Lens and Van Rie.msdijk, :0S, p. 42, pi. 6, fig. 51, 52. Diphyes anguslala Eschscholtz, '25, p. 743, taf. 5, fig. 16; '29, p. 136, taf. 12, fig. 6. Diphyes campanuUfera Eschscholtz, '29, p. 137, taf. 12, fig. 6; Gegenbaur, '60, p. 366, taf. 30, fig. 23-26. ? Ersaea gaimardi Eschscholtz, '29, p. 128, taf. 12, fig. 4. Eudoxid. Eudoxia lessonii Eschscholtz, '29, p. 126, taf. 12, fig. 2. Eudoxid. Diphyes boryi Blainville, '30, p. 123, fig. 100; '34, p. 135, taf. 5; Quoy and Gaimard, '34, p. 83, pi. 4, fig. 1-6. Diphyes regularis Van Meyen, '34, p. 334, tab. 46. Diphyes cucullus QuoY and Gaimard, '34, p. 92, pi. 4, fig. 21-23. Eudoxid. Cucullus doreyanus Blainville, '34, p. 131. Eudoxid. Eudoxia lessonii Huxley, '59, p. 57, pi. 3, fig. 6; Fewkes, 'SI, p. 166, pi. 6, fig. 8, 9; Chun, '97b, p. 26; Mayer, :00, p. 75; Lens and Van Riemsduk, :08, p. 50. Eudoxid. Diphyopsis compressa Haeckel, '88a, p. 35, '88b, p. 153, pL 33, 34. Cundlus lessonii Haeckel, '88a, p. 32; '88b, p. 110. Eudoxid. Ersaea compressa Haeckel, '88a, p. 32; '88b, p. 123, pi. 34. Eudoxid. Diphyopsis dispar Haeckel, '88b, p. 152; Chun, '97b, p. 27. Diphyopsis angusiata Haeckel, '88b, p. 1.52; Ag.\ssiz and Mayer, :02, p. 162, pi. 8, 10, fig. 37, 42. Diphyopsis campanuUfera Haeckel, '88b, p. 153; Chun, '97b, p. 26; Mayer, :00 p. 75, pi. 28, fig. 93-95; Lens and Van Riemsduk, :08, p. 51, pi. 8, fig. 63. Di/ihyopsis compressa var. picta, Bedot, '96, p. 372. Ersaea oppendicidala, Agassiz and Mayer, :02, p. 161, pi. 9, fig. 2. Diphyes nierstraszi Lens and Van Riemsduk, :08, p. 43, pi. 7, fig. .53. Diphyopsis anomala Lens and Van Riemsduk, :08, p. 54, pi. 8, fig. 69, pi. 9, fig. 70. This species was taken at Stations 4571, 4574, 4583, 4587, 4588, 4592, 4596, 4609, 4615, 4617, 4619, 4627, 4630, 4646, 4684, 4698, 4720, 4721, 4725, 4727, 4734, 4737, and 4743. The records are from surface hauls, and hauls with open nets from 300 fathoms to the surface. The material consists of two entire colonies, ninety-seven superior necto- 258 DIPHYOPSIS MITRA. phores, and twenty-four inferior nectophores. I have also had access to a large series from other parts of the Pacific, and from the Atlantic. The Eudoxid was taken at Stations 4570, 4571, 4588, 4615, 4617, 4646, 4659, 4663, 4676, 4692, 4694, 4696, 4700, and 4707. For the synonymy of this stage, see Chun ('97a) and Lens and Van Riemsdjik, (:08, p. 50). As noted elsewhere (p. 249) the "Ersaea appendiculata" of Agassiz and Mayer (:02, p. 161, pi. 9, fig. 40) belongs to this species. Comparison of Atlantic and Pacific specimens shows no specific difference. Diphyopsis dispar is so well known that no account is necessary here. The diagnostic features of the superior nectophore are given in the key (p. 246). So far as my observations on Atlantic and Pacific material go, the inferior necto- phore never shows such prominent serration of its ridges and base as is to be seen in Haeckel's figure ('88b, pi. 33, fig. 4). On the contrary, these regions are entirely smooth in tffe "Albatross" specimens. An interesting feature of the posterior nectophore is, that the lateral flaps which cover the hydroecium remain separate, instead of uniting to form a closed canal. Chun ('97b) has already pointed out that the superior nectophore is ex- tremely variable in form. In several of the specimens the groups of appendages were far enough advanced to show both gonophore and special nectophore (Plate 11, fig. 3). It is interesting that in one individual with eight groups, only the oldest bore both buds, the younger ones having only the common bud. This observation illustrates the difficulty of determining from a study of young material, or of specimens with only the younger parts of the stems and append- ages intact, whether any given species belongs to Diphyes or to Diphyopsis. Diphyopsis dispar is known from the Mediterranean, from various local- ities in the Tropical Atlantic, from the Gulf Stream (Hargitt, : 05, p. 60) and even as far north as Newfoundland (Bigelow, :09b, p. 316). Its range also includes the Indian Ocean (Quoy and Gaimard, Lesson), the Malaysian region and the Tropical Pacific in general. Its distribution through the warmer waters of all oceans, parallels that of Rhopalonema velatum and of Aglaura hemi- stoma among holoplanktonic Medusae. Diphyopsis mltra (Huxlev). Plate 7, fig. 9; Plate 9, fig. 4; Plate 10, figs. 4, 5; Plate 11, fig. (5; Plate 12, fig. .5. Diphyes milra Huxley, '59, p. 36, pi. 1, fig. 4. Cymbonecics milra Haeckel, '88a, p. 34, '8Sb, p. 133. Muggiaea mitra Chun, '92, p. 89. Muggiaea kochi (partim. non Will, '44) Schneider, '98, p. 88. Diphyes gracilis Bedot, '96, p. 370, pi. 12, fig. 4, 8 (non D. gracilis Gegenbaur, '53). Diphyopsis diphyoides Lens and Van Riemsdijk, : 08, p. 51, pi. 8, fig. 65, 66. DIPHYOPSIS MITRA. 259 Station 4583 300-0 fms. 4 4587 (( (( 5 4598 u a 9 4611 surface 1 4613 300 to surface 5 4634 a a a 8 4638 a ii (i 4 ; 4639 a u li 4 4640 surface 4 4644 surface 6 4646 300-0 fms. 2 4650 a li 2 4657 surface 4659 300-0 fms. 4665 u a 4669 a a 4673 surface 4676 800-0 fms. 3 4676 300-0 fms. 2 4679 CC ii 2 4681 U ii 8 4683 li ii 1 4687 a a 1 4688 ii n 1 4705 ii a 1 4707 ii a 2 4715 a ii 4 4716 600-0 fms. 1 4717 300-0 " 3 4719 ii ii 4 4734 ii ii 1 anterior nectophores. 1 posterior nectophore. Also several typical specimens from the West Indies. The anterior nectophores of this species have been well described by Lens and Van Riemsdijk. They are readily separated from those of Diphyes appendicu- lata which they resemble in general appearance by the following characters: the general form is high, pyramidal, ridges but slightly arched; symmetrical. There a,re five ridges at the apex; and there is no variation from this number 260 DIPHYOPSIS MITRA. in any specimen which I have seen. The nectosac extends nearly to the apex. There are no basolateral teeth, and the dorsolateral tooth is very small (Plate 9, fig. 4). The length of the hj^droecium below the opening of the necto- sac is much greater than its extent above that level. At the top it is truncate, an outline which with the short pear-shaped somatocyst, separates D. inilra from other Pacific Diphyids. The somatocyst reaches only to the mid-level of the nectosac. The dorsal wall of the hydroecium below the bell opening is divided into two wings, as it is in D. appendiculata, but they are more pointed than in the latter, and the left hand one invariably (?) bears a triangular secondary flap or tooth (Plate 9, fig. 4, To. H ). The basolateral margins are distinctly concave. All the ridges of the nectophore are serrate, except near the apex. But the prominence of the serrations is variable. In all these features both Eastern Pacific and West Indian specimens resemble the "Siboga" material on which Lens and Van Riemsdijk based their D. diphyoides, while there is such a close agreement between all of these and Huxley's figures of Diphyes mitra that I have no doubt of their identity with it. Huxley's specimen differs from those more recently described only in being somewhat broader, in having an even smaller dorsal tooth, and less concave basal hydroecial margins, divergences all of which are too trivial to suggest specific difference. The supposition that D. mitra is a Monophyid (Haeckel, '88b, Chun, '92), rests merely on the absence of an inferior nectophore in Huxley's single and ''obviously imperfect" ('59, p. 37) specimen. That this absence was accidental can hardly be questioned in view of the resemblance between his figure and the undoubted Diphyids of the "Siboga" and "Albatross" collections. My identification of Bedot's Diphyes gracilis as a synonym of the species under consideration rests on the truncate hydroecium, the short pear-shaped somatocyst, and the conformation of the base (Bedot, '96, pi. 1'2, fig. 4), as well as on the form of the inferior necto- phore noted below. Inferior nectophore. In the "Siboga" series only the buds for inferior nectophores were present; and this is true of most of the "Albatross" specimens. But in one this structure is sufficiently developed to identify an inferior necto- phore, found loose in the collection (Plate 10, fig. 4) as belonging to D. mitra. There can be little doubt about this identification, because the differences between the two are only such as might be expected at such different stages in growth. The more important features are that the hydroecial canal is open, though covered over near the upper end bj- two flaps, of which the left one is CHUNIPHYES. 261 the larger, and that there is a prominent basal tooth on the right hand side, while the corresponding angle on the left side is merely acute and somewhat prominent. Two inferior nectophores, agreeing perfectly with those of D. mitra, were referred, doubtfully by Lens and Van Riemsdijk, to D. chamissonis ( = D. weberi Lens and Van Riemsdijk), and these authors have noted the close resem- blance between them and Bedot's figures of the corresponding nectophores of his D. gracilis { = D. mitra), in which the hj'droecium is apparently open as it is in the "Albatross" specimen. This feature alone, is sufficient to show that Bedot's D. gracilis has nothing to do with Gegenbaur's D. gracilis, which is a synonym of Diphyes appendiculata (p. 248). And the structure of both necto- phores shows that D. gracilis Bedot, is identical with D. mitra. Cormidia. The position of this specis in Diphyopsis rather than in Diphyes rests on the discovery, by Lens and Van Riemsdijk, of a special necto- phore in the groups of appendages. In the "Albatross" material even the most advanced cormidia bear only one bud, not yet old enough to show its final destination (Plate 11, fig. 6). D. mitra occurred regularly on all our lines, both on surface, and in inter- mediate hauls. It was not taken in closing nets. Huxley's specimen was taken in the Indian Ocean, southeast of Mauritius. The Atlantic series, in the Museum of Comparative Zoology, shows that it is common among the West Indies. The possibility that it may be identical with Diphyopsis hispaniana Mayer, likewise a West Indian species, has been noted (p. 244), but I do not feel sufficiently sure to include this in the synonymy. CHUNIPHYES Lens and Van Riemsdijk, 1908. Until we know the structure of the groups of appendages in this genus, it is impossible to formulate a final definition for it. I retain it in the sense used by its proposers, because the general structure of the nectophores of its type and single representative is sufficiently characteristic to warrant generic sepa- ration. My reasons for including it among the Diphyopsiinae are given above (p. 241). In addition to the specimens listed below I have had the advantage of studying the more extensive series collected by Mr. G. H. Fowler in the Bay of Biscaj^ (Bigelow, :11b, p. 348). Comparison of the two collections has con- vinced me that the differences in the form of the nectosac and of the somatocyst described below (p. 263), are so slight and inconstant as to be quite worthless as 262 CHUNIPHYES MULTIDENTATA. specific characters. So far as I can judge from the account of the rather frag- mentary "Siboga" specimens they too were identical with the present series. All known representatives of the genus, then, must be referred to its type species. Chuniphyes multidentata Lens and Van Riemsdijk. Plate 8, fig. 9, plate 10, fig, 7, plate 12, fig, 6. Chuniphyes multidentata Lens and Van Riemsdijk, :08, p. 13, pi. 1, fig, 9-11, pi. 2, fig, 12-15; BiGELOw, : lib, p. 348. Station 4703 300 fathoms to surface 1 specimen with both nectophores still connected. " 4724 " " " " 2 anterior and one posterior necto- phores. In none was anything but the proximal end of the stem preserved. In the entire specimen the superior nectophore is 22, the inferior 26 mm. long. The loose superior nectophores measure 20 and 17 mm., the inferior one 24. The complete specimen is in good enough condition to allow a much more detailed study than Lens and Van Riemsdijk were able to make from the frag- mentary and much distorted "Siboga" material. And in this case, as so often, it turns out that what at first seemed complex and remarkable on fragmentary specimens, is easily explained from better material. Anterior nectophore. There are four ridges at the apex, one ventral, one dorsal, and two laterals. As the describers of the species observed, the ventral ridge runs undivided to the opening of the hj^droecium, whereas both the dorsal and the lateral ridges branch dichotomously. The result is that there are seven ridges at the base of the nectophore, one ventral, two dorsal, and on each side a dorsolateral and a ventrolateral. These ridges enclose a narrow triangular dorsal facet, and on each side a triangular dorsolateral facet extending from base to apex, a shorter, triangular medianlateral one, and a ventrolateral of irregular outline. There is of course no ventral facet, since the ventral ridge does not branch. The facets have been described in great detail, by Lens and Van Riemsdijk for the "Siboga" specimens. The dorsolateral ridges end in prominent teeth, the two dorsals and the two ventrolaterals in minor ones. There is no ventral tooth. There is a prominent tooth breaking the basal mar- gin of each medianlateral facet as noted by Lens and Van Riemsdijk, and likened by them to the letter Z. Hydroecium. The hydroecium is in the form of a deep furrow reaching to the level of the upper end of the nectosac, open ventrally for its entire length. CHUNIPHYES MULTIDENTATA. 263 and with its deepest point, at which the stem is attached, at about its mid-level. In the "Siboga" specimens it apparently extended nearly to the apex, but this was no doubt due to their fragmentary condition. The hydroecium shows some resemblance in general outline to the corresponding structure in Diphyes arctica (Chun, '97b, pi. 1, fig. 4). Nectosac. This structure, wholly destroyed in the "Siboga" material, is in fair condition in one of the "Albatross" specimens, as it was also in the Bis- cayan collection. It is short, reachhig only shghtly above the mid-level of the nectophore, and rounded at the top; of about the same diameter throughout its length. In the Biscayan specimens it is proportionately slightly longer, though of the same general form. But in view of the possibility of distortion due to contraction so slight a difference can not be considered as indicating the existence of two separate species. In one individual the canals, though much damaged, could be traced throughout most of their extent. In the figure (Plate 8, fig. 9) they are necessarily somewhat reconstructed. Somatocyst. In the only specimen in which this structure was in good enough condition to describe, it becomes dilated shortly above its point of origin (Plate 8, fig. 9) ; but then narrows once more to become tubular. It extends very nearly to the apex. In the other specimens its length is equally great; but in them its central region is entirely destroyed. In the Biscayan specimens the dilation, present in all is transversely pro- longed into a horn on either side (Bigelow :11b). But since these horns show various gradations in size, and are very small in one example, I doubt whether any sharp line can be drawn between specimens where they are present and those in which the dilation is a simple spheroid. The "appendage, so strangely divided into three" described by Lens and Van Riemsdijk (: 08, p. IS)* and provisionally identified by them as the somatocyst was in reality three distinct structures, viz., the basal part of the somatocyst, the pedicular canal of the inferior nectophore from which the latter was detached, and the proximal end of the corresponding canal of the superior nectophore (Plate 12, fig. 6). Nothing is left of the stem but the proximal end, and a number of immature siphons. Inferior nectophore. The inferior nectophore of the complete specimen, though attached when taken, was broken off before it reached Cambridge. Fortunately, however, a sketch of the position was made before preservation, and the accompanying figure (Plate 8, fig. 9) is based on this. As observed 264 ERSAEA BOJANI. by Lens and Van Riemsdijk the asymmetrical nectophore has only three ridges at the apex, a dorsal and two laterals. But all of these branch so that there are six at the base. The hydroecial canal, or in this case furrow, though limited by the two ventrolateral ridges, is entirely open for the greater part of its length. But near its proximal end it is closed over by two short flaps (Plate 10, fig. 7) one on either side, much as it is in Diphyopsis mitra. Apparently these flaps were destroyed in the inferior nectophore referred pro- visionally, but no doubt correctly, by Lens and Van Riemsdijk to Chuniphyes. Each of the six ridges terminates at the base in a serrated tooth, the ventrolateral on the right hand side being much the largest (Plate 10, fig. 7). The nectosac is somewhat battered, but its canals, so far as these could be traced, are of the usual Diphyid type. Lens and Van Riemsdijk supposed that the mode of attachment of the two nectophores must be a very singular one, but as the ".\lbatross" specimens show, it is of the usual type. One of the most noticeable external features, already noted by these authors is the transparency of both superior and inferior nectophores, and the brownish color of the ridges. This species has not been taken on the surface. The "Siboga" record is from between 1,500 fathoms and the surface, and the Biscayan specimens were collected both in open net hauls from 300-0 to 1,250-0 fathoms, and in closed nets at depths of 1,500-750 and 2,000-1,000 fathoms. These captures show that it is a typical "intermediate" or " mesoplanktonic " organism, a habitat wliicli no doubt explains the fact that it so long escaped notice in the Atlantic. Ersaea bojani (Eschschowz) Chdn. Plate 11, fig.s 7, 8. Eudoxia bojani Eschscholtz, '2.5, p. 743, taf. .5, fig. 1.5; '29, p. 125, taf. 12, fig. 1; Huxley, '.59, p. 59, pi. 3, fig. 7. Cucullus gracilis Haeckel, '88b, p. 110. Ersaea dispar Haeckel, 'S8b, p. 361. Ersaea bojani Chun, '88, p. 1154; '92, p. 108, fig. 7; Lens and Van Riemsdijk, : OS, p. 0, fig. l-fi. Ersaea picia Chun, '92, p. 98, 101, fig. G, pi. 11, fig. 8. The family relationship of tliis Eudoxid is uncertain; it was taken at Sta- tions 4587, 4590, 4598, 4605, 4661, 4663, 4667, 4669, 4673, 4676, 4688, 4707, 4710, 4725, 4732, and 4741, in both surface hauls and hauls with open nets from 300 fathoms. The series consists of forty-three excellent specimens. Lens and Van Riemsdijk, who have made a critical examination of an even larger series, have found that neither of the two characters which Chun ('92) ERSAEA BOJANI. 265 used to separate an Atlantic from a Pacific species, i. e. sliape of tlie somatocyst, and degree of serration of the bract, are sufficiently stable to be of value for diag- nosis, because in their material they found every gradation between the two supposed forms. In this I entirely agree with them. Thus in some specimens of the present series, the somatocyst is symmetrically rounded; in some it has the asymmetrical lateral process which, according to Chun, characterizes the Pacific species. E. bojani has been described so well by Huxley, by Chun, and by Lens and Van Riemsdijk, that no account is necessary here. It is of a very characteristic form, easily recognizable by the transverse phallocyst, and by the conformation of the base of the special nectophores. The accompanying figures may serve for identification. Chun identified the Pacific form with his Doromasia bojani, which now proves to be a Diphyid: but the union of the two rested merely on supposition. According to him the Atlantic form is the free Eudoxid of Doromasia picla Chun; an identification generally accepted. The association of E. bojani with Doro- ynasia picta is made certain, according to Chun ('92, p. 100) by the resemblance between its tentilla and bract and the corresponding structures in the oldest cormidia of Doromasia. He does not seem to have observed its actual develop- ment from the latter. The tentilla do not afford a safe clue, for, so far as they are concerned, the Eudoxid might belong to any one of several Diphjaids. When we compare Chun's figure of the bract of Doromasia ('92, taf. 8, fig. 3) with the bract of the Eudoxid we find that the resemblance is certainly no closer than between it and the bract of the Pacific Dipkyes bojani. Indeed the bracts of Doromasia and of Diphyes bojani resemble each other so closely, even in details, that they might well belong to one species. In short, then, Ersaea bojani might as well be the Eudoxid of one as of the other. The case is further compli- cated by the fact that not only in the form of the bract, but in every other respect Doromasia picla and Diphyopsis dispar resemble each other so closely that there would be slight reason for separating them, were it not that one is a Monophyid, the other a Diphyid. The evidence that Doromasia has only one nectophore is that Chun ('92, p. 95) foimd no posterior one, f)r even the bud for one, in anj' of the forty specimens which he studied alive. This evidence is valuable; but inasmuch as Chun's specimens were all young as shown by the fact that very few of them had as many as four developing Eudoxids, and since Mayer (:00) has recently noted a form from the West Indies resembling Doromasia in every respect except that it has two bells,' it is not conclusive. I may point ' Dr. Mavcr in conversation hsus coiifirmptl this. 2GG ARCHISOMA NATANS. out that the second bells of undoubted Diphyids may first appear at a late stage, i. e. in D. mitra (p. 260). The collection contains a single large Eudoxid which can not be located in its proper systematic position until we know from what polygastric form it is liberated. In the form of the bract and of the gonophore it differs widely from any other Eudoxid yet known, and since the animal must have some name, if only for convenience sake, it may be called Archisoma natans. Whether or not this name proves permanent will depend, of course, on whether the poly- gastric state has been described, or whether it is as j^et unknown. The rounded form of the bract suggests that the Eudoxid in question belongs to some Prayid, possibly to Nectodroma reticulata. Such a connection is also suggested by the structure of the somatocyst. ARCHISOMA, gen. nov. Archisoma natans, sp. nov. Plate 20, fig. 6. Station 4719. 300 fathoms to surface. 1 specimen in good condition. Type. In the single example the bract is of the remarkable length of 37 mm. Bract. The soft transparent bract is greatly elongate both above and below the point of attachment of the stem. Anteriorly it is pyramidal, ending in an acute point, but with rounded edges. Posteriorly its dorsal face is rounded, its ventral face so deeply furrowed, that it encloses a well-marked hj'droecial groove which is deepest proximally. The bracteal canals (somatocyst) follow an unusual course. Two main trunks arise at the usual point of origin, one ascending, the other descending. The former follows a somewhat sinuous course to the apex of the bract, giving off a single transverse branch which extends to the dorsal surface. The descending trunk, shortly after its origin, branches dichotomously, the two resultants running along the two sides of the hydroecial groove. But instead of continuing independent, the two canals reunite at the end of the hydroecium, to run as a single vessel to the extremitj' of the bract (Plate 20, fig. 6). Nectophore. The special nectophore, like the bract, is very large (15 mm. long) and is of a characteristic form. Apically it is rounded, but basoventrally it is prolonged in a narrow conical prominence, just above which lies the mouth of the nectosac. Bract and nectophore together form an "arrow head." The canal sj'stem of the nectophore, like that of the bract, is complex. PHYSOPHORAE. 267 Just below the point of attachment of the nectophore, its somatic canal gives off a short transverse branch. It connects with the subumbrella by a single trunk as is usual. At about the mid-level of the bell-cavity there are a pair of short branches. Finally just below the lower level of the nectosac there is a single dorsoventral branch. Below this point the axial somatic canal runs in a wavy course to the extremity of the nectophore. Owing to the condition of the specimen I could not trace the subumbral canals. Gonophore. The specimen has one small gonophore, apparently 9 , and the bud for a second one. The older gonophores, if any had been developed, have been detached. The siphon is of the usual type, the tentacle has been stripped of most of the tentilla. Such of the latter as are intact are too j'oung to show their final form. The specimen is colorless. Physophorae Eschscholtz, 1829. Physoneduc Haeckel, 1888. Five families of Physophorae, Apolemidae, Agalmidae, Physophoridae, Forskaliidae, and Anthophysidae, are so generally accepted and seem so well founded that their status need not be discussed. There is every reason to believe that each of them represents a natural grouping of intimately related species. The Nectaliidae of Haeckel (represented by the genus Nectalia) is retained as a separate family by Chun ('97b), but united with the Agalmidae by Schneider ('98) . For the reason given elsewhere (p. 289) Nectalia is considered more closely allied to the Agalmidae than to other Physophorids ; but its diver- gence from its nearest allies is sufficiently great to warrant a subfamily at least. In addition to these families there is another group of genera which must be included in this order, namely the forms united by Haeckel in his order Auronectae. Claus ('89) long ago pointed out that the resemblance of the Auronectae to the Physophorids was so close that they actuallj^ formed a family of the latter, a conclusion subsequently supported by Chun ('97b), by Schneider ('98), and by Lens and Van Riemsdijk (:08). Since the status of Haeckel's Auronectae is discussed in detail in con- nection with the description of the "Albatross" representatives of the group, it will suffice to say that I entirely subscribe to the foregoing view. Chun em- ployed the name Auronectidae for the family, but this name is invalid because not derived from a generic name. Schneider and Lens and Van Riemsdijk 268 PHYSOPHORAE. have avoided this difficulty b\- using the older name Angelidae of Fewkes. But Angela, the genus from which "Angelidae" is derived, belongs to a different family, the Anthophysidae (p. 301). This fact invalidates Angelidae, and to replace it Rhodaliidae Haeckel ('88a, p. 43, '88b), based on Rhodalia Haeckel may be revived. Two other families of Physophorae, both monogastric, were described bj' Haeckel ('88b), i. e., Circaliidae and Athoriidae. The only representative of the latter which has been sufficiently described, Aihoria larvalis, was undoubtedly a larval stagp, probably belonging to some Agalmid. Circalia stephanoma the type of the Circaliidae, though retained by Chun in his list of Atlantic Siphono- phores ('97b, p. 104), is also probably a young stage: indeed the mere fact that it is monogastric is almost proof that such is the case, for no other Siphonophore is known to retain the primitive monogastric condition permanently. Circalia has been associated provisionally by Schneider and by Vanhoffen (:06, p. 34) with the Rhodahidae, as the young of Stephalia, but whether it actually belongs there can only be settled on fresh material. The phylogenetic relationships between the various families of Physophorae form an inviting field for speculation; and especially is this true of the resem- blance between Athorybia and the '"Athorybia" larvae of various Agalmidae. It is easy to summarize the known facts in a few lines. Some Agalmidae, and probably all, according to the recent studies of Woltereck (:05a, :05b), pass through a complex larval stage, the "Athorybia" stage. This larva assumes the adult structure as the result of a metamorphosis in which the primitive bracts are lost. Now, Athorybia resembles this larva to an extraordinary degree. It is true that we do not yet know whether the bracts of Athorybia are the primitive ones permanently retained; but the development of the individual bracts of the neighboring genus Anthophysa is so typical, and so different from the early stages of nectophores as the latter are known in other Physophorids, that it shows they are true bracts, not degenerate nectophores as some authors have suggested. Chun's ('97b) discovery of rudimentary nectophores in Athorybia makes the resemblance between it and that stage of the "Athorybia" larva just previous to the dropping of the primitive bracts, when the buds for the future nectophores are first visible, especially significant.. On the other hand the pneumatophore of Athorybia is more highly specialized in its internal structure, particularly in the great number of septa, than that of any Agalmid. The specialization of the pneumatophore and of the bracts, and the oblitera- FORSKALIIDAE. 269 tioii of the siphosome, far advanced in Athorybia, and complete in Anthophysa, together with the absence of a secondary porus in the pneumatophore of Athory- bia, contrasted with its presence in Physophora, show that though both these latter genera have the stem reduced in length, they are not members of a single developmental series. Now, although the complexitj^ of the pneumatophore of Athorybia is good evidence that the genus is not ancestral (Chun, '97), the resemblance between it and the "Athorybia" larva is too close to be accidental. The most plausible explanation is one partially advanced by Schneider ('98, p. 159), namely that Athorybia represents the "Athorybia" larva become sexu- ally mature without undergoing the usual metamorphosis but with the pneu- matophore highly specialized. In other words, it is an instance of development arrested in some lines, accelerated along others. Derived from the parent Agalmid stock are four groups with shortened axis. These are: 1, Nectaliinae, with axial pneumatochone, with both nectophores and bracts, and siphosome alone reduced; 2, Physophoridae, with highly specialized ventral pneumato- chone, with nectophores and no bracts, and much reduced siphosome; 3, Anthophysidae, with highly specialized bracts, rudimentary nectophores if any; no specialized pneumatochone; 4, Rhodaliidae, with highly specialized dorsal pneumatochone, with nectophores, but no bracts. The probable position of Anthophysidae has just been noted. Physo- phoridae and Rhodaliidae could both be derived from Nectalia. But it is impos- sible to connect the two in direct genetic series with each other or with the Anthophysidae. The position of the pneumatochone is an unsurpassable ob- stacle to regarding Physophora as the parent of the more highly specialized Rhodaliidae, while the absence of nectophores and presence of bracts, and the regressive development of the pneumatochone in Anthophysidae, forbids the association of that group with either. They represent diverging lines of evolu- tion. Forskaliidae Haeckel, 1888. Haeckel ('88b) recognized four genera in this family: viz Strobalia, Fors- kalia, Forskaliopsis , and Bathyphysa. But as Bedot ('93a) has pointed out in his revision of this family, the only species of Forskaliopsis, F. rnagnifica Haeckel, was never described; it was probably a Forskalia. Strobalia is equally vague, only the generic characters having been given by Haeckel, and it is at least problematic whether any existing species corresponds to his account. Finally it has been shown that Bathyphysa belongs to a different suborder, the Rhizo- 270 FORSKALIA. physaliae (p. 320). Neither Bedot ('93a), Chun ('97b), nor Schneider ('98) recognize more than the one genus of Forskahidae, Forskalia; this view is undoubtedly correct. Lens and Van Riemsdijk have included the little-known genus Erenna among the Forskaliidae. And this course is followed in the present Memoir, though the location of this genus is only provisional (p. 271). FORSKALIA Kolliker, 1853. The synonymy of Forskalia is perhaps more confused than that of any other Siphonophore genus. Bedot ('93a) and Schneider ('98) the two authors who have most recently attempted to revise its species have come to very dif- ferent results; the former recognizing five, the latter three species. The rela- tions between the two sj^stems are shown in the following table: Bedot ('93a). Schneider ('98). F. contorta Milne Edwards (partim). F. leuckarti Bedot (= contorta Leuckart) F. cuneata Chun F. edwardsi Kolliker } = F. ophiura Delle Chiaje. F. tholoides Haeckel F. contorta Milne Edwards (partim) \ = F. contorta Milne Edwards. F. hydrostatica Delle Chiaje. Chun ('97b) recognizes three Atlantic species, F. contorta Milne Edwards, F. ophiura (Delle Chiaje) Leuckart, and F. cuneata . Chun. Lens and Van Riemsdijk report F. contorta Milne Edwards, and F. edwardsi Kollikei' from the "Siboga" collection. The key given by Schneider ('98, p. 199) is: 1. Nectophore with red pigment spots on the subumbral canals; contorta: 2. Nectophore with yellow fleck on the velum; ophiura: 3. Nectophore without pigment spots ; hydrostatica. Bedot ('93a, p. 250) likewise bases his diagnosis chieflj^ on color. It is hopeless to arrive at any sound conclusion as to the respective value of these schemes without a study of extensive series of living or well-preserved material of the different forms. It is especially necessary to test the constancy of the relatively trivial characters, e. g. pigmentation and shape of the necto- phores, and shape and relative size of the appendages of the siphosome, by ERENNA RICHARDI . 