[fraser] HYDROIDS OF THE VANCOUVER ISLAND REGION 205 



depth as were the specimens of this species. Those dredged north of 

 Lasqueti were in a depth of 25-30 fathoms and the others in a depth 

 still less, 15-20 fathoms. The largest specimen was obtained in 

 Northumberland Channel near the entrance to Dodds Narrows on 

 August 12. It was well provided with gonangia. 



Genus PLUMULARIA 



Trophosome. — Hydrocladia unbranched, pinnately arranged, each 

 having more than one hydrotheca; hydrotheca with entire margin; 

 all nematophores movable. 



Gonosome. — Gonangia without extra protection. 



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



A. Septal ridges pronounced in all parts of the hydrocladia; col- 



onies rather large. 



a. Colony much branched P. corrugata 



b. Colony unbranched or but slightly branched. . . P. lagenifera 



B. Septal ridges absent or inconspicious on some of the internodes 



at least; colonies small. 



a. Internodes of the stem often have more than one hydro- 

 cladium; no intermediate internodes in the hydrocladia P. goodei 



b. Internodes of the stem with one hydrocladium only; inter- 

 mediate internodes present in the hydrocladia P. setacea 



Plumularia corrugata Nutting 



PI. XXXV, Fig. 133 



Plumularia corrugata Nutting, American Hydroids, pt. 1, 1900, p. 64. 

 Plumularia corrugata Fraser, West Coast Hydroids, 1911, p. 82. 



Trophosome. — Stem simple, erect, with irregular annulations at the 

 base, divided into regular internodes, each of which gives off a hydro- 

 cladium from a process at its distal end; hydrocladia alternate lying 

 in the same plane, the proximal ones unbranched but the distal usually 

 giving off several branchlets; hydrocladia slender, consisting of alter- 

 nating hydrothecate and non-hydrothecate internodes; the proximal 

 internode is short, with one septal ridge, non-hydrothecate, the second, 

 with usually four well pronounced ridges, bears a hydrotheca, which 

 is about as deep as broad, placed slightly distad to the centre, the third 

 has two septal ridges, and the remainder of the hydrocladium consists 

 of internodes like the second and third, alternating; the intermediate 

 internode is somewhat shorter than the hydrothecate but each 

 is rather long and slender; there are two supracalycine nemato- 

 phores, a mesial on each hydrocladial internode with the 



