Copies of this Book were first issuec*

AUG9 1910



Introduction i~4

Synopsis of Genera of the Hydromedusas 5-16

Medusae Milleporinae 16

Anthomedusae 17-196

Genera of the Anthomedusae:

Pachycordyle 21 Zancleopsis 91 Podocoryne 135

Amaithasa 22 Pteronema 92 Turritopsis 143

Pennaria 23 Eleutheria 93 Oceania 146

Trichorhiza 28 Mnestra 96 Stylactis 149

Steenstrupia 29 Ctenaria 98 Thamnostylus 151

Hybocodon 37 Cladonema 98 Thamnitis 152

Microcampana 44 Dendronema 102 Lymnorea 153

Dicodonium 44 Protiara 105 Bougainvillia 155

Sarsia 47 Heterotiara 107 Nemopsis 172

Stnuridiosarsia 64 Stomotoca 108 Rathkea '75

llydrichthys 66 Dissonema 115 Chiarella 182

Eucodonium 68 Pandea 116 Bythotiara ..185

Ectopltura 68 Turns I2O Sibogita 186, vol. 2 4QI

Corynitis 71 Conis 130 Niobia 187

Slabberia 73 Calycopsis 130, vol. 2 491 Proboscidactyla. . . . . . 188

Margelopsis 80 Cytsis ... ,:. .-...- ... 132 Willsia . . 193

Zanclea 85

Leptomedusae '..'.' .196-230

Genera of the Leptomedusae:

Thaumantias 198. Staurodiscus 213 Dichotomia m

Laodicea 201 1'tvchogena 214 Dipleurosoma 224

Melicertum 207 I'olyorchis 218 Toxorchis 228

Melicertissa 209 Spirocodon 219 Netocertoides. . . .229

Orchistoma 21 r Cannota 221 Monobrachium. . --230

Timoides . . ..212 Cuvieria 221




This work was commenced in 1892 at the suggestion of Dr. Alexander Agassiz while I was a student in his marine laboratory at Newport. Dr. Agassiz's plan was that we produce conjointly a work upon the Medusae, Siphonophora, and Ctenophorae of the Atlantic coast of North America. In pursuance of this plan, Dr. Agassiz sent me upon expeditions to Halifax, Nova Scotia; Eastport, Maine; Charleston, South Carolina; and Tortugas, Florida. It was also my privilege to accompany him as his assistant upon his expeditions to the Bahamas, and to the coral regions of the tropical Pacific. During these years the majority of our American species were captured and drawings of them made from life.

The description of all of the then known American Atlantic forms was com- pleted by me in 1900, but unfortunately the pressure of other and more important work prevented the revision of the manuscript by Dr. Agassiz, and thus it remained in the Museum of Comparative Zoology at Harvard University until 1904, when Dr. Agassiz generously returned it to me with permission to publish it in any manner whatsoever. Thus the original plan was reluctantly abandoned.

During the four years that elapsed while the manuscript lay unstudied at Harvard, new forms had been discovered along our coast; and Nutting and Hargitt had published their papers upon the hydroids and medusae of the Woods Hole region.

It was necessary to thoroughly revise the manuscript, and in order to render it of greater service, I have attempted to extend the original work to include descrip- tions of all known forms of medusae from all parts of the world. This extension was made possible through the generous establishment by the Carnegie Institution of Washington of a Marine Research Laboratory at Tortugas, Florida. Many forms were collected upon a cruise of the Carnegie Institution yacht Physalia from Boothbay Harbor, Maine, to Tortugas, Florida; and new or interesting medusae have been obtained each season upon excursions over the tropical Gulf Stream, and among the Bahamas. My official position in connection with the laboratory has afforded me every possible facility in time and opportunity tor tilt- prosecution of these studies, and I can not too kindly express my sense of gratitude to the executive officers of the Carnegie Institution tor their generous support.

To Geheimrath Prof. Dr. Anton Dohrn, and to his able corps of associates at the Stazione Zoologica, I am indebted for numerous kindnesses shown to me during my visit to the laboratory at Naples from November to February, 1907 and 1908.

I have also enjoyed full privileges of study in the libraries of the Museum of Comparative Zoology at Harvard University; in the Boston Society of Natural



History; the American Museum of Natural History; Columbia University, the National Museum at Washington, and the Museum of the Brooklyn Institute of Arts and Sciences. Through these facilities I have been enabled to review nearly all of the published works upon medusae, but the review of literature can not pre- tend to completeness for 1907 and 1908, although all papers of those years which the author could discover are recorded.

Moreover, Profs. William K. Brooks and Louis Murbach have been so kind as to lend some of their original drawings, which are reproduced in this work, and the following gentlemen have generously granted permission for the reproduction of figures from their published works, thus enabling us to present text-figures of many forms which would otherwise have been represented merely by descriptions: Dr. Alexander Agassiz, Director of the Museum of Comparative Zoology at Harvard University; Dr. Henry B. Bigelow, of Harvard; Dr. R. P. Bigelow, of the Massa- chusetts Institute of Technology; Prof. Edward T. Browne, of the University of London; Prof. Dr. Carl Chun, of Leipzig; Prof. Dr. S. Goto of Tokyo; Geheimrath Prof. Dr. Ernst Haeckel, of Jena; Prof. C. W. Hargitt, of Syracuse University; Prof. Dr. Cl. Hartlaub, of Helgoland; Prof. W. C. M'Intosh, of Aber- deen University; Prof. Dr. Otto Maas, of Miinchen; Prof. C. C. Nutting, of Iowa; Prof. Henry F. Perkins, of Vermont; and Prof. Dr. Ernst Vanhoffen, of Kiel.

