478 



THE DIVING BIRDS — PYGOPODES. 





U. ringvia," summer dress. 



" Columbus langvia, Olaff, Reise n. Isl. p. 562" (Bryant). i 



Colymbus troilc, var. /3, Donndokff, Bcytr. Zool. II. pt. i. 1794, 875. 



Colymbus troilc, var. y, Donndorff, t. c. p. 876. 



; Uria lachrijma-iis, Valenc. in Choris, Voyages Pitt, autour du Monde, Aleout, 1822, 27, pi. 23. 



t Uria troilc Icucophthahnos, Fabeii, Prodr. Isl. Orn. 1822, 42 ; Isis, 1824, 146. 



? Uria Iciccopsis, Bueum, Beitr. Vogelk. III. 1823, p. 880 ; Isis, 1826, 888. 



Hab. Coasts and islands of the North Atlantic, north to at least 80°, south, in America, to 

 Southern New England in winter ; breeding from Nova Scotia northward. 



Sp. Char. Adult, summer jilumage : Head and \\QG\i, including the pilcum and nape, unUorm 

 smoky brown, scarcely — never conspicuously — darker above ; in some specimens ( =: i7. " ring- 

 via "), the edge of the eyelids, forming 

 a ring completely round the eye, and 

 a narrow postocular line, white. Up- 

 per parts uniform dusky, sometimes 

 nearly black, the secondaries narrowly 

 tipped with white. Lower parts, in- 

 cluding the jugulum, white, this color 

 anteriorly forming more or less of an 

 angle on the fureneck ; exterior feathers 

 of the sides and flanks broadly edged 

 on both webs with smoky gray or fuli- 

 ginous-dusky. " Bill black ; inside of 

 mouth gamboge-yellow ; feet black " 

 (Audubon). Winter plumage: Simi- 

 lar to the above, but whole throat, 

 cheeks, auricular region, and a broad 

 stripe on each side of the occiput white, 

 the latero-occipital stripe separated from the white below it, except posteriorly, by a narrow stripe 

 of dark smoky brown along the upper edge of the auriculars. Stripes along the sides and flanks 

 indistinct. Bill and feet dull brownish. Young : Similar to the winter plumage, but no white 

 on the sides of the occiput, and that of the foreneck faintly mottled with dusky. Downy young : 

 Head, neck, and upper parts smoky grayish brown, the head and neck finely streaked with 

 dingy whitish ; lower parts dingy white 

 centrally. 



Total length, about 17.00 inches; 

 extent, 30.00 ; wing, 7.75-8.30 (aver- 

 age, 7.99) ; culmen, 1.70-1.90(1.81); 

 gonys, 1.05-1.20 (1.14) ; depth of bill 

 through angle, .50-.60 ; tarsus, 1.40-1.60 

 (1.51) ; middle toe, 1.60-1.75 (I.70).2 



With regard to the perplexing form 

 with white eyelids and postocular streak, 

 we must confess ourselves undecided. 

 The theory that it is an individual va- 

 riation of troile seems the 'only one 

 which can be adopted, in view of the 

 asserted Tact that the feature in ques- 

 tion is not seasonal or sexual, and that 

 the two forms " are known to copulate 



with each other" (cf. CouES, Pr. Philad. Acad., 1868, 78). There may be some mistake, how- 

 ever, as to these supposed facts ; at any rate, were they true, it seems very strange that the same 

 phase is never assumed by the western form of the species (calif arnica) . 



^ By typograpliical error printed " Plafif." in original. The correct quotation is probably Colymbus 

 langvigia, Olaffs. lleise, p. 562. 



^ Extremes and average of nine adults. 



U. troile, summer dress. 



