478 



THE DIVING BIRDS— PYGOPODES. 



" Columbus Umgvia, Olaff, Reison. Isl. p, 562" (Bryant). 1 



Colymbiu troilt, var. ft DonndorfFj Beytr. Zool. II. pt i. 1794,876. 



Oolymbus troile, var. ->. Donndorff, t. c. p. 876. 



i Oria lachrj/mans, Valekc. in Choris, Voyages Pitt, autour du Monde, Alcout, 1822, 27, pi, '23. 



tl/ria troiU UucopUhalmos, Fader, Prodr. Isl. Orn. 1822, 42; Isis, 1824, 146. 



/ Urin leueopsis, Brehm, Beitr. Vogelk. III. 1823, p. 880; Isis, 1826, 888. 



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

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



Si'. Char. Adult, summer plumage: Head am! neck, including the pilewm and nape, uniform 

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



via"), tin: edge of the eyelids, forming 

 a ring completely round the eve, and 

 a narrow postocular line, white. Up- 

 per parts uniform dusky, sometimes 



nearly ldaek, the secondaries narrowly 

 tipped with while. Lower parts, in- 

 cluding the juguluni, white, this color 

 anteriorly forming more or less of an 

 angle mi the foreneck ; exterior leathers 

 of the sides and Hanks broadly edged 

 mi both webs with smoky gray or fuli- 

 ginous-dusky. "Bill black; inside of 

 mouth gamboge-yellow ; feet black " 



(Audubon). JVinter plumage: Simi- 



— ^. " " lor lu the above, but whole throat, 



" U. ringvia " summer dress, cheeks, auricular region, and a broad 



stripe on each side of the OCCipilt while, 

 the latero-OCCipitol stripe separated from the while below it, except posteriorly, by a narrow stripe 

 of dark smoky brown along the upper edge of the auricnlars. Stripes along the sides anil Hanks 



indistinct. Hill 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. Doumy young: 



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



dingy whitish ; lower parts dingy while 



centrally. 



Total length, about IT. on inches ; 

 extent, 30.00 ; win-, 7.7. r >-s.:so (aver- 

 age, 7.!)!>) ; culmen, L.70-1.90 (LSI) ; 



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

 through angle,. 50-.60; tarsus, 1,40-1.60 

 (1.51) ; middle lor. L.60-1.75 (1.70). s 

 With regard to the perplexing form 



with white eyelids and postocular streak, 



We must confess ourselves undecided. 

 The theory licit ii is an individual va- 

 riation of troilt seems the 'oIiIn one 

 which can be adopted, in view of Un- 

 asserted [fact that the feature in ques- 

 tion is not seasonal or sexual, and thai 

 the two forms "are known to copulate 



will, ,,ch other" (cf. Corns, Pr. Philad. Acad., 1868, 78). There may be some mistake, how- 

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

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



1 By typographical error printed "Plaff." in original. The correct .(notation is probably Oolymbus 

 langvigia, Olaffs. Reise, p. 562. 



4 Extremes and average of nine adults. 



( T . troile, summer dress. 