271 which the supposed species are distinguished. Unfortunately all the specimens in the "Albatross" collection are so fragmentary that I have. been unable to do this. Indeed they have all lost every trace of appendage except a few necto- phores and the pedicles to which the siphons were attached. Specific identifi- cation is therefore impossible, but their position in the genus Forskalia is fairly well assured by the shape of the few remaining nectophores and by the pedicles. FORSKALIA species? Forskalia was taken at Stations 4665, 4667, 4671, 4683, and 4731, one specimen at each Station. The captures were both from surface hauls and from open net hauls from 300 fathoms. The examples, all of which are violently contracted, range in length from 10-25 mm. ERENNA Bedot, 1904. The genus Erenna has been recorded only twice, by Bedot ( : 04) who studied detached tentacles, and by Lens and Van Riemsdijk (:08) who were able to figure a fairly complete example, as E. bedoti, from the "Siboga" collection. It is to these authors that we owe our knowledge that the genus is an undoubted Physophore, with the typical structure of nectosome and siphosome, though with peculiar and charactei'istic tentilla. But its systematic • position must remain doubtful until the arrangement of the nectophores has been studied in better material than any yet available. Its closest affinities are apparently with the Forskaliidae where it is classed by Lens and Van Riemsdijk. The "Albatross" collection contains a single very fragmentary specimen which must be referred to this genus because of the structure of its tentilla. Unfortunately it has lost all its nectophores, as well as most of its bracts and siphons, while the few that remain are so much crumpled and torn that accurate description is out of the question. Furthermore the stem is twisted and con- tracted. In fact the condition is so bad that it is impossible to state whether or not it is specifically identical with the "Siboga" example. Nor, for that matter, is it clear whether the latter is chstinct from Bedot's E. richardi. Erenna richardi Bedot. Erenna richardi Bedot, :04, p. 10, pi. 2. Station 4715, in trawl from 1743 fathoms. 1 very fragmentary specimen. 272 AGALMIDAE. Agalmidae Hkandt, 1835. The history of the Agahnidae has been reviewed in detail by Bedot COG) in his revision of the family. The species here included form a homogeneous group. But though several of them are now well known the two students who have attempted to revise theni s'nce Haeckel ('88b), have come to totally opposite conclusions as to what charac rs are generic and how manj' genera deserve recognition. Bedot ('96) concluded that the most important systematic char- acter within the family is the structure of the tentilla, and that general "habitus," whether long and contractile, or short and stifi', and form of the l^racts whether thick or thin, are of subordinate value only. Proceeding on this basis, he recognizes eight genera and thirteen species. Schneider ('98) accepts onlj- one of Bedot's genera, Anthemodes. All the other species, or supposed species, according to his view, properly fall provisionally into three genera, Stephanomia, Agalmopsis, and Cupulita. Instead of using the tentilla as generic characters, he states that they are entirely worthless, and bases his classification "einzig und allein in Riicksicht auf den characteristischen Habitus dreier Artgi-uppen" ('98, p. 118) that is to say, his Stephanomia comprises short, stiff forms; his Agalmopsis is longer, softer, and more contractile; while his Cupulita, with extremely extensible axis and loosely arranged bracts, is the end of the series. The adoption, entirely or in part, of one or other of these schemes, depends on the relative value of tentilla and of general form. I have been unable to find any other characters which could possibly be considered of generic value, in any of the five species which I have studied. General form, particularly contractility of the stem and shape of the bracts, was long ago used by Haeckel ('88b) to distinguish two subfamilies of Agalmidae, i. e., Crystallodinae and Anthemodinae. But a critical examination of this character shows that it is not so significant as he supposed. It is true that every species, so far as known, is comparatively constant in this respect. But the various species, from the shortest and most rigid, to the longest and most contractile, form an unbroken series which is divisible by purely artificial lines only. Furthermore, relative length can not be correlated in a natural grouping with any other characters. Thus species with tricornuate tentilla may be either stiff, or soft and slender; and the same is true of those with unicornuate tentilla. "Habitus," then, seems to me, as to Bedot, quite worthless as a generic character, although it is no doubt one of the most useful field marks for specific determination. AGALMIDAE. 273 The form of the tentilla is much more precise. The primary tentacle of all Agalmids in which it is known, bears tentilla quite different from those of the later formed cormidia. They are usually only transitory, in fact the oldest siphon is usually dropped bodily. But in one species all the tentacles have tentilla of the primitive type. This species is the only representative of the genus Anthemodes. In all other Agalmids the definitive tentilla have either one terminal filament, two filaments and a median ampulla, or many filaments with an ampulla; in other words they are eithei- unicornuate, tricornuate, or polycornuate. The latter condition characterizes one species alone, Agal- mopsis utricular ia Claus {Lychnagalma vesicularia Haeckel). This species is not included in Chun's ( '97b) list : l)ut the description and figures of it are detailed, and show that it is a very well-defined form. In the development of the individual tentilla, so far as is known, the rudi- ments for the full number of filaments, and the ampulla if present are formed simultaneously at a very early stage. They are not added successively. Later on, the involucre develops in those species in which it occurs. It is evident that we can speak of successive degrees of specialization of the tentilla, something we cannot do in connection with the general "habitus"; and a character show- ing degrees of specialization is eminently fit to serve as the basis foi' classifica- tion. Now, in the two groups with unicornuate and with tricornuate tentilla, other minor characters, e. g., foi-m of the bracts, distinguish several species; and therefore it is entirely justifiable to follow Bedot ('9(i) in using the structure of the tentilla as the chief generic character. On this basis, two genera, Anthemodes with tentilla of the primitive type, and Ljehnagalma in which the tentilla have a whorl of eight (or more?) terminal filaments and a very large median ampulla, may be accepted without further discussion. The only Anthemodes yet known is .4. ordinata Haeckel (A. moseri Agassiz and Mayer has unicornuate tentilla and is a synonym of Ste-phanomia (Cupulita) bijuga Delle Chiaje). Lychnagalma vesicularia Haeckel ('88b) the type of its genus was later shown to be a synonym of Agalmopsia ulricularia Claus ('79). Neither of these genera is represented in the "Albatross" collection. The remaining species of Agalmidae are divided by Bedot into six genera, Agalma, Crystallomia, Stephanopsis, and Agalmopsis with tricornuate; Hali- stemma and Cupulita with unicornuate tentilla. The members of the first group are separated by such minoi' characters that I have no hesitation in uniting them. Thus the supposed hydroecial cavity of Agalma is probably accidental. 274 AGALMA. as Schneider has pointed out, and even if normal it would indicate merelj- a special arrangement of the bracts. The feature on which Bedot's genus Stephan- opsis is based, namely, that the terminal filaments of the tentilla can be retracted within the involucre, is certainly not of importance equal to that of the essential structure of those organs. Cupulita and Halistemma (Agalmopsis Schneider) are separated by the presence of an involucre in the former, contrasted with its absence in the latter. But the involucre is a secondary structure in develop- ment and its absence therefore is not sufficiently important to necessitate a separate genus; at most it may indicate a subgenus; and certainly the slight difference in the arrangement of the palpons described bj' Chun ('88) and by Schneider ('98) is not more than a specific character. Accordingly two genera, one tricornuate, the other unicornuate are recognized in addition to Anthe- modes and Lychnagalma. The earliest undoubtedly tricornuate species is Agalma okeni Eschscholtz ('25), the type of the genus Agalma. The siphosome of a species of the second, unicornuate, genus was described by Peron and Lesueur in 1807 as Stephaiiomia nmphitrides. Fortunately the figure, though schematic and on a small scale, clearly shows that each tentillum has a coiled cnidoband with single terminal fila- ment (this is not to be seen in the copy by Lesson '43, pi. 10, fig. 1, la), and this species, studied later by Huxley, is represented in the present collection. Stephanomia, of course, long antedates both Cupulita, and Halistemma; indeed, it was the first Agalmid described. It must therefore be used for the uni- cornuate genus. AGALMA Eschscholtz, 1825. Agalma comprises two well-known species which have often been recorded, a third, which has been well described and is quite distinct, but which has been taken very seldom, and a fourth which is of doubtful validity. And, in addi- tion, some of the older descriptions listed below (p. 354) as unrecognizable may belong here. The two well-known Agalmas have usually been known as Cry- stallomia ipohjgonala Dana (Crystallodes rigidus + vitreus Haeckel) and as Agal- mopsis or Agalma elegaris Sars {A. sarsi Kolliker). But, as Schneider has recently shown, the former is in reality Agalma okeni Eschscholtz. Esch- scholtz's figures are so accurate and show so clearly the characteristic "habitus" and the very diagnostic prismatic bracts ('29, pi. 13, fig. 1), that Fewkes long ago proposed this union, and it is surprising that it has not been generally adopted. Bedot ('96) seems to have overlooked the importance of the bracts as specific AGALMA. 275 characters, and in consequence groups A. okeni with A. eschscholtzi Haeckel, from which it is easily distinguished by the outhnes of these organs as well as by other minor features. The fragments described by Quoy and Gaimard ('34) as Stephanomia triangularis, S. alveolata, and S. heptacantha probably belong here. At any rate there is nothing in their figures to suggest that they were dealing with more than one species, while the form both of bracts, and of necto- phores, and the tricornuate tenillae agree very well with A. okeni. The Agahnid siphosome which Lesson ('26) combined with Abylopsis tetra- gona (p. 225) under the name Plethosoma crystalloides, likewise suggests ^4. okeni. Schneider has identified with A. okeni the detached nectophores described by Eysenhardt ('21a, p. 369) as Cuneolaria incisa. But the only ground for this is the supposition that the nectophores in question were identical with the frag- ment described and figured by Chamisso and Eysenhardt ('21) as Stephanomia amphitritis. The latter, it is true, probably does belong to A. okeni, but in view of the facts that the incisa nectophore was neither figured, nor described, that Chamisso and Eysenhardt themselves disagreed as to its identity with their "Stephanomia amphitritis," and that it might equally well belong to any Agalma, or even to a Stephanomia, it is useless to identify it with A . okeni. Agalma pourtalesii Agassiz and Mayer ('99) resembles A. okeni in the thick- ness of its bracts and in their prismatic form, as well as in general habitus. It is true that Mayer ( : 00) has described its tentilla as without involucre, although tricornuate. But Dr. Mayer himself informs me that later studies have shown that an involucre is present, and he has very kindlj- shown me drawings in which this character appears. Furthermore, the probable type of pourtalesii (now in the collection of the Museum of Comparative Zoology) differs in no way from A. okeni, so far as its rather vuisatisfactory preservation allows me to judge. For these reasons there is every justification for uniting it with the latter species. Lens and Van Riemsdijk have described the Agalmas ("Crystallomias") of the "Siboga" expedition, all of which are of the general okeni type, under two headings, " Crystallomia Spec. Group I."; and "C. Spec. Group IL," separating them by the structure of the tentilla. The excellent condition of the present series of A. okeni has allowed me to make a careful test of the sup- posed divergences, and since the tentilla are described below (p. 280) in detail, it will suffice here to state that the differences between them are all evidences either of different stages in growth, or of individual variation. The second well-known Agalma was first described by Sars ('46), who combined it with a Stephanomia usually known as Cupulita picta, under the 276 AGALMA. name Agalmopsis elegans. It has long been recognized that Sars's A. elegans was a combination of two different species. Indeed this was pointed out by Sars himself in a subsequent publication ('57) and for this reason both Kolliker ('53) and Bedot ('96) have abandoned the name elegans altogether, calling the Agalma (Agalmopsis) constituent of the pair by the second name under which it appeared, A. sarsi Kolliker. Fewkes ('81) and Schneider, on the other hand, retain the name elegans for the Agalma ; and the latter has justified this course on the ground that the Stephanomia constituent had long before been described by Delle Chiaje ('42) as Physsophora bijuga. This identification is apparently well founded (p. 283) ; and the name elegans therefore belongs to Sars's Agalma. Besides these two well-known species of Agalma, the following forms must be referretl to it, viz.: — Agalma breve Huxley; A. sarsi Fewkes (non Kolliker); A. clausi Bedot, the type of his genus Stephanopsis ('96); and J., eschscholtzi Haeckel. The first of these may perhaps be a sjaionym of A. okeni, but Huxley's ('59) figures are not sufficiently detailed to show definitely whether this is the case. ^4. sarsi Fewkes and A. clausi Bedot undoubtedly belong to one species, and fortunately Bedot's ('88) account and figures are sufficiently detailed to give a good idea of its characters. It is readily distinguished from A. okeni by the foliaceous form of the bracts and b,y their red pigment spots, as well as by its large size, and fnjm A. elegans by the stiff non-contractile stem, and the thickness of the siphosome, as well as by minoi' details in the shape of the bracts and of the nectophores. It is likewise the only species of the genus, so far as we know, in which the terminal filaments of the tentilla can be retracted within the involucre. The name clausi must be used for this species instead of the earlier sarsi of Fewkes, because the latter was already preoccupied by Kolliker. Schneider ('98, p. 121) has united .4. clausi Bedot and A. eschscholtzi Haeckel inider the name sarsi Fewkes; and there can be no doubt that the two resemble each other closely in genei'al "habitus," as well as in the shapes of the necto- phores and bracts. But inasnuich as the nectophores are pigmented in Haeckel's species, and the bracts are not, while the reverse is true in clausi, it is better to postpone the union of the two until fresh material from the Indian Ocean (the type locality of eschscholtzi is Ceylon) can be studied. Haeckel's choice of eschscholtzi as the specific name for his species was unfortunate, because Agalma eschscholtzi had long before been preoccupied by Lesson ('43, p. 511) for a form figured, but not named, by Eschscholtz ('29), AG ALMA OKENI. 277 Eschscholtz's specimen was too fragmentary for identification with anj- actual species. But the facts that it was clearly an Agalmid, and that it had involu- crate tricornuate tentilla (Eschscholtz, '29, taf. 13, fig. 4c) place it in Agalma. This leaves Haeckel's Ceylon species nameless, and I propose haeckeli, until the question of its validity is finally settled. Agalma okeni Eschscholtz. Plate 17. Agalma okeni Eschscholtz, '25, p. 744, taf. .5, fig. 17; '29, p. 1,51, pi. 13, fig. la-Id; Lesson, '43, p. 510; Gegenb.\ur, '60, p.403, taf. 32, fig. 45, .50-52; Fewkes, 'S3b, p.81; '80, p. 964; Bedot, '96, p. 405. Stephanomia Iriangularis + alucolntn + hcplacanlhn Qtjoy and Gmmard, '34, p. 71-76, pi. 3, fig. 1-7, 16-18, 19-23. Crystallomia polygonaln Dana, '58, p. 4.59, pi. 1; Bedot, '96, ]). 406; Chun, '97a, p. 84, fig. 18; '97b, p. 103; Lens and Van Riemsdijk, : 08, p. 70. Cryslallodes rigidinn Haeckel, '69a, p. 49, pi. 10, fig. 65-71 : Chun, '88, p. 1 170. Crystallodes rigida Haeckel, '8Sa, p. 40. Cryslallodes vilraea Haeckel, '88a, p. 40; '88b, p. 222, pi. 17. Agalma polygonaia Haeckel, 'S8a, p. 40; '88b, p. 366. Agalma rigidtim Bedot, '88, p. 78. Stephanomia incisa Schneider, '98, p. 120. Agalma, pourhdesii Agassiz and Mayer, '99, p. 180; Mayer, :00, p. 79, pi. 31, fig. 106, 107; pi. 32, 33. ? Stephanomia amphitrides Chamisso and Eysenhardt, '21, p. 367, taf. 33, fig. 5a-5f. ? Cuneolaria incisa Eysenhardt, '21a, p. 369. ? Agalma merlensii Brandt, '35, p. 34. ? Agalma breve Huxley, '59, p. 75, pi. 7. ? Crystallodea mertensii. Haeckel, 'S8a, p. 40; '8Sb, p. 222. Agalma okeni was taken at Stations 4596, 4600, 4611, 4617, 4619, 4624, 4627, 4631, 4635, 4640, 4642, 4644, 4657, 4659, 4681, 4708, 4710, 4713, 4714, 4715,4716 ,4717, 4728, 4743, and at Station 3397, "Albatross " Panamic expedi- tion, 1891. The records are mostly from surface hauls, but the .species was taken five times in open net hauls from 300 fathoms, and twice in the trawl. The material, which is in very good condition, consists of ninety-three entire specimens (fifty- seven from Station 4600), varying in length from 5-95 mm., and of a great num- ber of detached cormidia, bracts, and nectophores. I was also able to study an example from the Fiji Islands, which is probably the type of the Agalma pourtalesii of Agassiz and Mayer, besides several excellent specimens from the West Indies; none of these differ from the Pacific series listed above in any important feature. Representatives of this species, both from the North Atlantic and from Ceylon, have been fully described and figured by Haeckel ('69a, '88b). But the very good state of preservation of the "Albatross" specimens and the fact that I was able to study them alive, allows me to add some details to his account, 278 AGALMA OKENI. as well as to that by Lens and Y&n Riemsdijk. The characters most readily distinguishing A. okeni from other Agalmids are the short, non-contractile stem and the thick, stiff, closely crowded bracts. Its general form and its habit of floating horizontally in the water are so characteristic that it is recognizable at first sight. The largest examples in the "Albatross" series measure about 95 mm. in length, while Dana's single example was about 60 mm. long. This size, equalled by only one of the "Siboga" specimens, is apparently about the maximum, for Chun's ('97a) largest specimen was only 75 mm., while Haeckel's examples and those which I have examined from the West Indies were all much smaller. Nedosome. The pneumatophore is invariably deeply pigmented apically. The arrangement of the nectophores, which are closely crowded together in two regular opposed rows, has been described and figured by Haeckel. In the largest specimen there are about twenty-eight nectophores (excluding several very young ones which had not attained their definitive form). Chun has recorded twenty-four in his largest example (75 mm.). In examples 40-50 mm. long, there are usually 14-18 nectophores, and in tlie younger individuals proportionately fewer. The exact number cannot be determined for any of our small specimens, for all of them had lost most of their nectophores. Indeed they were in all ways less satisfactory than the larger ones. The nectophores themselves are of such a characteristically flattened and prismatic form (Plate 17, fig. 12) that they are readily recognizable even when detached. And the course of their subumbral canals agrees perfectly well with Haeckel's figure ('69a, pi. 10, fig. 67). The nectosac itself is prolonged laterally into two horns, a character- istic form which is constant even in the most contracted specimens. The largest nectophores measure 11-12 mm. in breadth. Siphosome. The largest number of siphons in any colony was nine, the same number that Chun records for his largest examples; most of the speci- mens (40-50 mm. long) had six or seven. The smallest number (except in some mutilated fragments) was two, in a somewhat contracted colony 4 mm. long. Bracts. The bracts have been well described by Haeckel. They are prismatic in outline, roughly triangular (Plate 17, fig. 10, 11), and thickest at the distal end. The distal margin is divided into four concave facets by three vertical transverse ridges in an extremely characteristic manner, and the number of facets, which are very early developed (Plate 17, fig. 9), is apparently constant. The only exception to it which I have seen among many hundred bracts is that in very small specimens the bracts associated with the oldest (primary ?) siphon AGALMA OKENI. 279 have only two distal facets, there being only one transverse ridge. The peri- pheral glands discovered by Lens and Van Riemsdijk (:08, pi. 13, fig. 104) are present in some bracts at least, but apparently not in all. The arrangement of the bracts on the stem is extremely precise and regular. The firm and regular pavement-like cylinder of closely opposed bracts has been aptly described by Haeckel ('88b) as a "carapace," but he is in error in stating that the dorsal half of the axial trunk is "exclusively composed of bracts." In reality the bracts are attached exclusively to the ventral half of the stem, a fact easily demonstrated on well-preserved specimens. The bracts occupy the space between the siphons as Haeckel supposed, for being ventral hke the latter, they must necessarily alternate with them. Each bract is borne on a semilunar muscular lamella, the youngest ones ventral, and nearest the siphons; the older ones more dorsal, and nearer the centre of the "internodes" (Plate 17, fig. 13). The broad axis of each bract lie transverse to the long axis of its mus- cular lamella; and by the curving of the older lamellae the armor of bracts is made even more complete on the dorsal than on the ventral side of the sipho- some. Chun's statement ('88) that only the bracts nearest the siphons have canals is only partly correct. In point of fact, every bract has a canal when young, but as they grow older and are forced further and further dorsad, the canals become less conspicuous, and in some cases cannot be detected at all. The largest bracts which I could find are 15 mm. broad, and all are extremely hard and rigid. The succession of the siphons, palpons, and gonophores is regular and characteristic. If we take any well-preserved segment of the stem, we find in each cormidium the siphon, several palpons, and the two gonodendra, 9 and cf . The gonodendra lie immediately distal ' to the siphon, in conjunction with two or three palpons; the 9 next to the siphon (Plate 17, fig. 13). Proximal to each siphon is a cluster of several palpons. I have found no essential variation from this arrangement in any of the cormidia studied, except that the shorten- ing of the stem in contracted material may cause the gonodendra to lie nearly midway between pairs of siphons. - But in expanded examples the true condi- tion is easily traced, and in such there is a free space, occupied only by bracts, between each two cormidia. Chun ('88, p. 1 170) it is true, says that "die mann- lichen geschlects trauben proximal, die weiblichen distal angeordnet sind," but he does not give any figures of this. The cf and 9 gonodendra differ so ' I speak of the end of the siphosome nearest the nectosome as proximal, that furthest from it (i. e., oldest) as distal. 280 AGALMA OKENI. much in general appearance that they are easily recognizable. In the former the gonophores are stalked and loosely clustered, and the gonophores them- selves are comparatively large, with their cavities entirely' filled by the swollen spadix. In the 9 , the individual gonophores are much smaller, each contain- ing but a single large egg, and they are closely crowded on one main stalk (Plate 17, fig. 13). The palpons (Plate 17, fig. 14) are of the usual type, each bearing a contrac- tile filament near its base. The siphons show no features of special interest. Tentilla. The tentilla deserve special mention, since it was a supposed diversity in these organs which lead Lens and Van Riemsdijk to separate the Agalmas ("Crystallomias") of the "Siboga" Expedition into two groups. These authors describe four types of tentilla. Of these, types III and IV, as they them- selves recognize, are merely successive stages of one type, which is the usual condition in all but the youngest cormidia. The others, I and II, are small, and occur only on a few of the oldest cormidia. It is according to the presence either of I or of II, on the earliest formed tentacles, that they limit their two groups of Agalmas. All these kinds of tentilla occur in the "Albatross" series, and the better material allows me to state definitely that there is no essential difference between types I and II of Lens and Van Riemsdijk. Indeed, accord- ing to their own account both have a closed involucre and from one to two and one half turns of the cnidoband, with the terminal filaments and ampulla typical of the genus. The only difference between the two is that in II the lateral filaments are coiled, in I they are not. This is an umimportant feature, so much so that I have seen both types on one tentacle. In younger stages of their tj^pe I + II the involucre only partially encloses the cnidoband and the earliest stages are indistinguishable from those of the type described below. This small form of tentilla, with but few coils, is characteristic of the oldest siphons. I have never found an individual with moi-e than one tentacle of this sort, and only two showing them at all. But Lens and Van Riemsdijk found examples with as many as four such cormidia. In the later formed cormidia the tentilla are much larger, as those authors observed and the cnidoband has many more coils when matui'e. The involucre, at first only a basal swelling (Plate 17, fig. 4j, encloses more and more of the coils with its progressive, development (Plate 17, fig. 5, 6), and may finally enclose them all (Plate 17, fig. 7). But there is evidence that it does not always do so, for I have found old tentilla with up to as many as seventeen coils of which at least half pro- truded, while others on the same tentacle had only fiom seven to nine, all AGALMA ELEGANS. 281 enclosed. The study of the development of these organs is much facilitated by the fact that there is apparently no exception to the rule that they are formed exclusively near the base of the tentacle, and that the most distal ones are the oldest. The finer structure of the tentilla resembles that in other Agalmidae and has been described by Haeckel. These facts show that the division of the "Siboga" specimens into two groups was an unnecessary one. But it is not clear whether or not the tentilla of the small type correspond to the kidney-shaped tentilla developed in some other Agalmidae in conjunction with the primary siphon. The fact that these tentilla may occur in connection with as many as four siphons argues against such a homology (Lens and Van Riemsdijk, :08). But the question can be set- tled only when better material of the young stages has been studied. Apparently the small tentilla (which are after all essentially similar to the larger ones), are developed in connection with a variable number of the earlier formed siphons. Their absence from all of our large specimens means merely that the oldest siphons have been broken off. The large number of detached but otherwise normal cormidia in the "Siboga" and in the "Albatross" collections shows that fragmentation does take place easily, perhaps even normally. And the absence of loose cormidia with the young type of tentilla would easily be explained on the supposition that they were detached while still very small. Color. In life the pigment spots of the pneumatophore are reddish purple, the stem is opaque white or yellow, the tentilla brilliant brick-red. Distribution. Enough records of A. okeni have been made to show that it is very generally distributed over the warmer regions of all three great oceans, and that it occurs in the Red Sea (Schneider, '98, p. 120). Agalma elegans (Sars) Fewkbs. Plate IS, fig. 9-13; Plate 19, fig. 1-4. Agalmopsis elegans Sars, '46, p. 32, tab. 5, 6 (partim). Agalmopsis sarsii Kolliker, '53, p. 10, taf. 3; Leuckart, '54, p. 331, taf. 12, fig. 21-27, taf. 13, fig. 1; Haeckel, '88b, p. 234; Bedot, '96, p. 409. Agaima puuclata Leuckart, '53, p. 3, taf. 1, fig. 1, 19, 20, taf. 2, fig. 1, 2, 5-7, 23; (non Koli.iker, '53; non VoGT, '54). Agaima davala Leuckart, '53, p. 3, tab. 2, fig. 3; '54, p. .337, tab. 13, fig. 2-12. Agalmopsis clavalum L. Agassiz, '62, p. 369. Agaima elegans Fewkes, '80a, p. 141; '80b, p. 618, fig. 1 ; '81, p. 163, pi. 9, 10; '82b, p. 301 ; Schneider, '98, p. 122; Romer, :02, p. 178. C uneolaria elegans Haeckel, '88a, p. 40. Agalmopsis catena Haeckel, '88b, p. 234. Agalmopsis elegans Haeckel, 'S8b, p. 234; Chun, '97b, p. 104; Schneider, '98, p. 122; Romer, :02, p. 178; Vanhoffen, :06, p. 24, fig. 31-36. "iCupulita sarsi Damas, :09, p. 107. 282 AGALMA ELEGANS. Station 4637 300 fathoms to surface 2 specimens, 10 mm. long, fairly well preserved. " 4646 surface 3 specimens, two of 10 mm., with most of the nectophores gone, and one of 20 mm. (Plate 19, fig. 1). " 4714 " 1 specimen of 15 mm., with only one complete cormidium, 3 bracts and 4 nectophores. I have likewise been able to study an excellent specimen from Naples, 150 mm. long. Romer (:02) has retained both the Agalmopsis elegans of Sars, and the Agalma elegans of Fewkes as separate species. But in saying that the former is known from the original record onh', he has overlooked the fact that it is identical with a well-known Mediterranean form. Geographic distribution points to the identity of the forms described by Sars and Fewkes, instead of suggesting that they are distinct, because the former penetrates yearly the Norwegian Sea from the South (Damas, :09, p. 107), a phenomenon long known for the northerly records of Agalma on the American coast. Our largest example is at about the same stage as the young specimen figured by Fewkes, and much resembles it (compare Plate 19, fig. 1, with Fewkes, '81, p!. 9, fig. 1). But, although the colony as a whole is so small, its tentilla, bracts, and nectophores already show the adult characters so plainly that they make the identification positive. This species has been so well described and beauti- fully figured by Sars ('46), Kolliker ('53), Leuckart ('53, '54), and especially Fewkes ('81), that I need merely summarize its diagnostic features. General "habitus." In young stages the stem is short and but slightly contractile. In the adult it is long and contractile, and the siphosome so much more slender than in A. okeni that the two species are separable at first glance. In the adult the siphosome is much longer than the nectosome. The nectophores are flattened as in A. okeni, but their margins are rounded instead of being distinctly facetted, and the nectosac is deeper, more nearly triangular with broader mouth. The difference might seem trivial, were it not so constant. The bracts (Plate 18, fig. 12) are triangular, foliaceous, thickest near the centre and very thin at the distal margin, instead of truncate and facetted distally as they are in A. okeni. So pronounced is the difference in form between the bracts of the two species that isolated ones may be identified STEPHANOMIA. 283 readily. The distal margin of the bract is tridentate and its upper surface marked by three ridges. The tentilla are of the tricornuate type, and when adult the involucre entirely encloses the cnidoband (Plate 18, fig. 10, c/. Fewkes, '81, pi. 9, fig. 21). Apparently this is the invariable condition in fully developed tentilla. In their individual development these organs pass through the same stages that they do in A. okeni (p. 280). A. elegans was previously known from the Mediterranean, from the coast of Europe as far north as Norway; the east coast of North America from the West Indies to Cape Cod, perhaps even to the Bay of Fundy. So far as I can learn, there is no previous record of its occurrence in the Pacific, but it has been recorded from Malayan waters (Amboina, Bedot, '96). STEPHANOMIA P^ron and Lesueur, 1807. According to Schneider ('98) the various forms described up to that time which fall in Sephanomia as here defined, all belong to one or other of three species. E.ssentially this same conclusion was previously reached by Bedot ('96), but though he suggested the identity of Nanomia cara A. Agassiz ('65) and of Anthemodes canariensis Haeckel ('69b) with the well-known S. (Cupu- lita) pida Metschnikoff, he maintained them temporarily as distinct. These three are united by Schneider ('98) under the specific name bijuga Delle Chiaje. The identification of Delle Chiaje's form with the well-known "pida" is justified, because his figure ('42, pi. 181) of the young tentilla shows both the coiled cnidoband with a single terminal filament, and the basal swelling fated to grow into the involucre (c/. Claus, 78, taf. 1, fig. 6c). Adoption of this view will establish the nomenclature of the Agalmidae on a firmer basis than heretofore, because it will leave Sars's ('46) Agalma in undisputed possession of the name elegans (p. 276). Bedot ('96) does not include Delle Chiaje's name in his synonymy. On the other hand, both Chun ('97b), Romer (:02), and Vanhoffen (:06) retain the name cara, for the northern form, as distinguished from the southern bijuga (= pida). There is some evidence in favor of this course, although the two are close allies. Thus, cara grows to an enormous size (four feet long when expanded, three feet when contracted according to Fewkes, '88a), whereas bijuga is a rather small form. Then, the bracts are apparently more obtuse in the former than in the latter, the tentilla of the primary tentacles of the two 284 STEPHANOMIA BLJUGA. are of different shapes (c/. Plate 20, fig. 3, with Fewkes, '88a, pi. 2, fig. 8). The geographic occurrence of the two points in the same direction, for cara is restricted to and typical of Arctic waters, rarely straggling as far south as Massachusetts Bay, whereas bijuga is at home in the Mediterranean, at the Canaries (Chun, '88), and among the West Indies (Fewkes, '82a). But a definite answer to the question will depend upon an actual com- parison of specimens. Certainly it can never result from Fewkes's rather generalized account or figures. I made a visit to Grand Manan during the summer of 1910, with this in view, but although Fewkes found cara very common there, I did not see a single specimen. Until such a comparison is made, it is better to retain cara as a distinct species, lest by combining the two the necessity for a critical examination of them be obscured. The description of Sars's Norwegian Stephanomia is so incomplete that it is impossible to determine whether it is identical with the southern bijuga until it is reexamined. In the meantime the whole question of the geographic distribution of the cara-bijuga group must be left unsettled. A third species of Stephanomia is the S. {Halistemma) rubra of ^"ogt, the tentilla of which have no involucre; a fourth is Stephanomia amphitrides Petron and Lesueur, the type of the genus. Recently Lens and Van Riemsdijk (:08), have described as new S. {Hali- stemma) cupulifera, distinguished from S. rubra by the terminal filament of each tentillum bearing "at its terminal end a small acorn-shaped appendage" (:08, p. 85). Judging from their figure (:08, pi. 16, fig. 117) the tentilla seem sufficiently distinct to warrant recognizing at least provisionally their species. Stephanomia bijuga and S. amphitridis are represented in the "Albatross" col- lection, and I have been able to study excellent examples of »S. rubra from Naples. Stephanomia bijuga (Delle Chiaje). Plate 19, figs. 5-11, Plate 20, figs. 1-3. Physsophora bijuga Delle Chlue, '42, pi. 181, fig. 3-6. ? Agalmopsis elegans Sars, '46, p. 32, tab. 5, 6; Claus, '78, p. 38 (partim). Anthemodes canariensis Haeckel, '69b, p. 36, taf. 1; '88a, p. 40; Chun, '88, p. 1170. Halistemma pidum Metschnikoff, '70, p. 305, tab. 2; Chun, '88, p. 1167. Stephanomia {Anthemodes) canariensis Metschnikoff, '74, p. 36. Stephanomia jrictum Metschnikoff, '74, p. 36. Halistemma lergeslinum Claus, '78, p. 1, taf. 1, 2. Agalmopsis fragile Fewkes, '82a, p. 267, pi. 5, fig. 2, pi. 6, fig. 16, 17, 23-25. Anthemodes picta Haeckel, '88a, p. 40. Halistemma fragile Haeckel, '88a, p. 40. Cupulita picta Haeckel, '88b, p. 367; Bedot, '90, p. 407. STEPHANOMIA BIJUGA. 