780 



BULLETIN 50, UNITED STATES NATIONAL MUSEUM. 



Winter plumage. — Coloration as in summer, including white heud- 

 plumes, but corneous supranasal horn and gonydeal ridge wanting, 

 the former, however, indicated (at least in freshly killed specimens) 

 by a more or less pronounced swelling, covered by membrane.'^ 



Young. — Similar to winter adults, but white head-plumes wanting 

 and bill smaller and darker in color. 



Downy young. — ^Uniform sooty grayish brown, slightly paler on 

 under parts of body. (Very similar to the corresponding stage of 

 Lunda cirrhata but rather lighter in color and with more slender biU.) 



Adult inale.—Wmg, 175-183 (177.8); tail, 42.5-60.5 (55); exposed 

 culmen, 32.5-36 (34); tarsus, 27-30 (28.2); middle toe, 39.5-43 

 (40.4).^ 



Adult female.— Wmg, 160-181 (175.6); tail, 52-56.5 (55.5); exposed 

 culmen, 32-39 (34.7); tarsus, 27-29 (28); middle toe, 38-41.5 (39.9).^ 



Coasts and islands along border of northern Pacific Ocean; breed- 

 ing from Sitka, Alaska, southward to Washington (Smiths Island, 

 Puget Sound; Protection Island), formerly to Farallon Islands, Cali- 

 fornia, and on Kuril Islands;'^ southward in winter to southern Cali- 

 fornia (Santa Barbara; San Diego, Dec, Jan.; Santa Catalina Island, 

 Dec, March), Ijower California (San Miguel Island; Cerros Island, 

 June), and northern Japan (Hakodate; Tsushima; Otarunai, near 

 Sapporo; Nagasaki), and southeastern Siberia (Qsuri Bay; Vladi- 

 vostok). 



Alca monocerata Pallas, Zoogr. Russo-Asiat., ii, 1S26, 362 (Cape St. Elias to 



Kodiak Island, Alaska). 

 Chimerina monocerata Reichenbach, Natatores, 1850, pi. 6, figs. 2706, 2707. 



a See Henshaw, Auk, ii, 1885, 387, 388. 

 ''Six specimens. 



e Almost certainly breeding on some of the intervening islands also. 



