HYDROIDS OF EASTERN CANADA 143 



Genus Syncoryne. 



Trophosome. Colony nnbranched or slightly branched; tentacles strongly capi- 

 tate. 



Gonosome. Gonophores producing free medusae with four radial canals and 

 four rudimentary tentacles. 



' Syncoryne mirahilis (Agassiz). 



Trophosome. Colony unbranched or slightly and irregularly 

 branched; hydranth stout; tentacles 15 or more. 



Gonosome. Gonophores nearly spherical, borne among or below the 

 proximal tentacles. 



Family BIMEKID.E. 



Trophosome. Hydranth with conical or dome-shaped proboscis, surrounded by 

 a single whorl of filiform tentacles. 



Gonosome. Gonophores producing fixed sporosacs. 



KEY TO GEXERA. 



a Sporosacs permanently surrounded by perisarc. 



h Sporosacs not permanently surrounded by perisarc. 



Bimeria. 

 Garveia. 



Genus Bimeria. 



Trophosome. Colony usually branched, invested with a conspicuous perisarc, 

 which covers the base of the tentacles; hydranths fusiform. 



Gonosome. Gonophores covered with perisarc throughout the whole period of 

 development. 



Bbneria hrevis Fraser. 



Trophosome. Zooids often appearing singly but 

 sometimes as unbranched or slightly branched colonies; 

 8 mm. in height ; branches given off irregularly ; peri- 

 sarc wringled but not annulated ; creased around the 

 base of the small hydranth; tentacles 11-12. 



Gonosome. Unknown. 



No. 7. 

 Bimeria brevis. 



