68 SERTULARITE. 



ployed by Agassiz, Leuckart, and Vogt. Sars, in his paper on Cory- 

 morpha, has developed it fully, quoting many instances in suj^port of 

 this theory. Allman, in a recent paper on the Classification of Hy- 

 droids, has carried the same method out for the Tubularians. 



Suborder SERTULARIiE Agass. 



Scrtularue Agass. Cont. Nat. Hist. U. S., IV. p. 348. 18( 

 Serlularina Ehrenb. Corall. Ues roth. Meeres. 

 Sertularina Johnst. Bi-it. Zooph., p. 56. 



Family OOEANID^ Esch. {rest. Ag.). 



Oceaniflce Escn. Syst. d. Acal., p. 96. 1829. 



EucopidiB Gegenb. (p. p.). Versuch eines Syst. d. Med., p. 241. 1856. 



Oceanidce Agass. Cont. Nat. Hist. U. S., IV. p. 352. 1862. 



The free Medusae which belong to this family are characterized in 

 their adult condition by the flatness of the bell, and its thinness, long, 

 hollow tentacles, not very numerous, four chymiferous tubes, marginal 

 capsules, and a short proboscis. The Hydrarium is remarkable for its 

 ringed or pedunculated reproductive calycles. 



The genus Thaumantias, until the time of Forbes, contained in it 

 Medusa3 belonging to several genera. Forbes first proposed to divide 

 it, and suggested the name Cosmetira for his lliawnantias pilosella. 

 Gegenbaur, in 1856, proposed another name, that of Eucope, which in- 

 cluded several species of the genus Thaumantias, belonging to a dif- 

 ferent family, the Eucopidse. 



As long as the numerous species of Thaumantias, described by Forbes, 

 have not been investigated again with sjiecial reference to the marginal 

 capsules, it is impossible to assign many of them their true position in 

 the genera Eucope, Oceania, and Laodicea, which have been distin- 

 guished in these Acalephs. It seems to me doubtful whether the genus 

 Epenthesis of McCrady can be retained, and I think it will eventually 

 prove identical with Oceania, if we limit the genus to such species as 

 Thaumantias hemis2)hairica of Forbes. The Hydra of Oceania is a 

 Wrightia ; that of the Eucope diaphana of our coast is a Laomedea, 

 resembling the L. geniculata of England. The genus Eucope of Gegen- 

 baur would be limited to those species which have small ovaries, occu- 

 pying but a short .space of the chymiferous tubes ; and instead of 

 having the long, thin, and exceedingly contractile tentacles of Oceania, 

 have short, . stout, knotty tentacles, which are carried straight from the 

 edge of the disk, are hardly contractile, and have a prolongation inside 

 of the circular tube. 



