[fraser] HYDROIDS OF THE VANCOUVER ISLAND REGION 147 



This species varies much in size, some specimens being very 

 minute; even at the largest it is not of great size. The fluted hydro- 

 theca is characteristic but the wall is so thin that it is difficult some- 

 times to note the lines for any great distance form the margin. 



Genus EUCOPELLA 



Trophosome. — Stem unbranched, arising from an anastomosing 

 stolon; hydrothecse with very thick walls and smooth margins. 



Gonosome. — Gonophores produce large medusoid structures, 

 never more than two, one large and one small, in the gonangium at 

 one time. They are of an elongated dome shape. They differ from 

 ordinary medusae in not having mouth or digestive cavity. 



Eucopella caliculata (Hincks) 



PL XIV. Fig. 45 



Campanularia caliculata Hincks, Ann. and Mag. N.H., 2nd ser., 11, 



1853, p. 178. 

 Eucopella caliculata Fraser, West Coast Hydroids, 1911, p. 36. 



Trophosome. — Stem unbranched serving as the pedicel for the 

 hydranth, varying in length, slightly wavy or annulated, with a distinct 

 double annulation below the hydrotheca; hydrotheca with very thick 

 wall and entire margin. 



Gonosome. — Gonangium large irregularly obovate, the distal end 

 regularly rounded or somewhat truncate, attached to the stolon by 

 means of a short pedicel. Within the gonangium are two medusoid 

 structures one large occupying the greater portion of the space and 

 a much smaller one below. These are of an elongated oval shape 

 and when liberated are devoid of mouth and digestive cavity. 



Distribution. — Pt. Wilson, Port Townshend, Bremerton (Calkins); 

 San Juan Archipelago (Fraser) ; off Massett, Dodds Narrows, Gabriola 

 Pass, off Matia I., off Fossil I., Friday Harbor, particularly abundant 

 in material from Pt. Richardson, growing on red alga 1 , Coupcville, 

 Pt. Grenville. 



Genus GONOTHYR^A 



Trophosome. — As in the family. 



Gonosome. — Reproduction by fixed medusiform sporosacs fur- 

 nished with tentacles, that at maturity become extracapsular, remain- 

 ing attached until their contents are discharged. 



Key to species of Gonothyrœa found in the Vancouver I. region. 



A. Hydrotheca with castellated margin G. clarki 



B. Hydrotheca with deeply cut, acute teeth G. gracilis 



C. Hydrotheca with entire margin G. inornata 



Sec. IV, 1914—11 



