118 THE ROYAL SOCIETY OF CANADA 



over the body of the hydranth to the body of the tentacles; tentacles 

 10 in number. 



Gonosome. — Gonophores borne on the stolon; sporosacs, oval or 

 globular borne on distinct pedicels, nearly as long as the vertical 

 diameter of the sporosacs. The sporosac is at first covered with 

 thin perisarc which is like a thin sack, but this soon ruptures, leaving 

 a somewhat wrinkled or flapped portion to form the cup at the base 

 of the sporosac. Unlike G. nutans, the peduncle of the sporosac 

 is very short so that the base of the sporosac is but a short distance 

 above the cup-like prominence on the perisarc of the pedicel. 



Color .—Stem inconspicuous, hydranth yellowish-green. 



Distribution. — Dodds Narrows, Gabriola Pass, Gabriola Reefs, 

 Whaleboat Passage, Swiftsure Shoal, off Matia I., off O'Neale I., 

 Pt. Townshend. 



Levinsen, in the original description of this species, gave 

 no figures and hence it is difficult to be sure that one has the same 

 species, even if it answers exactly to his description. Nutting reports 

 G. nutans from the Alaskan coast, 11 but these specimens certainly do 

 not belong to that species as G. nutans is a much coarser species with 

 a much branched stem and the peduncle of the sporosac is con- 

 siderably elongated. 



Family Bougainvillidae 



Trophosome. — Hydranths fusiform or clavate; proboscis conical 

 or dome-shaped; tentacles filiform but somewhat short and rigid, 

 in one whorl around the base of the hydranth body. 



Gonosome. — Gonophores producing free medusae. 



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



A. Colony much branched; medusae with clusters of tentacles 



Bougainvillia 



B. Colony unbranched or sparingly branched; medusae with ten- 



tacles arranged singly Perigonimus 



Genus BOUGAINVILLIA 



Trophosome. — Colonies fascicled, much branched; perisarc well 

 developed on stem and branches; hydranths fusiform, proboscis dome- 

 shaped or conical. 



Gonosome. — Gonophores supported on short pedicels; medusae 

 with four radial canals and four clusters of tentacles; tentacle bulb 

 ocellate. 



11 Harriman Hydroids, 1901, P. 166. 



