274 SYNCORYNIDiE. 



has been shown to take place through actinula^, tlie onl}' other genera which have as yet 

 afforded evidence of this mode of development being Tahiilaria, Myriothela, and Hydra} 



SYNCORYNIDv^. 



TROPHOSOME. — Hydrocaulus developed or not developed, hyduanths with 

 scattered, or partly scattered and partly verticillate capitate tentacles. 



GONOSOME.' — Gonopliores in the form of raeduslform planoblasts with four 

 radiating- canals and simple (rarely undeveloped) marginal tentacles. 



SYNCOEYNE, Ehrenberg (in part). 



Name. — From aw, indicating union, and Koovvn, a club, in allusion to the numerous club-shaped 

 hydranths united into a common colony. 



TROPHOSOME. — Hydrophyton consisting of a simple or branching uyuro- 

 CAULUs, with a creeping filiform hydkokhiza; the whole invested by a chitinous 

 PERiSARC. Hydranths claviform, with scattered capitate tentacles. 



GONOSOME. — Planoblasts, developed upon the body of the hydranth. Medusa, 

 at the time of liberation, with a deep bell-shaped umbrella ; manubrium moderately 

 large, destitute of oral tentacles ; marginal tentacles four, with bulbous bases usually 

 furnished with an ocellus ; or the medusse may never become free, the marginal 

 tentacles remaining at the same time in an imperfectly developed state. 



When Sars saw the necessity of reducing to some kind of zoological consistency the 

 confused state into which the genus Coryne had fallen, he founded, as has been already said,*^ his 

 genus Stipula for the reception of all the known claviform hydroids with scattered capitate 

 tentacles. We have seen, too, that Ehrenberg's name of Syncoryne afterwards took the place of 

 Stijjula, and since then it has been by many authors adopted in its stead. 



As the species thus included under Syncoryne increased in number by fresh discoveries, it 

 became evident that very different plans of gonosome were to be found among them ; we now 

 know that some carry only sporosacs, while others give origin to medusee, and still further these 



' Sec Pmt I, p. 94. ■ Vide supra, p. 265. 



