MEDUSAE OF THE WORLD. 



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. 



