140 



DEPARTMENT OF THE NATAL SERVICE 



Sub-order B. Calyptoblastea. 



Hydroids with hydrantlis protected by hydrotbecse and gonopbores protected by 

 gonangia or other similar structures. 



a Hydranths with trumpet-shaped proboscis and campanulate hydrotbecse. 



' CampanularidicB'. 



aa Hydranths with conical proboscis and tubular or turbinate hydrotbecse. 

 h Hydrothecae with an operculum of converging segments. 



Campanulinidcp. 

 hh. Hydrothecae without operculum. 

 c Gonosome a coppinia mass. 

 cc Gonangia not collected into a mass. 



aaa Hydrotbecse reduced to saucer-shaped hydrophores, 



aaaa Hydrotbecse sessile, adnate to main stem or branches. , 



d Hydrothecae arranged on both sides of branches. 

 dd Hydrotbecse on one side only of branches. 



Lafoeidoe. 

 Hehellidce. 



Halecidce. 



ScrtularidiB. 

 Plumularid'V. 



Sub-order GYMNOBLASTEA. 

 Family GLAVID^. 



^ Trophosome. Hydranths elavate or fusiform with scattered filiform tentacles. 

 Gonosome. Gonophores producing fixed sporosacs. 



KEY TO GENERA. 



a Colony branched. 



b Zooidfi rising singly from the stolon. 



ordylophora. 



Clava. 



Genus Cordylophora. 



Trophosome. Colony branched, main stem well developed; hydranths with scat- 

 tered filiform tentacles; proboscis fusiform. 



Gonosome. Gonophores borne on the stem or branches, produce fixed sporosacs. 



Cordylophora lacustris AUman. 



Trophosome. Colony regularly branched, main 

 branches also branched, 6 cm. in height ; branches and 

 pedicels annulated at the base; hydranth with 16-20 

 scattered filiform tentacles. 



Gonosome. Gonophores oval on very short, annu- 

 lated pedicels, borne on the stem or branches, invested 

 by a thin perisarcal covering. 



No. 1. 

 Cordylophora lacit^tris 