285 Cupulita tergestina Haeckel, '88b, p. 367. Cupulita fragilis Haeckel, '88b, p. 367. Cupulita canariensis Haeckel, '88b, p. 367; Bedot, '96, p. 408. Cupulila (Halistemma) picla Chun, '97a, p. 86, fig. 19. Cupulita bijuga Schneider, '98, p. 123. Antheinodes moseri Agassiz and Mayer, : 02, p. 167, pi. 12. (For the synomymy of - fragmentary specimens, although they found no stages connecting the simple and very uniform papillae of the aurophore with the complex cormidia lying below. The actual evidence to which they had access was entirely of a negative kind. Nor can any more weight be laid on their observation that no buds are now to be found opposite the aurophoi-e in the "Challenger" specimens of Rhodalia, because the latter were somewhat frag- mentary to start with, and by now have passed through so many hands that any buds which were originally attached might well have been torn or shaken off. However, we must admit that in view of the usual dorsoventral orienta- tion, and of the frequent inaccuracies of Haeckel's work, their standpoint was perhaps the most reasonable one. Simple and attractive as was their explana- tion that new nectophores and cormidia are formed on the aurophore itself, the conditions in Dromalia, in Angelopsis and in the excellent example of Archan- gelopsis mentioned (p. 303) show beyond any question that it is the exact reverse of the truth. And if we compare the photographs of the ventral zone of pro- liferation in Dromalia (Plate 24, fig. 1, 2) with Haeckel's figures of a longitudinal section and an apical view of Rhodalia, and his figure of the blastocrene ('88b, pi. 4, figs. 15, 16, 17), it is evident that they are very accurate. I may mention that the figure of the blastocrene clearly shows that the cormidia are arranged in spiral, exactly as they are in Dromalia. On Haeckel's figure of an apical view, with the nectophores in place ('88b, Plate 1, fig. 1), Schneider ('98) and Lens and Van Riemsdijk thought they could discern internal evidence that the young nectophores were budded on the same side as the aurophore. But, as Haeckel himself states ('88b, p. 303), it is a reconstruction; and even if the arrangement of the nectophores, as represented, is correct, it is not necessary to assume that the small ones near the aurophore are the youngest. On the contrary, the fact that the nectophores in this region are smaller than their neighbors in Dromalia, as shown by the shortness of their muscle-plates (p. 307), whereas proliferation undoubtedly takes place on the opposite side of the corni, indicates that in Rhodalia likewise, those nearest the aurophore are the oldest instead of the j'oungest, although small. 316 RHODALIIDAE. The determination in Dromalia, and in well-preserved material of Archan- gelopsis, that aurophore and zone of proliferation lie upon opposite sides of the corm, is gratifyingly easy; and to find a satisfactory explanation for this phenomenon is not so difficult at it appears at first. It is true that we are once more face to face with the anomaly experienced by Chun, from which Lens and Van Riemsdijk tried to escape, that while in Physophora the pneumatochone with its enclosed portion of the gastro vascular space is ventral, in Rhodaliidae the organ which exactly corresponds to it is as certainly dorsal. The explana- tion, as already suggested (p. 269), is that Physophora is not the parent of the Rhodaliidae, but that both are descended from members of the Agalmid stock. And in the Agalmidae, as is well known, the primitive pneumatochone is neither dorsal nor ventral, but axial. Even in the highly specialized genus Nectalia this is the case, and it is also true of Anthophysa, in which the pneumatochone organ may be supposed to have undergone regressive changes. For light on this question we must await renewed researches on more exten- sive material. Especially desirable would be a knowledge of the very young stages of any one of the Rhodaliidae; but of these we yet know practically nothing, because Haeckel's ('88b) account of his "Auronula" larva was so superficial and based on such a fragmentary specimen that it is of little value. Distribution of the Rhodaliidae. Stephalia is recorded from the eastern part of the Gulf Stream, from the Faroe Channel and Shetland Islands, and Stephonaha from the South Pacific; west of New Zealand, lat. 38° 50' S., long. 69° 20' E. (Haeckel); Angelopsis, from the Gulf Stream (Fewkes), from the Tropical Atlantic (Haeckel) and Tropical Eastern Pacific ("Albatross"); Rhodalia, from the South Atlantic, 37° 17' S., 53° 52' W. (Haeckel), and prob- ably from the Tropical Pacific in the neighborhood of the Galapagos (Brooks and Conklin, '91); Archangelopsis, from the Malaysian region ("Siboga") and from the northwest Pacific ("Albatross"). Respecting the bathymetric range of the Rhodaliidae I may point out that all the hauls from which they have been recorded were made with open nets and therefore afford no real clue to the depths from which the specimens in question came. That they are not such good evidence of abyssal habitat as Haeckel supposed is indicated by the fact that the "Siboga" specimens of Archangelopsis were taken within 100 and 112 m. of the surface. Moreover Fewkes ('89a), and more recently Lens and Van Riemsdijk have given strong reasons for believing that the extraordinary development of the pneumatophore suggests a habitat near the surface, rather than at great depths. RHIZOPHYSINAE. 317 Rhizophysaliae Chun, 1SS2. According to Schneider ('98, p. 164), and to Lens and Van Riemsdijk, (:08, p. 100), the two main subdivisions of this group, Rhizophysids and Physa- Uds, are too closely alhed to each other to deserve the appellations of suborders "Rhizoidea" and " Physaloidea " given them by Chun. However, they form well-marked families. Haeckel divided the Rhizophysids (exclusive of the Bathyphysids which he classed among the Physophorae) into four famihes, Cystaliidae, Rhizophysidae, Salaciidae, and Epibuliidae. But as Chun ('97b) has pointed out, the Cystaliidae are merely the young stages of Epibulids, while Salacia, the only genus of Salaciidae, is so closely allied to Rhizophysa that it certainly is of not more than generic rank. Chun himself recognized two fami- lies of Rhizophysids, Epibuliidae and Rhizophysidae, dividing the latter into two subfamilies, Rhizophysinae and Bathyphysinae. Schneider unites all these in one family, but Lens and Van Riemsdijk, who do not give any com- plete scheme, mention two families, Rhizophysidae and Bathyphysidae. It seems to me that Schneider's reduction goes too far, especially in the case of the Epibuliidae, which are sharply demarked from their allies by a very much shortened stem, exactly as are the Nectaliinae from the typical Agalmidae (p. 289) . On the other hand it would certainly be erroneous to class the Epibuhds and Bathyphysids as subdivisions of as high rank as the Physalids, for they are too closely allied to the Rhizophysids by the presence of hypocystic villi in the pneumatophore, and by the structure and arrangement of the appendages. They are therefore regarded, in this Memoir, as subfamilies, Rhizophysinae, Bathophysinae, and Epibuliinae, of the Rhizophysidae. Rhizophysidae Brandt, 1835. Rhizophysinae Chun, 1897. Two genera of Rhizophysinae can be distinguished, Rhizophysa and Sala- cia, the former with monogastric, the latter with polygastric cormidia. Schneider ('98), it is true, has united the two, but it can not be ciuestioned that this differ- ence in the structure of the cormidia is more important than the differences in the tentilla usually considered of specific significance in Rhizophysa. Salacia is monotypic. I have not had an opportunity to study S. uvaria Fewkes. 318 RHIZOPHYSA. RHIZOPHYSA Peron and Lesdeur, 1807. For criticism of Haeckel's genera Cannophysa, Linophj-sa, Aurophj'sa, and Nectophysa, and foi- the reasons which show that they are synonyms of Rhizophysa, I refer the reader to Chun ('97b, p. 77), who also includes Lino- physa Haeckel. Although this genus is not valid, the species for which it is instituted, Rhizophysa conifera Studer ('78) belongs, not to Rhizophysa but to Pterophysa (Schneider, '98, Lens and Van Riemsdijk, :08, p. 106). Apart from conifera, Chun ('97b, p. 104) recognized the following species in the compound genus Rhizophysa: — R. filiformis Forskal, R. eysenhardtii Gegen- baur, R. clavigera Chun (= Cannophysa filiformis Mayer), R. gracilis Fewkes, and R. murrayana Haeckel. But Fewkes's account of R. gracilis and Haeckel's description and beautiful figures of R. {Cannophysa) murrayana agree so well with R. filiformis, especially in the form of the tentilla, that I follow Schneider, and Lens and Van Riemsdijk in uniting them with the latter. WTiether R. clavigera is reallj^ a distinct species can hardly be determined from Mayer's very confused account, or from his figure which was evidently drawn from a fragmen- tary specimen. My opinion is that it was probably R. filiformis, with siphons and tentacles twisted together. Schneider includes in this genus the R. uvaria of Fewkes, but this form has polygastric cormidia, and therefore belongs to Salacia (Haeckel and Chun). Lens and Van Riemsdijk, after examining the literature of the genus, came to the conclusion, with which I entirely agree, that only two species, filiformis and eysenhardtii, are valid. These are distinguished from each other by the presence in the former of three kinds of tentilla, tricornuate, dendritic, and "vogelkopfahnlich," and in the latter of simple filiform tentilla only. Schneider ('98) used the name R. mertensi Brandt to replace eysenhardtii Gegenbaur, evidently supposing that Brandt's ('35, p. 33) description of the tentilla as "Tentacula composita ramulis, i. e. tentaculis porpriis, simplicibus" meant that they were filiform. But Haeckel ('88b, p. 329) who examined Mer- ten's unpublished figures of this species expressly states that it "exhibits distinctly two different kinds of branched tentilla." Unfortunately I have not been able to verify this statement; but under the circumstances there seems to be only one course open, namely, to consider mertensi a synonym of filiformis, on the strength of its having two kinds of tentilla, and to retain the name eysenhardtii, as is done by Lens and Van Riemsdijk, for the species with filiform tentilla. The name filiformis Forskal is now universally used for the form with RHIZOPHYSA FILIFORMIS. 319 complex tentilla; and it is in every way desirable to maintain this position for the sake of definitely locating the old descriptions. But I may point out that in none of the accounts of the genera before that of Gegenbaur ('53) were the tentilla described in detail. Rhizophysa filiformis (ForskAl) Lamarck. Physsophora filiformis Forskal, 1775, p. 120; 1776, tab. 33, fig. F; Modeer, 1789, p. 282; G.melin, 1790, p. 31.59. Rhizophysa planenloma Peron and Lesueur, '07, pi. 39, fig. 3; Eschscholtz, '29, p. 1-17; Blainville, '34, p. 118; Lesson, '43, p. 491. Rhizophysa filiformis Lamarck, '16, p. 477; Blainville, '34, p. 118; Lesson, '43, p. 490; Gegenbaur, '53, p. 324, pL 18, fig. 5-11; Haeckel, '88b, p. 329; Chun, '97b, p. 104; Schneider, '98, p. 170; Richter, : 07, p. 559, taf. 27, fig. 1-13; Lens and Van Riemsdijk, : 08, p. 100, pi. 18, fig. 141-145. Epibulia filiformis Eschscholtz, '29, p. 148. Rhizophysa gracilis Fewkes, '82a, p. 269, pi. 6, fig. 1-6. Cannophysa gracilis Haeckel, '88a, p. 44. Cannophysa murrayana Haeckel, '88a, p. 44; '88b, p. 324, pi. 24. Pneuinophysa gege7ibauri Haeckel, '88b, p. 328. Cannophysa eysenhardtii M.\yer, '94, p. 239, pi. 3, fig. 1-4. Rhizophysa murrayana Chun, '97b, p. 84; Mayer, : 00, p. 72. ? Epibulia (Macrosotna) merlensi Brandt, '35, p. 32. ? Rhizophysa merlensi Lesson, '43, p. 492; Haeckel, '88b, p. 329. ? Pneumophysa merlensi Haeckel, '88b, p. 45. ? Cannophysa filiformis Mayer, '94, p. 241, pi. 3, fig. 3. ? Rhizophysa clavigera Chun, '97b, p. 104. Station 4638 300 fathoms to surface 1 specimen, pneumatophore, 4 cor- midia. " 4707 " " " " " specimen, pneumatophore 8 mm. long, 3 cormidia. " 4715 " " " " " specimen, pneumatophore, lack- ing stem, 9 cormidia. " 4730 " " " " " specimen, pneumatophore, 4 cor- midia. All of the specimens came up on the dredging M'ire, and all were fragmentary; those individuals in which trifid tentilla were detected are included here. Their condition was too poor to allow me to add anything to the accounts given by Gegenbaur ('53), by Haeckel ('88b), and by- Lens and Van Riemsdijk (:08). The description and figures by the latter authors are especially pertinent since they give the only detailed account of Indo-Pacific specimens of the species. The capture of this species in the Eastern Tropical Pacific and its previously known distribution in the Mediterranean, in various parts of the Tropical Atlantic, and in the Malaysian Region ("Siboga") indicate that its range, like that of so many other pelagic Coelenterates, extends over the warmer waters of all oceans. 320 BATHPHYSINAE. Rhizophysa eysenhardtii Gegenbaur. Rkizophysa filiformis Huxley, '59, p. 90, pi. 8, fig. 13-20 (non Forskal). Rhizophysa eysenhardtii Gegenbaur, '60, p. 408, taf. 31, fig. 46-49; Fewkes, '83b, p. 82, pi. 1, fig. 1; Chun, '97b, p. 83; Lens and Van Riemsdijk, '08, p. 103, pi. 20, fig. 147, pi. 21, fig. 150, pi. 24, fig. 172. Nectophysa wyvillei Haeckel, '88a, p. 45; '88b, p. 327, pi. 23; Agassiz and Mayer, :02, p. 169, pi. 8, fig. 36. Aitrophysa ordinala Haeckel, '88a, p. 44; '88b, p. 323. Pneumophysa merlensii Haeckel, '88a, p. 45; '88b, p. 328. Rhizophysa merlensii Schneider, '98, p. 170 (non Brandt). ? Rhizophysa inermis Studer, '78, p. 13, taf. 1, fig. 3, 8-10. ? Aurophysa inermis Haeckel, '88a, p. 44; '88b, p. 324. Station 4653 surface 1 specimen, pneumatophore and 3 cormidia. Although the single specimen was in very poor condition, the tentilla were sufficiently well preserved to show the simple thread-like form characteristic of R. eysenhardtii, well described and figured by Huxley for his specimen from the Indian Ocean. The specimen differs in no way from the "Siboga" specimens of this species described by Lens and Van Riemsdijk. R. eysenhardtii was previously known from various parts of the Tropical Atlantic, from the Indian Ocean (Huxley, Haeckel), and from the Malaysian region. Its occurrence in the Eastern Tropical Pacific shows that, like R. fili- formis, it occurs throughout the warm regions of all oceans. Epibuliinae, nom. nov. Epibulidae Haeckel, 1888. Only one genus, Epibulia, of this subfamily, is known. For the early history of the name, see Haeckel ('88b, p. 334). One species, E. ritteriana Haeckel, from the Indian Ocean, has been carefully described and beautifully figured. Two others from the Pacific, E. (Rhizophysa) chamissonis Eysenhardt, the type, and E. erythrophysa Brandt, are known, but from such incomplete accounts that their relationship to Haeckel's form remains doubtful (p. 350). The genus is not represented in the "Albatross" collection. Bathphysinae Chun, 1897. Bathyphysidae Bedot, :04; Lens and Van Riemsdijk, :08. Lens and Van Riemsdijk (:08) have reviewed the history of this little- known group, and their own researches on the material of the "Siboga" expe- dition have afforded detailed information as to the anatomy of three species. PHYSALIIDAE. 321 They recognize two genera, Pterophysa, in which the siphons are sessile, i. e. attached directly to the stem, and Bathyphysa, in which they are borne on long pedicles. Judging from their descriptions this distinction seems to be a valid one. The minor features such as might be expected to serve for specific diag- nosis within the two genera are still but little known, the only species sufficiently well described being Pterophysa grandis Fewkes (Lens and Van Riemsdijk, :08). The "Albatross" collection throws no light on the question. There are two known species of Bathyphysa, B. abyssorum Studer, and B. sibogae Lens and Van Riemsdijk. We may safely assume that these two are distinct because the latter authors were able to examine Studer's original speci- men. In Pterophysa there are P. (Rhizophysa) conifera Studer, P. {Bathyphysa) grimaldii Bedot, and P. grandis Fewkes. These three are so closely allied that I doubt whether they can be distinguished. Finally there is the Pterophysa {Bathyphysa) studeri of Lens and Van Riemsdijk, which the describers were unable to class definitely in either genus. The Bathyphysinae are represented in the present collection by some frag- mentary segments of the stem with a few siphons attached. They can not be identified, except that the presence of pedicles throws them into Bathyphysa rather than into Pterophysa. Bathyphysa species ? Station 4645 300 fathoms to surface on sounding wire ; fragments. " 4689 " " " " " dredging " " 4724 800 " " " " " " " Physaliidae Brandt, 1835. I follow Chun ('97b) and his successors in recognizing only a single genus of this family, Physalia. The three other genera diagnosed by Haeckel ('88b), are merely as many stages in its development, as Chun's ('87b) earlier work had shown. The early history of Physalia has been given in much detail by Chun ('97b). As is well known, the genus, long accepted by zoologists in general, was founded by Lamarck (1801) for the Holothuria physalis of Linne (1758). Gill (:07), it is true, has recently maintained that this species must be regarded as the type, not of Physalia, but of Holothuria, in which it was the first example mentioned 322 PHYSALIA. by Liiine, on the ground that "Unquestionably the type of the genus and descrip- tion was the first species." But Poche ( : 07), who has reviewed the early history of Holothuria in detail, and whose conclusions are in accord with the Inter- national code of nomenclature, has shown that this conclusion is not justified. He points out that inasmuch as "Linne einem typus naturlich nicht bestimmt hat, so mussen wir zur Festlegung desselben das Eliminations — verfahren aus- venden." He has shown that the use of this method of choosing the type abso- lutely precludes the selection of physalis, since this species was removed from Holothuria to Physophora by Modeer in 1789, while two of the species enumer- ated in the former genus by Linne in the 10th edition of the Systema Naturae were still allowed to remain in it. Under the International code it is one of the latter which must be selected as its type. The choice of Linne's Holothuria 'physalis for the type of Lamarck's genus Physalia, is then valid, and the further fate of the genus Holothuria need not concern us. The relationship between Physalia and Holothuria is the same as that between Porpita and Medusa (p. 329). In both the same conclusions are reached as to the validity of the Siphonophore genera in question, a result fortunate for the sake of stability. PHYSALIA Lamarck, 1801. The collections of Physalia which I have examined, from the Atlantic, Pacific, and Indian Oceans, entirely support Chun's ('97b) view that there are two species, and two only, an Atlantic and an Indo-Pacific, the former chiefly char- acterized by the presence of many, the latter of only a single "Haupttentakel." Schneider ('98), believes that the two are merely varieties of one species. But the fact that among the considerable number of specimens of the Pacific species which have now been studied, not only by the early authors, but recently by Chun ('97b), Agassiz and Mayer (:02), Lens and Van Riemsdijk ( : 08) and by myself, none have more than one main tentacle, is good evidence that this condition is the final one in this form. The fact that in its adult state the Pacific species resembles an immature stage of the Atlantic Physalia has led to much confusion in the early literature of the subject. Justification of the choice of utriculus as the specific name for the Indo- Pacific species is given by Chun ('97b, p. 86), to whom I refer the reader for a more extended review of the subject. I have not been able to consult the original description myself. The Atlantic species is P. physalis Linne. Many authors have used the earlier name arethusa Browne (1756), but this is pre-Linnean. PORPITIDAE. 323 Physalia utriculus (La MABTmifcRE) Eschscholtz. Medusa utnculus La MARTiNifeRE, 1787, p. 365, pL 2, fig. 13, 14; Gmelin, 1788, p. 3155; La Pekouse, 1798, atlas, pL 20, fig. 13, 14. Physalis lamarUnieri Tilesius, '10, p. 99; Eysenhardt, '21, p. 421; Blainville, '30, p. 103. Physalis cornuta + fosbeckii + afer Tilesius, '10, p. 104. Physalia utriculus Eschscholtz, '29, p. 163, taf. 14, fig. 2; Bl.unville, '34, )). 113; Lesson, '43, p. 557; Huxley, '59, p. 101, pi. 10, pi. 12, fig. 12; Haeckel, '8Sb, p. 351; Chun, '97b, p. 86; Agassiz and Mayer, : 02, p. 169; Browne, : 04, p. 744; Lens and Van Ribmsdijk, : 08, p. 118, pi. 24, fig. 174, 175. Physalia ausiralis Lesson, '26, p\. 5, fig. 1, 2; '30, p. 38. Physalia inegalisia Brandt, '35, p. 37; Bigelow, : 04, p. 265 (non I'eron and Lesueur, '07). Alophota merlensii Haeckel, '88b, p. 348. Arelhusa Ihalia Haeckel, '88b, p. 349. Physalia physalis Schneider, '98, p. 190 (partim). Station 4695 Surface 1 1 specimen 60 mm. long, " 4730 3 a both about 30 mm. " 4542 Hyd. 5 iC 10-30 mm. " 4544 " 2 it both 17 mm. Easter Island 1 li 60 mm. Manga Reva I. 1 it 40 mm. A critical revision of the species of Physalia from the region of the Cape of Good Hope, where they are described as abundant, would be of the greatest value. Chondrophorae CH.unsso and Eysenhardt, 182L Disconeclae Haeckel, 1888. This suborder contains two well-marked families, the Torpitidae and the Velellidae. Porpitidae Brandt, 1835. The Porpitidae are readily separable into two groups, one with high vaulted conn, the other flattened and disc-like. Haeckel proposed two genera for the former, on the supposition that the tentacles in this subdivision were arranged after two distinct plans, either in separate groups, or regularly over the entire surface of the tentacular zone. The former condition, according to his view, characterizes Porpalia, the latter Porpema. His own figures, however, show that the distinction is not a valid one, because in his figure (pi. 48, fig. 2) of the denuded corm of Porpalia prunella the tentacle-scars are not arranged in groups, but are evenly distributed exactly as they are in Porpema or in Porpita. The apparent grouping of the tentacles in this case corresponds exactly to the 324 PORPEMA. similar phenomenon in his supposed genus Porpitella, where it merely represents difference in size between tentacles of different ages. Additional evidence that Porpalia is the young of Porpema is afforded by the facts that Haeckel's speci- men of Porpalia was only 4-5 mm. in diameter, and, still more important, that only eight gonozooids appear to have been present. But I can not follow Schneider ('98) in uniting both Porpalia and Porpema with the species with disc-like corm, i. e., Porpita, because as I shall show there are very important structural differences which distinguish them from Porpita. Chun, in his mono- graph of the Siphonophores of the "Plankton" expedition, mentions neither Porpalia or Porpema in text or in synonymy; or even in his list of Atlantic species ('97b, p. 102) including all "bisher aus dem Atlantischen Ocean beschrie- benen und ausreichend charakterisirten Siphonophoren." I have chosen Por- pema, rather than Porpalia, as the name for the compound genus because while both were proposed in the same publication the former was based on the adult, the latter on a young stage. Modern authors agree in uniting all Porpitidae with flattened corm in one genus, Porpita. PORPEMA Haeckel, 1888. Porpalia Haeckel, 1888. Haeckel proposed several specific names under Porpalia and Poi-pema, with neither descriptions nor figures, nor any indication whatever except the localities of capture; a fact which makes systematic revision of the genus difficult. The oldest species which can be referred to Porpema is globosa, of Eschscholtz ('29); his brief description, and figures are amply sufficient for generic and perhaps even for specific identification. Haeckel ('88a) referred P. globosa to Porpalia, and mentioned as a second species P. prunella, from the Pacific, which he shortly after ('88b) described in detail. Under Porpema he mentions ('88a, and '88b) P. lenticula from the Indian Ocean and P. pileata from the coast of Chile by name only, and fully described P. medusa from the Atlantic. Fortunately he clearly designated a type species for Porpalia, in the words ('88b, p. 58) "the genus Porpalia is founded upon a new species, Porpalia prunella " and this is a starting point. A comparison of Eschscholtz's ('29) figures of P. globosa and Haeckel's account of P. medusa shows a close agreement between the two; and inasmuch as both were taken in the Tropical Atlantic, I have no hesitation in uniting them. PORPEMA PRUNELLA. 325 The relationship of P. globosa to the Pacific P. prunella can not be deter- mined from the accounts yet pubhshed, because Haeckel studied only young stages of the latter. Fortunately, however, the present collection contains a large and excellently preserved series of adults, which differ from P. prunella only in such features, i. e., greater number of gonozooids and tentacles, as are undoubtedly due to a more advanced stage in growth, and which must therefore be referred to that species, as indeed we would expect from the locality of capture. A comparison between them and Haeckel's account and figures of P. globosa ("P. medusa"), shows that it is doubtful whether any specific demarcation can be drawn between the Atlantic and Pacific forms. Such minor differences as do exist in form, number, and size of tentacles are readily explained as due to slightly different stages in growth and to different methods of preservation. But Haeckel's account is too general and his figures too diagrammatic to allow of a certain conclusion. And since I have no Atlantic specimens at hand, it is better to follow the more conservative course of retaining prunella and globosa as two separate species, at least until Atlantic material can be restudied. Judging from the localities of capture it is probable that P. lenticula Haeckel, from the Indian Ocean, and P. pileata Haeckel from Chile are both in reality P. prunella; but in the absence of any description, we can not be certain of this. They must be treated as nomena nuda, since a mere geographic location can not be considered as "indication" in the nomenclatural sense. Discalia medusina Haeckel is the young of some Porpitid; the compara- tively great thickness of its disc suggests that it belongs to Porpema, and its locality, South Pacific, points to identity with P. prunella. Porpema prunella (Haeckel). Plate 25, 26, 27; Plate 28, fig. 11, 15. Porpalia prunella Haeckel, '88a, p. 30; '88b, p. 58, pi. 48. ? Discalia medusina Haeckel, '88a, p. 20; '88b, p. 46, pi. 49, fig. 1-6. Porpila globosa Schneider, '98, p. 195 (part ini). Station 4685 surface 37 specimens, 5-6 mm. in diameter, preserved in formalin, in alcohol, in corrosive acetic, and in Flemming's fluid. " 4686 " 4 specimens, 6 mm. in diameter. The general structure of a young stage of this species has been described and figured by Haeckel in some detail. The present adult specimens differ from his account in the various characters which change with growth, while 326 PORPEMA PRUNELLA. in several particulars better material allows correction and emendation of his observations. In general outline the largest specimens are rather higher than his, height and breadth, leaving out of account the central gastrozooid, being about equal, whereas his figures are almost twice as broad as high; but the fact that his description was based entirely on contracted alcoholic material, makes it imsafe to lay stress on this apparent difference. It may be a concomitant of different stages in growth. Adult individuals of P. globosa (= P. medusa), according to his figures, agree in height with the "Albatross" specimens. The tentacles, as already pointed out, are distributed evenly over the tentacular zone, not in groups. Haeckel ('88b, pi. 48, fig. 4) represented the limbus as radially lobed, instead of entire, as it is in the "Albatross" specimens and in Porpita. But since he has himself shown it entire in two other views ('88b, pi. 48, fig. 1,2), and since it is often artificially split radially in alcoholic material, the apparent lobes were probably the result of mutilation. Indeed, although he states in his diagnosis of the genus that the margin is lobed, in his account of the "limbus umbrellae" of this species he fails to mention any such appearance. As shown by Haeckel, the limbus is proportionately very much broader than it is in Por- pita, and the palial canal system much less complex. In his view of the upper surface ('88b, pi. 48, fig. 4) he shows fifteen broad radial canals near the centre, connected with one another by a ring canal, and branching irregularly so that at the margin of the limbus there are forty-one. In one of the present speci- mens there are fourteen canals near the centre of the disc, and forty-five at the margin (Plate 26, fig. 3). The entoderm of the canals, especially near the outer end in the region of the limbus, sends out numerous amoeboid processes, simple and branched, just as happeuvS in the canals of the limbus in Porpita. At the margin of the limbus, the radial canals are connected by a circular canal, but so crowded are the marginal muciparous glands that it is only on sections that this canal can be distinguished. Each radial canal branches at the zone of junction of limbus and pneumatophore, one branch running into the limbus, the other running downward into the tentacular zone as will be described later. Pneumatocyst. In the specimens sectioned, there were from 12-15 circular chambers, besides the central chamber. There are no radial chambers; but, as is seen in the cross sections, the outer wall of the central chamber is folded so as to form eight vertical pockets (Plate 26, fig. 4). Haeckel states that the central chamber is surrounded by eight radial chambers; but his figures PORPEMA PRUNELLA. 