790 MrSS HEl.KN PIXELS OX 



somewhat sickle-shaped setae (fig. 5 c). These setae were, un- 

 fortunately, not examined before being preserved, and as 

 St.-Joseph (24. p. 338) points out, a lengthened immersion in 

 alcohol tends to reduce the curve of the sickle. 



In general structure this species resembles P. capensis Mcintosh 

 (13) fairly closely, but differs in the shape of the setse and 

 uncini : in the latter respect and in some other points it differs, 

 too, from F. diomedece Benedict (1). There are many character- 

 istics distinguishing it from P. su.perha Moore (19) and other 

 Pacific species that have been described. P. atypha Bush (3) 

 might possibly be a young specimen of this same species. 



Genus Chitinopoma Levinsen (10), 1883. 



Generic characteristics : — • 



1. ISTo thoracic membrane. 



2. Collar seta3 with fin-like expansion at base of blade. 



3. Some of the other thoracic setae are sickle-shaped. 



4. Abdominal setas geniculate. 



5. Uncini with 9 or 10 fine teeth, the anterior one being 



larger and blunter than the others. 



6. Operculum with horny plate. 



6. Chitinopoma greenlandica. (PI. LXXXVIII. figs. 6 a-6 e.) 



Serjnda triqueter Fabricius (7), 1780. 

 Hydroides norvegica var. gronlandica Morch (20), 1863. 

 Hydroides (?) gronlandica Malmgren (14), 1867. 

 Chitinopoma fahricii Levinsen (10), 1883. 



Specific characteristics : — 



1. Bodies elongated, somewhat cylindrical. 



2. About 6 pairs of branchiae with ends free from pinnae. 



3. Operculum enclosing central stalked vesicle. 



Numerous specimens from Departure Bay and neighbourhood, 

 one incomplete one from Victoria. In thick sinuous tubes 

 adherent to shells, stones, etc., and having a very conspicuous 

 dorsal keel generally ending in' a spine overhanging the aperture. 

 One tube was U-sha,ped with the two ends close together. The 

 largest specimen was about 12 mm. long (fig. 6«). The whole 

 animal was practically colourless, the pedicle of tlie operculum 

 and the branchiae sometimes having faint transverse bands, and 

 the contents of the alimentary canal were in some specimens 

 dark red. 



The branchiae varied very much in number (from 6 to 8 in each 

 lobe) and some were frequently found in a rudimentary state : 

 one specimen had 7 in the right, and only 3 fully-developed 

 functional ones in the left. The operculum was in every case 

 on the left dorsal side, and I have found no trace of a secondary 

 one on the other side. 