I have always felt that each working naturalist owes it as a duty to science to produce some general systematic work, and this has been an actuating motive in the production of this book. But chiefly have I been moved to the task through respect for the wishes of my generous friend and master in science, Alexander Agassiz. Nor can one remain insensible to the rare grace of form and delicate beauty of color of these creatures of the sea, associated as their study is with mem- orials of the labors of a host of distinguished naturalists. Dry though these pages must be to the reader, to the writer they are replete with memories of the ocean in many moods, of the palm-edged lagoons of coral islands sparkling in the tropic sun, of the cold, gray waters of the northern sea bestrewn with floating ice, of days of withering calm in the heat of the torrid zone, and of adventure in the hurricane ; all centering around the absorbing study of the medusa?. Love, not logic, impels the naturalist to his work.

This book attempts to present a new classification of the medusae. With every respect for Haeckel's great work, it has appeared to me that its subdivisions are often too precise to be convenient, and too artificial to accord with nature. More- over, many of Haeckel's genera are founded upon intergrading characters, and are thus imperfectly separated. The young of many medusae appear in one genus, and the adults in another. The aim of Haeckel's system is to emphasize distinctions, whereas my aim is to indicate relationships. I therefore attempt to separate genera upon positive, not upon relative, distinctions. For example, if we define one genus as having a narrow manubrium (Margelis), and another as having a wide manu- brium (Boiigamvillta), we must either institute a third genus for newly-discovered medusae with manubria of moderate width or place them doubtfully in one or the other of the genera of the extreme members of the series.

On the other hand, if we define one genus as having eight tentacles, and another as having nine or more tentacles, there can be no confusion between them, for the difference, although slight, is positive and numerical, not qualitative and intergrading.

I have not described hydroids which do not produce free-swimming medusae, although I grant it is wholly illogical to admit Podocoryne into a system which excludes Hydractmia, or to include only those species of Stylactis which produce


medusae and to exclude those which produce sessile gonophores. Nevertheless this should be clearly understood and must be accepted as an artificial limitation of the work.

I have thus attempted to describe only such hydroids as are known to produce medusae, and have endeavored to bring the systematic arrangement of the medusa more nearly into accord with that of the hydroids. A strictly natural system includ- ing both hydroids and medusae can not be constructed, for many of the hydroids remain undetermined. Moreover, dissimilar hydroids (Svm-tjrv>if, StanriJinim may give rise to similar medusae (Sarsia); or the reverse may be the case, as in the medusae of Bongamvillia and Nemopsis, or that of the two sorts of medusa- (Sarsia and Cladoncrna] which may arise from hydroids of Stauridia.

These and many other cases of a similar nature interpose a barrier to our attempts to invent a natural system which includes all hydroids and medusa" within its embrace. At present, I believe, we must content ourselves with a compromise between a natural and an artificial arrangement, confiding in the belief that as more and more of the hydroids are discovered it will become correspondingly more possible to arrange the medusae in a natural system. After consultation with Prof. C. C. Nutting we have mutually decided that the promulgation of such ;i system is at present inadvisable. Such a system has, indeed, been proposed by von Lendenfeld, 1884 (Zool. Anzeiger, Bd. 7), but has gained no acceptance.

Much confusion has been introduced through the habit, in vogue among marine expeditions, of sending all of the medusa" to one specialist and the hydroids to another. Thus the sessile and the reproductive stages of the same animals are worked upon independently from different view-points by different men.

I am inclined to regard the Trachymedusae and Narcomedusa" as being transformed actinutae, for they commonly develop through an actinula larva in which the bell grows out as a collar-like, or intertentacular lappeted expansion from the sides of the body after the tentacles have appeared, and the tentacles of the actinula become those of the medusa. The medusa of the Anthomedusas and Leptomedusae is formed upon a different plan, for the tentacles grow outward from the bell-margin after the bell has developed. I believe, therefore, that the bell of the Trachymedusae and Narcomedusae is not homologous with that of the Antho- medusa and Leptomedusae. It is evident that the entodermal otoliths of the Trachymedusa" and Narcomedusae are not homologous with the ectodermal otoliths of Leptomedusae. Budding and alternation of generations occur in both classes of veiled medusae.

I believe that the medusa-shape has been acquired independently in the Trachyhna and Leptolma forms of veiled medusae.

The colored plates contained in this volume consist of drawings, from life, of medusae of the Atlantic coast of the United States. The text-figures, on the other hand, are chiefly outline tracings from the illustrations of many authors; and are presented in order to spare the reader the trouble of consulting numerous scattered works of reference. These outline copies of previously-published drawings of medusae were carefully traced from the originals by Mr. Carl Kellner, artist of the Tortugas Marine Laboratory of the Carnegie Institution.

Other outline figures are from life, and the majority of these were drawn by the author while studying at Mousehole, Cornwall, England, and at the Naples Zoological Station during the autumn and winter of 1907 and 1908.

This book aims to be something more than an old-fashioned systematic treatise, for it attempts to record, if not to review, all works upon the embryology, cytology, oecology, physiology, etc., of all forms coming within the scope of the text.


Many of the medusae are modified more or less profoundly by environmental conditions, and this gives rise to numerous local races, the determination of the relationships between which is all but impossible in the present state of our knowl- edge. Experimental work in this field is in its infancy, yet the few observations of Hallez on Bongainvillia and of Browne in his experiments in maintaining various hydroids under different conditions in aquaria suggest that the results of more extended studies will be of great benefit to the systematist in determining the natural limitations of species. A striking example of the profound effect of environ- mental changes is seen in the experiments of Goldfarb, 1906, upon Eudendrium, wherein he showed that after the regenerative process had entirely ceased in the dark, it could be recalled into activity by an exposure of only five seconds to the daylight.

At present the natural classification of the species of such genera as Obclia, Phialidnnn, Etttnna, Bougamvillia, etc., is impossible, and the Linnean system is inadequate to the task of expressing their actual relationships. Indeed, with the exception of the sponges and corals, there is no phylum of the animal kingdom more difficult to classify than the medusae.

In a work of this magnitude there must needs be both errors and omissions, and for these I can but present my apologies in advance of their discovery, trusting that all such will soon be discovered and announced, and that science may be more advanced than hindered through the publication of this book. I trust that none of my esteemed contemporaries will feel aggrieved at such criticisms of their labors as may appear in the following pages, for should anyone find cause for such offense, he may console himself in the fact that I am obliged to confess to having found more to criticize and amend in my own previously-published papers than in those of any other living naturalist.



