[fraser] HYDROIDS OF THE VANCOUVER ISLAND REGION 119 



Key to the species of Bougainvillia found in the Vancouver I. 

 region. 



A. Branches twining around the stem; gonophores in clusters 



B. glorietta 



B. Branching loose ; gonophores single B . mertensi 



Bougainvillia glorietta Torrey 

 PI. IV, Fig. 9 

 Bougainvillia glorietta Torrey, Hydroids of San Diego, 1904, p. 7. 

 Bougainvillia glorietta Fraser, West Coast Hydroids, 1911, p. 23. 



Trophosome. — Stem fascicled, branched, reaching a height of 20-30 

 cm.; branches with a tendency to twine around the stem; perisarc 

 smooth or wavy, but without annulations; tentacles about 20 in number 

 in an irregular whorl. 



Gonosome. — Gonophores borne on the branches, in clusters of 3 

 or some times only 2. Medusae with 4 pairs of tentacles. 



Color. — Stem horn color, other parts lighter. 



Distribution. — Near the entrance of Hammond Bay. 



Torrey reports that the medusae have 8 ocelli present before they 

 are set free. The height given is also taken from his description; I 

 have obtained none so large. 



Bougainvillia mertensi Agassiz 



PI. IV, Fig. 10 



Bougainvillia mertensi Agassiz, Cont. Nat. Hist. U.S., IV, 1862, p. 344. 

 Bougainvillia mertensi A. Agassiz, N. A. Acalephae, 1865, p, 152. 

 Bougainvillia mertensi Fraser, West Coast Hydroids, 1911, p. 24. 



Trophosome. — Main stem thick, fascicled, reaching a height of 

 10 cm.; branching loose, larger branches fascicled; hydranths on rather 

 short pedicels, far apart on the distal branches but not so much so on 

 the proximal; perisarc smooth or wavy, slightly annulated on the 

 pedicels. 



Gonosome. — Gonophores borne singly on short branches, that in 

 some cases are without hydranths. There may be more than one 

 gonophore on a branch but they are not in pairs or clusters. The 

 gonophore is provided with a short pedicel. 



Color. — As in B. glorietta. 



Distribution. — Gulf of Georgia (Agassiz) ; Nanoose Bay, Dodds 

 Narrows, Gabriola Pass, Griffin Bay, Upright Channel, Friday Harbor. 



Genus PERIGONIMUS 



Trophosome. — Colony unbranched or slightly branched; hy- 

 dranths clavate with conical or dome-shaped proboscis. 