327 show that his specimens of P. prunella and P. globosa both exhibit the condition seen in the present series. No doubt he was deceived by surface views, mistaking the lobes of the central chamber for separate compartments. This error is a natural one, on account of the location of the eight inner stigmata which surround the central stigma and which, in surface views, appear to open into the eight lobes of the latter. Their true location, however, is shown in longitudinal sec- tions (Plate 26, fig. 2, Plate 27, fig. 5), on which it is seen that the central chamber broadens basally, and that the first circular chamber partly covers it distally. The eight "primary" stigmata in reality open into the first circular chamber. I shall have occasion to return to this subject in the account of Porpita (p. 335). In a specimen 5 mm. in diameter there are eight rows of stigmata (Plate 26, fig. 3) ; but their number in each row varies at different ages with the increase in the number of concentric chambers. The vaulted form of the pneumatocyst and the ridges in its lower surface which interlock with the radial ridges of the centradenia have been described in detail by Haeckel ('88b). The tentacles (Plate 25, fig. 6) and gonozooids (Plate 25, fig. 8, 9) resemble the corresponding organs in Porpita. In the long and the two short rows of tentacular nematocyst knobs there are the same number, 19-24, in adult tentacles. The number of these is a systematic char- acter of some importance in Porpita, and it may prove to be significant in the present genus. Canal system of the tentacular zone. Although Haeckel's account of the general organization of Porpema leaves little to be desired, his description of the vascular system requires some correction. The canals which proceed down- ward from the junction of limbus and pneumatophore break up in the tentacular zone into an irregular network (Plate 26, fig. 5, C. T.) which connects with the hollow entodermic cores of the tentacles. This canal-net is represented in the "Challenger" report (Haeckel, '88b, pi. 48, fig. 3) as continuing downward between the centradenia and the bases of the gonozooids, and finally opening into the central zooid. As a matter of fact, however, the canals of the tentacular zone open into the superior canals of the centradenia, exactly as they do in Porpita. The gonozooids open directly into the centradenial canals; thus neither tentacles nor gonozooids are in communication with the central zooid except through the medium of the centradenia. Haeckel's description of P. globosa ('88b, p. 62) suggests that he himself observed this fact, though his figure is not clear. Centradenia. The conical form of this structure in Porpema (Plate 26, 328 PORPEMA PRUNELLA. fig. 2) has been noted by Haeckel ('88b) as has the fact that its structure is less complex than in Porpita. Its apical surface, as seen when stripped of the overlying pneumatocyst and surrounding tentacular zone, bears prominent radial ridges (Plate 27, fig. 12), interlocking with the lower surface of the pneu- matocyst. In one specimen there are seventeen ridges (each indicating the course of one of the superior canals) at the periphery; but of these only the "octoradial liver star" of Haeckel, reaches the apex. In the centre there is a small circular area where no ridges are present, but in this region the union of the eight primary superior canals (Plate 27, fig. 13) can be easily traced. The figure thus formed more nearly resembles that in Velella (Bedot, '85b, pi. 9, fig. 2) than in Porpita (Plate 28, fig. 16). Between the canals the tracheae, passing down into the underlying region (Plate 27, fig. 6), can be seen. The main mass of the centradenia, as in Velella and Porpita, consists of a dense parenchyma of ectoderm cells and cnidoblasts in every stage of develop- ment, through which the complex network of canals can be traced. The latter arise in the apical region as downward branches from the superior canals, exactly as they do in Porpita (p. 336) ; basally they connect with the central zooid. Haeckel ('88b, p. 62) states that even in the adult {P. medusa) there are only eight canals opening into the latter. Judging from analogy with the condition in Porpita (p. 338) this statement is probably true of very young stages. But in the large specimens collected by the "Albatross", in addition to these eight primary openings, there are about thirty others, which lie near the periphery of the base of the zooid (Plate 28, fig. 11). These are easily traced on sections (Plate 27, fig. 7, 8, 9) ; but in alcoholic material the lumen of the canals is often entirely masked. The eight primary canals do not run directly to the eight primary superior canals of the centradenia as Haeckel supposed, but connect with the general canal-net of that organ. Concerning the tracheae I need merely confirm Haeckel's statement that they ramify throughout the centradenia, and frequently run into the walls of gonozooids and of the central gastrozooid. The entodermic walls of the centradenial canals in Porpema are less complex histologically than they are in Porpita. There is some distinction between the canal walls in the upper "liver" ' and in the lower "kidney" portions; it is less marked than in the latter genus. In the "liver" portion the cells are small, and pale-staining, containing granules; in the "kidney" they are more columnar, and enclose masses of large pigmented spherules lying both in the cell bodies and in the intercellular spaces, while among them are to be seen larger, deeper- ' The use of the terms " hver " and " kidney " in this connection is purely conventional. PORPITA. 329 staining cells of irregular outline (Plate 28, fig. 15). In none of the specimens sectioned have I been able to find the guanin crystals so characteristic of the "kidney" region in Porpita. In this respect Porpema resembles Velella, as indeed it does in the general simplicity of the centradenia. Color. Porpema prunella is a very beautiful object when floating on the water, the central disc being deep ultramarine blue, most intense at the centre, on which the radiating ridges are marked by pale lines. WTien seen from the side, the pneumatophore shines through the nearly transparent zone composed of the bases of the tentacles as a deep blue central core ; the general mass of the centradenia below it is a pale reddish purple. The gonozooids are pale blue, their medusae yellowish; tentacles bluish at the base, but soon becoming pale yellow, their nematocyst knobs violet. PORPITA Lamarck, 1801. It has recently been suggested that the name Medusa, instead of Porpita, should be employed for the genus now under consideration. I may therefore summarize the grounds upon which I retain the latter. The first appearance in binomial literature of an animal referable to this genus is in the 10th edition of the Systema Naturae, where, under the name Medusa porpita, Linne briefly diagnoses a form earlier (1754) described by him under the name "Medusa (Porpita) orbicularis" and which from his earher figures (1754) is undoubtedly founded on a fragmentary Porpita. In 1776 O. F. Miiller described the Atlantic Porpita under the name Medusa uvibeUa. Forskal (1775, 1776), however, who gave an excellent account of the Mediterranean form now generally known as P. umbella, referred it to the Holothuria denudata of Browne, although, as Chun ('97b) has recently pointed out, the latter name evidently belonged to a frag- mentary Salpa. Gmelin (1790) retained Forskal's species in the genus Holothuria, as H. nuda, distinguishing, and rightly, between it and Browne's H. denudata, but he doubted whether H. nuda really belonged to Medusa umbella. Almost simultaneously Modeer (1790) used for Porpita the name Phyllodice, apparently without realiz- ing that the animal (Velella) to which Browne (1789) had already applied that name was generically distinct. The genus Porpita was instituted in 1801 bj- Lamarck, for the Medusa porpita of Linne. Since that date it has been usuallj' accepted. The only grounds on which the name Medusa could be substituted for Porpita would be that the species porpita, of Linne, was the type of the genus Medusa. 330 PORPITA. ^Aji exactly parallel case, that of Coluber, has recently been examined by Dr. L. Stejneger (:07). Both Coluber and Medusa are Linnaean genera, each including widely diverse species now referred to various genera and even families, and of course Linne did not indicate a type species for either. From each, the early reviewers, Lamarck in the case of Medusa, removed certain species, and left certain other species in the original genus, without, however, designating any species as types. As Stejneger points out, according to the International code of nomenclature, subsequent designation of the types for the Linnaean genera must be made from among the species left in them by the first reviewers. Although the first reviewer did not designate a particular species as type, still the fact that he allowed certain species to remain in the original genus shows that it is one of these which is to be considered as typifying it. Such being the case, whatever species may, or might have been selected as type of the genus Medusa, it can not be M. porpita; and therefore there is no justification for discarding Porpita in favor of Medusa. The question, how many species of Porpita deserve recognition, is difficult to answer because of the brief and unsatisfactory nature of the descriptions upon which many of the proposed names rest. It is important however, to reach a sound conclusion in this regard. Porpita is such a tj-pical pelagic surface animal that an accurate knowledge of the occurrence of its species would be of much service to students of the geographic distribution of pelagic organisms in general. For that reason I attempt a review of the subject, though it can not be final without additional knowledge of the Pacific, and especially of the Indian Ocean forms. In treating the Atlantic and Mediterranean forms there is every reason to follow Chun ('97b) in uniting all described forms under the name P. umbella (O. F. Miiller, 1776). We must next consider the species which have been recorded from the Pacific. The oldest notice is by Lesson ('26) who figured and named P. chrysocoma from near New Guinea, and P. pacifica from off the coast of Peru, in the atlas of the zoological results of the voyage of "La Coquille." In the interim between the appearance of these figures and his very meagre and alto- gether insufficient description (1830), Eschscholtz ('29) gave his account of the Tropical Pacific P. ramifera and P. coerulea. The first of these was based on very young specimens ("Eine halbe Linie" in diameter). There is nothing in the description to differentiate them specifically from any of the various recorded races of Porpita. P. coerulea, however, was based on larger specimens, up to PORPITA. 331 25 mm. in diameter, on which Eschscholtz noted the well-marked tubercles on the upper surface of the disc, which since prove to be a verj- important char- acter. Afterward, another Pacific species, P. radiaia Brandt, was recorded, with only a very cursory diagnosis. The accounts of P. pactfica Lesson, and P. radiaia Brandt, based as they are on such trivial features as size, color, and the form and length of the tentacles, contain nothing to show that they are not identical with P. coerulea Eschscholtz. The localities of capture add further support to such a union. P. ramifera Eschscholtz likewise comes under the same category, as a young stage of coerulea. To the combined species thus formed, the oldest name, P. pacifica Lesson ('26) must be applied. P. paciUca has recentlj' been recorded by Agassiz and Maj-er (:02) and by Mayer (:06) from the Tropical Pacific, and from the Hawaiian Islands. The case of P. chrysocoma is less clear, inasmuch as the bright yellow coloi' of limbus and tentacles figured and noted by Lesson ('30) differs markedly from the brilliant blue of these parts in the Pacific specimens which I have examined in life. In P. umhella, however, I have found that these regions may appear yellowish in certain lights and against certain backgrounds. The locality of capture of chrysocoma, close to New Guinea, suggests that it was probabh' identi- cal with the "iSiboga" specimens from the Malaysian region studied by Lens and Van Riemsdijk, and referred bj^ them to P. umbella. Finally, to conclude our survey of the Pacific species, we must examine Haeckel's two species, Porpita fungia and Porpitella pectanthis, both of which were described and figured in detail. The two are placed l)y him in separate genera on the supposition that the tentacles in Porpita are evenly distributed over the tentacular zone, but arranged in groups in Porpitella. In the latter genus he includes P. coerulea Lesson and P. radiaia Brandt. This separation is exactly analogous to the distinction drawn by him between Porpema and Porpalia (p. 323). Porpitella is the young of Porpita; and I may note that exactly similar stages have been long known for P. umbella (A. .\gassiz). Since Porpitella pectanthis and Porpita fungia were both taken in the same general region of the Pacific, it is almost certain that they represent two stages in the growth of but a single species. A comparison between Haeckel's description of P. fungia and Eschscholtz's account of P. coerulea shows such close resemblance between the two, especiall}' in the presence of prominent tubercles on the upper surface of the float, that I have no hesitation in uniting them. All Porpitas, then, as yet known from the 332 PORPITA. Pacific, except the problematical P. chrysocoma which more properly belongs to the Malaysian region, must be referred to P. pacifica Lesson, a species, as I shall later show, very distinct from the Atlantic P. umbella. To P. pacifica must likewise be referred the Pacific species of Haeckel's genera Discalia and Disconalia, because the supposition that these forms are monogastric, the sole ground for distinguishing between them and very young Porpitas, appears to rest on no better evidence than the surface views of the gonozooids. Of course to prove that these organs possess no terminal openings would require the study of serial sections. Haeckel also mentions, as new, P. australis; but since this name rests on neither description nor figures, nor even any more definite localitj' than that it is a "Southern form" it is of course a nomen nudem. Finally, before describing our series of P. pacifica, I may summarize brieflj* our extremely scanty knowledge of the Porpitas from the Indian Ocean. The oldest of these, as pointed out above (p. 329), is the P. porpita of Linne ( =P. indica Bosc). There have since been described P. lutkeana Brandt, besides Disconalia pectyllis Haeckel, which is undoubtedly the young of some Porpita. As pointed out, P. chrysocoma may belong here, as do the specimens recorded by me (: 04) from the Maldives under the name P. lutkeana Brandt, and from the Malaysian region by Lens and Van Riemsdijk (:08) as P. umbella. Probably all of these are identical, and ought to be united under the old name P. porpila. Unfortunately our knowledge of them is not sufficient to give a definite answer to the question whether P. porpita is identical with the Atlantic P. umbella, or with the Pacific P. pacifica, or whether, as is possible, it is a species distinct from either. The published descriptions, so far as they go, and my own insufficient exami- nation of the Maldive specimens, seem to favor their union with P. umbella, rather than their retention as distinct, as I formerly believed. The conclusion that they are not referable to P. pacifica rests on the ground that though the tubercles of the latter are prominent features even in macerated specimens, no such structures were observed either on the "Siboga," or in the Maldive specimens. The strongest evidence in favor of the view that P. porpita and P. umbella are identical is the statement by Lens and Van Riemsdijk ( : 08, p. 123), that they "found no difference whatever between them and Porpita linnaeana." Unfortunately, however, their material was not of the best, and until better series can be examined the identity of the Indian forms must remain in doubt. A study of Porpitas from the region of the Cape of Good Hope, and a knowledge PORPITA PACIFICA. 333 whether the geographic range of the Indian and Atlantic forms is continuous or discontinuous, would be of great value. Porpita pacifica Lesson. Plate 28, fig. 1-10, 12, 1.3, 14; Plate 29. Porpila pacifica Lesson, '26, pi. 7, iig. 3, 3 ' ; '30, p. 2, 59; Agassiz and Mayer, : 02, p. 159; Mayer, : 06, p. 1134, Porjtita ramifera Eschscholtz, '2(), p. 745; '29, p. 178, taf. 16, fig. 3. Porpita coendea Eschscholtz, '25, p. 744; '29, p. 179, taf. 16, fig. 5. Porpila radiata Brandt, '35, p. 40. Porpita species ? Hu.xley, '59, p. 122, 126, fig. A-C. PorpiteUa coendea Haeckel, '88a, p. 130. Porpitella radiata Haeckel, '8Sa, p. 30. Porpita fungia Haeckel, '88b, p. 67, pi. 45. Porpitella peclanlhis Haeckel, '88b, p. 64, pi. 46. Porpitella coerulea Haeckel, 'S8a, p. 30. Disconalia ramifera Haeckel, '88b, p. 357. Disconalia gastrohlasta H.aeckel, '88a, p. 30; '8Sb, p. 48, pi. 49, fig. 7-12; pi. 50, fig. ? Discalia primordialis Haeckel, '88a, p. 30; '88b, p. 46, 1 specimen 3 mm. in diameter, fragmentary. 2.5 mm. in " " both 3 mm. in diameter, well pre- served. " 4631 " 2 " 1.5 and 4 mm. in diameter, well pre- served. " 4640 " 1 " 11 mm. in diameter, fairh^ preserved. 4649 " 18 " 40-55 mm. in diameter, well pre- served. At this Station a swarm was en- countered. " 4707 " 1 " 12 mm. in diameter, fair. Also:— Lat. 9°57'N., long. 1.37° 47' W.; surface ("Albatross" Ex. 1899- 1900, Station 13). 7 specimens, 14-25 mm. in diameter in excellent condition, being the specimens recorded by Agassiz and Maj^r ( : 02) ; and Hawaiian Is- lands:— surface ("Albatross" Hawaiian Expedition 1902, Station 4188); 4 specimens 7-16 mm. in diameter, recorded by Mayer (:06). The large series from Station 4649, where a swarm was encountered, gives opportunity to add something to our knowledge of P. pacifica. The general external form, and arrangement of zooids, in which it resembles P. umbella, has been well described and figured by Haeckel. Certain features, however, need Station 4585 surface 1 " 4613 a 1 " 4619 a 2 334 PORPITA PACIFICA. special mention on account of their specific importance. Chief among these are the tubercles on the superior surface of the disc. Haeckel ('88b) observed and figured these; but he gave them no systematic weight. In the large speci- mens collected by the "Albatross" (Plate 28, fig. 1) they are very prominent, easily visible to the naked eye, largest and most crowded near the centre of the disc. They have no connection with the stigmata and this fact is important, because in P. umhella the latter organs, especially in large specimens, are sur- rounded by slight collars, causing a roughness, noted by A. Agassiz ('83). The tubercles in P. pacijica are conical thickenings of the chitinous layer of the pneumatocodon; and the canals of the pneumatophore often pass over them (Plate 28, fig. 4). Although the tubercles are extremely prominent, the radial plications of the surface of the disc are so slight as to be hardly noticeable except near the margin. In P. umhella, on the contrary, the ridges are rather promi- nent. The presence of tubercles in Huxley's ('59) specimens seems to me suffi- cient reason for including them in P. pacifica. A second feature which proves to be of systematic importance is the arrange- ment of the stigmata. In the adults of P. umhella, as has long been known, these organs are extremely numerous in the marginal region of the disc, although in large specimens the stigmata in the central region become closed (Plate 28, fig. 13). In P. pacijica (Plate 28, fig. 2) the stigmata are very much less numer- ous. There are no open ones for a distance from the centre of almost 2 the diameter of the disc; and even beyond this point very few open into each cir- cular chamber of the pneumatocyst. In a small specimen (1.5 mm.) the stig- mata in the central region are still open, as Haeckel has described them ('88b, " Porpitella pectanthis"). A third specific distinction, though of minor importance, is that in large specimens of P. pacifica the limbus is relatively much narrower than it is in P. U7nbella of about the same size (Plate 28, fig. 2, 13). Further points of dif- ference are found in the canals of the limbus, and in the tentacles. In P. umhella the former permanently retain their general radial arrangement (Plate 28, fig. 14), though with much branching and irregularity. In P. pacifica, however, the canals form an irregular network in adults (Plate 28, fig. 5) though in small specimens they are of the same type as in P. umhella. Finally the tentacles, at least in large specimens, form an excellent specific character, for whereas in P. umhella the stalked tentacular nematocyst clusters are not known to sur- pass 9-12 in the long, and 6-8 in the two short rows (A. Agassiz, '83, Chun, '97b), a fact I have been able to substantiate on numerous specimens, there are from PORPITA PACIFICA. 335 25-29 in the long rows, and from 11-14 in each of the short rows in the largest specimens of P. pacifica. In general structure the pneumatocyst agrees with Haeckel's account, except for the important fact that there are no radial chambers surrounding the central chamber. As Bedot ('85a) has pointed out for P. umbella, the sup- posed radial chambers are nothing more than radial lobes of the central compart- ment, just such as occur in Porpema (p. 326). The supposed septa separating them, which are very noticeable on surface views, are nothing more than furrows on the upper surface of the central chamber (Plate 28, fig. 7). The structure of this region was accurately described by Huxley ('59, p. 123), who also observed that the stigmata near the centre of the disc were closed. Ceniradenia. Adult. The courses of the tracheae have been so thoroughly worked out by Kolliker ('53), Huxley ('59), A. Agassiz ('83) and others, that I will merely note that my slides show frequent instances of the penetration of these organs into the walls of the central gastrozooid and of the gonozooids. The general structure of the centradenia is now fairly well known, but we possess little more information as to its finer details in Porpita than is contained in the brief account (without figures) by Bedot ('85a). It is therefore fortunate that the present series is sufficiently well preserved to allow the study of serial sections. In general form the centradenia of P. pacifica agrees closely with that of P. umhella, as it does in its finer anatomy, so far as that of the latter is known. The superior surface (Plate 28, fig. 3) of this organ, in P. pacifica as in P. umhella, is thrown into numerous ridges interlocking with the plications of the floor of the pneumatocyst. Haeckel ('88b, p. 69) calls these ridges "innum- erable radial folds (thirty-two of which are stronger)." In point of fact, there are only about sixteen at the centre, while the number increases distally until in a specimen 55 mm. in diameter upwards of two hundred could be counted near the margin. At the centre there is a small circular, or sometimes octagonal, area, corresponding in size to the superposed central chamber of the pneuma- tocyst, where the surface is smooth. In this region the canals, which further distally occupy the radial ridges, unite in an irregular network (Plate 28, fig. 16) the exact form of which varies in different specimens. In the space between the canals, groups of tracheae pass downwards into the substance of the centradenia. Haeckel says of the inferior surface of the central gland that it is divisible into a white central disc ("kidney") and a peripheral brown radiate zone ("liver"). Leaving out of account the colors, the present specimens show that 336 PORPITA PACIFICA. this statement, though essentially correct, needs emendation.' The mass of canals known as the "kidney" occupies the entire lower face of the central gland outward from the central zooid so far as the inner margin of the tentacular zone, and it is only by removing the latter that the outer ends of the superior ("liver") canals become visible from below (Plate 29, fig. 1). The radial canals, which run downward from the junction of limbus with disc, open into the outer ends of the superior canals or sinuses (Plate 29, fig. 1). The latter in their turn connect with the tentacles by means of a complex net of thin-walled canals, which form a plexus underlying the entire tentacular zone (Plate 29, fig. 1). So far as I have been able to learn from a study of numerous sections, only the youngest, most peripheral tentacles ever connect directly with the radial canals. This is evidently only temporary, for with growth the point of demarcation between the two categories of canals moves further and further distally, successively overlapping the new tentacles shortly after their formation. The difference between the structure of the tentacular zone in Porpita and in Porpema (p. 327) is no doubt correlated with the differences in the shape of the corm in the two genera. There are a few gonozooids scattered among the tentacles and these connect either directly or via the tentacular plexus with the superior canals (Plate 29, fig. 1). Haeckel is thus correct in stating that some of the gonozooids are connected with the "kidney" others with the "liver." Central to the tentacular zone the superior canals rest upon the mass of ectoderm cells and cnidoblasts traversed by the inferior canals, which form the great bulk of the centradenia. The inferior canals arise, as noted by Bedot ('85a) as down- ward branches from the superior canals (Plate 29, fig. 7) and form a complex network. At the inferior surface of the centradenia, immediately in contact with the supporting layer ("lamelle anhiste" of Bedot, '84) they give rise to an extremely close reticulum of small horizontal canals (Plate 29, fig. 6) to which alone the term "inferior" was applied to Bedot. It is, however, in their arrange- ment alone, not in their structure, that the latter differ from their parent canals. According to Haeckel ('88b, p. 70) there are sixteen main canals, arising from the central gastrozooid and running peripherally, "Along the subumbrella toward the peripheral edge of the limb. . . .they give off innumerable branches; of these the ascending ones enter into the centradenia, the descending vessels ' To avoid the use of the terms "hver" and "kidney" until more accurate linowledge of the func- tions of the various regions of the centradenia is gained, the following nomenclature, somewhat emended from that of Bedot ('84) is employed. The canals forming the ridges on the upper face of the organ are known as "superior," those below forming the greater mass of the organ ("kidney"), as "inferior". The canals running downward from the level of the limbus toward the tentacular zone, following Haeckel, as radial." PORPITA PACIFICA. 337 partly into the gonostyles, partly into the tentacles." This concept, as Bedot's work has already suggested, is entirely erroneous. In the first place many more than sixteen canals, arranged in two definite series, an inner and an outer, open into the central gastrozooid. These canals are more fully described below, (p. 339) in small specimens. Instead of running meridionally over the lower surface of the centradenia, they enter the formation of the general complex of inferior canals (Plate 29, fig. 4). The gonozooids (except such as are interpolated among the tentacles in the tentacular zone) connect directly with inferior canals, either with ones passing into the deeper regions of the centradenia, or with the network covering its lower surface. And the cavities of the larger gonozooids often connect with two, or even more canals. Furthermore, contrary to Haeckel's views, a study of sections shows that the canals which open into the central zooid never connect with the tentacles except through the medium of the superior canals, a statement agreeing with Bedot's observations on P. umbella. The brief account by the latter author of the histology of the superior and inferior canals in P. umbella agrees so closely with the conditions in P. pacifica that I can do no more than substantiate it. But as he did not illustrate it, I add a few figures. The layer of ectoderm underlying the chitinous pneuma- tocyst is composed of flat tile-shaped cells with deep-staining nuclei (Plate 29, fig. 12). Separating this tissue from the entoderm of the superior canals is a well-marked supporting layer. The walls of these canals are composed of several layers of small, round, closely crowded cells, with large nuclei and granular cytoplasmic bodies of a greenish color in formalin material. They do not enclose the colored spherules so characteristic of the superior canals of Velella. Scattered among them, but much fewer in number, are deep-staining cells, with much larger oval nuclei, and fairly large cytoplasmic bodies of irregular outline. The walls of the inferior canals are composed for the most part of a single layer of columnar cells, with large cytosomes and small nuclei. Scattered among them there are occasional deep-staining cells with cytosomes resembling those of the deep-staining cells in the walls of the superior canals, but with much smaller nuclei (Plate 29, fig. 14). Throughout the courses of the inferior canals the columnar cells frequently contain masses of large dense spherules, reddish brown in formalin material. Near the lower surface of the centradenia the spherules occur in the intercellular spaces as well as within the cytoplasm of the cells. Bedot suggests that the spherules result from a metamorphosis of the small granules which fill the bodies of the small round cells in the walls of the superior canals. But the fact that 338 PORPITA PACIFICA. there are apparently no stages connecting the two types of granules, even in the transition region between inferior and superior canals, seems to forbid this conclusion. In general appearance as well as in their relation to the cells, they strongly suggest the colored granules which are so prominent in the endoderm of various Medusae, and I believe they are by-products of digestion. The entoderm cells of the inferior canals enclose great numbers of the transparent greenish guanin crystals (Plate 29, fig. 13) so often described for P. umbella. They occur in greatest numbers nearest the lower surface of the centradenia, {. e., furthest from the superior canals. I have likewise observed them in the radial canals of the medusa-buds on the gonophores. It is to be observed that thoy do not occur in the walls of the canals which open into the central gastro- zooid, at least in the neighborhood of the latter; indeed, if they are to be regarded as by-products of digestion, as is no doubt true, their presence would not be expected there. With regard to the probable function of the different regions of the centra- denia but little can be said with confidence. The region of the superior canals was long ago suggested as a liver, that of the intermediate and inferior canals a kidney. The canal system of the whole is no doubt digestive, and the inter- pretation of the guanin secreting portion as a kidney is probably correct. How- ever it is doubtful whether there is any region of actual excretion. On the con- trary, in the absence of excretory pores, it should be rather looked on as an organ for the storage of the waste products of metabolism. The interpretation of the superior canals as functioning as a liver in Porpita is supported by little actual evidence. Whether or not it is correct is doubtful. Young stages of Porpita pacifica, 1.5-4 ^nyn. in diameter. Although the studies of Woltereck (:04) on the larval stages, and of Bedot ('85b) on the "Rataria" stage of Velella have afforded an excellent survey of the develop- ment of that genus, the early ontogeny of Porpita still remains almost unknown. A. Agassiz ('83) it is true, was able to trace the changes which take place in the canals of the limbus and of the pneumatophore with development, as well as the formation of tentacles of successive generations after what may be known as the " Discalia " stage. But our only knowledge of the early structure of the centradenia is contained in the brief account by Haeckel of the "Dis- conula" larvae, and of the "Discalia" and "Disconalia" stages. Of the former he says ('88b, p. 32) that "in the smallest Disconula-larvae which I observed the centradenia is a small circular, biconvex, lenticular disc; its upper face is in direct contact with the pneumatosaccus, whilst its lower face is separated from PORPITA PACIFICA. 339 the central siphon by the gastrobasal plate ("plancher" of Bedot). The entire mass of this solid disc is composed solely of exodermal cells and cnidoblasts; it is not traversed by any canals. The only canals of the centradenia are the eight simple radial canals which run upon its upper face; they arise from the eight ostia of the basigaster, embrace the surface of the lenticular centradenia like eight meridian lines, and unite in the centre of its uj^per face, forming a typical octoradial 'liver star'." A similar condition is described by him ('88b, p. 48) for the "Discaha" stage. Although no figures of the "Disconula" are given as evidence for this account, the structure as he outlines it agrees so closely with the oldest Velella larva figured by Woltereck (:04, taf. 19, fig. 18) that we can safelj- assume that it is correct. A somewhat more advanced, but still very i:)rimitive condition is to be seen in specimens of P. pacifica 1.5-2 mm. in diameter, with eight gonozooids, and twenty-four tentacles (Fig. B). A surface view of the centradenia of one of these shows that the eight primary superior canals, uniting at the centre as ob- served by Haeckel, fork di- or trichotomously until there are twenty canals or ridges at the margin, and, as can be worked out on serial sections, the number of ostia opening into the central zooid has increased to twenty-eight. These are arranged in two series, an inner row of eight, connecting by means of short vertical canals with the eight primary superior canals, and an outer series of twenty, close to the margin of the zooid. The outer ostia connect with the outer ends of the canals (fig. B) by solid cell strands without lumen, a fact which, of course, indicates that the communication between them and the canal system of the central gland is more recent than it is in the case of the eight ostia of the inner series, which no doubt correspond to the eight gastric ostia of Haeckel's "Disconula" larva. In our specimen each inner ostiinn connects with a canal -P Fig. B. Section of young Porpita pacifica 2 mm. in diameter. Ch., circular chamber. C.S.. superior canal. C',C'., descend- ing canals of the younger and older series. C. T., tentacular canal. Go., gonozooid. Ga., central gastrozooid. L, linibus. T', T-, older and younger tentacles. St, central stigma. 340 PORPITA PACIFICA. with open lumen, but Woltereck's observations show that this is a secondary condition, for in his larva of Velella these eight first-formed points of communi- cation are represented at first by solid entodermal strands (: 04, taf. 19, fig. 18, K), just as are the communications of the outer series of ostia in our specimens. As yet there is no differentiation betw^een the cell elements composing the walls of the superior canals and the trunks connecting them with the gastric ostia. In a specimen 4 mm. in diameter, with eleven circular chambers, the gastric ostia of the outer series have increased to about thirty-two, with a corresponding increase in the branching of the superior canals. Furthermore in most instances the connections between the ostia and the latter are by means of open canals, no longer direct but in a network joining the gonozooids on one hand, and the superior canals on the other. The connection, too, between the eight ostia of the inner .series and the superior canals, is now indirect, by a network which is only slightly less complex than it is in the adult. Histologically as well as morphologically, superior and inferior canals can now be separated. In both, the walls are composed of a single layer of cells of two kinds, the first and most numerous, columnar, with granular bodies, the second, small, deep-staining, irregular in outline. In the cells of the inferior canals there occur the large dense spherules, often in masses, which give the characteristic reddish brown color to the lower portion of the centradenia in the adult. But as yet, no crystals have been formed, though they are present in specimens but slightly larger (7 mm.). Pneumatophore. The smallest specimen is intermediate with respect to this structure between the "Discalia" and "Disconalia" stages described by Haeckel, "Discalia" having one, the "Albatross" specimen five, and "Disconaha" seven circular chambers. Radial sections of this example (Fig. B) and of the individual of 4 mm. show that there are no radial chambers here, any more than there are in the adult. On the contrary the eight stigmata of the innermost circle open into the first circular chamber, just as they do in Porperna (p. 327). Surface views of this region are deceiving, because owing to the partial enclosure of the central by the first circular chamber, these eight stigmata appear to open into the former, while the eight ridges on the "ceiling" of the pneumatosaccus appear to divide it into eight compartments. In these stages, all the stigmata are open. I have not been able to determine at what age the central ones become closed over. Before closing this description I may mention two features, interesting though of less importance than the preceding. These are the limbus and the VELELLA. 