Medusae with a velum, or diaphragm, which partially closes the marginal opening of the bell. When ripe the sexual products are found in the ectoderm.

With a double marginal nerve-ring, one above and one below the velum.

Without gastric filaments. Development either direct from actinula larvae or through alternation of generations from hydroids.

Order 1. ANTHOMEDUS/E Haeckel, 1879.

Hydromedusae with gonads in the ectoderm of the manubrium. Without otocysts. The hydroids are of the Tubularian order.

Family No. i, CODONID.&.

Anthomedusae with ring-like gonad encircling the manubrium. Four to six simple, unbranched radial-canals. Simple, unbranched tentacles.

Subfamily No. i, SARSIANJE. Some or all of the tentacles arise singly, not in clusters, from bell-margin.

PACHYCORDYLE, Weismann, i8%$ = Parvanernus ( ?), Mayer, I9°4-

Degenerate medusae without tentacles, radial or circular canals. Hydroid: Pachy- cordyle Weismann.

AMALTH^EA, Schmidt, 1854.

Four rudimentary tentacles, four radial-canals, and a ring-canal. Hydroid: Corymorpha.

PENNARIA, Oken, 1815; Goldfuss, i%2O = Globiceps, Haeckel, 1879. Similar to Amalthaa, but the hydroid is Pennana.

TRICHORHIZA, Russell, 1906.

Medusa resembles Pennaria, but the hydroid is Tnchorhiza.

STEENSTRUPIA, Forbes, iS^.6 = Eup/i\s(i, Forbes, i$4.% = Eupliysora, Maas, 1905.

Four radially situated tentacles, one of which is long, the other three short. Bell radially

symmetrical. Hydroid: Corymorpha. HYBOCODON, L. Agassiz, \%()2 = HybocodonJt-Amphicodon, Haeckel, 1879.

One or more well-developed tentacles arise from base of one of the four radial-canals. With rudimentary tentacles at the bases of the three other radial-canals. Bell asym- metrical. Hydroid: H ybocodon Agassiz.

MICROCAMPANA, Fewkes, 1889.

With one long and five short tentacles, arising at ends of six radial-canals.

DlcoDONlUM = Dicodonium + Dincmti, Haeckel, 1879.

Two well-developed and two rudimentary tentacles. No meridional lines of nettle-cells

over exumbrella. SARSIA, Lesson, i^^.^ = CoJontutn + Sarsia + S'vnJii'tyon, Haeckel, 1879.

Four equally developed tentacles with abaxial, ectodermal ocelli. No meridional lines

of nettle-cells over the exumbrella. Hydroid: Syncoryne. StauriJiosarsia new subgenus. Medusa similar to Sarsia, but the hydroid is Stuundia.

HYDRICHTHYS, Fewkes, 1888.

Medusa resembles Sarsia, but there are no ectodermal ocelli upon the tentacle-bulbs. Hydroid: H vJrichthys, Fewkes; commensal or parasitic upon fish.

EUCODONIUM, Hartlaub, 1907.

Medusa resembles Sarsia, but stomach is mounted upon a gelatinous peduncle. The four tentacles terminate each in a knob-shaped extremity.

ECTOPI.EURA, L. Agassiz, 1862 (sens. ampl.).

With two or four tentacles. Eight meridional lines of nettle-cells over the exumbrella. Hydroid: Ectopleura.


CORYNITIS, McCrady, 1857.

Four knobbed tentacles. Manubrium cruciform in cross-section. Ocelli upon tentacle- bulbs. Hydroid: Syncoryne (Hargitt).

SLABBERIA, Forbes, lB^6 = Slabberia + Dif>urena + BathycoJon, Haeckel, 1879.

Four knobbed tentacles. Manubrium tubular and encircled by two or more ring-like gonads. Hydroid: Syncoryne.

Subfamily No. 2, MARGELOPSIN^E.

Four radially placed clusters ot marginal tentacles. No oral tentacles. A ring-like gonad encircles the stomach. Four simple, unbranched radial-canals. Hydroids are pelagic Tubularians, and the medusae arise by budding from their sides.

MARGELOPSIS, Hartlaub, 1897.

Characters of the medusa are those of the subfamily. Hydroid: Margelopsis, in which the tentacles are disposed in definite circlets.

PELAGOHYDRA, Dendy, 1903.

Medusa similar to Margelopsis. Hydroid: PelagohyJra. Its tentacles arise irregularly from sides of the hydranth, and are not disposed in definite circlets.

Family No. 2, CLADONEMID^E.

Tentacles branch dichotomously or complexly, or give rise to a linear series of nematocyst- bearing filaments along their abaxial sides. Gonads ring-like, or segregated upon the inter- radial and adradial sides of the manubrium.

Subfamily No. i, PTERONEMINJE.

Manubrium without oral tentacles.

ZANCLEA, Gegenbaur, l8^6 = Zanclea + Gernmaria, Haeckel, 1879.

With two or four tentacles, each of which gives rise to an abaxial row of nematocyst- bearing branches. With meridional rows of nettle-cells upon the exumbrella. No ocelli upon the tentacle-bulbs. No brood-pouch above the stomach. Hydroid: Gemmaria McCrady; Allman.

ZANCLEOPSIS, Hartlaub, 1907.

Similar to Znticlea, but without meridional lines of nettle-cells over the exumbrella. With ectodermal ocelli upon the outer sides of the tentacle-bulbs.

PTERONEMA, Haeckel, 1879.

Similar to Zanclea, but with a brood-sac above the stomach. Four tentacles.

ELEUTHERIA, Ouatrefages, 1842.

Four to six bifurcated tentacles, and an equal number of simple unbranched radial- canals. There is an ectodermal brood-sac above, but not connected with the stomach. The medusa is hermaphroditic and the germ-cells develop in the brood-sac. Hydroid: Clavatella Hincks.

