[frasrrI HYDROIDS OF THE VANCOUVER ISLAND REGION 155 



. Obelia surcularis Calkins 



PI. XVII, Fig. 58 



Obelia surcularis Calkins, Hydroids of Puget Sound, 1899, p. 355. 

 Obelia surcularis Fraser, West Coast Hydroids, 1911, p. 40. 



Trophosome. — Colonies grow from a branched stolon; each main 

 stem gives rise to several branches arranged in quite- regular alter- 

 nation; stems and large branches usually end in long tendrils that may 

 or may not have hydrothecse at the distal ends; on the branches the 

 internodes are often quite short; stem and branches annulated above 

 the nodes; pedicels annulated throughout or at the ends only; hydro- 

 thecse regularly campanulate with the margin sometimes slightly 

 everted; margin entire. 



Gonosome. — Gonangia numerous in the axils of the branches and 

 pedicels towards the base of the colony; they are rather long expanding 

 gradually from base to extremity; collar low. 



Distribution. — On water grasses abundant in Scow Bay, Port 

 Townshend (Calkins); Kanaka Bay. 



Family Campanulinidae 



Trophosome. — Colonies branched or unbranched, hydrothecse 

 pedicellate or sessile, always operculate, the operculum formed of 

 converging segments; hydranths with conical proboscis. 



Gonosome. — Gonophores producing planulae or free medusa?. 



Key to the genera of Campanulinidae in the Vancouver I. region. 



A. Hydrotheca pedicellate 



a. Hydrothecal margin distinct 



1 . Hydrotheca tubular Calycella 



2. Hydrotheca turbinate Lovenella 



3. Operculum shaped like an A-tent Stegopoma 



b. Hydrothecal margin indistinct 



1. Hydrotheca oval or ovate; reproduction by free medusae 



Campanulina 



2. Hydrotheca elongated oval ; reproduction by fixed 



sporosacs Opercular 'ell a 



B. Hydrotheca sessile 



Hydrotheca tubular; margin not very distinct Cuspidella 



Genus CALYCELLA 



Trophosome. — A creeping stolon gives rise to tubular hydrothecse 

 on annulated pedicels; hydrothecal margin distinct. 



Gonosome. — Gonangia borne on the solon; acrocysts are produced. 