341 gonozooids. Regarding the former, it is interesting to note that it is formed much later in Porpita than in Velella. While in the latter it is present in the Conaria larva even before metamorphosis into the Rataria, in the smallest specimen of Porpita collected bj' the "Albatross" it is only just appearing as a slight ridge on the margin of one side of the disc (fig. B). In the 4 mm. speci- men it is well developed. In the smallest specimen only one of the eight gono- zooids has a terminal opening, so far as I could determine; in the 4 mm. indi- vidual, however, all have open mouths. The fact that they all bear young medusa buds as well, even at this early stage, argues strongly against Haeckel's view that the presence of buds in his "Discalia" and "Disconalia" was evidence of maturity. Velellidae Brandt, 1835. Chun ('97b) has considered in such detail the reasons for reuniting Haeckel's ('88a, '88b) Rataria and Armenista with Velella, that I need only state that like Schneider ('98) and Lens and Van Riemsdijk (:08) I entirely agree with his conclusion that they represent nothing more than early and mature stages in the life history of the later. Velella thus remains the only representative of the family. VELELLA Lamarck, 1801. Modern students of Siphonophores generally support Chun ('97b) in his conclusion that the numerous species of Velellas which have been described from the Atlantic and from the Mediterranean, are at most only local varieties of a single species. For this form Chun employed the name V. spirans Forskal. But according to the rules of nomenclature, Schneider was justified in substi- tuting the older name V. velella of Linne, because the earliest appearance of the species in binomial literature is Medusa velella Linn. No less than eleven species of Velella have been described from the Indo- Pacific region, but it is certain that they are not all distinct. Chun ('97b, p. 96) though with hesitation on account of the paucity of his material, suggests that all of them, like all of the Atlantic forms, represent only one good species, which he believes to be distinct from the Atlantic V. velella. This standpoint has been adopted by Agassiz and Mayer ( : 02) and by Lens and Van Riemsdijk ( : 08), who record their specimens from the Pacific and from the Malaysian region, as V. pacifica Eschscholtz. But Schneider ('98, p. 194) has taken the more radical 342 VELELLA. ground, from a study of specimens "aus den verschiedensten Meeresgebieten," that all Velellas, both Atlantic and Indo-Pacific, belong to but a single species. Leaving out of the discussion the early descriptions, none of which are based on sufficiently stable features to be of any real assistance, we find the following characters suggested as points of difference between the Atlantic and Indo- Pacific Velellas. According to A. Agassiz ('65) the numerous specimens which he collected in the Straits of Fuca are much more nearly rectangular in outline than those from the West Indies. Chun ('97b, p. 96) found that "die Form des Mantels (limbus) weicht immerhin so auffallig von jener der V. spirmis ab, dass jedenfalls die pacifische Art von der atlantischen zu trennen ist." Unfor- tunately, however, he gave no details as to exactly what the difference is. Fewkes ('89b) and Lens and \an Riemsdijk (:08) suggest that the Pacific spe- cies is characterized by a triangular crest. , I have been able to test the importance of these supposed differences on the considerable series from various parts of the Pacific and Atlantic, listed below, with the result that I believe that the separation of the two species is justified. The difference in form, especially of the shell, suggested in Esch- scholtz's figures ('29, taf. 15), appears to be constant even if slight, the breadth in proportion to the length being greater in Pacific than in Atlantic specimens: in the former the shell is more nearly rectangular with the long sides straighter; in the latter, it is elliptical, with the long sides more curved. The exact proportions of a series of sixteen specimens of each species are given in the table below, from which it is also evident that the difference is not only considerable, but discontinuous since all the Pacific examples are broader proportionately than any of the Atlantic specimens. The difference can not be regarded as signifying local variation, for the representatives of the two classes were selected from widely separated localities. Preserved specimens furnish less satisfactory data on the form of the limbus than they do on the outlines and proportions of the shell. However, in very large Pacific specimens (30-40 mm. long) preserved in formalin, in which this region was in good condition, it is entire, the onlj- subdivisions being obviously acci- dental tears, instead of irregularly lobed as it has so often been described for T'. velella. In other respects, I could find no constant difference. The supposed difference in the form of the crest is not borne out by the series studied, for in small specimens both from the Atlantic it is triangular. Even in the Pacific species this character is transitional, the crest becoming rounded in large specimens: but the triangular form seems to be retained longer in them than it is in V. velella. VELEI>LA LATA. 343 So far as specimens from different regions of the Pacific are concerned, the present collection shows no features to differentiate more than the one species, and I have no hesitation in following Chun in uniting all previously described Pacific Velellas. However, I am not prepared to follow him in uniting with them the various Indian forms, simply for the reason that it is futile to attempt any revision of the latter without access to a considerable series of specimens from the Indian ocean. It is impossible to tell from the descriptions by Chamisso and Eysenhardt ('21), Eschscholtz ('29) and Brandt ('35) whether their material more nearly resembled the Atlantic, or the Pacific species, or whether they formed a connecting link between the two. In determining a specific name for the composite Pacific species I maj^ point out that although A. Agassiz ('65b) called his specimens V. septentrionalis Esch- scholtz, and in spite of the fact Agassiz and Mayer (:02) and Lens and Van Riemsdijk ( : 08) used the name V. pacifica Eschscholtz for Tropical Pacific and Malaysian Velellas, two Pacific species had been described previous to Esch- scholtz's work. These are V. oblonga and V. lata of Chamisso and Eysenhardt ('21). My choice as between the two falls upon lata, for the reason that, while both are described on the same page and figured on the same plate, lata agrees very well in general form with the Pacific specimens I have examined, whereas oblonga is so much longer in proportion to breadth than even the longest Atlantic specimens that it is probably founded on an abnormal individual. The only Velellas described from the Pacific within i-ecent years, so far as I can learn, are V. meridionalis Fewkes ('89b) from the coast of California, and V. lobata, Haeckel ('88b) from the South Pacific. The first of these, founded on young specimens as Fewkes himself suggested, is supposed to be separated from the other species from the same region (F. septentrionalis = T^. lata Cham- isso and Eysenhardt) by a more oval mantle. But the fact that in the "Albatross " series small specimens have a rounded, larger ones a more nearly rectangular, outline shows that this difference is merely a growth character. 1'. lobata Haeckel was neither described nor figured. It is, therefore, a nomen midem. Velella lata Chamisso and Eysenhardt. Velella lata Chamisso and Eysenhardt, '21, p. 364, tab. .32, fig. 3 A-B; Eschscholtz, '29, p. 172. Velella oblonga Ch.^mi.sso and Eysenhardt, '21, p. 3(54, tab. 32, fig, 2 A-C; Eschscholtz, '29, p. 171; Haeckel, '8Sb, p. 83. Velella sandwichiana de Haan, '27, p. 493. Velella radackiana de Haan, '27, p. 493. Velella emarginala QuoY and Gaimard, '24, p. 586, pi. 86, fig. 9. Velella seiplenirioiialix Eschscholtz, '29, p. 171, taf. 15, fig. 1; A. .Vcassiz, 'ti.")b, p. 217. 344 VELELLA LATA. Velella pacifica Eschscholtz, '29, p. 174, taf. 14, fig. 4; Agassiz and Mayer, : 02, p. 159; Lens and Van Riemsdijk, : 08, p. 123. Velella cyanea Lesson, '26, pL 6, fig. 3, 4; '30, p. 54. Velella patellaris Brandt, '35, p. 38. Velella oxyolhone Brandt, '35, p. 39. Vellaria oblonga Haeckel, '88a, p. 31. Armenisla lata Haeckel, '88b, p. 84. Velella meridionalis Fewkes, '89b, p. 112, pi. 1, fig. 1-3, pi. 2, fig. 3. Velella velella Schneider, '98, p. 194 (partim). ? Velella indica Eschscholtz, '29, p. 175, taf. 15, fig. 5. ? Velaria indica Haeckel, '88a, p. 31. Station 4691 14 specimens 1-5 mm. long; Rataria stage. 4694 1 6 mm. " 4696 5 All about 2 mm. long; Rataria. 4698 1 7 mm. long 4707 1 li a 11 4708 2 3 and 8 mm. long. 4710 3 All about 8 mm. long. 4714 2 9 and 12 mm. 4718 1 5 mm. 4720 2 8 and 10 mm. Also :— 5° 36' N., 86° 55' W. ; 1 specimen 10 mm. long. Long Beach, California 13 specimens all about 50 mm. long. Hawaiian Islands 20 " " "40 mm. " Hawaiian Islands 2 " " " 35 mm. " Japan or China? 18 " 10-60 mm. " "Voyage S. Francisco-Unalaska ", 8 specimens 20-55 mm. long. Port Townsend, Washington 2 29° 52' N., 116° 15' W. 4 Point Buchon, California 9 Ponape, Caroline Islands 42 28°3'N., 126°57' W. 2 21° 18' S., 173° 31' W. 1 Bonin Islands 7 "Off Lower California" 3 about 50 mm. " " 40 mm. " 25-40 mm. long 30-50 mm. long: poor condition 70 mm. and 110 mm. long. 22 mm. long 20-30 mm. long, all about 50 mm. I have been able to compare these specimens with large series from Key West and the Tortugas, as well as with a few individuals from Bahia Honda, and from the Mediterranean. The absence of mature specimens in the "Albatross" collection of 1904-1905 is made even more striking by the fact that only a single large Velella was seen during the Expedition. The clue to this phenomenon is to be found in the fact VELEIJ.A LATA. 345 that the smallest Ratariae were taken in the earliest hauls, while the individuals of later cajjtures grow on the whole larger and larger. A month later large specimens might have been abundant. The actual dimensions of the shells in a series of Atlantic and Pacific speci- mens is given in the following table. Atlantic Pacific Ratio Ratio lireadl li Length Breadth — length Hicadlli Lengtli Hreadth — length (approximate) (approximate) 11.5 31 1-2. S U 23 1-2 13 5 3.1 1-2 . S IS 35 1-1.9 16 43 1-2.7 19 39 1-2 17 .52 1-3 19 40 1-2 I 17 54 1-3 1 20 42 1-2.1 18 r>2 1-2.8 + 21 42 1-2 18 53 1-2.9 19 43 1-2 2 19 51 1-2.7 20 44 1-2 2 20 63 1-3 1 22 45 1-2 21 60 1-3 22 47 1-2 1 22 63 1-2.8 24 52 1-2 1 22 69 1-3 1 25 54 1-2 1 23 68 1-2 9 27 57 1-2 1 24 74 1-3 26 59 1-2 , 2 25 67 1-2. ti 36 73 1-2 30 82 1-2.7 46 104 1-2.2 Extremes 1 . -2 7, 1-3 .1 E.xtremes 1-19, 1- -2 2 Of the one hundred and thirty-eight Pacific specimens which are large enough to show obliquitj' of the crest, seventy-three are "S. W." 04 "X. W." (according to the nomenclature of Chun, '97b). This, together with the fact that the crest is N. W. in all of the five "Siboga" specimens recorded by Lens and Van Riemsdijk (:0S, p. 123), contrasted with Chun's observations of 71 S. W. to () N. W. in r. velella, and A. Agassiz's failure to fiiul a single N. W. specimen among the many hundreds of that species which he studied, shows that the N. W. condition is much more common in the Pacific ]'. lata than in the .\tlantic 1'. relella. Distribution. The records of V. hita show that it is very generally dis- tributed over the warmer regions of the Pacific, extending northward to Japan, and to Puget Sound. How far it may extend southward is not yet known. 346 SPECIES NOT COLLECTED BY "ALBATROSS." SYNONYMICAL LIST OF SPECIES NOT COLLECTED BY THE "ALBATROSS."'! Sphaeronectidae. Sphaeronectes irregularis (Glaus). Monophyes irregularis Cl.\us, 73, p. 259; '74, p. 32, taf. 4, fig. 'j, ti, i.t, 16; Chun, '88, p. ll.")4; H.\ECKEL, '88b, p. 128; Chun, '92, p. 82; Chun, '97b, p. 102. Monophyes bremtruncala Chun, '88, p. 1153; '92, p. 79, taf. 8, fig. 1, 2, taf. 9, fig. 1-4; '97b, p. 102. Sphaeronectes truncata .'Schneider, '98, p. 78 (partim). Sphaeronectes princeps H.\eckel. Sphaeronectes princeps H.\eckel, '8Sa, p. 34. Monophyes princeps Haeckel, '88b, p. 129, pi. 27, fig. 13, 14. Sphaeronectes trimcata Schneider, '98, p. 78 (partim). Doromasia picta Chun. Doromasia picta Chun, '88, p. 1154; '92, p. 91, taf. 8, fig. 3-5, taf. 9, fig. .5-10, taf. 10, fig. 1-9; '97b, p. 9. Muggiaea bojani Schneider, '98, p. 88. Diphyopsis picta Mayer, : 00, p. 75. For the synonymy of the Eudoxid referred to this species by Chun, see p. 264. *Nectopyramis thetis Bigelow. Nectopyramis thetis Bigelow, : lib, p. 338, pi. 28, fig. 1-4. Prayidae. Stephanophyes superba Chun. Stephanophyes superba Chun, '88, p. 1164; 91, p. 3, pi. 1-7; '97b, p. 102. Rosacea dubia Schneider, '98, p. 79 (partim. non Praya dabia Quoy and Oaimard). Desmophyes annectens Haeckel. Desmophyes annectens Haeckel, '88a, p. 36; 'S8b, p. 170, pi. 30. Rosacea diphyes Schneider, '98, p. 81 (partim). Diphyidae. Galeolaria truncata (Sars) Huxley. Diphyes truncata Sars, '46, p. 41, pi. 7, fig. 1-12. Galeolaria truncata Huxley, '59, p. .38; Haeckel, '88b, p. 151; Chun, '97b, p. 17; Vanhoffen, : 06, p. 15, fig. 10-12; Lens and Van Riemsdijk, : 08, p. 57. Epibulia truncata Haeckel, '88a, p. 35. Diphyes appendiculala Schneider, '98, p. 85 (partim). ' This list includes the names of forms entitled to specific recognition. .\n * indicates the species I have studied. SPECIES NOT COLLECTED BY "ALBATROSS." 347 ? Diphyes conoidea Kefperstein aud Ehlbbs, '61, p. 16, taf. 5, fig. 6, 7. ? Epibulia inflata Chdn, '88, p. 1157. ? Galeolaria inflata Chun, '97b, p. 17. Diphyes arctica Chun. Diphyes arctica Chun, '97b, p. 19, taf. 1, fig. 1-10; V.^nhoffen, '98, p. 274, taf. 2, fig. 3; Ro.mer and ScHAUDiNN, '99, p. 245; : 00, p. 55; R6.\ier, : 02, p. 174; Vanhoffen, :06, p. 17, fig. 16-18; Damas and Koefoed, : 07, p. 348; Bboch, : 08, p. 3. Diphyes borealis Chun, '97b, p. 99. Muggiaea arctica Schneider, '98, p. 89. Eudoxia eschscholtzii Johansen and Levinsen, : 03, p. 282 (non Busch, '51). Muggiaea atlantica Bull Conseil Int. :04, p. 84, 118, 156 (non Cunningham, '92). Romer in his synonymy (:02, p. 174) credits Cymbonectes borealis to Van- hoffen, '98, p. 274; but it does not occur at that citation, nor in Vanhoffen's explanation of plates. Diphyes steenstrupi Gegenbaur. Diphyes steeristrupiGEQEHBAVR, '60, p. 369, taf. 29, fig. 27-29; Chun, '97b, p. 103; Lens and Van Riems- DiJK, : 08, p. 44. Diphyes dispar Schneider, '98, p. 84 (partini). Diphyes serrata Chun. Diphyes serrata Chun, '88, p. 1158; '97b, p. 26; Lens and Van Riemsdijk, : 08, p. 44. Eudoxia serrata Chun, '88, p. 1159; '97b, p. 26. Diphyes appendiculata Schneider, '98, p. 85 (partim). D. steenstrupi and D. serrata are closely allied to each other, and to D. bojani (p. 245). *Diphye3 subtilis Chun. Ersaea elongata Will, '44, p. 8, pi. 2, fig. 30, 31. Eudoxid (non Diphyes elongata Hyndman, '41). Monophyes gracilis Chun, '85, p. 513, (partim) fig. 3-5 (non Claus, '74). Diphyes subtilis Chun, '86, p. 681; '97b, p. 103; Lens aud Van Riemsdijk, : OS, p. 47. Monophyes diptera Haeckel, '88b, p. 129. Cucullus subtilis Haeckel, '8Sb, p. 111. (Eudoxid.) Diphyes elongata Schneider, '98, p. 85 (non Hyndman, '41). Diphyes subtiloides Lens and Van Rie.msdijk. Diphyes subtiloides Lens and Van Riemsdijk, : 08, p. 46, pi. 7, fig. 59-61. *Diphyopsi3 chamissonis (Huxley). Diphyes chamissonis Huxley, '59, p. 36, pi. 1, fig. 3; Browne, : 04, p. 742, pi. 54, fig. 6; : 05, p. 155. Muggiaea chamissonis Haeckel, '88a, p. 34; '88b, p. 137; Chun, '92, p. 89. Muggiaea kochii Murbach and She.arer, : 03, p. 189. Diphyopsis weberi Lens and Van Riemsdijk, : 08, p. 53, pi. 8, fig. 67, 68. Diphyopsis hispaniana Mayer. Diphyopsis hispaniana Mayer, : 00, p. 76, pi. 29, fig. 98-99. Ersaea hispaniana Mayer, : 00, p. 78. Closely allied to D. mitra, p. 244. 348 SPECIES NOT (■()LLK( TED 15V -'ALBATROSS." Apolemiidae. Apolemia uvaria iLamakck> Eschscholtz. Stephaiiomia uvaria Lamahck, '10, |). -ttj'i {Slephaiiomia unfonnis Lesueur, Ms.)- Apolemia uvaria Eschscholtz, '29, p. 143, t;if. 13, fig. 2; Kolliker, '.53, p. 18, taf. 0, fig. G-9; Gegen- BAUR, '53, p. 319, taf. 18, fig. 1-4; Kefferstein and Ehlers, '61, p. 2.5; Cl.\us, '63, p. .537, laf. 46; Chun, '97b, p. 103; Schneider, '98, p. 117. .4po!e7«io itranm Blaiptville, '34, p. 119, pi. 3, fig. 1. l.-i. 11) (fopicrl from I.EsrEX'R, yia.). Physophora ulophylla Costa, '36, p. 12, taf. 4. Apolemia leseuria Lesson, '43, p. 518. Agalma punclaln Vogt, '54, p. 83, taf. 12. Apokmopsis uviformia (or Apolemia lesueuria) Haeckel, '88b, p. 213. ? Dicymba diphyoptfin Haeckel, '88a, p. .39; '88b, p. 210. pi. IS, fig. 1^7. '? Apokmopsis dubia Brandt, '35, p. 35. ? Apolemia dubia Haeckel, '88a, p. 39. Forskaliidae. It is useless to attempt a synonymical list of the species of Forskalia, with- out studying series of specimens from various localities (p. 270). For lists of citations of the genus see Bedot, '93a, p. 250-252, and Schneider, '98, p. 157. Erenna bedoti Lens and \'ax Riemsduk. Ei-enna bedoti Lens and ^■A^• Riemsdlik, :0S, p. 06, pi. 11, fig. 8.5-00. Closely allied to E. rkharcli, p. 271. Agalmidae, Anthemodes ordinata Haeckel. Anlhemodes ordinata Haeckel, '88a, p. 40; '88b, p. 229, pi. 14, 15; Bedot. '96, p. 409; Cnrx, '97b, p. 104; Schneider, '98, ]>. 117. Agalma clausi Bedot, '88. Agalma sarsi Fewkes, '80a, p. 137, pi. 2, fig. 2 (non Agaimopsis sarsii Kolliker, '53, p. 1(11. taf. 3). Agalma clausi Bedot, '88, p. 74, pi. 3, 4. Crystallodes clausi Bedot, '88, p. 91. lilephanopsis clausi Bedot, '96, p. 406. Slephnnomin snrsi Schnkidkk, '98, p. 121. Agalma haeckeli, noni. nov. (p. 277). Agalma eschselioltzi Haeckel, '88b. p. 226, pi. 18. fig. 8-17: Rf.dot, '96, ji. 405. ('non Lesson, '43, p. 511). Slephanomia snrsi Schneider. '98. p. 121 (partini). Closely allied to A. clausi Bedot (p. 276). *Stephanomia rubra V'oot). Agalma rubra VooT, '52, p. .522; '54, p. 62, taf. 7-11. Agaimopsis punctata Kolliker, '.53, p. 15, tab. 4. Agaimopsis rubra Leuckart, '53, p. 3; Schneider, '98, p. 123; '99, p. 27, taf. 4, fig. 34-42. SPECIES NOT COLLECTEU BY "ALBATROSS." 349 Agatma rubrum Leuckart. '54, p. 321, taf. 12, fig. 12-20; Sch.neidek, '96. Agalma minimum Gr.veffe, '60, p. 15, taf. 2, 3. Halistemma ruhntm Huxlev, '59, p. 70; Haeckel, '88b, p. :i(j7; Bedot. '90, p. 407; \\ oltereck, :051j, p. 612. Stephanomia cupulifera 1 1, ens and Vax Riemsdijk). Halistemma cupulifera Lens ami \an Riemsdijk. : 08, p. 85, pi. 16, fig. 116-119. Stephanomia cara (A. Agassiz) Metschnikoff. Nanomia cara A. Agassiz, '65a, p. 181 ; '65b, p. "200, fig. 331-350; Moss, '79, p. 123; Fewkes, '88a, p. 213. Stephanomia cara Metschnoikoff, '74, p. 62. Agalmopsis (cara) Fewkes, '80, p. 135. ^ Agalmopsis (Xanomia) cara Fewkes, '89a, p. 965. Halistemma carum H.\eckel, '88a, p. 40. Cuptdita cara H.ieckel, '88b, p. 367; Bedot, '98, p. 408; Chun, '97b, p. 103; Romer, : 02, p. 177; V.INHOFFEN, : 06, p. 177. For a complete list of references, see Romer (:02). Lynchnagalma utricularia Clahs. Agalmopsis utricularia Claus, '79, p. 1 (190), taf. 18. Calliagalma utricularia Fewkes, '82a, p. 268, footnote. Agalma utricularia Cahus, '85, p. 48. Lynchmigalma resicularia Haeckel, '88a, p. 40; '88b, p. 235, pi. 16. Lijnchnagalma utricularia Haeckel, '8Sa, p. 40; '88b, p. 235; Bedot, '96, p. 410. Cupulila utricularia Schneider, '98. p. 124. Anthophysidae. Athorybia rosacea (F"orskal) Eschscholtz. Physophora rosacea Fobskal, 1775, p. 120: 1776. taf. 43, fig. B; Modeeu, 17S9. p. 2.S3. Rhizophysa rosacea Lam.arck, '16, p. 478. Rhizophysa melo Quov and Galm.\rd, '27, p. 180. pi. of, fig. 1-9. Rhizophysa heliantha QroY and Gai.mard, '27. p. 177, pi. 5a, fig. 1-8. Athorylna heliantha + melo + rosacea Eschscholtz, '29, p. 153, 154. Rhodophysa helianthus Blainville, '30, p. 112; '34, p. 123. Rhodophysa melo Blaixaille, '30, p. 112; '34, p. 123. Rhodophysa rosacea Blainville, '30, p. 112; '34, p. 123. Athorybia rosacea Kolliker, '53, p. 24, taf. 7; Schneider, '98, p. 162. Athorybia heliantha Gecenbaur, '60, p. 412, taf. 32, fig. 43, 44. Athorybia melo Chun, '88, p. 1172. Athorybia rosacea + heliantha H.aeckel, '88b, p. 275. Athorybia. ocellata Haeckel, '88a, p. 42; '88b, p. 276, pi. 11, pi. 12. fig. 10-18. Melophysa melo Haeckel, '88a, p. 42; '88b, p. 274. Athorybia melo Chun, '97b, p. 49, taf. 4. Athorybia rosacea Chun, '97b, p. 49. ? Athorybia rosacea Huxley, '59, p. 86, pi. 9. ? Athorybia indica Haeckel. 'S8b, p. 275. Anthophysa formosa (Fewkes) H.aeckel. Athorybia formosa Fewkes, '82a, p. 271-275, pi. 5, fig. 3, 4, pi. 6. fig. 7-14; Schneider, '98, p. 162. Pheophysa agassizii Fewkes, '88b, p. 317, pi. 17, fig. 1, 2. LHploryhia (Jormosa) Fewkes. 'SSb. p. 320. footnote. 350 SPECIES NOT COLLECTED BY "ALBATROSS." Anthophysa fornwsa Haeckel, '88a, p. 43; '88b, p. 278. Anthophysa darmnii Haeckbl, '88a, p. 43; 'S8b, p. 278, pi. 12, fig. 7-9. Anthophysa formosa Chun, '97b, p. 61, taf. 3, fig. 7, 8; Bedot, : 04, p. 5, pi. 1, fig. 4-15. ? Angela cytherea Lesson, '43, p. 496, pi. 9, fig. 1. Closely allied to A. rosea (p. 296). Rhodaliidae. Rhodalia miranda Haeckel. fihodalia miranda Haeckel, '88a, p. 42; '88b, p. 302, pi. 1-5; Chun, '97b, p. 104; Lens and Van RiEMSDiJK, : 08, p. 91. Angelopsis globosa Schneider, '98, p. 157 (partim). ? Rhodalia species Brooks and Conklin, '91. Stephalia corona Haeckel. Stephalia corona Haeckel, '88a, p. 43; '88b, p. 297, pi. 7; Chun, '97b, p. 104; Vanhoffen, : 06, p. 33, fig. 52. Stephonalia bathyphysa Haeckel, '88b, p. 298, pi. 6. Angela corona Schneider, '98, p. 156. ? Circalia stephanoma Haeckel, '88b, p. 198, pi. 21, fig. 1-4; Vanhoffen, : 06, p. 34, fig. 54. Angelopsis globosa Fewkes. Angelopsis globosa Fewkes, '86, p. 972, pi. 10, fig. 4, 5; 'S9a, p. 146, pi. 7, fig. 1-3; Chun, '97b, p. 104; Schneider, '98, p. 157 (partim). Lens and Van Riemsdijk, : 08, p. 89. Auralia profunda Haeckel, '88a, p. 42; '88b, p. 301. Closely allied to A. dilata (p. 310). * Archangelopsis typica Lens and Van Riemsdijk. Archangelopsis typica Lens and Van Riemsdijk, : 08, p. 91, pi. 17, pi. 18, fig. 137-140. Rhizophysidae. Epibulia ritteriana Haeckel. Epibulia ritteriana Haeckel, '88b, p. 335, pi. 22, fig. 6-8. Cystalia challengeri H.\eckel, '88a, p. 44. Cystalia monogastrica Haeckel, '88b, p. 316, pi. 22, fig. 1-5. Epibulia erythrophysa Schneider, '98, p. 172. ? Epibulia {Brachysoma) erythrophysa Brandt, '35, p. 33; Haeckel, 'S8b, |). 334. ? Rhizophysa chamissonis Etsenhardt, '21b, p. 420, pi. 35, fig. 3. ? Epibulia (Rhizophysa) chamissonis Eschscholtz, '29, p. 149; Haeckel, '88b, p. 334. ? Brachysoma chamissonis Lesson, '43, p. 493. ? Brachysoma erythrophysa Lesson, '43, p. 493. ? Cystalia larvalis Haeckel, '88a, p. 44. ? Arethusa erythrophysa Haeckel, '88a, p. 46. ? Arethusa chamissonis Haeckel, '88a, p. 46. Salacia uvaria (Fewkes) Haeckel. Rhizophysa uvaria Fewkes, '86, p. 967, pi. 10, fig. 6; Schneider, '98, p. 170. Salacia polygastrica Haeckel, '88a, p. 45; '8Sb, p. 331, pi. 25; Chun, '97b, p. 104. Salacia uvaria Haeckel, '88a, p. 45; '88b, p. 330. SPECIES NOT COLLECTED BY "ALBATROSS." 351 Bathyphysa abyssorum Studer. Bathyphysa aht/ii.-,^, am Studek, 78, p. 21, taf. 3; Haeckel, 'SSb, p. 248; Chun, '97b, p. 104; Schneider, '98, p. 171 (partim); Lens and Van Riemsdijk, : 08, p. 105. Bathyphysa sibogae Lens and Van Riemsdijk. Bathyphysa sibogae Lens and Van Riemsdijk, : 08, p. 1 14, pi. 20, fig. 148, pi. 2:3, fig. 160-164, pi. 24, fig. 173. Pterophysa studeri Lens and Van Riemsdijk. Plerophysa (Bathyphysa) studeri Lens and Van Riemsdijk, : 08, p. Ill, pi. 20, fig. 149, pi. 22, fig. 153- 155, 157-159, pi. 23, fig. 165, pi. 24, fig. 171. Pterophysa grandis Fewkes. Pterophysa grandis Fewkes, '86, p. 969, pi. 10, fig. 1-3; Chun, '97b, p. 104; Lens and Van Riemsdijk, : 08, p. 107, pi. 19, pi. 24, fig. 167-170. Bathyphysa grandis Haeckel, '88b, p. 249. Bathyphysa abyssorum Schneider, '98, p. 171 (partim). ? Rhizophysa conifera Studer, '78, p. 4, taf. 1, fig. 2, 4-7. taf. 2, fig. 13-18. ? Linophysa conifera Haeckel, '88a, p. 45; '88b, p. 326. ? Pterophysa conifera Schneider, '98, p. 171 ; Lens and Van Riemsdijk, : 08, p. 106. Pterophysa grimaldii (Bedot) Lens and Van Riemsdijk. Bathyphysa yrimaldii Bedot, '93b, p. 4, pi. 1; : 04, p. 14, pi. 3, 4; Chun, '97b, p. 104. Pterophysa abyssorum. Schneider, '98, p. 171 (partim). Pterophysa grimaldii Lens and Van Riemsdijk, : 08, p. 107. Closely allied to Pt. grandis (p. 321). Physaliidae. * Physalia physalis (Linn^) Schneider. Hololhuria physalis Linne, 1758, p. 657; Gmelin, 1790, p. 3139. Medusa, caravella O. F. MtJLLER, 1776, p. 190, taf. 2, fig. 2; Gmelin, 1790, p. 3156. Physsophora physalis Modeer, 1789, p. 285, taf. 10, fig. 1, 2. Physalis pelagica L.iM.ARCK, '01, p. 356; Bory de St. Vincent, '04, p. 288, pi. 54, fig. 1; L.a.marck, '16, p. 480; Eysenhardt, '21b, p. 45, taf. 35, fig. 2; Eschscholtz, '29, p. 162; Olfers, '32, p. 38; Lesson, '43, p. 545; Huxley, '59, p. 100; Haeckel, '88b, p. 351; Mayer, : 00b, p. 73. Physalia pelasgica Bosc, : 02, p. 159. Physalia gigantea Bory de St. Vincent, '04, p. 288. Physalia arethusa Tilesius, '10, p. 91; Eysenhardt, '21b, p. 420, pi. 35, fig. 1; Olfers, '32, p. 155, taf. 1-2; Delle Chiaje, '41, taf. 33, fig. 1; L. Auassiz, '62, pi. 35; Chun, '97b, p. 89. Physalis glauca Tilesius, '10, p. 92; Blainville, '34, p. 113. Physalis pelagica Tilesius, '10, p. 94. Physalia elongata Lamarck, '16, p. 481. Physalia tuberculosa Lamabck, '16, p. 481. Physalia caravella Eschscholtz, '29, p. 160, taf. 4, fig. 1; Carus, '85, p. 49; Chun, '88, p. 1173. Physalia atlantica Lesson, '26, pi. 4, fig. 3, 4, '30, p. 36. Physalia antarctica Lesson, '26, pi. 5, fig. 2, '30, p. 36. Physalia azoricum Lesson, '26, pi. 5, fig. 4; '30, p. 42; '43, p. 555. Physalus arethusa Blain^'ille, '34, p. 113. Physalia (Alophota) olfersii Brandt, '35, p. 37. Physalia utricuhis Leuckart, '51, p. 190, taf. 6, fig. 1-6 (non Eschscholtz, '29; Chun, '97b; Lens and Van Riemsdijk, :08). 352 SFKCIK.S NOT COLLKCTKI) BY "ALBATROSS." I'hysuUa olfersii Qcatkefages, '54, p. 109, pi. 3, 4. Physalia aurigera McCrady, '57, p. 74. Alophola olfersii Haeckel, '88a, p. 46. Alophola gillschiatui Haeckel, '88a, p. 40; '88b, p. 348, pi. 26, fig. 1-3. Arelhusa chalkngeri Haeckel, '88a, p. 46; 'S8b, p. 349, pi. 26, fig. 4-8. Caravella maxima Haeckel, '88b, p. 352, pi. 26, f. 1, 2. Caravella giganiea Haeckel, '88b, p. 352. Physalia maxima Goto, '97, p. 175, taf. 15. Physalia phjsalis Schneider, '98, p. 190; Richter, : 07, p. 571, taf. 27, fig. 14-18, taf. 28, fig. 19-26. ? Physalia megalisla P£ron and Lesdeur, '07, p. 42, pi. 29, fig. 1; Lamarck, '16, p. 481 (non Brandt, '35; Bigelow, :04). '.' Physalia gaimardii Blainville, '26, p. 132. Porpitidae. Porpema globosa (Eschscholtz). Poipitu globosa Eschscholtz, '25, p. 744; '29, p. 178, taf. 16, fig. 4; Schneider, '98, p. 195 (partim). PorpaUa globosa Haeckel, '88a, p. 30; '88b, p. 58. Porpema medusa Haeckel, '88a, p. 30; '88b, p. 61, pi. 47. * Porpita uznbella (O. F. MtJLLERi Eschscholtz. Hololhuria denudala Forskal, 1775, p. 103; 1776, taf. 264. Medusa umbella O. F. Muller, 1776, p. 295, taf, 9, fig. 2, 3. Hololhuria nuda Gmelin, 1790, p. 3143. Phyllodice denuduta Modeer, 1790, p. 201. Porpila nuda BurouifcRE, 1791, p. 139, taf. 90, fig. 3-5. Porpita glaiulifera Bruguiere, 1791, p. 139, taf. 90, fig. 6-7; Lamahck, '16, p. 485; Blainville, '34, p. 307. Porpita radiata Bory de St. Vincent, '04, p. 97, pi. 5, fig. 2A-2D. Porpita giganiea Peron and Lesueur, '07, pi. 31, fig. 6; Lamarck, '16, p. 485; Lesson, '43, p. 589. Porpila granuldtu Cranch, '18, p. 418. Porpita atlantica Les.sox, '26, pi. 7, fig. 2, '30, p. .58. Polybrachioniu itnneana Guilding, '27, p. 297. Porpita forskali Van der Hoeven, '28. Porpila monela Risso, '26, p. 305. Porpita umbella Eschscholtz, '29, p. 179; Hixi.ky, '59, p. 121; Haeckel, '88b, p. 67; Chun, '97b, p. 90. Porpita medilerranea Eschscholtz, '29, p. 177; Lesson, '43, p. .586; Kolliker, '.53, p. 57, taf. 12; Huxley, '.59, p. 1-20; Bedot, 'S.5a, p. 189; Haeckel, 'S8b, p. 67. Porpila linneatia Lesson, '43, p. .588; McCr.\dy, '.57, p. 42; L. Agassiz, '62, p. 366; A. Aga.s8iz, '65b, p. 218; '83. p. 12, pi. 7-12; Mayer, : 00, p. 72. I'orpila porpita Schneider, '98, p. 194 (partim). ? Rails medusae Lesson, '30, p. 60; '43, p. 592. ? Acies palpehraris Lesson, '30, p. 61; '43, p. 592. Porpita umbella and the following species P. porpita Linn6 are treated sep- arately in this synonymy, because it is not yet known whether the Atlantic and Indian Porpitas are identical (p. 332). Should they finally be united, umbella must be superseded by porpita. SPECIES NOT COLLECTED BY "ALBATROSS." 353 Porpita porpita (Linn6) Schneideh. Medusa porpita Linn6, 1758, p. 659. Porpita indica L.\marck, '01, p. 355; Bosc, '02, p. 155. Porpita porpita Schneider, '98, p. 194 (partim). ? Porpita reinu-ardtii DE Haan, '27, p. 493. ? Porpita forskahli de Haan, '27, p. 493. ? Porpita kiildi de Haan, '27, p. 494. ? Porpita chrysocoma Lesson, '26, pi. 7, fig. 1, 1'; '30, p. 58. ? Porpita ambella Lens and Van Riemsdijk, : 08, p. 122. Velellidae. * Velella velella (Linn6) Schneider. Medusa velella Linne, 1758, p. 660; Gmelin, 1790, p. 3155. Holothuria spirans Forskal, 1775, p. 104; 1776, taf. 26k; Gmelin, 1790, p. 3143; BRUOuifcRE, 1791, pi. 90, fig. 1, 2. Phyllodice relella Browne, 1789, p. 387, pi. 48, fig. 1. Velella mutica L.4..marck, '01, p. 355; '16, p. 282; Bosc, '02, p. 158; Lesson, '26, pi. 6, fig. 1, 2; '30, p. .52; '43, p. 571, pi. 12, fig. 1. 2; A. Ag.\ssiz, '83, p. 2, pi. 1-6. Velella tentaculaia L.\marck, '01, p. 355; Bosc, '02, p. 159, pi. 19, fig. 3, 4. Velella scaphidia P£ron and Lesueur, '07, p. 44, pi. 60. Velella pocillum Fleming, '15, p. .500. Medusa pocillum Montagu, '15. p. 201, pi. 14, fig. 4. Aglaura crista Oken, '16, p. 125. Velella limbosa Lamarck, '16, p. 482; Grant, '33, p. 14; Blainville, '34, p. 304. Velella pyramidalis Cr.^nch, '18, p. 419. Velella emarginala QnoY and Gaimaru, '24, j). .586, pl.86, fig. 9; Lesson, '43, p. 576; Thompson, '44, p. 281. Velella auslralis DeHaan, '27. Ralaria mitrata Eschscholtz, '29, p. 168, pi. 16, fig. 2. Ralaria pocillum Eschscholtz, '29, p. 168. Velella aurora Eschscholtz, '29, p. 171. Velella spirans Eschscholtz, '29, p. 172; Kolliker, .53, p. 47, taf. 1 1. fig. 9-15; Vogt, '54, p. 5, pi. 1, 2; Bedot, '84, p. 491; Haeckel, '88b, p. 83; Chun, '97b. p. 93. Velella caurina Eschscholtz, '29, p. 173, pi. 15, fig. 2; Haeckel, '88b, p. 83. Velella tropica Eschscholtz, '29, p. 174, pi. 15, fig. 3. Armcnistarium vtlclhi Costa, '41, p. 187, pi. 13, fig. 2. Chrysomiira striata Gegenbaur, '56, p. 232, taf. 7, fig. 10, 11 ; Carus, '85, p. 49. (Medusoid gonophore.) Ralaria cristata Haeckel, '88a, p. 31; '88b, p. 79, pi. 44. Velaria mutica Haeckel, '88a, p. 31. Rataria cristata Haeckel, '88a, p. 31. Arme7dsta sigmoides, Haeckel, '88b, p. 84, pi. 43 Armenista mutica Haeckel, '88b, p. 84. Velella velella Schneider, '98, p. 194 (partim). Velella suhemarginata Stephens, : 05, p. 65. ? Velella antarclica Eschscholtz, '29, p. 175. 1 Armenisla antarclica Haeckel, '88b, p. 84. 354 DOUBTFUL SPECIES. DOUBTFUL SPECIES. Forms insufficiently described which can not be identified, even provision- ally, with any known species. The earher names have appeared under various synonyms. For their history see Lesson, ('43) and Bedot, ('96). Calycophorae. Enneagonum hyalinum Quoy and Gaimard. Enneagonum hyalinum QuoY and Gaimard, '27, p. 18, pi. 20, fig. 1-6. Diphyes enneagona QuoY and Gaimard, '34, p. 100, pi. 5, fig. 1-6. Tetragonum belzoni Quoy and Gaimard. Tetragonum belzoni Quoy and Gaimard, '24, p. .579, pi. 86, fig. 11. Diphyes truncata C^uoy and Gaimard. Diphyes Iruncata QuoY and Gaimard, '34, p. 97, pi. .5, fig. 21-23. Diphyes hispida Quoy and Gaimard. Diphyes hispida Quoy and Gaimard, '34, p. 103, pi. 5, fig. 24. Diphyes tetragona Quoy and Gaimard. Diphyes tetragona Quoy and Gaimard, '34, p. 101, pi. .■), fig. 2.5, 26. Diphyes quinquedentata C^uoy and Gai.mard. Diphyes quinquedentata Quoy and Gaimard, '34, p. 102, pi. 5, fig. 27-29. Diphyes cucubalus Quoy and Gaimard. Diphyes cucubalus Quoy and Gaimard, '34, p. 94, pi. 4, fig. 24-27. Diphysa singularis Blainville. Diphysa singularis Blainville, '30, p. 107; '34, p. 117. Galeolaria quadridentata (Judy and Gaimard. Galeularia quadridentata Quoy and Gaimard, '34, p. 45, pi. 5, fig. 32, 33. Galeolaria ovata Kefperstein and Ehlers. Diphyes ovata Kefferstein and Ehlers, '61, p. 17, pi. 5, fig. 1-5. Galeolaria ovata Chun, '97b, p. 14, fig. 1; Lens and Van Riemsdijk, :08, p. 57. Desmalia imbricata Haeckel. Desinophycs imbricata Haeckel, '88a, p. 36. Desmalia imbricata Haeckel, '88b, p. 169. DOUBTFUL SPECIES. 