MNESTRA, Krohn, 1853; Giinther, 1903.

Degenerate medusa parasitic upon Phylhrrhoe. Four to no tentacles, each with an abaxial line of nettle-warts. Four perradial meridional lines of nettle-cells over the exumbrella. Four radial-canals. Throat is blocked by a cavernated mass of entoderm.

Subfamily No. 2, DENDRONEMIN^).

Manubrium with oral tentacles.

CTENARIA, Haeckel, 1879.

Two marginal tentacles with abaxial filaments. Four bifurcated radial-canals. Simple oral tentacles. Brood-sac above the stomach.


CLADONEMA, Dujardin, 1843.

Four or five bifurcated or eight to ten simple radial-canals. Branched marginal tentacles. Simple oral tentacles. No brood-sac above the stomach. Hydroid: Statin Jin Dujardin.

DENDRONEMA, Haeckel, 1879.

Similar to ClaJonema, but with branched oral tentacles and with brood-sac above stomach.

Family No. 3, OCEANID.S, sensu Vanhoffen.

Anthomedusae in which the gonads are segregated and developed upon the interradial or adradial sides of the manubrium. With unbranched marginal tentacles. Mouth with four lips.

Subfamily No. i, TIARIN.E.

Unbranched radial-canals. Marginal tentacles separate; not grouped into clusters. No oral tentacles. Tentacles hollow. When present the ectodermal ocelli are upon the abaxial sides of the tentacle-bulbs. With the exception of Calycopsis all of the genera have four radial-canals.

PROTIARA, Haeckel, i%jq = Halitiara, Fewkes, 1882.

Four radially placed, well-developed tentacles. Four interradial gonads with smooth outer surfaces. With or without marginal cirri. External surfaces of gonads smooth. Four cruciform, simple lips. No ocelli on the velar sides of the tentacles.

HETEROTIARA, Maas, 1905.

Eight or more tentacles. The ring-canal gives rise to blindly-ending centripetal vessels.

STOMOTOCA, L. Agassiz, \%()2 = Amf>hinema-\-Stomotoca + Codonorchis, Haeckel, 1879.

Two well-developed and many rudimentary tentacles. External surfaces of the adradial gonads are thrown into transverse folds. Hydroid: Pengonimus.

DISSONEMA, Haeckel, 1879.

Similar to Stomotoca, but the gonads finally migrate outward along the four radial-canals.

PANDEA, Lesson, 1843.

Four or more tentacles. Gonads four interradial, folded ridges on the sides of the stomach but these gonads are not completely separated in the four principal radii. Hydroid: Dcndroclava ( ? ?).

TURRIS, Lesson, 184.3 = Tiara + Turris + Catablema, Haeckel, 1879.

Four or more tentacles. Four interradial horseshoe-shaped gonads on the stomach wall. These are composed of more or less fused ridges or network-like swelling. They are completely separated in the four principal radii. Hydroid: Clirculu Wright.

CONIS, Brandt, 1834; Haeckel, 1879.

Similar to Pandea, but the tentacle-bulbs give rise to abaxially-placed clubs which bear ocelli.

CALYCOPSIS, Fewkes, 1882.

Sixteen simple, separate radial-canals. Eight transversely folded, adradial gonads. Ring-canal simple.

Subfamily No. 2, MARGELINjE.

With four unbranched radial-canals. With oral tentacles, or nematocyst-knobs, upon the lips. Tentacles solid. When present the ectodermal ocelli are upon the inner (velar) sides of the tentacles.

CYTVEIS, Eschscholtz, iS2() = Cytxis + Cubogastcr, Haeckel, 1879.

Four simple marginal tentacles. With simple, unbranched, oral tentacles.

PODOCORYNE, Sars, \?>Jtb = Dysmorf>hosa-\-Cytteandra, Haeckel, 1879.

Eight or more simple marginal tentacles. With simple, unbranched, oral tentacles. Hydroid: Podocoryne. When present the peduncle above the stomach is solid and gelatinous.


TURRITOPSIS, McCrady, 1856.

Eight or more simple marginal tentacles. The entodermal walls of the radial-canals above the stomach are composed ot vacuolated cells forming a peduncle-like base for the stomach. The mouth is studded with a row of nematocyst-bearing knobs. With ectodermal ocelli on the velar sides of the tentacles near their bases. Hydroid: DenJroclava (Brooks).

OCEANIA sensu Kolliker, 1853; Gegenbaur (in part) 1856.

Medusa similar to Turritopsis, but with solid gelatinous, non-vacuolated peduncle above the stomach. Hydroid: C lava-like.

STYLACTIS, Allman, 1864.

Degenerate medusae, with four to eight rudimentary marginal tentacles and no oral tentacles. Hydroid: Stylactis.

THAMNOSTYLUS, Haeckel, 1879.

With two simple, marginal tentacles, and with branched oral tentacles.

THAMNITIS, Haeckel, 1879.

Four radially placed, simple, marginal tentacles, and branched oral tentacles.

LYMNOREA, Peron and Lesueur, iSog Limnorea + Thamnostoma, Haeckel, 1879. Eight or more simple, marginal tentacles. Branched oral tentacles.

BOUGAINVILLIA, Lesson, \$4.T> = Margelis + Lizusa + Hif>pocrene, Haeckel, 1879.

With branched oral tentacles. The marginal tentacles are grouped in four radial clusters. All of the tentacles are filiform. Hydroid: Bougainvillia.

NEMOPSIS, L. Agassiz, 1849.

Similar to Bougainvillia, but each cluster of marginal tentacles consists of a median pair of clavate tentacles flanked by filiform tentacles. Hydroid: Bougainvillia.

RATHKEA, Brandt, lS^y = Lizzia + Lizella + Rathkea + Margellium, Haeckel, 1879.

With eight clusters of marginal tentacles. Simple or branched oral tentacles. Ring- canal simple.

CHIARELLA, Maas, 1897.

Sixteen (eight double) clusters of marginal tentacles. The ring-canal gives rise to centrip- etal vessels. Branched oral tentacles.

