912 THE CASSIN AITKT^KT. 



grasses and dun rocks, and is tlnis lust id Imstik' \ iew. lUit when a spt'cics 

 begins tn forsake tlie npcn and tliere is no longer need of liea\y pigmentation, 

 the egg tend-- to re\erl to the priniiti\e wliite: that is, to unpigniented calcium 

 carbonate. .\'o\v in the case of the Rhinoceros .\uklet's egg, we find traces of 

 an ancient cokir ])altern. nndouhtedl) hea\y. still persisting in f;iinl lines of 

 umber and in sul)(lued shell-markings or under-tints of la\'ender and lilac. 

 These to tlie ornithologist are ekKjuent of a time ages ago before the race 

 went moon-m.-ul. 



No. ,?66. 



CASSINVS AUKLET. 



.A. O. U. No. i6. Ftychoramphus aleuticus ( Pall.). 



Synoynms. — ALrU'Ti.XN .AuklivT. C.\ssin's .Ai'k. 



Description. — .tdult: Tlcad and neck all around, u])perparts, and sides 

 sooty- or ])hinil)eons-black, bluish tinge clearest on rump and scapulars; wings 

 and tail l.irownish dusky, ])aling un edges and exposed iiortious; lining of wing 

 partly white; a s|iiit (jf white over eye a little forward, ami a touch on lower lid 

 posteriorly; remaining underparts ])iux' white. Ihll (drying) black, changing to 

 yellow on base of lower mandible; iris greenish blue; feet chietly black, nails 

 black. No seasonal changes, /iiiiiiatiirc: Similar to adult, but wings blacker ; feet 

 and tarsus \ellnw befure. black behind. /'i)Ti7/\' voihui: Cbiefl}- brownish dusky, 

 white |iatteni of adult indicated b\' lighter gray on underparts; sides of head 

 and throat chietlv naked, orange \ellow ; bill .and feet as in immature. Length; 

 8.00-9.50 (203.2-241.3); wing 4.SV) |l2l.t)); bill .J~, ( lij.ll. depth at base .39 

 (9.9) ; tarsus i.oo (25.4). 



Recognition Marks. — Robin size; chunky ap|iearance; stout bill; blackish 

 and white plumage; absence of appendages or special adornments in itself nearly 

 distinctive save as regards the slenderer Marblefl Murrelet. 



Nesting. — Single eg;/, jiale greenish white, unmarked, placed at end of bur- 

 row three or four feet in length, nr in crevices of rock. .\v. size, i.So.x 1.33 

 (45.7x33.8). Season: -\pril-June; erne brood. 



General Range. — I\acitic Coast of North .America, breeding from the 

 Aleutians s<iuth to the Farallones and San (^.eronimo Island. 



Range in Washington. — Little known resident of coastal waters, breeding 

 sparingly on some of the ( )lympiades 1 .Alexander Islet, nhunyuatzachtahl, Carroll 

 Islet, etc. I. Casual on Puget Sound. 



Authorities. — |"Cassin's auk," Johnson, Rep. Gov. \V. T. 1884 (,1885), 23.] 

 Rhoads, Lroc. Acad. Nat. Sci. Phila. 1893, 30. L^ 



Specimens. — C. D. 