355 Clausophyes galatea Lens and Van Riemsdijk. Clausophyes galatea Lens and Van Riemsdijk, : OS, p. 12, pL 1, fig. 6-8. Physophorae. Stephanomia laevigata Quoy and Gaimard. Stephanomia laevigata Quoy and Gaimard, '24, p. 58.5, pL 86, fig. 2. Stephanomia imbricata Quoy and Gaimard. Stephanomia imbricala Quoy and Gaimard, '34, p. 71, pL 3, fig. 13-15. Stephanomia tectum Quoy and Gaimard. Stephanomia tectum Quoy and Gaimard, '34, p. 78, pL 2, fig. 26. Stephanomia foliacea Quoy and Gaimard. Stephanomia foliacea Quoy and Gaimard, '34, p. 74, pi. 3, fig. 8-12. Stephanomia cirrhosa Quoy and Gaimard. Stephanomia cirrhosa Quoy and Gaimard, '34, p. 79, pi. 3, fig. 22-25. Stephanomia contorta Melville. Stephanomia contorta Melville, '51. Cupulita boodwich Quoy and Gaimard. Cupulila boodwich Quoy and Gaimard, '24, p. 380, pi. 87, fig. 14-16. Polytomus lamanon Quoy and Gaim.ard. Pulytomus lamanon Quoy and Gaimard, '24, pi. 87, fig. 12. Pontocardia cruciata Lesson. Pontocardia cruciata Lesson, '27, p. 17, pL lOB. Plethosoma coerulea Le.sson. Plethosoma coerulea Lesson, '30, p. 66. Rhizophysa peronii Eschscholtz. Rldzophysa peronii Eschscholtz, '29, p. 148, pi. 13, fig. 3-3c. Physsophora alba Quoy and Gaimard. Physsophora alba Quoy and Gaimard, '34, p. 53, pL 1, fig. 1-9. Physsophora intermedia Quoy and Gaimard. Physsophora intermedia Quoy and Gai.mahd, '34, p. 56, pL 1, fig. 10-18. Physsophora australis Quoy and Gaimard. Physsophora australis Quoy and Gaimard, '34, p. 57, pL 1, fig. 19-21. 356 EUDOXIDS. Agalma eschscholtzii Lesson. Agolma eschscholtzii Lesson, '43, p. 511. Agalma gettyana MtiLviLLH. Agalma geltyana Melville, '.51. Agalma papillosum Fewkes. Agaliiiii papillosum Fewkes, '82a, p. 2G6, pi. 5, fig. .5, 6, pi. 6, fig. 27. Agalma viridis Mayer. Agalma riridis M.WEit, : 00, p. 80, pi. 35, fig. 119-121. Athoria larvalis H.\eckel. Alhoria larralis Haeckel, 'S8a, p. 39; 8Sb, p. 202, \A. 21, fig. .5-8. Athoralia coronula Haeckel. Athoraha roraniila Haeckel, '88a, p. 39; SSb, p. 204. The four preceding forms are larval Agalmids which can not be connected with adult species. Rhodophysa corona Haeckel. lihodophysa curuna Haeckel, '88a, p. 42; 88b, p. 274 (non Blainville, '30; '34). Haliphyta magnifica Fewkes. Haliphgia magnifica Fewkes, '82b, p. 302. pi. 1, fig. 37-40.' Pleurophysa insignis Fewkes. Pleurophysa insignis Fewkes, '89c, p. 517.' Plutus cnidoporus Schneider. Pliilus cnidopanis HcHNSiDKR, :0(), p. 18, pi. (50, fig. 13, ])1. 3, fig. 129. I'M). p\. o, 186. EUDOXIDS NOT CONNECTED WITH THEIR PARENT SPECIES. Ceratocymba sagittata (^uoy and Gaimahd. Cymha sagitlala C^uoy and (iALMAHD, '27, p. 10, i)l, 2C, fig. 1-9; Eschscholtz, '29, p. 134; Les.son, '43, p. 454. Diphyes cymha QuoY and Gaimard, '34, p. 95, pi. 5, fig. 12-17. Nacella sagittata Blainville, '30, p. 120; '34, p. 131, pi. 4, fig. 2. Ceratocymba speclabilis Chun, '88, p. 1160. Ceratocymba sagittata Chun, '97b, p. 33 (non Bedot. :04). ' Fragment ai\v material. GEOGRAPHICAL DISTRIBUTION. 357 Enneagonoides quoyi Huxley. Enneayonoiilts qniii/i Hrxi-EV, '59, p. ti"), pi. 4, fijr. 6. Enneagonoides picteti Bedot. Enneaqnnniihs pirleli Bedcit, '(Hi, p. 377, \>l. I'i, fi^. 7. Eudoxia rigida Schneider. Endo.rUi litjidn Schneider, 'OS, p. (Ki. GEOGRAPHICAL DISTRIBUTION. I. The Tropical Pacific. The oceanographic features of the region traversed by the "Albatross" during the winter of 1904-1905 have been described in full by the leader of the Expedition (A. Agassiz, : 06). But for a clear understanding of what is to follow, I must recapitulate here such facts as are of interest to the zoogeographer. In the first place the Eastern Tropical Pacific, one of the largest oceanic areas on the globe, is interrupted by but few small islands. "Here, if anywhere we might expect to find the pelagic fauna unaffected by the disturbing elements, such as vertical circulation of water, food supply, and the like, which are asso- ciated with every coast line, no matter how abrupt it may he." (Bigelow, :09a, p. 221). In the second place the holoplanktonic coelenterate fauna of the region was previously known only from a few scattered records. And lastly, and most important, the lines run by the "Albatross" were planned to give sections of the great "Humboldt" or "Chile-Peruvian" Current and to afford a comparison between the fauna of its cold waters and that of the warmer regions to the west, southwest, and northwest of it. This Current, long known to geog- raphers, has but seldom been brought to the notice of zoologists. Its axis lies close to the coast, and its westerly margin is but poorly defined. At about 12° S. it bends to the westward; and between that point and the Gala pagos merges into the general south-equatorial drift. In breadth, and in volume it is comparable to the Japan, the Benguela, and to the Guinea currents, or to the Gulf Stream. But it is the reverse of the latter in being a mass of cold water penetrating into a much warmer mass. At the latitude of Valparaiso the surface temperatui-e in February is about 60°, from there northward the axis of the stream grows graduallj' warmer. Off Callao, in November, we observed 358 GEOGRAPHICAL DISTRIBUTION. a surface temperature of 65° (A. Agassiz, :06), and off Aguja Point, the lowest surface temperature of the Cruise was noted, 64°. North of Aguja Point the Humboldt Current is no longer traced as a definite current and the temperature rapidly rises to that of the Panamic region. Westward and southwestward from the axis of the stream the surface temperature rises steadily, though with various anomalies, until 74° is reached at Easter Island, and 80°-81° north- eastward of Manga Reva. Like most other ocean streams the Humboldt Current bears a very rich pelagic fauna and flora with it (A. Agassiz, :06, p. 15; Bigelow, :09a, p. 222). Indeed never, even in the Gulf Stream, have I seen a greater density of organic life than daily met our notice while our work lay within the Humboldt Current. This richness extends also to its westward flow, and to the general south-equa- torial drift into which it merges. On the other hand southwest of the Current there is an area as poor in all forms of life, bottom as well as pelagic, as the Current is rich. The older voyagers, especially New England whale fishermen, long ago observed the faunistic contrast here outlined (Maury, '55, pi. 9). But it remained for the "Challenger," and especially for Alexander Agassiz to bring it to the notice of zoologists, and to give it scientific standing. In plotting the distribution of the Siphonophores in the region explored by the "Albatross" I was struck by the fact that several of the species which were taken often enough to afford a fair estimate of their occurrence were taken only sporadically, if at all, in the colder axial region of the Humboldt Current, although they occurred with some regularity along our lines in the warmer regions to the west.' The members of this group are Diphyopsis dispar, Galea- laria monoica, G. australis, and Agalma akeni. These were taken respectively at Stations 32, 13, 29, and 25. On the accompanying chart (Plate 30), on which the occurrence of these four species is shown, it is seen that only one record of any species was made to the eastward of the curve of 68° surface tem- perature, and that all the captures lie considerably to the westward of the region where the temperature at twenty-five fathoms is 67° or less." Most species of Siphonophores taken during the Expedition were captured both in the cold waters of the Current, and in warmer waters. The records of five of the commoner of these, Abylopsis tetragana, Bassia bassensis, Diphyes appendiculata, Diphyes bojani, and Diphyapsis mitra, are shown on Plate 31. ' For these curves, see explanation of the chart. ^ I should point out that the small number of records on t lie passage Manga R(>va-Acapulco is due to the fact that unfavorable weather interrupted our work (Agassiz, : 06, p. X). GEOGRAPHICAL DISTRIBUTION. 359 Except for the difference between the cold waters close to the coastal slope, and the warmer regions to the west, the entire area explored was remarkably uniform so far as its qualitative Siphonophore fauna was concerned. The holoplanktonic surface Medusae showed no evidence of any faunal division (Bigelow, :09). On the contrary all the surface Medusae which occurred regularly enough for me to plot their distribution, were met with throughout the entire range of surface temperatures which we encountered. Quantitative distribution. The interesting feature from this point of view is, of course, the conditions in the Humboldt Current and the equatorial flow on the one hand, and in the desert area on the other. The Siphonophores, like the Medusae and other pelagic organisms, illustrate the difference between the two. To show the comparative richness of the one and the poverty of the other, I have reckoned up the average number of specimens taken per haul, to the northeast and to the southwest of the dividing line between rich and poor surface fauna as plotted by A. Agassiz ( : 06, pi. 3c) for several of the commoner species, with the following results. The best illustration is afforded by the polj-- gastric state of Abylopsis tetragona, because this species is so large and conspic- uous that I was able to pick out all, or nearly all, the specimens in each haul, even when the catch was a solid mass of Salpae, pteropods, etc. In the case of the smaller Diphyids, on the contrary, many specimens were apt to be overlooked in rich hauls, while in the poor ones every example of every species was easily separated.^ In the case of Abylopsis tetragona the average number per haul in the rich region of the Current was 19, per haul in the barren region, 2. In other words the proportion are roughly as 9.5 to 1. But in reality the discrep- anc}^ was much greater, because a swarm was encountered at one Station (4052) in the Current, and no swarms were met with elsewhere. Agalma okeni affords a second example. Leaving out of consideration the cold axis of the Current where it did not occur at all, we find that the proportion between specimens per haul, "Current" and "extra Current," is about 13 to 1. And in the case of this species, the discrepancy between the desert and the total remaining area traversed is much greater than it is for Abylopsis tetragona, for out of a total of upwards of eighty colonies, only one was taken in the barren region. Other common species, e. g., Diphyes appendiculata, D. bojani, Diphyopsis ' In this estimate I consider only our lines Galapagos — Callao — Easter Island — Manga Reva. The results are obtained by dividing the total number of specimens by the total number of hauls, made in the corresponding region. 360 GEOGRAPHICAL DISTRIBUTION. dispar, D. mitra, and Galenlaria australis illustrate the same point though in less degree. Although the Sij)honoi)hores show the quantitative difference between the two regions in a well-marked fashion, it is much more extreme among the Medusae. Thus Rhopalonema and Aglaura were represented at the "barren" stations by only one or two individuals, if at all, instead of by swarms, as in the Current (Bigelow, :09a, p. 223). In other words the Siphonophores are much more evenly distributed quantitatively than the holoplanktonic Medusae, though less so qualitatively. Up to the time of the Expedition, the following well-authenticated species of Siphonophores had been described from the Tropical Pacific, under various names : — Sphaeronectes truncata Agalma okeni Cuboides vitreus Stephanomia amphitridis Pray a cymbiformis Stephanomia bijuga Nectrodoma dubia Physophora hydrostatica Abyla leuckartii Athorybia rosacea Abyla trigona Anthophysa rosea Abylopsis tetragona Abylopsis eschscholtzii Rhizophysa filiformis Bassia bassensis Rhizophysa eysenhardtii Diphyes appendiculata Physalia utriculus. Diphyopsis chamissonis Porpema prunella Diphyopsis dispar Porpita pacifica Velella lata Ersae bojani and likewise the genera Hippopodius, Galeolaria, Forskalia, Apolemia, Ste- phalia, and Epibulia have been recorded, for species whieli can not now be identified with certainty. Of the twenty-five identifiable species, no less than twenty-two are repre- sented in the "Albatross" collection, and of the remaining three, one, Athorybia rosacea, is a form which has seldom been taken anywhere. Most of the species were previously known from the Pacific by a few scattered captures only. Indeed, the only ones which have been recorded often enough to allow their distribution to be plotted for the Pacific as a whole are Velella and Porpita. Both of these genera are very generally distributed over the entire tropical and subtroi)ical regions of that ocean, and most of their recoi-ds lie within the isotherms of ()8°F., for the hottest months of the year. There are a few records of Velella GEOGRAPHICAL DISTRIBUTION. 361 far to the north of this limit, from waters of much lower temperature. But this genus, owing to its" sail," is readily influenced by winds so that its occurrence c3 p. 3 fin O 362 GEOGRAPHICAL DISTRIBUTION. in Puget Sound, and off the southern coast of Alaska is probably accidental, just as are its occurrences off the Irish coast; these occurrences are not indi- cations of its normal habitat. (Fig. C.) About all we know of the north- ward extension of the Tropical Pacific Siphonophore fauna is contained in Dofiein's ( : 06) brief notes in his graphic account of the oceanography of the coastal waters of Japan. From these we learn that Physalia, Porpita, Velella, and Forskalia, with other tropical organisms, are common in Sagami Bay when its shores are washed by the warm Kuro Shiro Current. But when the wind is west or north- west this warm water, with its inhabitants, is driven off shore, and replaced by the cold northern stream in which no Siphonophores were observed. This cold water carried with it a characteristic Arctic fauna, and it would be very interest- ing to know whether any of the Siphonophores known from the Arctic and Sub- arctic Atlantic are at home in the Pacific also. It is clear, from Dofiein's observations, that Japan is a transition region for Siphonophores, as it is for Medusae. On the American coast tropical species, e. g. Sphaeronectes, have been taken as far north as the Santa Barbara channel (Lat. 34° N.). Up to the present time we know nothing whatever about the Sipho- nophore fauna of the Arctic, or Antarctic parts of the Pacific; or even whether the group is represented in those regions. Comparison between Pacific, Malaysian, and Indian Species. Within recent years two very important papers on the Siphonophores of the Malaysian region have appeared. These are Bedot's ('96) report on his collection made at Amboina, and the extensive memoir by Lens and Van Riemsdijk (: 08) based on the "Siboga" collection. These two combined give the following list, leaving out a few doubtful forms, e. g. the genus Clausophyes Lens and Riemsdijk. Sphaeronectes truncata Bassia bassensis Cuboides vitreus Diphyabyla hubrechti Praya cymbiforniis Galeolaria quadrivalvis Rosacea plicata Galeolaria australis Rosacea medusa Galeolaria monoica Hippopodius hippopus Diphyes appendiculata Abyla irigona Diphyes contorta Abyla haeckeli Diphyes bojani Abyla leuckariii Diphyes subtiloides Abylopsis tetragona Diphyopsis dispar Abylopsis eschscholtzii Diphyopsis mitra GEOGRAPHICAL DISTRIBUTION. 363 Diphyopsis chamissonis Ch uniphyes mult ide nta ta Forskalia contorta Forskalia edwardsi Erenna bedoti Agalma okeni Agalma elegans Stephanomia rubra Stephanomia cupulifera Stephanomia amphitridis Stephanomia bijuga Physophora hydrostatica A nthophysa rosea Archangelopsis typica Rhizophysa filiformis Rhizophysa eysenhardtii Pterophysa grandis Pterophysa studeri Bathyphysa sibogae Physalia utriculus Velella lata Porpita umbella (?) The species in italics are contained in the "Albatross" collection. Of the total of forty-four the "Albatross" collection contains thirty-two and of the remaining twelve, four are described as new from the "Siboga" collection, and two genera which were well preserved in the "Siboga" collection are likewise represented by fragments in the "Albatross" collection. On the other hand, all but fifteen of the fifty-one species collected in the Eastern Pacific are known from the Malaysian region as well. Considering how few collections have been made either in the Pacific or in the Malaysian area, the agreement between the two is so close that it is impossible to draw any faunal line between them, so far as their Siphonophores are concerned. Our knowledge of the Siphonophore fauna of the Indian Ocean is due chiefly to Huxley, to Haeckel, and to a few scattered records by other authors. So far as I can learn, the list of well-authenticated species is restricted to the following : — Sphaeronectes truncata Sphaeronectes princeps Muggiaea huxleyi Cuboides vitreus ? Desmalia imbricata ? Desmophyes annectans Abyla trigona Galeolaria australis Diphyes appendiculata Diphyopsis dispar Diphyopsis mitra Diphyopsis chamissonis Apolemia uvaria Leaving out of consideration the may be nothing but Physophora Agalma okeni Agalma haeckeli Stephanomia amphitridis Lynchagalma utricularia ? Discolabe quadrigata ? Rhodophysa corona ? Athorybia rosacea Rhizophysa eysenhardtii Epibulia I'itteriana Velella lata Porpita porpita Physalia utriculus doubtful Discolabe quadrigata Haeckel, which hydrostatica, and the problematical Desmalia 364 GEOGRAPHICAL DISTRIBUTIOxX. imhricata Haeckel, Desmophyes annectens Haeckel, and Rhodophysa corona Haeckel, the only Indian species which are certainly not known from the Pacific are Sphaeronectes princeps, Muggiaea huiieyi, and Lychnagalma uvaria. Until we know more about the Pacific Apolemia and Epibulia it is impossible to say definitely whether they are identical with the members of these genera from the Indian Ocean. But there is nothing in the published descriptions of them by Brandt ('35) to suggest that this is not the case. The agreement between the two oceans is the more striking when we recall how few records of Indian Sipho- nophores have yet been published. These facts of distribution show that so far as the Siphonophores are con- cerned the Indian and Pacific oceans can not be separated. On the contrarj', the entire tropical belt from the west coast of America on the one hand, to the western side of the Indian Ocean, on the other, is a single uninterrupted faunal zone. We have, as yet, no evidence of a distinctive Panamic fauna among Siphonophores, indeed, it was not to be expected in a purely holoplanktonic group. In their distribution the Siphonophores agree with the holoplanktonic surface Medusae, and they differ correspondingly from the typical leptoline forms, with long fixed, and short medusa stage, which, for distribution, are in the same category as littoral organisms in general. For the latter, the Tropical Pacific is "Separable into two more or less clearly defined areas; its western half being closely connected to, if indeed at all separable from, the Malaysian region . . . .and its eastern shores on the other hand having a close aflfinity to the Gulf of Mexico and to the tropical Atlantic " (Bigelow, : 09a, p. 228) . And I may forestall my forthcoming account of the Philippine Medusae collected by the "Albatross" so far as to state that the data afforded by it is entirely in accord with these generalizations. Comparison behueen the Species of the Indo-Pacific and the Atlantic regions. The intensive studies which have been made in the Mediterranean, among the West Indies, and at the Canaries; the explorations of the "Plankton" expedition, the investigations of the "Research" in the Bay of Biscay and the numerous records from the coasts of North America and Europe, as well as from scattered localities throughout the Atlantic, have given us a knowledge of its Siphonophore fauna as nearly complete as that of any other purely pelagic group of animals, though no doubt many gaps remain to be filled. Up to very recently our knowledge of the Indo-Pacific members of the group was insufficient for a comparative study of value between the representatives from the two GEOGRAPHICAL DISTRIBUTION. 365 oceans. But the collections made by the "Siboga" and by the "Albatross" are so extensive that such a comparison is now possible and timely. The most important question to answer is whether these purely pelagic organisms support the thesis of the uniformity of the oceanic plankton in tropical and subtropical regions throughout the globe. The table of species (p. 383) shows that out of fifty Calycophorae, twenty-three occur both in the Atlantic and in the Indo-Pacific; twelve are as yet recorded only from the Atlantic, fifteen from the Indo-Pacific. And I may point out that in most cases my identification of Pacific with Atlantic Calycophores rests not only on published descriptions of the latter, but on studies of series from both oceans. At the first glance these numbers suggest a remarkably close resemblance in the Sipho- nophore faunae. And the unity becomes even more complete when we analyze the status of the exclusively Atlantic and Indo-Pacific species. One of the Atlantic forms, Galeolaria ovata Kefferstein and Ehlers, is problematical, and therefore can not be used one way or the other. One, Diphyopsis hispaniana Mayer (p. 344) is of doubtful validity. The Diphyes steenstrupi-serrata group is represented in the Pacific by an ally so close that it is very doubtful whether it is distinct. .\nd the same is true of Galeolaria biloba. Two species, Necto- pyramis ihetis Bigelow and Stephanophyes superba Chun,, are known from only one or two records each, and may, not improbably, come to light in the Pacific later. One, Diphyes arctica Chun, is an Aj'ctic and Subarctic species and therefore would not be expected in the warmer zones of the Indo-Pacific, which are the only parts of that oceanic region from which any Siphonophores are known. This leaves only seven warm water Atlantic species which are certainly not yet known from the Indian Ocean, or from the Pacific. These are, Sphaer- onectes irregularis, Doromasia picta, Ncctopyramis ihetis, Stephanophyes superba, Diphyes subtilis, Vogtia pentacantha, and probably Galeolaria truncata. But con- sidering how few studies of the Siphonophores of the Indo-Pacific have been made it is not at all improbable that some of these will be found there. Two of the peculiarly Indo-Pacific species, Desmalia imbricata Haeckel and Desmophyes annectens Haeckel, are problematical. It has been suggested that they belong to Pray a cymbiformis and to Rosacea plicata, but they are recognized here provisionally. Two species, Sphaeronectes princeps Haeckel and Muggiaea huxleyi Haeckel, are known from only one record each; their validity has been questioned. Galeolaria australis and Diphyes bojani are represented in the Atlantic by allies so close that it is doubtful whether they are distinct. This leaves only Nedopyramis diomedeae Bigelow, Nectrodroma dubia Quoy and Gaim- 366 GEOGRAPHICAL DISTRIBUTION. ard, Nedrodroma reticulata Bigelow, Abyla haeckeli Lens and Van Riemsdijk, Diphtjabyla hubrechti Lens and Van Riemsdijk, Diphyes contorta Lens and Van Riemsdijk, Diphyes spiralis Bigelow, and Diphyopsis chamissonis Huxley. Some of these may be found in the Atlantic in the future, a suggestion rendered prob- able by my own discovery of Abyla leuckartii (p. 321) and of Diphyopsis mitra (p. 261) in the West Indies. The list includes twenty-seven Physophorae, twelve recorded from both oceans, besides the genus Forskalia (p. 270), seven so far recorded only from the Atlantic, eight from the Indo-Pacific. Of the Atlantic species four, Ayahna clausi, Erenna richardi, Anthophysa formosa, and Angelopsis globosa are repre- sented by extremely close allies in the Indo-Pacific. These are Agalma haeckeli, Erenna bedoti, Anthophysa rosea, and Angelopsis dilata. One Atlantic species, Stephanomia car a, is doubtful; at this moment it is impossible to determine whether or not it is distinct from S. bijuga (p. 283). If so, it is a boreal form. And it is likewise impossible to state from Brandt's ('35) brief description, whether the Pacific Apolemia is the same as, or different from the Atlantic representative of the genus (p. 348). The Indian Apolemia, however, {"Dicymba diphyopsis" Haeckel, '88b) is apparently indistinguishable from the Atlantic A. uvaria. This leaves only Anthemodes ordinata, Stephalia corona, Rhodalia miranda as Physo- nectae peculiar to the Atlantic ; and it is possible that the latter belongs to the Paci- fic also (Brooks and Conklin, '91). The following exclusively Pacific species are well grounded : — Stephanomia amphitridis Peron and Lesueur, Dromalia alexandri Bigelow, and Archangelopsis typica Lens and Van Riemsdijk. But the last two, like Rhodalia, belong to a group so little known that no inferences as to distri- bution can yet be drawn from their few records. Another Stephanomia, S. cupulifera Lens and Van Riemsdijk was described as new from the "Siboga" collection; but its distinctive character was so trivial (p. 284) that its standing is doubtful. Discolabe quadrigata and Rhodophysa corona likewise require further stud3^ There are eleven recognizable Rhizophysaliae, of which four are known from both oceans, three from the Atlantic only, and four from the Indo-Pacific. Each region has its own peculiar species of Physalia, and to the Indo-Pacific belongs the interesting genus Epibulia, while Salacia is so far known only from the Atlantic. The other Rhizophysalids peculiar to one or the other region only belong to the Bathyphysinae, a subfamily whose members have been taken so seldom that their records can not be used yet as a basis for geographic discussion. Among Chondrophorae the genus Porpema is common to both oceans: but GEOGRAPHICAL DISTRIBUTION. 367 whether its representatives in the two are specifically distinct or identical can be determined only by a fresh study of Atlantic specimens. Porpita and Velella, like Physalia, are represented in the Atlantic and in the Pacific by distinct, though closely allied species. But the exact relationships of the representatives of these genera from the Indian Ocean are not known. In the case of Velella it is probable that we can speak of an Indo-Pacific species, just as we can of Physalia. But there is some, though not conclusive, evidence, that the Indian form of Porpita is more closely allied to the Atlantic than to the Pacific species. Summarizing these results, and omitting the problematical species, and those whose validity is doubtful, we find no less than forty-one valid species of Siphonophores, out of a total of about 95, i. e. almost half, are already known to occur both in the Atlantic and in some part of the Tropical Indo-Pacific areas; six which are known only from one are represented in the other by allies so close that it is doubtful whether they are distinct; twelve are so far known only from the Atlantic, and sixteen from the Indo-Pacific. And judging from the rich harvest brought to light by the recent deep-sea expeditions, there is every reason to expect that this number common to the two great oceanic divisions will be augmented by the report on the "Valdivia" Siphonophores, now in preparation by Dr. Chun. There is no great discrepancy between Calycophores and Physophores, so far as the proportion of species common to both oceans is concerned. But while several of the former, as for example Abylopsis teiragona, Diphyes appen- diculata, and Diphyopsis dispar are constantly met with in the warmer portions of all oceans, this is the case with comparatively few Physophores, though many species of them are known from' various localities in both the Atlantic and the Pacific. The only Physophore encountered by the "Albatross" with anything like the regularity of the commoner Calycophores was Agalma okeni, and only two others, Physophora hydrostalica and Anthophysa rosea, were taken at more than five stations each. The "Plankton" expedition took only four Phy- sophores:— Nedalia loligo at two stations, Physophora hydrostalica, Anthophysa formosa, and Athorybia rosea at one station each (Chun, '97b). In the Bay of Biscay the "Research" found no Physophores at all, except one fragmentary Athorybia. The Anthophysidae and Rhodaliidae as a whole seem to be rare everywhere. But Forskaliidae and the long-stemmed Agalmids are common in the Mediterranean, at the Canaries, among the West Indies. Agalma elegans and Stephanomia cara occur regularly at various localities along the Atlantic coasts of North America and of Europe, and Stephanomia bijuga swarms at times 368 GEOGRAPHICAL DISTRIBUTION. among the Ellice group (Agassiz and Mayer, :02, p. 168). Chun ('97b) has suggested that the scarcity of Physophores in the Tropical Atlantic in summer observed by the "National," was a seasonal phenomenon, to be explained on the assumption that at that time the species in question were passing through their larval existence at considerable depths. Evidence in favor of this view is afforded by the facts that the Siphonophore fauna collected by the "National" agreed very closely with that observed by Chun ('88) himself at the Canaries from Sep- tember to the last of December. It was only in winter that Forskalia, Agahna etc. appeared on the surface. Furthermore, it has long been well known that the Physophoras and Agalmids of the Mediterranean are seen regularly on the surface only during the autumn and winter, and Chun ('87) has found that during the suminer the larvae of Physophora are living there at considerable depths. On the other hand the "Research" obtained no Physophore larvae even in the deepest hauls, and the latter were made so frequently that these organisms could hardly have escaped had they been as abundant as any of the commoner Calycophores. Furthermore, I have been unable to disco\er that any Forskalia, or Agalmid except Agalma okeni, occurs regularly anywhere on the high seas far from land, either in the Atlantic or the Pacific, at any season. The evidence afTorded by their occurrence suggests that these animals find their most favorable environment in enclosed and sheltered basins, or near shore and among islands, not in open sea. The explanation is, I believe, twofold. In the first place, as Chun has shown, most of the long-stemmed forms are undoubtedly seasonal in their appearance. During the rather extended period during which they pass through their lar\al existence they may live at considerable depths, and in any case they are then small, and easily overlooked. The second explanation, and as it seems to me the more important one, rests on the anatomic structure of the species in question. The only typically oceanic Agalmid, A. okeni, is of unusually short, stiff, non- contractile "habitus," and its nectophores, bracts, siphons, etc., are very firmly attached to the stem. Specimens of this species, like Physophoras and Antho- physas, may even be removed from the water without injury. Such organisms are well fitted to withstand buffetings by waves and currents. On the other hand, Forskalias, and the long-stemmed Agalmids in general, are proverbially delicate. They fall to pieces at the slightest touch, or even when the vessel in which they are contained is jarred. (For a graphic account of such dissolution, see Lens and Van Riemsdijk, : 08, p. 64.) Evidently during heavy weather such animals are likely to be seriously damaged unless they can sink below the shallow GEOGRAPHICAL DISTRIBUTION. 369 zone where wave action is violent. Agalmids and For.skalias are such feeble and erratic swimmers that it can hardly be supposed that they can transport themselves to a more placid environment as the result of tactile stimulus. A Forskalia caught on the surface by a breaking sea, is likely to suffer the same fate that befalls a large and unwieldy Aurelia or Cyanea when o\'ertaken by the same circumstances at the end of the season, i. e. to be broken to pieces. Thus physical conditions in the high seas prevent their attaining the faunal promi- nence in oceanic regions which they possess in the Gulf of Naples or among the Canary Islands. Oceanic temperatures and their relation to distribution. We know one Siphonophore, and one only, Diphyes arctica Chun, of which we can say without hesitation that it is restricted to Arctic and Subarctic regions. Three other species may finally be grouped with it, Galeolaria truncata Sars, G. biloba Sars, and Stephanomia cara A. Agassiz. It is true that the first of these has been identified by Lens and Van Riemsdijk (:08) with a species from the Canaries, G. inflata Chun (p. 235) ; but the latter is so insufficiently described that the relationship is doubtful. Galeolaria biloba is indistinguishable, so far as Sars's ('46) rather brief description goes, from the Indian Pacific G. australis; and there is a possibility that it is likewise identical with the Mediterranean "Diphyes turgida" of Gegenbaur. But to settle this question will require a fresh study of the Norwegian and Mediterranean forms. Stephanomia cara is certainly closely allied to S. bijuga; but if it be identical with it, it would afford an anomalous case of distribution (p. 284). Arctic specimens of »S. cara, as of G. biloba, must be reexamined with their specific relationships in view, before the question of its standing can be settled. Diphyes arctica is of more than ordinary interest in its geographic relations because of its temperature range. It is common at Spitzbergen (Romer); in the Arctic Ocean north of Russia (International committee lists), in the Greenland Sea both at the surface and at considerable depths (Damas and Koefoed) ; and along the coast of Norway to the Skagerak, where it is known from intermediate hauls only, the shallowest being 200 meters. On the Nor- wegian coast it occurs only accidentally, if at all, on the surface, but is a common constituent of the mesoplankton. Its records from the "Plankton" expedition are from 59° 20' N., 11° 8' W., and 60° 30' N., 27° 0' W., between 400 meters and the surface. Damas and Koefoed (:07) recenth' discussed the distribution of this species at some length. I agree with their conclusion that its occurrence 370 GEOGRAPHICAL DISTRIBUTION. is independent of the origin of the waters, Atlantic or Arctic, in which it is found. But to say as they do that it is independent of temperature is true only if we mean that its horizontal occurrence irrespective of vertical distribution is independent of slight differences in surface temperature. As a matter of fact there is good evidence that D. ardica is limited in dispersal chiefly by temperature. It is a form adapted to cold waters; and in truly Arctic regions, such as the Green- land Sea, is found indifferently on the surface, and in the intermediate depths. Further to the south, where the surface temperature is higher, as for example along the coast of Norway and in the Skagerak, it is exclusively confined to the mesoplankton. At the present moment it is not possible to state precisely what its temperature limits are. But it is known from only a few degrees above the freezing point of salt water, and it has never been found regularly in water warmer than 42° (Skagerak, 200 m., August). A few species of Siphonophores are known to occur throughout a wide range of temperature. The best known member of this group, Diphyes appen- diculata, is common on the surface throughout the Tropical Pacific (p. 248, Agassiz and Mayer, : 02, p. 160) in temperatures of 78°, 80° or over. In the Atlan- tic it is common in the high surface temperatures of the tropics, e. g. among the West Indies, and is of very general occurrence. In this ocean it is known from much lower temperature than any as yet recorded for it from the Pacific. In the Mediterranean, Chun ('87) has recorded it from temperatures as low as about 56°, and in the Bay of Biscay it was abundant at 53°-52° (surface to 100 fathoms), and was apparently not only alive but reproducing itself at a temperature of about 50°. D. appendiculata has never, so far as I can learn, been taken in any numbers in water colder than this, though once recorded from below 45° (Chun '97b, p. 110, 60° 2' N., 22° 7' W.; closing-net, 800-1,000 meters). And since we now have so many records of the constituents of the surface Plankton of the boreal Atlantic, it is probably safe to say that its normal temperature range does not extend much, if any, below 50°. Physophora hydrostatica, among Physophorae, occurs throughout a range of temperatures almost as great as those occupied by D. appendiculata. But unlike the latter, Physophora has been but seldom recorded from temperatures above 70°. The only recent records of this species from tropical regions which I have been able to find are the Canaries, 1° 1' N., 16°40' W. ("Plankton" expedition), and Malaysian region (Lens and Van Riemsdijk), But the Canary records are all from the winter months (Chun, '88, Haeckel, '69a), when the surface temperature is from 65° -68°; the "Plankton" record is from an intermediate GEOGRAPHICAL DISTRIBUTION. 