Subfamily No. 3, DENDROSTAURINjE.

With branched radial-canals. No oral tentacles. Marginal tentacles arise singly, and are not grouped into clusters. Tentacles hollow. No cirri or marginal clubs.

BYTHOTIARA, Giinther, 1903.

Four bifurcated radial-canals and a ring-canal. Four interradial gonads.

SIBOGITA, Maas, 1904.

Four principal radial-canals, which branch complexly. Four interradial gonads. Ring- canal present.

NIOBIA, Mayer, 1900.

Four principal radial-canals, two of which bifurcate so that six canals reach the circular vessel. Four interradial gonads. The marginal tentacles develop into medusae, and are cast off.

PROBOSCIDACTYLA, Brandt, \%Tfi=Dyscannota + Dicranocanna+ Willeta

-\-Proboscidactyla, Haeckel, 1879.

The four primary radial-canals give rise to simple or branched side branches. No ring- canal. With intertentacular lines of nematocysts upon the exumbrella above the bell-margin. Gonads on the adradial sides of the stomach extending outward along the sides of the four main radial-canals.



WILLSIA, Forbes, 1846.

Similar to ProbosciJactyla, but with six or more primary radial-canals. The hydroid belongs to the genus Lar Gosse.

Order 2. LEPTOMEDUSjE Haeckel, 1886.

Hydromedusae with gonads upon the radial-canals. When present the otoliths are of ectodermal origin. The medusae arise through alternation of generations from Campanu- larian hydroids.

Family No. i, THAUMANTIAD^).

Leptomedusae without lithocysts.

Subfamily No. i, MELICERTIN^.

With simple, unbranched radial-canals and an equal number of lips, without oral ten- tacles. Cirri or marginal clubs may or may not be present.

THAUMANTIAS, Eschscholtz, \%29 = Tetrtinfmti + T/iiiii>tiiinti(is, Haeckel, 1879.

Four or more tentacles. Four radial-canals. No marginal clubs or cirri. Hydroid: T haumantias.

LAODICEA, Lesson, i$4$ = Octonema + Laodice, Haeckel, 1879.

Four or more tentacles. Four radial-canals, with marginal clubs or cirri. Hydroid: Cuspidella.

MELICERTUM, Oken, 1815; sensu L. Agassiz, i%ta=Melicertella+Melicertum, Haeckel, 1879. With eight or more tentacles. Eight radial-canals. No marginal clubs or cirri. Hydroid: Melicerturn Agassiz.

M.ELlCER.TlSSA = Mclicertissa + MflicfrtiJnitn, Haeckel, 1879.

Similar to Melicertum, but with marginal clubs or cirri between the tentacles.

ORCHISTOMA, Haeckel, 1879.

More than eight radial-canals. With or without marginal clubs or cirri.

TIMOIDES, H. B. Bigelow, 1904.

Four radial-canals. The ring-canal gives rise to blindly-ending centripetal diverticula. Numerous tentacles and cirri. Four gonads on the four radial-canals. Stomach mounted upon a peduncle.

Subfamily No. 2, POLYORCHIN.E.

The radial-canals give rise to branches which end blinJlv and do not connect with the marginal ring-canal.

STAURODISCUS, Haeckel, 1879.

With four radial-canals, each of which gives rise to two side branches, which end blindly.

PTYCHOGENA, A. Agassiz, 1862, 1865.

With four radial-canals which give rise to numerous blindly-ending side branches. Gonads leaf-shaped and developed upon the side branches of the radial-canals.

POLYORCHIS, A. Agassiz, 1862 to 1865.

With four radial-canals which give rise to numerous blindly-ending side branches. Numerous sac-like, sausage-shaped gonads attached to the radial-canals and to their side branches. Ring-canal simple. Bell-margin not cleft into lappets.

SPIROCODON, Haeckel, lS^g = Goniomeam/rus, Kirkpatrick, 1903.

Similar to Polyorchis, but the ring-canal gives rise to blindly-ending, centripetal branches, and bell-margin is cleft into lappets.


Subfamily No. 3, BERENICINJE. The radial-canals give rise to branches which connect with the ring-canal.

CANNOTA, Haeckel, 1879.

With four radial-canals, each of which gives rise to two side branches which join the ring-canal.

CuviERIA, Peron, 1807 = Berenice, Haeckel, 1879.

With four main radial-canals which give rise to numerous non-dichotomous side branches. Gonads on the terminal ramuli of the canals.

DICHOTOMIA, Brooks, 1903.

With four main radial-canals which divide dichotomously two or more times. The gonads extend outward from the stomach over the canals.

DIPLEUROSOMA, Axel Boeck, i$66 = Tetracannota, Mayer, 1900.

With three or more main radial-canals which give rise to non-dichotomous side branches. Gonads on the canals adjacent to the stomach. Hydroid: Cuspidella (?).

ToxoRCHiS = Toxorchis + ClaJocanna, Haeckel, 1879.

Four or more main radial-canals which branch dichotomously one or more times. Gonads on the outer branches of the canals near the ring-canal.


Eight main radial-canals which branch dichotomously. Gonads extend outward from the sides of the stomach along the radial-canals.

Family No. 2, EUCOPID^.

Leptomedusaewith lithocysts, and with less than eight radial-canals upon which the gonads are developed.

Subfamily No. i, OBELIN^E. With eight adradial lithocysts. Four radial-canals. Stomach without a peduncle.

EUCOPELLA, von Lendenfeld, 1883.

Degenerate medusae. No tentacles. No manubrium. Branched radial-canals. Hydroid:


AGASTRA, Hartlaub, 1897.

Degenerate medusae. No manubrium. Simple, unbranched radial-canals. Hydroid: Campanularia ( ?).

EUCOPE, Gegenbaur, 1856.

Basal bulbs of the tentacles are simple and hollow, and do not project inward into the gelatinous substance of bell. Lithocysts on bell-margin. Hydroid: Campanulana.

OBELIA, Peron and Lesueur, 1809.

