[fraser] HYDROIDS OF THE VANCOUVER ISLAND REGION 153 



Obelia griffini Calkins 

 PI. XVI, Fig. 54 



Obelia griffini Calkins, Puget Sound Hydroids, 1899, p. 357. 

 Obelia griffini Fraser, West Coast Hydroids, 1911, p. 39. 



Trophosome. — Stems much branched, giving the colony a decidedly 

 bushy appearance although it seldom reaches a height of 50 mm. 

 and is often not more than half that; stem and branches annulated 

 above the nodes; the shorter pedicels are annulated throughout and 

 sometimes the longer ones are also but at other times there is a smooth 

 place in the centre ; hydrothecae campanulate with convex sides, 

 margin entire. 



Gonosome. — The gonangia are borne in the axils on annulated 

 pedicels, more slender than usual in Obelia species, very gradually 

 increasing in diameter from base to apex, smooth or slightly wavy; 

 collar distinct. 



Distribution. — Puget Sound (Calkins); Departure Bay (Fraser); 

 Ucluelet, Dodds Narrows, Gabriola Pass, Porlier Pass, Friday Harbor, 

 off Sucia Is., Pt. Townshend, West Seattle. 



Obelia longissima (Pallas) 



PI. XVI, Fig. 55 



Sertitlaria longissima Pallas, Elench. Zooph., 1766, p. 119. 

 Obelia longissima Fraser, West Coast Hydroids, 1911, p. 39. 



Trophosome. — Stem filiform of great length, sometimes reaching 

 50 or 60 cm. ; much branched, branches alternate; stem usually sinuous 

 where the branches are given off; stem horn color or in old specimens 

 quite black, annulated at base and above each node as are also the 

 branches; pedicels short and annulated throughout or longer and 

 annulated at each end; hydrothecae campanulate; margin wavy but 

 sometimes the "waves are so shallow as to be almost imperceptible. 



Gonosome. — Gonangia in the axils, oval, with a distinct collar and 

 rather small aperture, usually smooth but sometimes corrugated. 



Distribution. — Banks I., Departure Bay, Dodds Narrows, San 

 Juan Archipelago (Fraser) ; everywhere in the vicinity of Departure 

 Bay, Lasqueti I., Nanoose Bay, Dodds Narrows, Gabriola Pass, 

 Sucia Is., Friday Harbor, West Seattle, Port Townshend, Griffin 

 Bay, Clayuquot Sound. 



This is the commonest shallow water campanularian in the 

 region. It grows throughout the whole year on the station float, 

 Departure Bay, and medusae are freed at many times during the year. 

 The medusae as they are freed usually have 26 tentacles but some- 

 times the number is 1 or 2 short of that. 



