1877.] 161 [Barrows. 



that of L. troile, but in the only specimens I have examined the head 

 *and back are much darker, being almost jet black with a bluish tint 

 especially on the head and hind neck, and becoming rather duller 

 on the back. The seasonal changes are said to be nearly the same 

 as in L. troile. Length 18 in. Wing 8-|- in. Four specimens. 



Two in winter plumage, mounted. 



No. 54772 ; summer, moulting; Kodiak. 



No. , winter plumage ; mounted ; Mass. coast. 



Genus Alca Linnaeus. 



Size large ; bill large, strong, much compressed, with vertical 

 curved furrows on the sides of both mandibles. Culmen strongly 

 convex; gonys slightly concave, with the angle rather rounded but 

 distinct. Tip of upper mandible more or less overhanging that of 

 lower. Rictus very long, its sides unfeatbered almost or quite to the 

 angle of the mouth. There is a deep groove at the base of the upper 

 mandible parallel to the outline of feathers, and separated from them 

 by a narrow ridge, which runs from the base of the culmen almost to 

 the commissure, with the edge of which it forms an angle of about 

 45° or 50°. Just at the apex of this angle the linear nostril begins, 

 'and extends backward parallel to the lower side, and completely cov- 

 ered by the short, thick feathers. Tarsus scutellate in front. Tail of 

 twelve or fourteen feathers, rather long and pointed. Color — head 

 and neck all around dark, as are also the back, wings and tail. Breast 

 and belly white ; some white on the face, and secondaries white- 

 tipped. 



The genus, as here framed, admits both A. impennis and A. toi'da, 

 for although they have been separated by many writers on account of 

 the imperfect wings of A. impennis, which prevent its flying, yet they 

 are so exactly similar in all other essential points that I can see no 

 reason whatever for placing them in separate genera. 



20. Alca impennis. 



Alca impennis Linnaeus, 1758, Briinnich, Latham, Gmelin, Pallas, 

 Temminck, Gray, Stephens, Audubon, Schlegel, Brandt. No spec- 

 imen. 



21. Alca torda. 



Alca torda Linnaeus, 1758, Briinnich, Pallas, Audubon, etc. Uta- 

 mania torda Leach, Stephens. 



Bill short, very deep and much compressed. Culmen regularly 