Entodermal cores of tentacles project inward into the gelatinous substance of the bell. Otocysts on bases of tentacles. Hydroid : Obelia.

TIAROPSIS, L. Agassiz, 1849.

An ocellus with entodermal pigment above each lithocyst. Tentacle-bulbs simple and hollow.

Subfamily No. 2, PHIALIN^.

With more or less than eight lithocysts. Four to five radial-canals. Stomach without a peduncle.

CLYTIA, Lamouroux, \%i2 = Ef>enthesis, McCrady, 1857.

Sixteen tentacles alternating with sixteen lithocysts. Four radial-canals. No cirri. Hydroid: Clytia.


PHIALIDIUM, Leuckart, i%$() = 0<:eania, Agassiz, 1862, 1865.

Sixteen or more tentacles. More than sixteen lithocysts. Four radial-canals. No rudi- mentary tentacles. No cirri. Hydroid: Campanulina.

PHIALUCIUM, Maas, 1905.

Similar to Phialidium, but with permanently rudimentary tentacle-bulbs. Hydroid un- known.


Numerous tentacles and lithocysts. Entodermal cores of some or all of the tentacles project inward into the gelatinous substance. Four radial-canals. No cirri. No permanently rudimentary tentacles.

PSEUDOCLYTIA, Mayer, 1900.

Five radial-canals, five lips, five gonads. Numerous tentacles and lithocysts. No cirri.

GASTROBLASTA, Keller, \?>?>^=Multioralis, Mayer, 1900.

Two or more manubria. No cirri. The medusa propagates by fission.

EUCHEILOTA, McCrady, 1857.

Four or more closed vesicular lithocysts. Four radial-canals. Marginal or lateral cirri. Hydroid: Campanulina ( ?).

MnROCOMA = Phialis + Mitrocoma + Mitrocomiurn + Mitrocomella, Haeckel, 1879.

Similar to Eucheilota, but the lithocysts are contained in open folds of the velum. No entodermal ocelli such as are found in Tiaropsis.

STAUROPHORA, Brandt, lS^ = Staurostoma + Staurof>hora, Haeckel, 1879.

Mouth an open, cruciform, gutter-like slit extending down the four radial-canals.

Subfamily No. 3, EUTIMINJE.

With eight adradial lithocysts. Stomach mounted upon a gelatinous peduncle. Four radial-canals.

SAPHENIA, Eschscholtz, 1829.

Two tentacles. Numerous cirri.

EUTIMA, McCrady, 1 857 = Eutima + Eutimeta + Octorchis + Octorchandra

-\-Eutnnalphcs, Haeckel, 1879.

Four or more tentacles. Numerous cirri or marginal warts. Four or eight gonads upon the four radial-canals. Hydroid: Campanopsis (Claus, Brooks).

JLwTIMlUM = Eutimium + Octorchi(lium, Haeckel, 1879.

Similar to Eutima, but without cirri. Hydroid: Campanulina ( ?)

Subfamily No. 4, EIRENINvE.

With more than eight lithocysts. Stomach mounted upon a gelatinous peduncle. Four or six radial-canals.

PHORTIS, McCrady, 1857.

Four or more tentacles. No cirri. Four radial-canals. Hydroid: P/iortis Brooks.

IRENOPSIS, Goette, 1886, non Ireniopsis, Mayer, 1894.

Six or more tentacles. Six radial-canals. Six lips. Six gonads.

EIRENE, Eschscholtz, i%2g= Irene +Irenittm, Haeckel, 1879.

Four or more tentacles. Numerous marginal warts or cirri. Four or eight gonads developed upon limited parts only of the four radial-canals. Hydroid: Campan- ulina ( ?)

TIMA, Eschscholtz, 1829.

Similar to Eirene, but with gonads upon the entire lengths of the four radial-canals. Hydroid: Campanulina ( ?)


Family No. 3, ^EQUORIDjE.

Leptomedusae with otocysts, and with eight or more radial-canals.

OCTOCANNA, Haeckel, 1879.

Eight radial-canals, 45° apart. Eight lips. No ocelli. (Is this a young jEquorea ?)

OCTOGONADE, Zoja, 1896.

Similar to Octocanna, but the marginal sense-organs have ocelli as well as lithocysts.

STOMOBRACHIUM, Brandt, lS^^ = Stomobrachium + Staurobrac/iium, Haeckel, 1879.

Eight or more simple, unbranched radial-canals, which arise at equal intervals from the margin of the stomach. Four lips.

HALOPSIS, A. Agassiz, 1863, 1865.

Radial-canals arise in four groups from the four perradial corners of stomach. Four lips.

^EQUOREA, Peron and Lesueur, i$og = &(juorea + R/iegmatoJes + Mesonema

-\-Polycanna, Haeckel, 1879.

More than eight simple, unbranched radial-canals which arise separately from the mar- gin of the stomach. More than four lips. Subumbrella smooth, without gelatinous papilla-like protuberances. Hydroid: Campanulina.

ZYGODACTYLA, Brandt, 1835; sensu Agassiz, 1862.

Similar to jEquorea, but with interradial rows of papilla-like, gelatinous protuberances upon the subumbrella.

, Haeckel, 1879.

With bifurcated or branched radial-canals which arise at equal intervals from the margin of the stomach. More than four lips. No peduncle.

ZYGOCANNULA, Haeckel, 1879.

Similar to Zygocanna, but the stomach is mounted upon a gelatinous peduncle.

Order No. 3. TRACHYMEDUS.E Haeckel, 1866.

Medusae with a marginal velum, and with lithocyst concretions of entodermal origin. With simple uncleft bell-margin.

Family No. i, OLINDIADJE.

Some or all of the tentacles project from the sides of the bell, above the margin, and have adhesive disks. Gonads linear, sac-like, or folded, and developed upon the four or six radial- canals. The tentacles arise separately and are not grouped in clusters.

GONIONEMUS, A. Agassiz, 1862, 1865.

