OENITHOLOGICAL EXPLORATIONS. 93 



gelb, ins OraDgefarbene spielend, der iibrige TLeil, welcben die dunkele 

 Langeufurclie au der Seite in zwei gleiche Hiilften zii theilen scheint, 

 blaszgelb, der liintere Theil des Oberschnabels uur der Scbneide ent- 

 lang hocbgelb, nach oben blasser, hier vom Schieferschwarz der Nasen- 

 rohre * * * begrenzt. * * * '? Cfr. also Knmlien's description 

 of the bill of the white phase " during the latter part of August, Sep- 

 tember, and fore part of October": " bright yellow bill," Bull. U.S. 

 Nat. Mus., No. 15, p. 101.) 



(3.) While the white phases of the Atlantic and the Pacific races are 

 indistinguishable as far as the color. ition of the feathering is concerned, 

 the dark phases are very readily distinguished, the Pacific one being 

 much darker all over. Its color is a saturated, plumbeous ash, more 

 or less tinged with sooty brown (in Museum specimen the color soon 

 turns brownish all over on account of the oxydation of the fatty matter, 

 I su])pose). The dark phase of the Atlantic bird is somewhat lighter 

 and of a more ashy hue. Both forms have, when alive, or freshly 

 killed, a tender, silky, olive-greenish gloss on the mantle as described 

 by Mr. Kumlien (Bull. U. S. Nat. Mus., No. 15, p. 101) in the Atlantic 

 race, and also observed by me in the birds of the Commander Islands. 



(4.) There seems to be a decided difference in the geographical range 

 of the two phases in both oceans ; it appears that the dark phase in 

 both instances is a particularly western bird, while* the light colored 

 ones seem to have a more eastern distribution. 



If the dark form had occurred breeding in Iceland, where Faber found 

 the white one exceedingly numerous, he could scarcely have escaped 

 mentioning it. Nor does it seem to have been found in Saint Kilda* 

 by John Macgillivray, and the form, at present, breeding on the F?er 

 Islands seems also to be the unmixed light phase ; in fact, I do not 

 think the dark form has been found breeding in any number before in 

 Davis's Straits and adjacent waters, where it occurs in great abundance. 

 In the Pacific a similar distribution obtains, the dark form being com- 

 paratively scarce on the American side, while it is by far the predomi- 

 nating form on the Asiatic shore, at least as far south as Kamtschatka. 

 The dark phase was found by me on the Commander Islands in countless 



*Froiu Mr. Dixon's interesting account of "The Ornithology of Saint Kilda," pnb- 

 lishecl in the Ibis for 1885, pp. 69, segr., received since the above was written, it is 

 learned that the " natives assert that there are two kinds, a light and a dark one, 

 but the latter is rare." This substantiates my view as to the scarcity of the dark 

 form in the east. On p. 94 Mr. Dixon has published a condensed account of the con- 

 clusions I have arrived at, and which I communicated to Mr. Seebohm during his visit 

 in Washington last autumn. 



