gia THE CASSIN AUKLET. | 
grasses and dun rocks, and is thus lost to hostile view. But when a species 
begins to forsake the open and there is no longer need of heavy pigmentation, 
the egg tends to revert to the primitive white; that is, to unpigmented caleium 
carbonate. Now in the case of the Rhinoceros Auklet’s egg, we find traces of 
an ancient color pattern, undoubtedly heavy, still persisting in faint lines of 
umber and in subdued shell-markings or under-tints of lavender and lilac. 
These to the ornithologist are eloquent of a time ages ago before the race 
went moon-mad. 
No. 3066. 
CASSIN’S AUKLET. 
A. O,. U. No. 16. Ptychoramphus aleuticus (Vall.). 
Synoynms.—ALeEUTIAN AUKLET. CAssin’s AUK. 
Description.—4du/t: Head and neck all around, upperparts, and sides 
sooty- or plumbeous-black, bluish tinge clearest on rump and scapulars; wings 
and tail brownish dusky, paling on edges and exposed portions; lining of wing 
partly white; a spot of white over eye a little forward, and a touch on lower lid 
posteriorly ; remaining underparts pure white. Bill (drying) black, changing to 
yellow on base of lower mandible; iris greenish blue; feet chiefly black, nails 
black. No seasonal changes. /mmature: Similar to adult, but wings blacker; feet 
and tarsus yellow before, black behind. Dozeny young: Chiefly brownish dusky, 
white pattern of adult indicated by lighter gray on underparts; sides of head 
and throat chiefly naked, orange yellow; bill and feet as in immature. Length: 
8.00-9.50 ( 203.2-241.3); wing 4.80 (121.9); bill .75 (19.1), depth at base .39 
(9.9); tarsus 1.00 (25.4). 
Recognition Marks.—Robin size; chunky appearance; stout bill; blackish 
and white plumage; absence of appendages or special adornments in itself nearly 
distinctive save as regards the slenderer Marbled Murrelet. 
Nesting.—Single egg, pale greenish white, unmarked, placed at end of bur- 
row three or four feet in length, or in crevices of rock. Av. size, 1.80 x 1.33 
(45.7 x 33.8). Season: April-June; one brood. 
General Range.—Pacific Coast of North America, breeding from the 
Aleutians south to the Farallones and San Geronimo Island. 
Range in Washington.—Little known resident of coastal waters, breeding 
sparingly on some of the Olympiades (Alexander Islet, Dhuoyuatzachtahl, Carroll 
Islet, ete.). Casual on Puget Sound. 
Authorities.—|“Cassin’s auk,” Johnson, Rep. Gov. W. T. 1884 (1885), 23.] 
Rhoads, Proc. Acad. Nat. Sci. Phila. 1893, 30. L?. 
Specimens.—C. D. 
