294 BIMERID^. 



and though the generic name of Dicori/ne must be retained, the specific name of stricta must 

 yield to that of covferfa. 



The trophosome of Dkoryne conferta resembles that of Heterocordi/le Conyhearei so closely 

 that it is difficult to find between them differences to which even a specific value can be attributed. 

 It is, however, quite another thing with the gonosome. That of Dkoryne is widely different 

 from that of Heterocordyle ; for while the gonophores of Heterocordyle are constructed upon the 

 common type of the sporosac, those of Bicoryne present a structure which is absolutely unique, 

 having nothing like it in any other hydroid with which we are acquainted. 



Dk-oryne conferta resembles Hydractinia echinata, in the fact of its selecting for its 

 habitat the surface of univalve shells. While Hydractinia echinata, however, is almost always 

 found on dead shells, whose cavity has been taken possession of by a hermit crab, Bicoryne 

 usually occurs on shells still occupied by their molluscan owners. 



A more detailed account of Bicoryne conferta is given above (Part I, p. 226), where it has 

 been made a subject of special anatomical study. 



BIMEUIBJE. 



TROPHOSOME. — Htdeocaulus developed and Invested with a perisaec, or 

 rudimental. Htdkanths with the hypostome not abruptly differentiated ; tentacles 

 filiform in a verticil round the base of the hypostome. 



GONOSOME. — GoNOPHOEES in the form of fixed sporosacs. 



GAEVEIA, StretUll Wright. 



CoRYTHAMNioN (provisionally), — Allman. 



Name. — From Inch Garvie, one of the rocky islets in the Firth of Forth. 



TROPHOSOME. — Hydrophtton invested with a conspicuous perisarc, and con- 

 sisting of a branching htdrocaulus, rooted by a filiform nxDRORHizA. Htdranths 

 fusiform, with filiform tentacles, which are disposed in a single verticil round the base 

 of a conical hypostome. 



GONOSOME. — Sporosacs developed from the hydrophyton, where they are borne 

 each on the summit of a short ramulus. 



It was at low water spring tides on some of the small rocky islets of the Firth of Forth, 



