BIRDS OF NORTH AND MIDDLE AMERICA. 761 
Range.—Pacific coast of North America, from California to Aleutian 
Islands. (Monotypic.) 
PTYCHORAMPHUS ALEUTICUS (Pallas). 
CASSIN’S AUKLET. 
Adults (sexes alike).—Upper parts plain grayish dusky or dull 
blackish slate, inclining to dull brownish slate on hindneck and post- 
ocular region, the rump and upper tail-coverts more decidedly slaty, 
the back and scapulars tinged with the same; an indistinct whitish 
bar or elongated spot near each eyelid; malar and rictal regions, 
chin, throat, and foreneck plain brownish gray (between quaker 
drab and deep mouse gray), the outer portion of sides and flanks 
pure gray (nearly neutral gray); under wing-coverts brownish gray, 
some of the larger coverts grayish white; rest of under parts 
‘immaculate white; bill black, the basal third of mandible pale 
brownish (yellowish or flesh colored in life?); iris white; legs and feet 
dusky brownish (bluish and dusky in life). 
Y oung.—Similar in coloration to adults. 
Downy young.—Upper parts deep sooty grayish brown, the sides 
and chest similar but paler; chin, throat, breast, and abdomen dull 
grayish white. 
Adult male.—Wing, 109.5-129 (120.7); tail, 28-34.5 (31.4); exposed 
culmen, 18.5~20 (19.3); tarsus, 23.5-25 (24.6); middle toe, 26.5-30 
(28.7).2 : 
Adult female—Wing, 120-122 (121); tail, 25-32.5 (29.3); exposed 
culmen, 18.5-19 (18.8); tarsus, 24-25 (24.3); middle toe, 28-28.5 
(28.2).° 
Pacific coast and islands of North America, from Aleutian Islands 
(Atka; Attu; Agatu; Unalaska) to Lower California (San Gerénimo 
Island, breeding; Los Coronados Islands, breeding; Cerros Island 
winter; Natividéd Island, April 14; San Benito Island, April 26; 
« Hight specimens. b Three specimens. 
rae Middl 
. 2 . ose le 
Locality. Wing. | Tail. | POS? | Tarsus. “780 
men. 
MALES, 
Two adult males from Alaska....-.........-2ee secon e eee eee 125 31.7 19.5 24.7 29.2 
Two adult males from California. ..........2.-2.-0eseeeeeeeeees 124, 2 33.2 19.5 24.7 29 
Four adult males from Lower California (three from Los : 
Coronados Islands). .......-.--+-sescecce ee Sec cee cee ceeseenee 116.7 30. 2 19.1 24.4 28. 4 
One adult female from Alaska...........---2-022.. eee ee ee eee 122 (25) 18.5 24 28 
Two adult females from California. ...............222.2.02eeeee 120.5 | 31.5 19 24.5 28. 2 