All of the tentacles project from sides of bell in a zone slightly above bell-margin. All have adhesive disks. Four radial-canals. Lithocysts external, on bell-margin. No centripetal canals. Development through an attached hydra stage. (Perkins.)

CUBAIA, Mayer, 1894.

Similar to Gonionemus, but with two sets of tentacles, one arising from the bell-margin and the other set projecting from the sides of the bell, as in Gonionemus.

VALLENTINIA, Browne, 1902.

Similar to Cubaia, but with lithocysts inclosed within the gelatinous substance of the bell, adjacent to the ring-canal, and on the inner side above the velum. (Is this a young Olindias])

OLINDIAS, F. Miiller, 1861.

Similar to / allentmia, but with blindly-ending, centripetal diverticula from the ring-canal.


OLINDIOIDES, Goto, 1903.

Similar to OlinJias, but with six radial-canals (two bifurcated and two simple). Six gonads. Four lips. The exumbrella tentacles project at various levels from the sides of the bell.

Family No. 2, PETASIDjE Haeckel, 1879.

Trachymedusae with tour radial-canals upon which the linear or sac-like gonads are developed. Tentacles without adhesive disks. Four lips.

PET ASUS = Pftasus + Dif>etasus + Petas(ita + Pftacli>: uni, Haeckel, 1879.

Tentacles arise at equal intervals, not grouped into clusters. No centripetal canals. Free marginal hthocyst-clubs.

AGLAUROPSIS, F. Miiller, 1865.

Similar to Petasus, but the lithocysts are vesicular, and project from the bell-margin between the tentacles.

CRASPEDACUSTA, Lankester, i$%o=LimnocoJium, Allman, 1880.

Tentacles arise singly as in Pi-tnsus and Aglauropsis, but the lithocyst concretions are each inclosed in a cavity within the gelatinous substance of the velum on the inner (centripetal) side of the ring-canal. (The medusa lives in fresh water among water- lilies.) The hydroid is devoid of tentacles.

MlCROHYDRA, PottS, 1885.

Is possibly identical with Limnocodiutn, but the mature medusa is unknown. The young medusa has no lithocysts, and it arises by budding from a minute hydroid which has no tentacles.

MJ^OTIAS, OstroumofF, 1896.

Tentacles arise at equal intervals, not in clusters. Numerous centripetal, blindly-ending canals arise from the ring-canal.

GOSSEA, L. Agassiz, 1862.

Tentacles grouped into clusters. No centripetal canals. Lithocyst concretions free or inclosed.

Family No. 3, LIMNOCNIDIDjE.

Numerous hollow tentacles which project singly, not in clusters, from the sides of the bell in a zone slightly above the margin. Tentacles without adhesive disks. Numerous inclosed lithocysts on the exumbrella side of the velum. Mouth a round opening. Gonads developed diffusely in the ectoderm of the stomach-wall. Four (occasionally five or six) radial- canals. Medusa-buds arise from the sides of the stomach, and are set free.

LIMNOCNIDA, Giinther, 1893.

Generic characters are those of the family. The only known species is /,. tanganjicd from the fresh-water lakes of Central Africa, and the Niger river.


Numerous more or less isolated clusters of tentacles, some of which bear adhesive disks. Numerous free lithocyst-clubs. Eight radial-canals. Four lips. Stomach eight-lobed. These stomach-lobes are in the radii of the radial-canals, and are bound to the subumbrella by means of eight mesenterial partitions. The gonads are upon the eight stomach-lobes, and each is more or less divided by the mesentery so there may be eight double (sixteen) gonads.

PTYCHOGASTRIA, Allman, iSfi^Pcctyllis + Pectis + Pectanthis, Haeckel, 1879. The generic characters are those of the family.

Family No. 5, TRACHYNEMID^E.

Trachymeduss with eight simple radial-canals upon which the gonads are developed. No mesenterial partitions in the subumbrella. Tentacles without adhesive disks. Ring- canal simple without centripetal branches.


Subfamily No. i, RHOPALONEMINjE.

Trachynemidae in which the stomach lacks a peduncle. RHOPALONEMA, Gegenbaur, iS^6=Trachynema (young medusa), Gegenbaur, 1854

= Trachynema + Rhopalonema + Marmanema, Haeckel, 1879.

With eight well-developed radial tentacles, and eight or more small cirrus-like or club- shaped interradial tentacles. All tentacles arise in a single row. Eight gonads localized on the eight radial-canals. Four lips. SMINTHEA, Gegenbaur, 1856.

Similar to Rhopalonema, but with only eight tentacles, one at the foot of each of the

eight radial-canals.

HOMCEONEMA, Maas, i8g3 = Colobonema, Vanhoffen, igo2 = lsonema (in part), Maas, 1906. Similar to Rhopalonema, but the tentacles are all of one sort. No small club-shaped or

cirrus-like tentacles. Four lips. PANTACHOGON, Maas, 1893 (sens. ampl.).

Gonads not localized as in Homceonema and Rhopalonema, but developed diffusely over

the radial-canals. Four lips. HALICREAS, Fewkes, i$82 = Halicreas + Haliscera, Vanhoffen, 1902

= Isonema (in part), Maas, 1906.

The mouth is a simple round opening, without four lips. (In all known species the radial-canals and ring-canals are very broad and flat.) Wart-like protuberances may be present upon the sides of the exumbrella. Radial tentacles large, interradial, small. Tentacles arise in a single row. BOTRYNEMA, Browne, 1908.

Similar to Halicreas, but the tentacles are grouped in linear clusters in a single row

around the bell-margin. CROSSOTA, Vanhoffen, 1902.

The tentacles arise in several rows from the bell-margin. Mouth with four lips.

Subfamily No. 2, AGLAURINjE.

Stomach mounted upon a peduncle. AGLAURA, Peron and Lesueur, 1809.

Eight gonads upon the peduncle above the stomach. Sexes separate. Development direct. AGLAmHA = /fglantha + 4glisi:ra, Haeckel, 1879.

Eight gonads upon the subumbrella, or at the turning points of the eight radial-canals

between the peduncle and the subumbrella. Sexes separate. AMPHOGONA, Browne, 1904.