371 liaul (-lOO-U m.), and at that Station the temperature at 200 m. was only 56° 6. The two "Siboga" records were from even deeper hauls (1,000-0 m., and 1,500- 0 m. respectively). None of these records, then, suggest that the species is common in very high temperatures. And the same is true of the series col- lected by the "Albatross," for the species was not found at all on the surface, but always in intermediate hauls, though the surface temperatures at the six stations of capture were all below 75°. Physophora is common on the surface in the Mediterranean during the winter, when the temperature falls to about 57°; but during the hot months it disappears from the surface (p. 380). In the Atlantic this species extends far northward. It is known from the coast of Scotland; is not uncommon on the Norwegian coast as far north as 71°. A list of its boreal occurrences has been given by Romer ( : 02) ; and since the appearance of his paper, the genus has been recorded from the south and west coasts of Iceland by Paulsen (: 09). But since it is not known from Spitzbergen, and since the Duke of Orleans did not encounter it in the Greenland Sea, it probably does not occur in temperatures lower than 45°. In short, the various records of the species shows that it is at home neither in the Arctic, nor in the hottest tropical temperatures. Agalma elegans is also found through a wide range of temperatures, i. e. tropics to Norway (p. 283). Nectalia loligo, likewise, has been taken at the Canaries, at a temperature of about 68° (Haeckel, January) ; south of Iceland (60° 2' N., 22° 7' W. ; Chun, '97b) at a temperature of 46° and in a closing-net haul at 600-800 m. in the south equatorial current (3° 6' S., 33° 2' W.), a level at which the temperature was below 50°. The only other Siphonophores which have been credited with a distribution reaching from the tropics to the Subarctic zone are Galeolaria biloba and Muggiaea atlantica. But as already pointed out the identity of the former with G. australis of the Tropical Indo-Pacific is open to question (p. 234), and Broch (:08) has recently shown that the records of M. atlantica from the Skagerak by .lohansen and Levinsen ( : 03) probably belong to Diphyes arctica. At present it is doubtful whether any Siphonophore is truly eurythermal, but if Stephanomia cura and »S'. bijuga finally prove to be identical, they would afford a typical example of this class of distribution. All the other Siphonophores which are yet known from the surface belong to warm-temperate or to tropical regions, the two supposed Antarctic records (Rennie, : 05 and Bedot, : 08) being respectively the tentacle of a Scyphome- dusa, and an Anthomedusa (Browne, :10). 372 GEOGRAPHICAL DISTRIBUTION. Eastern and Western Sides of the Tropical and Subtropical Atlantic. Thirty-two species of Siphonophores, excluding some doubtful records, are known from the warm waters off the eastern coast of the United States, i. e. from the West Indies or from the Gulf Stream, and twenty-five of these are likewise known either from the neighborhood of the Canaries, from the Mediter- ranean, or from the Bay of Biscay. None of the remaining seven, Diphyopsis hispaniana, D. mitra, Abyla leuckartii, Anthophysa formosa, Salacia uvaria, Angelopsis globosa, or Pterophysa grandis, are peculiar to the West Indies except the first, and this is a doubtful species (p. 244). Anthophysa formosa and Salacia uvaria are known from other parts of the tropical Atlantic, Diphyopsis mitra and Abyla leuckartii from the Pacific and Indian oceans; Pterophysa grandis from Malayan waters, while Angelopsis globosa is represeiated in the Pacific by an extremely close ally. On the other hand out of forty-seven Mediterranean and east-Atlantic spe- cies, over half are already known from the western Atlantic, and of those not yet recorded from there, all, except Sphaeronectes irregularis, Diphyes subtilis, Agalma clausi, Anthemodes ordinata, and Pterophysa grimaldii, have been found in the Indian Ocean, in the Pacific, or in both. The first two may have easily escaped notice in West Indian waters, indeed D. subtilis was long overlooked even in the Mediterranean; Agalma clausi is represented in the Indian Ocean by a close ally; Anthemodes ordinata is apparently very rare; and Pterophysa grimaldii belongs to a mesoplanktonic genus. Furthermore Chun ('97b) has pointed out that during the "Plankton" expedition several of the commoner Calycophorae were taken regularly throughout the warmer regions visited. Thus it is evident that there is no division in the Siphonophore fauna as we pass from one side of the Atlantic to the other, any more than there is in the Indo-Pacific region, though these are, of course, local anomalies. One of the most striking of these is afforded by Muggiaea atlantica. This species is so far known with certainty only from British waters, and from the Eastern Tropical Pacific, though it is probably recorded from the Canaries (p. 186). Judging from the temperature range through which it occurs, 83°- 52°, there would be every reason to expect to find it as widely and regularly distributed as Diphyes appendiculata; but apparently such is not the case. It is unlikely that its absence from the collections made by Dr. Fowler in the Bay of Biscay in July, 1900, is due to its being overlooked, because the methods employed on the Cruise were unusually painstaking and thorough. At any rate GEOGRAPHICAL DISTRIBUTION. 373 we can say without hesitation that it certainly was not a characteristic member of the plankton, yet at the same season it is approaching the zenith of its abun- dance in the English Channel. And it as certainly was not present in the large masses of West Indian plankton which I collected during Mr. Agassiz's Cruise in the winter of 1907. It is likewise surprising that it has not been found in the Mediterranean, though it may have been confused there with young Di-phyes appendiculata. Another instance is the fact that Stephanomia rubra, so common in the Mediterranean, has never been recorded from either side of the Tropical Atlantic, although Bedot ('96) found it in the East Indies, at Amboina. The occurrence of Diphyopsis mitra among the Canaries is extremely probable, yet neither Haeckel nor Chun detected it there. On the other hand Muggiaea kochii has not been found in the West Indian waters though it probably occurs there. Even if no line can be drawn between the warm-water Siphoriophores of the two sides of the Atlantic, they are not an altogether homogeneous group geographically, for, as Chun ('97b) has pointed out, there is a considerable list of species which are common in the Tropical Atlantic, but which do not occur in the Mediterranean, though most of the Mediterranean Siphonophores are known from the Atlantic. The species of Physophorae which were then known from the Mediterranean only were Stephanomia rubra, Agalma clausi, and Lynchn- agahna utricularia. But the first has since been found at Amboina; the second may be, and the third almost certainly is identical with a form from the Indian Ocean (p. 348, 349). In addition to these there are three Diphyids, Galeolaria turgida, G. conoidea, smdG.ovata. But the first two are probably synonj'ms of other species (p. 234, 235) and the third is a problematical form. And only one species, Plutus cnidoporus Schneider, has been added to the list within recent years. We may safely say, therefore, that it is doubtful whether any Sipho- nophores are confined to the Mediterranean. On the other hand the following inhabitants of the Eastern Tropical Atlantic which Chun mentioned as absent from the Mediterranean : — Diphyopsis dispar, the Diphyes serrata group, Abylopsis eschscholtzi, Abyla trigona, Bassia bassensis, Cuboides vitreus, Ceratocymba, Agalma okeni, Nectalia loligo, and Rhizophysa eysenhardtii, have not been recorded from that sea even yet. To make the list complete, we must add Amphicaryon acaule, Stephanophyes superba, and Anthe- modes ordinata: and if the survey be extended to the western side of the Tropical Atlantic, as it ought, for as we have seen the Siphonophores of the West Indies correspond verj' closely to those of the Canaries, we may include Abyla leuckurtii, 374 GEOGR.\PHICAL DISTRIBUTION. Diphyes fowleri, Diphyopsis mitra, and the genera Anthophysa, Angelopsis, Salacia, and Porpema. (The Bathyphysinae may be left out of consideration because of their mesoplanktonic habitat and because so httle is known about them). These are all such large and conspicuous animals that it is not likely that they would be overlooked in the intensive collecting carried on at Naples, and in the Adriatic. It is likewise significant that none of the common and well-known Tropical Atlantic species : — e. g., Abylopsis eschscholtzii, Diphyes serrata, Diphyopsis dispar, Cuboides vitreus, or even the oceanic Agalma okeni, was taken by the "Research" in the Bay of Biscay. These facts show that the faunal division drawn by Chun was an actual one, and not based on incomplete observations. And when they are taken in connection with the Indo-Pacific records, and the considerable amount of data from the east coast of the United States, from the Bay of Biscay, from the northern European coasts, and from various scattered localities in the north Atlantic, they show that the Siphonophores of warmer waters are separable geographically into two chief groups. The members of the first are found in tropical regions of all great oceans, either on the surface or at intermediate depths, or both, and are characteristic of the epiplankton of the Mediterranean. In this sea, some of them are strictly seasonal, appearing only in the cooler months of autumn, winter or early spring, for example Stephanomia rubra, Physophora, and Praya, while Forskalia and Muggiaea are common throughout the year. Several of them, likewise, are regularly found on the American coast as far north as the influence of the Gulf Stream is felt (e. g. Agahna elegans, Narragansett Bay), and others, as for example Diphyes subiilis, Hippopodius hippopus, and Rosacea plicata, in the cooler waters of the Bay of Biscay (Bigelow, :11b). As examples of this group I may mention Sphaeronectes truncata, Abylopsis tetragona, Geleolaria quadrivalvis, Praya cymbiformis, Hippopodius hippopus, Agalma elegans, Stephanomia bijuga, Stephanomia rubra, the genus Forskalia, Rhizophysa filiformis, Porpita and Velella velella. The species of the second group are exclusively tropical in their normal habitat : — they have been unable to establish themselves in the Mediterranean. There are also a few species which are so far known only from the Atlantic, from the Indian Ocean, or from the Pacific, but it is not unlikely that their range may be found to extend to the other oceans. And of course some have been recorded so seldom that their position in the distributional series is doubtful. The factor which limits the areas of distribution of the two groups is no doubt GEOGRAPHICAL DISTRIBUTION. 375 temperature. Chun ('97b) has already suggested this explanation, and pointed out that the currents in the Straits of Gibraltar would offer no barrier to the entrance of surface organisms, but just the reverse. The surface water at the Canaries where the typical tropical species are common in winter, never falls below about 65.5°, whereas in the western half of the Mediterranean, the surface temperature falls in winter to about 56°. This is far colder than any waters in which the tropical Siphonophores are regular characteristics of the surface plankton. And it is significant that Diphyopsis dispar and Agahna okeni were absent from waters below 68° in the Eastern Pacific. We can say in gen- eral that none of the tropical species are constant members of the plankton in any regions where the surface waters fall below about 65° at any season, though they may occur sporadically, or even more or less regularly far to the north within the sweep of the Gulf Stream, or any other warm current. Several tropical species, e. g. D. dispar, Bassia bassensis, and Ceratocymba, have been observed in the Straits of Gibraltar, as we might expect from the fact that the surface flow is into the Mediterranean. And it is probable, though not certain, that the Physalias which occasionally appear in the Bay of Naples are casual visitors from the Atlantic. The failure of these forms to establish theni- selves in the Mediterranean was correctly explained by Chun ('97b, p. 109) as due to the differences in temperature, which "der Reife der Geschlechtsprodukte von atlantischen und in das Mittelmeer eingeschwimmten Arten hinderlich in Wege stehen" is probably a correct explanation. Whether adult, or as larvae, they can not survive the winter of the western Mediterranean. At present we have no evidence that any of the mesoplanktonic Sipho- nophores, i. e. Chuniphyes or the Bathyphysinae, have penetrated into the Mediterranean. And if further research proves that such is the case, the absence could be explained by the currents in the Straits of Gibraltar. It has long been known that the lower strata flow out of the Mediterranean into the Atlantic, and the recent work of the "Michael Sars" (Hjort, :11) has shown that there is no inflow below about 75 fathoms at any stage of the tide; and that the maximal outflow at 100-175 fathoms may reach a velocity of two meters per second. These conditions would be quite sufficient to exclude deep-water Siphonophores from the Mediterranean had they occupied the intermediate waters since that sea acquired its modern oceanographic features and were they absolutely limited to the intermediate depths throughout their existence. But it is quite possible that they have been overlooked in the Mediterranean, for they are, apparently, luicommon everywhere. 376 GEOGRAPHICAL DISTRIBUTION. The foregoing data shows that the following thermal classes of surface Siphonophores can be distinguished : — 1. Arctic, with a maximum of about 45°. 2. Warm-water species, with a minimum of about 50°. 3. Tropical species, with a minimum of about 65°. 4. Species with a very wide temperature range, but not truly eurythermal because they do not exist under Arctic conditions; while one of them, at least, is seldom found in temperatures above 70°. 5. There are a few species which have been taken so seldom that it is impossible to make any statement about them as yet. Seasonal Fluctualions in Horizontal Distribution. A resume of our rather scant}- knowledge in this field follows naturally after the discussion of temperature. It has long been known that in sunmier certain warm-water Siphonophores often occur far to the north of their winter range in regions within the influence of the Gulf Stream. Examples are afforded by the almost yearly occurrence of Agalma elegans in Narragansett Bay, and the occasional capture of Diphyopsis dispar off the south coast of Newfoundland (Bigelow, : 09b) ; of Physalia in the Bay of Fundy, and of Velella at the Hebrides. Similarity, but more regularly, the Norwegian sea is invaded from the south via the Faroe-Shetland Channel in the middle of the summer by Physophora and Agal- midae ("Cupulita sarsi" Damas, :09, p. 107) which thereafter form a striking constituent of the plankton of the Norwegian Sea. The movements of Muggiaea atlantica in the English Channel and the Irish Sea are known in some detail, thanks to Gough (: 05). This species appears off Ushant at the end of April or beginning of May, and extends thence northward and eastward with the advance of the season. By September it has reached the Irish Sea, and has spread around the southwest shores of Ireland; but it never penetrates eastward in the English Channel beyond the Isle of Wight. By January it has once more disappeared from the region under consideration. Its northerly spread follows, but lags behind, the rising temperature of the surface waters. Thus it was noticed earliest in a temperature of between 50° and 52°. But whereas Muggiaea is not certainly known from north of Ireland, the isotherm of 52° includes the whole western coast of Great Britain, and the south- ern part of the Norwegian Sea by September; and by Januarj^ it has once again receded until it meets the swarm of Muggiaea. This discrepancy suggests that the fluctuation in range of this species is caused less by dispersal through currents GEOGRAPHICAL DISTRIBUTION. 377 than by rapid reproduction in regions of favorable temperature. The failure of Muggiaea to penetrate bej'ond the Isle of Wight in the English Channel can not be due to temperature, because by June the surface throughout the channel is 57° or over. Nor is there any evidence that it is due to the complex currents in this region and in the North Sea. As pointed out below, (p. 381) sahnity may be the active factor here. Bathymetric Range. The "Albatross" did not obtain any Siphonophores in closing-nets, although a good many Medusae were taken in such hauls (Bigelow, :09a). The only previous records of the present group from closing-nets, so far as I can learn, are the following : — 1. Cuboides vitreus, Guinea current, 1,000-1,200 M: " Plankton "; Chun ('97b). 2. Diphyes appendiculata, Mediterranean, surface down to about 750 fathoms (1,300 M); most abundant at 80-100 M (Chun, '87); 60° 2' N., 22° 7' W., 800-1,000 M; "Plankton"; (Chun, '97b, p. 110); Sargasso Sea, 31° 5' N., 5° 1' W., 900-1,100 M; "Plankton"; (Chun, '97b, p. 110); 14° 19' N., 27° 13' W. 300-350 M, and 1,000 M; "Monaco"; (Bedot, : 04, p. 26, 27); Bay of Biscay, four stations 200-100 fathoms, one station 500-400 fathoms, "Research" (Bigelow, : lib, p. 345). 3. Diphyes ardica, various depths from the surface down to 800 M; "Nansen" closing-net. (Damas and Koefoed, :07.) I may point out that these deep-sea records are unreliable, because Paulsen (:09) has proved that this type of closing-net often fishes while being lowered. 4. Chuniphyes multidentata, Bay of Biscay, three Stations 1,250-1,000 fathoms two Stations 1,500-750 fathoms, one Station 2,000-1,000 fathoms (Bigelow, :11b, p. 348). 5. Rosacea plicata, Bay of Biscay, two Stations 200-300 fathoms (Bigelow, lib, p. 342). 6. Hippopodius hippopus, larvae, Bay of Biscay, one Station 150-50 fathoms (Bigelow, :11b, p. 350). 7. Vogtia spinosa, Baj^ of Biscay, one Station 250-150 fathoms (Bigelow, :10b, p. 351). 8. Apolemia uvaria, Bay of Naples, one Station, 600 M (Chun, '87, p. 13). 9. Nedalia loligo, 3° 6' S., 33° 2' W., 800-600 M; "Plankton"; (Chun, '97b). And unidentifiable Bathyphysinae from 2,300 M (Chierchia, '85). All the other data on the vertical occurrence of Siphonophores consists of 378 GEOGRAPHICAL DISTRIBUTION. "intermediate" hauls with open nets of one sort or another, and of specimens entangled on sounding or dredging wire. The only species which have never been taken in surface hauls are Chuni- phyes multidentata, Nedopyramis diomedeae, Nedodroma reticulata, Erenna richardi, Erenna bedoti, Dromalia alexandri, Angelopsis globosa, Angelopsis dilata, Archangelopsis typica, and the various Bathyphysinae. Nedopyramis diomedeae and Nedodroma reticulata are known from so few records that they may well have come from the surface, and it is altogether probable that Dromalia, Archangelopsis, and Angelopsis did come from the surface (p. 316). This leaves only Chuniphyes, Erenna, and the Bathj'physinae belonging exclusively to the mesoplankton. The shallowest haul which has produced a specimen of the former was 250-0 fathoms (Bigelow, : lib, p. 348); and the records from closing-nets just cited show that it is at home at much greater depths. We do not know the precise level from which any Bathyphysid or Erenna has come. But all of them are so large and conspicuous that they would hardly have been overlooked on the surface in the warmer parts of the globe, did they occur there. And the surface waters off the coast of Norway, about Spitzbergen (Romer) and in the Greenland Sea (Duke of Orleans) have been so thoroughly examined within the last few years that we can hardly sup- pose that any of them regularly come to the surface in these cold regions. The great majority of Siphonophores are epiplanktonic at some time or place, many of them chiefly, or perhaps exclusively, so. Thus during the expedition of the "Albatross" seventy specimens of Galeolaria australis were taken in twenty-seven surface hauls, and only seven specimens in four inter- mediate hauls. The preponderance in favor of the former is so great that it strongly suggests a surface origin for the latter. Evidently this species was living in a shallow surface zone. In the Malaysian region, also, all (but perhaps one) of the "Siboga" specimens of G. australis were taken on the surface. As further examples of the epiplankton group I may mention Sphaeronectes trun- cata, Galeolaria monoica, G. quadrivalvis, and Diphyopsis dispar. Among Physophorae, Agalma okeni, Athorybia, and Anthophysa are char- acteristic surface forms. During the Expedition seventy-eight colonies of the former were taken on the surface, and only three in intermediate hauls. It is common, likewise, on the surface at the Canaries, among the West Indies, near Ceylon (Haeckel, '88b, "Cystallodes vitrea"), and among the Malaysian Archi- pelago. And of course Velella, Porpema, Porpita, and Physalia, in the adult state, are known from the surface only, though the larvae of the first and perhaps of the others, are inhabitants of the deeper layers (p. 380). GEOGRAPHICAL DISTRIBUTION. 379 Diphyes ardica has a considerable vertical range, and as already pointed out (p. 369), it follows down the isothermobath most favorable to it in regions where the surface waters are too warm. But there seems to be a limit to this vertical extension, because the species has never been taken at any depth south of 57° N. latitude, in spite of the many deep hauls which have now been made in various parts of the Atlantic. Were it independent of every physical factor except temperature, it would find a favorable environment at some depth in all latitudes. But since it is not found in tropical regions at any depth, there must be some other factor limiting its dispersal. I have elsewhere (Bigelow, : 09a) suggested the possibihty that the absence or presence of light may be a factor in determining the vertical range of holoplanktonic coelenterates, and Hjort (:11) has demonstrated that light is undoubtedly the factor governing the vertical range of the fishes of intermediate waters. Thus there is a group limited to darkness, and one occurring in the zone of very faint light, which show charac- teristic color differences. And, as I have pointed out (:lla), there is some evidence that the Medusae of intermediate waters can be divided into two corresponding groups, the iridescent — slightly pigmented forms occurring above the deeply pigmented red or brown species. Now that light has been shown to be so important in relation to the vertical distribution of other groups of pelagic animals, it would not be surprising to find it occupying a similar role in the case of the Siphonophores. We might suppose that D. ardica is positively phototropic to light above a certain intensity." Were this the case, being other- wise limited in its dispersal by heat, it would occupy the zone of most favorable temperature, i. e. 35°-45°, from the Arctic regions southward to the point where the latter sank below the level of appreciable 'light. But it would not extend further toward the tropics, because to follow its temperature downward would lead into regions when there is too little light for its ecologic needs. We could thus account for its occupancy of a zone from the surface downward for a con- siderable depth in the Greenland Sea; its absence from the surface further to the south, and its entire disappearance south of 57° N. It is true that Damas and Koefoed's ( : 07) records if taken at their face value, indicate a habitat below 400 fathoms. But as I have pointed out (p. 377) it is doubtful whether any of the specimens credited by them to 800 fathoms actually came from that depth. Whether or not light is the active factor can be determined only by actual experiment on the light reactions of D. ardica, which should not be a difficult task. Perhaps my suggestion may lead some Norwegian student to under- take it. 380 GEOGRAPHICAL DISTRIBUTION. . Diphyes arctica has been treated at some length because the data allows us to follow it over some twenty-five degrees of latitude, and because the question of its probable vertical limits is germane to the ecology of Siphonophores in general. But a considerable vertical range, irrespective of stage of development or of season, has also been established for Diphyes appendiculata. This species occupies a zone of considerable depth at all seasons in the Mediterranean, and the same is true of it in summer in the Bay of Biscay. But the numerous records of this species show that it is usually most abundant within seventy-five fathoms of the surface (Chun, '87, Bigelow, :11b). Seasonal Fluctuations in vertical Distribution. Seasonal fluctuations in vertical distribution are known for several Siphono- phores. The most important observations along this line are those made by Chun ('87), and Woltereck's (:04) studies on the development of Velella. Chun found that in the Mediterranean Physophora, Hippopodius, and Stephanomia rubruni, which are common on the surface during autumn, winter and early spring, seek deeper, and consequently cooler layers as summer approaches. During the summer the larvae of all these were taken by him at from 100-900 meters (for a complete list of the seasonal occurrence of Siphonophores in the Bay of Naples, see Lo Bianco, '99). In the Adriatic, the genus Praya is found on the surface from January to the middle of April, and appears again by the end of August; Stephanomia from October to February (Steuer, : 10, p. 571 ; Stiasny, : 11). As I have already pointed out temperature is the factor governing the vertical movements of these species, but this does not seem to be true of Velella. The life-cycle of this genus, as traced by Woltereck, is as follows : — it swarms on the surface in the Mediterranean at two periods, April- June, and October-December (Lo Bianco, '99); and the sexual Medusae (Chrysomitra) , set free on the surface, sink to considerable depths before becoming sexually mature. The larvae (Conaria) then gradually rise by "die Bildung speci- fische leichter Stoffe" to the surface, where they pass through the remaining stages of development from the "Rataria" to the adult Velella. The fact that our knowledge of Porpita has exactly the same gaps as did that of \"elella until its larvae were collected off Villefranche, suggests that it probably carries out the same vertical migration. And this may also be true of Physalia. Woltereck has suggested that the Chrysomitrae are negatively photo- tropic, which could easily be tested, and no doubt soon will be; or they may descend by simple passive sinking. gp:ographical distribution. 381 Salinity, in its relation to Distribution. We know very little about salinity as a factor determining the distribution of Siphonophores, except in the most general way. We can say that Siphono- phores are absent or at least uncommon in regions of very low salinity. Thus none have ever been recorded from the Black Sea or from the Baltic, although the Ctenophore Pleurobrachia pileus is found in both. The North Sea and the Baltic are especially instructive because the plankton of these regions has been so thoroughly explored. There is no dearth of Siphonophores in those parts of the Atlantic from which they might enter the North Sea. Thus various species are common in the Bay of Biscay (Bigelow, : lib) ; at least eight genera are known from Irish waters (Stephens, :05), and the yearly invasion of the Norwegian Sea by Physophora and Agalmidae has been noted (p. 371). In the English Channel, too, Muggiaea atlantica is an important member of the plankton, Agalma often appears from there in the lists of the International committee, and Galeolaria is likewise recorded. But according to Gough M. atlantica does not penetrate the Channel beyond the Isle of Wight, though the temperatures are no barrier to it in summer (p. 376); and though. Physophora hydrostatica and Diphyes arctica are known from the northern, and various Siphonophores have been recorded from the southern part of the North Sea, I can not learn that any Siphonophore ever attains any faunal prominence there. D. arctica extends as far as the Skag- gerak, where it is known from the intermediate waters, but further east, i. e. in the Baltic, the Gulf of Finland, and the Gulf of Bothnia, Siphonophores are unknown. Comparing these phenomena of distribution with the salinity charts of the International committee, it appears that Siphonophores, in the region in question, are almost a negligible factor in the plankton in waters with a salinity less than 35 "o", and that they are entirely absent where the salinity is below about 30%°. On the east coast of the United States the coast water is comparatively fresh; and here, too, Siphonophores never form a conspicuous or constant con- stituent of the plankton, though various Medusae and Ctenophores are often extraordinarily abundant. For example, Stephanomia cara appears only sporadi- cally in Massachusetts Bay or the Bay of Fundy, while the large collections from Labrador and Newfoundland which I have studied did not contain so much as a fragment of it. Agalma elegans enters Narragansett Bay only when the surface waters of the Gulf Stream are driven on shore by southerly winds, and 382 TABLE OF DISTRIBUTION. the same is true of the other species recorded from there. Off the mouths of large rivers, too, like the Amazon, Siphonophores are rare or absent (Chiui, '97b, p. 101). TABLE OF DISTRIBUTION. In the ensuing table, the well-authenticated occurrences of all valid, and several doubtful species are given, so far as I have been able to find them. Unplaced Eudoxids are omitted. The words "tropical," "temperate," etc, are vague, and do not always carry the same meaning. I have therefore divided the north Atlantic into four zones; 1, warm regions limited by the isotherm of 68°; 2, temperate, 68°-55°; 3, boreal, 55°-45°; and 4, Arctic, below 45°. These limits are all for the warmest month of the year, because the great majority of Siphonophores are warm-water forms, and often occur in summer far to the north of their usual range, particularly in the region of the Gulf Stream. The precise temperature limits have been chosen because they fit in best with the distribution of the group. A fifth region is the Mediterranean. The curves on the small chart are taken from Krummel, the Deutsche Seewarte atlas, the "Ingolf" Expedition, Nansen (North Polar Expedition), and from the data collected by the "Conseil International." The Indian and Pacific oceans are treated as a whole, because our knowledge of their Siphonophore fauna is practically limited to the tropical and subtropical regions. And the south Atlantic is omitted for the obvious reason that it is practically mare incognitum in this connection. A complete list of the records of Siphonophores in northern waters up to 1902 has been compiled by Romer (:02). The sign X indicates that the species is known; — ■ that it is represented by an ally so close that the two may finally prove to be identical. X indicates that the species is known from intermediate or closing net hauls only. Species preceded by ? are problematical. O signifies that the genus is known, but that its specific representative is doubtful. TABLE OF DISTRIBUTION. 383 Atlantic Zones Indo- Pacific 1. 2. 3. 4. i g 1 s g • West East Central 1 ^ 1 ^ Trop. Pad Malaysian Indian Oce Sphaeronectes truncata X X X X X " irregularis . 1 X X princeps . X Muggiaea huxleyi . . . X " atlantica . . . ? X X " kochii . . . X X X X Doromasia picta . . . X X X Cuboides vitreus . . . X X X X X X Nectopyramis thetis . . X " diomedeae . X Amphicaryon acaule . . X X X Rosacea plicata . .