BIRDS OF NORTH AND MIDDLE AMERICA. 779 
Wing moderate, the longest primaries (two outermost) exceeding 
distal secondaries by slightly more than half the length of wing. 
Tail less than one-third (but more than three-sevenths) as long as 
wing, slightly but distinctly rounded; rectrices 16-18. Tarsus 
much shorter than middle toe without claw, reticulate for greater 
part but with obliquely transverse scutella on lower half of acrotar- 
sium; outer toe (without claw) as long as middle toe (without claw) 
or very slightly shorter, the inner toe as long as first two phalanges 
of middle toe; claws moderate or rather small, slightly curved, 
rather blunt. 
Nuptial ornaments.—A prominent compressed obtusely conical 
knob or horn at base of culmen, surmounting the corneous nasal 
cuirass, of which it is part. 
Plumage and coloration.—Adults with two series of elongated 
narrowly lanceolate white plumes, one orginating at posterior angle. 
of eye and extending backward to side of nape, the other starting 
at rictus and extending back beneath suborbital and auricular 
regions to or beyond posterior end of the latter. Upper parts sooty 
blackish fading into brownish gray on chin, throat, foreneck, chest, 
sides and flanks, the remaining under parts white. 
Range.—Coasts and islands of northern Pacific Ocean, from 
California to northern Japan. (Monotypic.) 
CERORHINCA MONOCERATA (Pallas). 
RHINOCEROS AUKLET. 
Adults in breeding season (sexes alike).—Upper parts sooty black- 
ish, the scapulars, interscapulars, and feathers of rump indistinctly 
tipped with dark sooty grayish; sides of head deep hair brown (or 
between hair brown and fuscous), passing gradually into lighter hair 
brown or mouse gray on malar region; chin, throat, chest, sides, and 
flanks white, more or less clouded with brownish gray, especially on 
breast, the posterior under tail-coverts brownish gray; axillars and 
under wing-coverts uniform brownish gray, like sides and flanks; a 
line of straight, elongated, lanceolate white feathers originating at 
posterior angle of eye and extending backward along sides of occiput 
to nape, and another broader series starting at rictus and extending 
backward beneath suborbital and auricular regions to or beyond 
posterior end of the latter; bill orange-yellow or dull orange (in life) 
with culmen and both anterior and posterior edges of the hornlike 
supra-nasal appendage black; iris brown ? or pale amber;? legs and 
feet whitish yellow (in life), darker on joints of toes, the planta tarsi 
and soles blackish.? 
aW. A. Cooper, manuscript. bP. A. Holst, according to Grant. 
