124 THE ROYAL SOCIETY OF CANADA 



Eudendrium vaginatum Allman 



PI. VI, Fig. 17 



Eudendrium vaginatum Allman, Ann. and Mag. Nat. Hist., 3rd ser., 



11, 1863, p. 10. 

 Eudendrium vaginatum Nutting, Harriman Hydroids, 1901, p. 167. 

 Eudendrium vaginatum Fraser, West Coast Hydroids, 1911, p. 25. 



Trophosome. — Colonies growing in small clusters may reach a 

 height of 40 mm.; main stem much larger than the branches, the 

 latter usually short and apparently loosely connected with the stem; 

 tentacles fewer than 20; perisarc annulated throughout, the annulœ 

 being farther apart and not so distinct as in E. calif or nicum; the 

 perisarc passes up on the body of the hydranth to the base of the 

 tentacles, forming a cup-shaped portion that may be quite smooth 

 or may be somewhat wrinkled. 



Gonosome. — Male gonophores 2-chambered in a whorl about 

 the base of the hydranth which is not aborted; "female gonophores 

 in dense clusters around the bodies of hydranths that are usually 

 devoid of tentacles. Each gonophore is borne on a pedicel which 

 resembles that of a Garveia having a distinctly expanded collar a short 

 distance below the hydranth." (Nutting). 



Color. — Perisarc dark brown, hydranth vermilion. 



Distribution. — Swiftsure Shoal. 



No female gonophores are present in my material. The descrip- 

 tion and the figure are from Nutting. 



Family Hydractinidae 



Trophosome. — Colony formed of distinct nutritive and generative 

 zooids, growing from a common basal ccenosarc, which ordinarily 

 is beset with spines. Other kinds of zooids may also be present. 

 Hydranths with a row of filiform tentacles; proboscis conical or 

 clavate. 



Gonosome. — Gonophores in the form of fixed sporosacs on special 

 generative zooids. 



Genus HYDRACTINIA 



This is the only genus of the family Hydractinidœ. 



Key to the species of Hydractinia in the Vancouver I. region. 



A. Spines jagged; sporosacs with several ova H. aggregata 



B. Spines smooth; sporosacs each with one ovum H. milleri 



Hydractinia aggregata Fraser 



PI. VI, Fig. 18 

 Hydractinia aggregata Fraser, West Coast Hydroids, 1911, p. 25. 