• . X X X X " medusa . . . ? X X X X Praya cymbiformis . . X X X X ? Desmalia umbricata X ? Desmophyes annectens X Xectodroma reticulata X " dubia . . X StephaDophyes superba X X Hippopodius hippopus X X X X X X X X Vogtia pentacantha X X spinosa . . . X X X Abyla leuckartii . . . X ? X X X " trigona . . . X X X X X X '■ haeckeli . . . X X Abylopsis tetragona X X X X X X X " eschscholtzii . X X X X X X Bassia bassensis . . . X X X ■ X X ? Diphyabyla hubrechti . X X Galeolaria australis . . — X X X " biloba . . X ? — — — '■ quadrivalvis X X X X X " truncata ? " raoniea X X X ? " ovata . . . X Diphyes arctiea X X " subtilis . . . X X X " bojani . . . — — — X X " steenstrupi — X — — — " serrata . . . X X X — — " appendiculata X X X X X X X X X X X X " spiralis . . X " contort a . . X X fowleri X X X " subtiloidcs . . X Diphyopsis dispar . . • 1 X X X X X 1 X X X " mitra X X X X " chamissonis X X X ? " hispaniana X 1 Chuniphyes multidentata X 1 X X 384 TABLE OF DISTRIBUTION. Atlantic Zones ^ W ^ m ^ w § In do- Pacific .S O h S 5 Apolemia uvaria . . Forskalia ..... Erenna richardi . . ? " bedoti . . . Agalma okeni . . . elegans . . . clausi . . . haeckeli . . . Stephanomia amphitrides " bijuga cara . . Stephanomia rubra . . ? " cupulifera Anthemodes ordinata Lychnogalma utricularia Physophora hydrostatica Nectalia loligo . . . ? Discolabe quadrigata Athorybia rosacea . . Anthophysa formosa rosea . . ? Rhodophysa corona Stephalia corona . . Angelopsis globosa dilata Dromalia alexandri . . Rhodalia niiranda* . . Archangelopsis typica Rhizophysa filiformis eysenhardtii t Salacia uvaria . . . Bathyphysa abyssorum sibogae Pterophysa grand is . . grimaldii studeri . . Epibulia ritteriana . . Physalia physalis . . utriculus . . Porpema globosa . . prunella . . Porpita porpita . . . umbella . . . pacifica . . . Velella velella . . . lata .... X X X X X- X X X 0 X X X X X X X X X X X X X X X X X X X X X X X X X X X X 0 X X X X X X X ? X 0 X 1 X X X X X X X ? X X X X X X X X X X 0 * South .\tlantic, E. of Buenos Ayres, 37° 17' S, Lat., 53° 52' W. L. t South Atlantic, 21° 15' S., 14° 2' W. L, TABLE OF DISTRIBUTION. 385 Fig. D. Distribution zones of Nortli Atlantic. 386 GENERAL CONSIDERATIONS. GENERAL CONSIDERATIONS. As our knowledge of the geographic distribution of the various groups of pelagic Metazoa grows, it becomes increasingly profitable to compare them with one another. One field of discussion which has led to many interesting results in other groups, the relationship between Arctic and Antarctic faunae, is closed to us, because no Antarctic Siphonophore is yet known. But we have enough data to allow some important comparisons. The qualitative richness of the Siphonophore fauna of warm waters as compared to its poverty in cold latitudes is paralleled by Medusae (Maas, : 06) Ctenophores (Moser, :09), Pteropods (Meisenheimer, :08), Chaetognaths (Fowler, :06), Salpae (Apstein, :08) and by various other groups which share with Sipho- nophores a permanently pelagic existence, and helplessness to alter their environ- ment by directive horizontal swimming. The Siphonophores are as a whole restricted to an extremely uniform envi- ronment; much more so than the Medusae. Thus no Siphonophore has pene- trated into brackish, much less into fresh water. Even in oceanic regions of low salinity Siphonophores are not common. Not one has adopted the bottom as its usual habitat, as have certain Medusae ; none are parasitic, while Medusae are parasitic on molluscs, and on each other (various Narcomedusae). And like the cold-water members of several of these groups, the boreal and Arctic Siphono- phores are not structurally primitive. They certainly are not ancestral types. For genera or families which might be looked on in such a light, e. g. Monophyids and Prayids among Calycophores, Apolemia among Physophores, we must turn to warmer zones. And on the other hand none of the highly specialized Siphonophores are known from cold waters. Thus there is no Arctic Hippopo- did, no Anthophysid, no Rhizophysalid, no Chondrophorid. .\i-guing from such grounds Maas (:06), Meisenheimer (:05, :08) and Moser (:09) have reached the very important generalization that for Medusae, Pteropods, and Cteno- phores, the centre of development lies in warm or in temperate seas, and that they have spread thence into cold zones to the north or south, where they may or may not have become differentiated specifically. The Medusae have likewise made an incursion, important both numerically and physiologically, into the peculiar though uniform envkonment provided by the intermediate water layers. And there is every reason to extend these generalizations to the Siphono- GENERAL CONSIDERATIONS. 387 phores as well. In the case of the latter group there has been a small northerly spread, and an even smaller expansion downward. Wliether there has been any extension into the frigid zone of the southern hemisphere remains to be seen, though it is hardly conceivable that there should not. On this point, as on many others, we can expect much valuable information from the collec- tions made by the "Valdivia." The Siphonophores have been less successful in occupying cold waters than either Medusae or Ctenophores. The trachomedusan, narcomedusan, and scyphomedusan fauna of the Arctic and Antarctic waters, of which Maas ( : 06) has given a general account, are qualitatively rich, and quantitatively even more so. And when we turn to Ctenophores, we find that of eighty species recognized by Moser (: 09) as valid, nine are known from the Arctic, or from the Antarctic. But among the rather larger hst of Siphonophores (about 95), only three species have any claim to be regarded as normally Arctic forms. Specimens of other species, it is true, are occasionally taken far north, as for example Physophora and Diphyopsis dispar. But these records are nothing more than sporadic instances of the effects of currents. The animals have not succeeded in estab- lishing themselves there. The difference between Siphonophores and Cteno- phores in this respect is further emphasized by the fact that it is doubtful whether there is a single truly eurythermal Siphonophore, while there is at least one Ctenophore, Pleurobrachia pileus, the distribution of which is wholly independent of temperature. And the same is probably true of a second, Beroe cucumis. For the former, the known temperature range is from just above freezing to 28° C (82.4° F.) ; for the latter, from the same low limit to 23° C. (73.4° F.) . The extreme temperature range known for the most nearly eurythermal Siphonophore is from about 45° F. to about 80° F. ; considerably less than either of these Cteno- phores, while its normal range, from about 55° to about 80°, is still narrower. Another significant fact is that the Siphonophore component of the Arctic plankton is not only qualitatively, but quantitatively, much poorer than either the Medusae, the Ctenophore, the Pteropod or the Chaetognath component. Thus Diphyes arctica occurs far less regularly in Arctic currents than do the Pteropod Clione limacina, the Chaetognath Krohnia harnata, or the Tracho- medusa Aglantha digitale, though it has been captured from a wide range of localities. Nor has it ever been found so abundant anywhere as Clione, Aglantha, Pleurobrachia, or Mertensia, which often gather in enormous swarms. The same thing is true, also, of Stephanomia cam, though it is large and conspicuous. And this species is even more irregular in its appearance. 388 GENERAL CONSIDERATIONS. Even in temperate, "mischgebiete" regions Siphonophores are compara- tively unimportant members of the plankton, from the quantitative point of view, although, as I have already pointed out (p. 369), the number of species is already much greater than it is in colder waters. Thus in the Bay of Biscay for example, Mr. Fowler found only one Siphonophore regularly enough for me to plot its vertical distribution. But when we turn to the metazoan plankton of tropical and subtropical waters, we find Siphonophores relatively very much more important. It is true that they seldom fill the surface waters to the extent that Salpae often do ; but there are few pelagic forms more regular in their occur- rence in warm currents than Diphyes appendiculata, Diphyopsis dispar, or Abylopsis tetragona. And the swarms of Velella and Porpita have long attracted notice. The fact that the warm-water Siphonophores are divided into two main groups, one restricted to characteristically tropical temperatures, i. e. above about 65°; the other with a range wide enough to allow them to occupy the Mediterranean, is likewise significant, because no such division can be made for the holoplanktonic Medusae, the Pteropods (Meisenheimer) , nor Salpae (Apstein). When we come to compare the intrusion of Siphonophores into the inter- mediate water layers with that of the Medusae, we find a state of affairs very similar to the differences in their extensions into Arctic regions. Medusae have been very successful colonists of deep water; they are surpassed by fishes alone in the diversity of the ancestral stocks which have sent offshoots into this en- vironment. Thus among the Craspedotae no less than seven families, including Antho-, Lepto-, Tracho-, and Narcomedusae, have representatives among the mesoplankton ; while the Scyphomedusae are represented by six families. On the other hand there are only two families of Siphonophores which have members belonging exclusively to the mesoplankton, and no one of these occurs as regu- larly or as commonly as do several of the " intermediate " Medusae, for example Colobonema or Halicreas. In the poverty of their mesoplanktonic constituents the Siphonophores agree with Ctenophores (Moser, : 09). These various facts taken together point in the first place to the conclusion that Siphonophores are as a whole much more sensitive to temperature than either Medusae, Ctenophores, or Pteropods, and, in the second, that they have been less able to adapt themselves to changes in temperature, and to occupy the oceanic zones which would thus have been opened to them. They are, too, far more sensitive to differences in salinity (p. 380). GENERAL CONSIDERATIONS. 389 Note: — Dr. F. Moser's preliminary discussion of the Monophyids and Diphyids of the German South Polar expedition (Uber Monophyiden und Diphyiden. Zool. Anz., 1911, 38, p. 430-432) was received when the foregoing pages were in press, too late for extended review. While awaiting her final account I may note some of the more important systematic results. She unites as one species Diphyes bojani, D. gegenbauri, D. malayana, D. indica, and Doro- masia pictoides (cf. p. 244); and having Atlantic material she was able to prove that they are identical with D. steenstrupi Gegenbaur, a result suggested above. She asserts definitely that Doromasia picta Chun is not a Monophyid, but is a young stage of Diphyopsis dispar, thus bearing out my suggestion arrived at from less extensive material. In only one important point her observations contradict my own, namely in connecting the Eudoxid Ceratocymba in genetic series with Diphyabyla. The "Albatross" collection, on the contrary, affords strong evidence that the former is a stage in the life history of Abyla leuckartii. I had hoped that the next important collection would determine the parentage of Ersaea bojani. But Moser finds only a strong probability that it belongs to Diphyes steenstrupi (= bojani). Finally she mentions the discovery of new, and highly organized Monophyids. 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V, Dorsal, lateral, and ventral ridge? Sm Septinn Sti Stigmata S. L Stutzlamella PLATE 1. PLATE 1. Nectopyramis diomedeae. Fig. 1. Side view of the nectophore of Type. X 2. Fig. 2. Ventral view of same. Fig. 3. Left lateral view of hydroecium of another specimen. Fig. 4. Similar view of hydroecium of Type. (In figs. 3 and 4, the lettering C. Fed and C. Pa' should be transposed.) X 4. Fig. 5. Lateral view of the free Eudo.xid. X about 3. Nectrodroma reticulata. Fig. 7. Lateral view of young nectophore. X 6. Fig. 8. Dorsal view of same. ■Albatross" - Eastern Pacific Ex. Siphonophorae. Plate c.Pit] r.p.i.' alGELOV/ AND E, N. FI8CHER OFL HELICTYPE CO . BOSTON PLATE 2. PLATE 2. Praya cjrmbiformis. Fig. 1. The two definitive nectophores of a large colony, in their natural position. X 2.5. Fig. 2. Ventral view of the younger of the two nectophores. Fig. 3. Proximal portion of the corm, with buds for siphons, bracts, and gonophores, and the muscular lamellae which bore the nectophores. X -1. Fig. 4. A mature group of appendages, with bract, siphon, tentacle, and gonophore. X 15. Fig. 5. Male gonophore. Fig. 6. Portion of bract, showing the canals. ? Rosacea plicata. Fig. 7. Lateral view of the younger of the two chief nectojihores. X 3. Fig. 8. Ventral view of the same. Fig. 9. Ventral view of the older nectophore. X 3. ■Albatross" — Eastern Pacific Ex. Siphonophorae, Plate 2 / l'^^ /// r -.\\ .. <^.Ptd. St. Br. vk' C.Pa. t '■■C. K-.S. 6IG6LOW AKO E N. FISCHER DfL MEliOTVPE CO . BOSTON PLATE 3. PLATE 3. Nectodroma reticulata. Fig. 1. Ventral view of nectophore. Type; 55 mm. long. Fig. 2. Lateral view of same. Fig. 3. Apical view of same. X 2.5. Fig. 4. Somewhat oblique apicoventral view of nectosac, to show its canal system, and relation to the pedicular canal (C. Fed.). X 5. Fig. 5. Ventral view of hydroecium, showing the course and ramifications of the ascending palial canal. Fig. 6. Lateral view of bract. X 3. Fig. 7. Portion of same, to show its canals more highly enlarged. Nectodroma dubia. Fig. 8. Lateral view of nectophore. X 2. Fig. 9. Ventral view of same. ■■Albatross" — Eastern Pacific Ex. Siphonopliorae. Plate 3 r / '\llr. C./Vil. r.Su. BIGELO// AND E N. FISCHER DtL HELIOTVPE CO , BOSTON PLATE 4. PLATE 4. Amphicaryon acaule. Fig. 1. Lateral view of entire colony, showing relationship of the older nectophore (N.A) to the younger one (N.P). X 10. Fig. 2. Apical view of same, showing the relative sizes of the two nectosacs (Ns.A and Ns.P). Fig. 3. Central portion of the colony, showing the short corm with its appendages, and the canal system of the two nectosacs. The bract-hke older nectophore (N.A) is turned to one side to expose the hydroecial furrow, with the stem, and the muscular lamellae bearing the nectophores. X 15. Fig. 4. Dorsal view of the nectosac of the older nectophore. X 40. Fig. 5. Bract and female gonophore. X 50. Fig. 0. A group of appendages: siphon, bract, tentacle, and female gonophore. X 25. Fig. 7. Ventral view of bract. Fig. S. A very young colony, 3 mm. long, showing how the relatively large older nectophore (n.a) overlaps the younger one (N.P). "Albatross" — Eastern Pacitic Ex. Siplionophorae. Plate 4 Ns.p. r.ri. r.L. ^ ^/s.A. «r. SI. Br. r.Br. T.B. Go.p \ k- aiGELOW AND e N, FISCHER DEL hEliOTvPE CO . BOSTON PLATE 5. PLATE 5. Galeolaria quadrivalvis. Fig. 1. Lateral view of inferior nectophore. X 4.5. Fig. 2. Similar view of superior nectophore. X 4. Fig. 3. Basal view of inferior nectophore, to show basal wings (W.V) and teeth (To. D. To. L). X 8. Fig. 4. Similar view of superior nectophore. X 8. Fig. 5. Two successive cormidia, showing bract (Br), tentacle (T), siphon (S) and gonophore (Go). X 20. Fig. 6. Siphon (S), tentacle (T) and female gonophore (Go. 9) with bract detached. Fig. 7. Male gonophore (Go. cf ), siphon (S) and tentacle (T). Galeolaria australis. Fig. 8. Lateral view of superior nectophore. X 5. Fig. 9. Similar view of inferior nectophore. X 4. Fig. 9 (bis). Dorsobasal view of inferior nectophore showing the lateral ridges (R. 1). X 8. All figures from photographs. " Albatross "—Eastern Pacific Ex. Siphonophorae, Plate 5 3 Topy So. Tr, i).2 ToL. X W.V. St. ToD.i To D.' ir.v.' ii'.r.2 ; Go. 5 R.L. ..^ BIGELOW PHOTO E. O. COCKAYNE BOSTO N PLATE 6 PLATE 6. Galeolaria australis. Fig. 1. Lateral view of superior nectophore. X 6. Fig. 2. Ventral view of same to show subumbrul canals and vcntrobasal wings (W. V). Fig. 3. Lateral view of inferior nectophore. X 5. Galeolaria monoica. Fig. 4. Lateral view of inferior nectophore. X 8. Fig. 5. Ventral view of superior nectophore, with divided basoventral wing (W. V). X 8. Fig. 6. Basal view of superior nectophore, to show dorsal (To. D) and lateral (To. L) teeth, and ventral wings (W. V). From a photograph. Fig. 7. Ijateral view of base of inferior nectojihore, showing teeth (To. D, To. L, To. L-) and ventral wing. X about 16. Fig. 8. Lateral view of sujierior nectophore. X 9. Fig. 9. Dorsal view of base of inferior nectophore. *'AIhatr(>«-s" E.i'-tcrn P;u itii- Ex. Sipli(HMH>li(H";u.-. Pl.'itO ^1 ■it F' ( ■•-.■"> PLATE 7. PLATE 7. Fig. 1. Muggiaea atlantica; lateral view of nectophore. X 12. Fig. 2. Diphyes bojani; colony with two nectophores still connected. The superior nectophore shows wing-like expansions of the ridges in the upper j of their course. X about 8. Fig. 3. Diphyes bojani. Superior nectophore of another specimen, without wings. X 5. Fig. 4. Diphyes spiralis. Lateral view of superior nectophore strongly contracted. X 15. Fig. 5. Diphyes appendiculata. The two nectophores still connected. X 6. Fig. 6. Diphyes appendiculata. Superior nectophore of same colony detached, to show con- formation of base. Fig. 7. Diphyes contorta. Dorsal view of superior nectophore, to show dorsal facet. X 10. Fig. 8. Diphyes contorta. Lateral view of superior nectophore, showing asymmetrical somato- cyst. X 10. Fig. 9. Diphyopsis mitra. Lateral view of superior nectophore. X 8. All figures from photographs. 'Albatross" — Eastern Pacific Ex. Siphonophorae, Plate 7 :\ ^ ' \ BiGELOW PHOTO e. O. COCKAYNE SOSTO N PLATE 8. PLATE 8. Fig. 1. Diphyes spiralis. Lateral view of superior nectophore, not contracted {cf. PI. 7, fig. 4), showing the spiral course of the ridges (R. D, R. L). X 20. Fig. 2. Ventral view of same, showing spiral ridges, ventral facet, conformation of base, and asymmetrical position of the somatocyst (So). Fig. 3. Diphyes contorta. Apical view of superior nectophore. X 12. Fig. 4. Diphyes fowleri. Lateral view of superior nectophore, showing short hydroecium (H) and transverse position of the pear-shaped somatocyst. X 8. Fig. 5. Muggiaea atlantica. Lateral view of apex of nectophore, to show the ridges (R. D, R L, R. V, R. V2). Fig. 6. Diphyes bojani. Oblique dorsal view of apex of superior nectophore of a specimen in which the ridges are extended into wing-like enlargements. Fig. 7. Diphyes appendiculata. Dorsal view of apex of superior nectophore, showing origin of ridges. Fig. 8. Diphyes appendiculata. Oblique dorsal view of superior nectophore to show course and extent of lateral and dorsal ridges (R. L', R. L^, R. D). X about 6. Fig. 9. Chuniphyes inultidentata. Lateral view of colony with the two nectophores still con- nected. X 5. 'Albatross" — Eastern Pacific Ex. Siphonophorae, Plate 8 • K. r. R. L. eiGELOW ANO E. N. FISCHER DEL ELIOTYPE 00. 906TON PLATE 9. PLATE 9. Bases of superior nectophores of Diphyopsinae, and of Muggiaeii. Fig. 1. Diphyes bojani, lateral. X about 20. Fig. 2. Diphyes bojani, dorsal. X 15. Fig. 3. Diphyes spirahs, dorsal. X 50. Fig. 4. Diphyopsis mitra, dorsal. X 16. Fig. 5. Diphyes fowleri, dorsal. X 12. Fig. 6. Diphyes appendiculata, dorsal. Fig. 7. Muggiaea atlantica, lateral. X 18. Fig. 8. Muggiaea atlantica, dorsal. X about 15. 'Albatross" — Eastern Pacific Ex Siphonophorae, Plate 9 BIGELOW AND E. N. FISCHER DEL. e. O. COCKAYNE BOSTO N PLATE 10. PLATE 10. Inferior nectophores of Diphyopsinae. Fig. 1. Diphyopsis dispar, lateral. X 6. Fig. 2. Diphyes bojani, lateral. X 6. Fig. 3. Diphyes bojani, ventral. X 6. Fig. 4. Diphyopsis mitra, lateral. X 10. Fig. 5. Diphyopsis mitra, ventral. X 10. Fig. 0. Diphyes appendiculata, ventral. X 9. Fig. 7. Chuniphyes multidentata, ventral. X 4.5. Albatross"— Eastern Pacific Ex. Siphonophorae, Piate \ „ \ ( \ 1 1 i / f I" "■•'^' , 1^ v> rii.u' Tu.H? l. ^^rj»8%*^-''- * -**^^-'s^*»''^i-^ • » /.. Mil ■;- , ...A'- *. 0 ' *••^ ,JI» I i'n. (>. G. aiGELOW PHOTO ET DEU HELIO*^VFe CO BOSTON PLATE 22. PLATE 22. Angelopsis dilata. Fig. 1. Radial section of the colony, a little to one side of the mid-plane, especially to show the structure of the bulbous siphosome. From a photograph. X 9. Fig. 2. Radial section of the aurophore near the median plane. From a photograph. X 12. Fig. 3. A portion of the same more enlarged. X 30. Fig. 4. A similar section reconstructed from four adjacent .serial sections. Pn. C, pneumatocodon; Pn. S, pneumatosaccus; En, endoderm; Ec', primary, Ec-, secondary ectoderm; Ch, chitinous la)-er; Ca. P, pericystic space; Ca. H, hypocystic cavity. X 15. Fig. 5. Section through secondary ectoderm, chitinous layer, the evaginated portion of the pneu- matosaccus, to show histology of the various layers. SI, stutzlamella; other lettering as in fig. 4. X 250. Fig. 6. Longitudinal section through the wall of the nectosome in the lateral plane (transverse to the aurophore). X 25. Fig. 7. Part of the basal portion of the siphosoine, to show positions of siphons (S), and their connection with network of canals. Photographed from a dissection. X 20. Fig. 8. Small portion of the siphosome, showing branching canals. X 20. "Albatross"— Eastern Tacific Ex Pn. C. ; - P". S- En. Siphonophorae. Plate 22 Pn. s. t^t :w # ,i- 9IGE10W PHOTO ET DEL MELIOTVPE CO. BOSTON PLATE 23. PLATE 23. Anthophysa rosea. Fig. 1. Radial dorsoventral section of the entire colony. The thin wall of the lower part of the pneumatosaccus is torn. For lettering see PI. 22, fig. 4. From a photograph. X 25. Fig. 2. Radial section of the pneumatosaccus at the region where the secondary ectoderm (Ec') originates. En, endoderm; Ec', primary ectoderm; S. L, stutzlamella. X 150. Fig. 3. Bract, with its muscular lamella (L. Mu). X 10. Fig. 4. Mature tentillum of dendritic type. X 30. Fig. 5. Lower surface of denuded corm, to show the positions of siphons (S), palpons (P), gono- dendra (Go), and of the group of muscular lamellae (L. Mu). Only the stumps of the various append- ages remain. X 10. Dromalia alexandri. Fig. 6. Lateral view of Type. From a photograph. Only one young nectophore is intact (B. N), but the muscular lamellae (L. Mu) show the positions of the older ones. Immediately below the youngest nectophore are the buds for future siphons (B. S). The aurophore is seen at X, opposite the zone of prohferation. From a photograph. X 2. Fig. 7. Dorsal view of another specimen, showing the aurophore (X), the muscular lamellae, and the cormidia. Immediately below the aurophore is a naked zone reaching the entire length of the nectosome. From a photograph. X 2.5. Fig. 8. Apical view of part of the pneumatophore, showing the gelatinous prominences. From a photograph. X 2. Fig. 9. A compound cormidium, consisting of two siphons (S', S') with their tentacles (T) and several gonodendra (Go', Go=) with palpons, all situated on a single gelatinous prominence (St). X 5. Fig. 10. A young tentillum. X 50. Fig. 11. Basal view of the axial region of the siphosome, showing the spiral arrangement of siphons (St. S) and canals (C). Photographed from a dissection cleared in clove oil. X 4. ■Albatross" — Eastern Pacific Ex. Er.' Pn.C '>«. N" Siphonophorae, Plate 23 /. .11 11. fcv? » » a / K ^ • '^ r ^ K :^% ^'^ f •*■ ■^T:' BIG6.LOW PHOTO. ET. rJEL .^ HELiOTYpe CO. Boston PLATE 24. PLATE 24. Dromalia alexandri. Fig. 1. The region of proliferation. B.N, very youngnectophore; B. S,budsforthe future siphons; St. S', gelatinous stalk on which a younger, St. S^, on which an older, siphon was borne. L. Mu; muscu- lar lamella of older nectophore. X 4. Fig. 2. Enlarged view of same. Lettering as in preceding figure. Photographed from a dissec- tion cleared in xylol. X 6. Fig. 3. Still more enlarged view of the youngest nectophores, and buds for siphons. X 9. Fig. 4. Radial section of colony through the aurophore (X) and zone of proliferation (B. S). Pn, pneumatophore; Pn. pr, gelatinous prominence of pneumatocodon; Pa. Pr, papilliform processes of aurophore; C, canals of siphosome. X 3. Fig. 5. Similar section of larger specimen. Lettering as in fig. 4. X 4. Fig. 6. Radial section of the aurophore. Ec', primary, Ec^, secondary ectoderm; En, endoderm; Sm, septum connecting pneumatosaccus with pneumatocodon; Pa. Pr, papilhform process. X 20. Fig. 7. Transverse section of aurophore in its mid-region. Lettering as in fig 6. X 20. Fig. 8. Radial section of axial region of aurophore. Lettering as in fig. 6. This photograph hag been slightly retouched. X about 30. Fig. 9. Radial section of terminal portion of papilliform process, showing the open terminal pore. X40. All figures from photographs. 'Albatross" — Eastern Pacific Ex. Siphonophorae. Plate 24 St. S. :% 6 Pn. Pt. ^^M rSS% En. K. S N(. S. ^^ ■• __ X. Pn. p.i. Pr- Sm. ... £f . alGELOW PHOTO. HEUOTvPE CO. B06T0^ PLATE 25 PLATE 25. Porpema prunella. Fig. 1. A specimen floating in the natural position; seen from above. X 2.5. Fig. 2. Lateral view. The tentacles have been partly stripped off to show the conical rorm. X 4. Fig. 3. Another specimen, seen from below. X 4. Fig. 4. Upper surface of the disc. X 8. Fig. 5. The corm, denuded of tentacles and gonozooids. X 7. Fig. 6. A tentacle. X 12. Fig. 7. Tip of a tentacle, more enlarged. X 18. Fig. 8. A gonozooid. X 12. ^ Fig. 9. Another gonozooid, contracted. X 12. All figures from photographs. 'Albatioss" — Eastern Pacific Ex. S i 1 1 1 1 o n o p li o r.'i c Plate 2^ El'OTyPE CO. BOSTON PLATE 26. PLATE 26. Porpema prunella. Fig. 1. Radial section, from a photograph. Lettering as in fig. 2. X 11. Fig. 2. Reconstructed radial section. The left half is between two radial ridges of the centra- denia, the right half in the plane of one of the ridges. Sti', primary; Sti', secondary stigmata, opening into the central chamber (Ch), and into the circular chambers (Ch. C',Ch.C-); Li, linibus; Gl.Mu, mucous gland; C. Li, canals of the limbus; C. T, radial canals of the tentacular zone; C. S, superior canals of the centra- denia(Cd); Tr, trachea; Gz, central gastrozooid; Go, gonozooid; T, tentacle. X about 20. Fig. 3. Apical view, showing radial rows of stigmata (Sti), pahal canals (C. Pa), and marginal mucous glands (Gl. Mu). X about 20. Fig. 4. Transverse section of the pneumatophore close to the apex. Lettering as in fig. 2. From a photograph. X 35. Fig. 5. Transverse section of corm just below the apex of the centradenia. Lettering as in fig. 2. From a photograph. X 20. Fig. 6. Similar section at the mid-level of the centradenia. From a photograph. X 20. Fig. 7. Longitudinal section of young tentacle. From a photograph. X 90. •Albatross"— Eastern Pacific Ex. Siphonophorae, Plate 2fi C. Vd. • "i^'Sf^^^l JIGELOW PmOTO. ET. DEL MELIOTyPE CO. BOSTON PLATE 27. PLATE 27. Porpema prunella. Lettering as in Plate. 26. Fig. 1. Transverse section of corm near base of tentacular zone. At X the section passes through a parasitic treniatode. From a photograph. X 20. Fig. 2. A portion of wall of section shown in fig. 5, pi. 26, more highly magnified. From a re- touched photograph. X 80. Fig. 3. Similar section at level of fig. 6, pi. 26. From a photograph. X 40. Fig. 4. Portion of the same more highly magnified to show the connection between the tentacular canal (C. T) and the endoderm of the centradenia, and relationship between the cnidoblast mass of the centradenia (X) and the ectoderm of the pneumatosaccus (Ec ^). From a photograph. X 80. Fig. 5. Radial section through apex of the pneumatophore. Ce, centradenia. Other lettering as in PI. 26. From a photograph. X 50. Fig. 6. Section through apex of pneumatophore showing cell layers and stigmata (Sti', Sti=). X about SO. Fig. 7. I.,ongitudinal section through base of corm, showing the centradenia of one of the canals (C. Ce) by which it connects with the margin of tlie central gast rozooid (Gz) . From a photograph. X 40. Fig. 8. A similar section, showing the open lumen of the canal. From a photograph. X 40. Fig -9. A similar section, showing one of the canals (C. Ce) of the inner series wliich connect with the gastrozooid (Gz). From a photograph. X 40. Fig. 10. Longitudinal section of the wall of the central gastrozooid. From a photograph. X SO. Longitudinal section through a young tentacle, to show histology. From a photograph. Fig. 11 X80. Fig. 12 Fig. 1.3 Apical view of a model of the centradenia, constructed by the plate process. X 40. Apical view of centradenia, reconstructed from serial sections, showing the superior canals (C. S) and trachea (Tr). X about 80. 'Albatross" — Eastern Pacific Ex. '''• .V. Siphonophorae, Plate 27 (■••. T. ...... Be. _ .F.n. GELOW PMOTO. ET. DEL C' Ell. fcV. HELIOTYPE CO. BOSTON PLATE 28. PLATE 28. Porpita pacifica. Figs. 1-10, 12, 16. Porpema prunella. Figs. 11, 1.5. Porpita umbella. Fig.s. 13, U. Fig. 1. General view of a specimen 50 mm. in diameter from above. From a photograph. Fig. 2. A segment of the upper sm-face of the pneumatophore and limbus, to show the promi- nences (Pr) and stigmata (Sti). From a photograph. X 4. Fig. 3. A segment of the upper surface of the centradenia, with the pneumatophore stripped off. T, tentacle. From a photogi-aph. X 3.5. Fig. 4. Central region of upper surface of float, to show the pahal canals. From a photograph. X9. Fig. 5. A segment of the hmbus with its canals (C. Li) and marginal mucous glands (Gl. Mu). C. pa, palial canal. X 12. Fig. 6. A portion of one of tlie canals of the limbus. X 40. Fig. 7. Roof of central chamber and first cu'cular chamber of the pneumatocyst, from below, to show the aborted primary stigma (Sti') opening from the former, and the aborted secondary stigmata (Sti-) from the latter. Reconstructed from serial sections. X 40. Fig. 8. Vertical section tlirough central part of pneumatocyst; Ch, central chamber; Ch. C, circular chamber; Sti, primary stigma. From a photograph. X 40. Fig. 9. Vertical section through the aborted primary stigma; more enlarged. X 150. Fig. 10. A dissection showing the extremities of the superior canals of the centradenia (C. S), from above; C. Li, canals of the hmbus. X 12. Fig. 11. Porpema prunella. Roof of the central gastrozooid, seen from below, to show the open- ings of the inner and outer series of the centradenia canals (C. Ce', C. Ce^). Reconstructed from serial sections. X 20. Fig. 12. Porpita pacifica. Extremity of a mature tentacle. X 5. Fig. 13. Porpita umbella. Segment of the pneumatophore and limbus. From a photograph. X8. Fig. 14. Porpita umbella. Portion of the hmbus, with its canals. X 20. Fig. 15. Porpema prunella. Section through the endoderm wall of one of the superior centradenia canals. X 250. Fig. 16. Porpita pacifica. The centre of the centradenia, from above. X 20. ■Albatross" — Eastern Pacific Ex. Siphonopliorae, Plate 28 • • • « * tV^MH y« « • • • • • »».»»»liorioptmr;n\ Plnle an . Hvck or Albatross in IS9} . Track of Albatross in ISS9 „ TrackorAtbiOross mJS04 I. Sutlenst denote srrial ientfierature. PLATE 31. PLATE 31. Occurrence of Abylopsis tetragona (O), Bassia bassensis (X), Diphyes appendiculata (f ), Diphyes bojani, (Z) and Diphyopsis mitra (A) in the Eastern Tropical Pacific. Temperature curves as in Plate 30. ■AUijitrojis' — Kystcrn F(icifK|Fx Siphonwplior.'in. t*laic :u _ _ Irackof Albatross iii!S9l ThacJtofAUiairvss inl»99 TrackoCAUiainss in 1904-1905 SlitUwtsl. denote strOU temperatrm PLATE 32. PLATE 32. Distribution of five Siphonophores representative of three thermal groups, arctic, warm to temperate, and tropical. Diphyes arctica T. Diphyes appendiculata ©. Physophora hydostatica ® Diphyopsis dispar • . Abylopsis eschscholtzii X. •AUmli'dSs"— Hasleni l\.( ifn- 1*.\ Siplionophiirac. Plate aa 90 100 'go "30 f*0 •%0 160 170 ISO 110 ISO ISO MO 120 110 100 SO "^ 10 ;)a 20 10 0 10 ;o ao 4d so so lo ao 9Ci_ •mlsStlk--. PUBLICATIONS MUSEUM OF COMPARATIVE ZOOLOGY AT HARVARD COLLEGE. There have been published of the Bulletin Vols. I. to LIL; of the Memoirs, Vols. I. to XXIV., and also Vols. XXVI., XXVIII., XXIX., XXXI. to XXXIII., XXXVII., XXXVIII., and XLI. Vols. LIII. and LV. of the Bulletin, and Vols. XXV., XXVII., XXX., XXXIV. to XXXVI.. XXXIX. to XL., XLII. to XLVII., of the Memoirs, are now in course of publication. A price list of the publications of the Museum will be sent on appli- cation to the Curator of the Museum of Comparative Zoology, Cambridge, Mass. MreX'Sit.b ■mi TROriCAL PACIFIC. The following I'uhliraiions of the Museum contain Reports on the Dredging Operations in charge of Alexander Agassiz, of the U. S. Fish Commission Steamer "Albatross." during 1S09 and 1900, Commander Jefferson F. Moser, U. S. N., Commanding. I. A. Agassiz. Preliminary Report and List of Stations. With Remarks on the Deep- Sea Deposits by Sir John Murray. Mem. M. C. Z., Vol. XXVI. No. 1. Janu- ary, 1902. 114 pp. 21 Charts. II. A. G. Mayer. Some Species of Partula from Tahiti. A Study in \'ariation. Mem. M. C. Z., Vol. XXVI. No. 2. January, 1902. 22 pp. 1 Plate. III. A. Agassiz and A. G. Mayer. Medusae. Mem. M. C. Z., Vol. XXVI. No. .3. January, 1902. 40 pp. 13 Plates, 1 Chart. IV. A. Agassiz. The Coral Reefs of the Tropical Pacific. Mem. M. C. Z., Vol. XXVIII. February, 1903. 33,410 pp. 238 Plates. V. C. R. Eastman. Shark's Teeth and Cetacean Bones from the Red Clay of the Tropical Pacific. Mem. M. C. Z., Vol. XXVI. No. 4. June, 1903. 14 pp. 3 Plates. VI. W. E. HoYLE. Cephalopoda. Bull. M. C. Z., Vol. XLIII. No. 1. March, 1904. 71 pp. 12 Plates. VII. H. LuDWiG. Asttroidea. Mem. M. C. Z., Vol. XXXII. July, 1905. 12, 292 pp. 35 Plates, 1 Chart. VIII. W. E. RiTTER and Edith S. Byxbee. The Pelagic Tunicata. Mem. M. C. Z., Vol. XXVI. No. 5. August, 1905. 22 pp. 2 Plates. IX. Mary J. Rathbun. The Brachyura. Mem. M. C. Z., Vol. XXXV. No. 2. August, 1907. 54 pp. 9 Plates. X. C. H. Gilbert. The Lantern Fishes. Mem. M. C. Z., Vol. XXVI. No. 6. July, 1908. 24 pp. 6 Plates. XI. A. Agassiz. Echini; The Genus Colobocentfotus. Mem. M. C. Z., \o\. XXXIX, No. 1. November, 1908. S, 33 pp. 49 Plates. XII. J. Murray and G. V. Lee. The Depth and Marine Deposits of the Pacific. Mem. M. C. Z., Vol. XXXVIII. No. 1. June, 1909. 170 pp. 5 Plates, 3 Maps. XIII. W. C. Kendall anil E. L. Goldsborough. The Shore Fishes. Mem. M. C. Z., Vol. XXVI. No. 7. Fei)ruary, 1911. 106 pp. 7 Plates. XIV. H. He.-vth. The Solenogastres. Mem. M. C. Z., Vol. XLV. No. 1. June, 1911. ISO pp. 40 Plates. XV. A. M. Westergren. Echini: Echinoneus and Micropetalon. Mem. M. C. Z., Vol. XXXIX. No. 2. .\ugust, 1911. 34 pp. 31 Plates. Harvard MCZ Library niiiiiiii 3 2044 066