Similar to Aglantha, but medusa is bisexual, four of gonads being male, and four female. STAURAGLAURA, Haeckel, 1879.

Four gonads, one upon each alternate radial-canal. PERSA, McCrady, 1857.

Two gonads on two of the radial-canals, 180° apart. The six other radial-canals are sterile.

Family No. 6, GERYONIDjE.

Trachymedusae with four or six radial-canals upon which the flat, expanded, leaf-like gonads are developed. Stomach mounted upon a gelatinous peduncle. The ring-canal gives rise to blindly-ending centripetal canals. LIRIOPE, Lesson, i%^ = Linantha -\-Lirwpc + Glossocodon -\-Glossoconus, Haeckel, 1879.

Four radial-canals. Four gonads. Four lips. With four primitive, solid, radial, and four solid interradial, and four hollow, flexible, radially-placed tentacles; all twelve of which may be found upon the medusa at one and the same time. Development direct through a free-floating, actinula-like larva. GERYONIA, Peron and Lesueur, i8og = Geryones + Geryonia + Carmaris

+ Carmarina, Haeckel, 1879. Similar to Liriope, but with six radial-canals, six gonads, six lips, etc.; instead of four.


Order No. 4. NARCOMEDUS^ Haeckel, 1879.

Veiled medusae with bell-margin cleft into intertentacular lappets. With free lithocyst- clubs, containing concretions of entodermal origin. These medusx develop from actmula larvae either directly or by budding. The bell grows outward from the sides ot the body of the actinula, or the medusa-bud, leaving the tentacles stranded in the partially closed-over clefts between the lappets of the bell. The Narcomedusae are thus medusiform, actinula-like animals, the bell of which is not homologous with that of the Anthomedusae or Leptomedusae.

Family No. i, SOLMARIDjC.

Narcomedusae in which the outer margin of the stomach is plain, entire, and without peripheral stomach-pouches. Saccules may, however, arise from the subumbrella floor of the stomach.

o/)'fo//>a (young) + Sohnaris, Haeckel, 1879. Without subumbrella saccules. Gonad is a simple annulus in ectoderm of subumbrella

floor of stomach. PEGAJXTBA=Pegasia+Polyxenia+Pegantha+SoImoneta (in part), Haeckel, 1879.

With out-pocketings on the subumbrella floor of the stomach. The gonads are developed in these subumbrella saccules.

Family No. 2, jEGINID^E, sens. ampl.

Narcomedusae in which the central stomach gives rise to simple or cleft marginal out- pocketings in the radii of the tentacles.

CUNANTHA, Haeckel, 1879.

Four tentacles. Four peronial strands in the tentacular radii. Four simple, uncleft, peripheral stomach-pouches in the radii of the tentacles. This "genus" is prob- ably only a young stage of JEgina. JEciNA, Eschscholtz, i$2g = Cunarcha + £gina + SolmunJus, Haeckel, 1879.

Four tentacles. Four peronial strands. Four cleft ( = eight peripheral) stomach-pouches, outer margins of which may be still further divided.

SoLMUNDELl.A=dlgi>iella + SolmunJella, Haeckel, 1879.

Two tentacles. Four peronial strands. Four cleft ( = eight peripheral) stomach-pouches. An apical (exumbrella) sense-organ is present in larva, but does not persist in adult. Derived from jEgina by the disappearance of half ot its tentacles.

HYDROCTENA, DawydofF, 1903.

Two tentacles. No peronial strands. Two simple, uncleft stomach-pouches in the tentacular radii. There is an apical (exumbrella) sense-organ consisting in a ciliated pit containing two lithocyst-clubs. A median axial canal extends upward from the stomach to the bottom of the sensory pit.

CUNOCTANTHA, Haeckel, 1879.

Eight tentacles. Eight peronial strands. Eight simple, uncleft stomach-pouches in the tentacular radii.

unoctona + ^Eginura, Haeckel, 1879.

Eight tentacles. Eight peronial strands. Eight cleft ( = sixteen peripheral) stomach- pouches. The outer margins of these pouches may be still further divided so as to give thirty-two marginal pouches.

S, Brandt, 1835.

Four tentacles. Eight peronial strands. Eight cleft ( = sixteen peripheral) stomach- pouches. Derived from jEginura by the disappearance of half of its tentacles.

CUNINA, Eschscholtz, 1829.

Nine or more tentacles, and an equal number of peronial strands. Peripheral stomach- pouches simple, uncleft and equal in number to the tentacles, in the radii of which they are developed. With otoporpae above the sense-clubs.


SOLMISSUS, Haeckel, 1879.

Similar to Cunina, but without otoporpae.

CvNlSSA = Cnnissa + ^EginoJorus, Haeckel, 1879.

Nine or more tentacles, and the same number of peronial strands. Peripheral stomach- lobes twice as numerous as the tentacles, being cleft in the tentacular radii.

jEciNODiscus, Haeckel, 1879.

Eight tentacles, sixteen peronial strands. Sixteen cleft ( = thirty-two peripheral) stomach- pouches.


Under this heading we may place the degenerate, free-swimming medusae of Millepora. They have no velum and are thus separated from the veiled medusae or Craspedotae. Not only is the velum absent, but the medusa is also devoid of a peripheral canal system and of marginal tentacles.

The medusae Milleponna? and Craspedotae are doubtless derived from a common ancestral phylum, but have departed widely, one from the other, so that the Craspedotae are constantly characterized by a diaphragm-like membrane, or velum, which partially closes the opening of the bell-cavity at the tentacular margin; whereas this structure is absent in the Milleporinae.

The only known forms of Medusae Milleporinae are those of Millepora.

Millepora alcicornis (Medusa).

Millepora (medusa*), HICKSON, 1900, Proc. Roy. Soc. London, vol. 66, p. 3, figs. i-io. DUERDEN, 1899, Journal of the Institute of Jamaica, March, 1899. HICKSON, 1906, Cambridge Natural History, vol. I,