NATURAL SCIENCES OF PHILADELPHIA. 57 



American and Asiatic Coasts of the North Pacific. Kamtschatka, Japan 

 Seas. Sitka, Russian America, (Mus. Smiths. Inst.) Mas. Acad. Philada. 



With the form, etc, typical of the 

 genus, as above described. 



Adult, high breeding plumage, (No. 

 46558, Mus. Smiths. Sitka, R. A.) Bill 

 whitish, or yellowish, culmen and base 

 of both mandibles abruptly black ; legs 

 and feet anteriorly a])parently whitish, 

 or yellowish ; posteriorly, with both sur- 

 faces of the webs, black. Head all 

 Fig.l3.—^y»W(i/6or/,amp;(wsan<!3!(M«,(Gmel.) around, and throat, black; pure and 

 Nat. size. intense above, on the sides below, chin 



and throat, tinged with fuliginous brown. A conspicuous stripe of pure white 

 beginning over each eye, and extending backwards over the sides of the occi- 

 put, connected across the nape by some white feathers, and spreading on the 

 sides and back of the neck, as a large disconnected series of trenchantly de- 

 fined white streaks. Trace of white on each eyelid. Entire upper parts clear 

 dark plumbeous, blackening on the upper tail coverts and tail. Upper surface 

 of wings the same, or rather darker, the edge of the wing all along from the 

 elbow, and the exposed parts of primaries, blackish ; entire under surface of 

 wings white, except just along the edges where it is mottled with dusky ; the 

 basal portion of the inner webs and shafts of primaries whitish ; secondaries 

 like the wing coverts, or rather darker, their bases whitish. Sides of the body 

 under the wings pure velvety black, in marked contrast to the clear plumbeous 

 of the upper parts and white of the lower. These black feathers are poste- 

 riorly greatly elongated, reaching quite to the tail, and overlying the sides of 

 the rump and the flanks, which latter, however, are seen to be pure white on 

 raising the elongated supercumbent feathers. This black along the sides 

 extends anteriorly in front of the wings, and, still strongly contrasted with the 

 plumbeous of the interscapulars, continues on as a band quite to the nape, 

 which it crosses to become confluent with its fellow of the opposite side. On 

 the sides of the neck it is thickly marked with the pure white streaks already 

 described. The fuliginous black of the chin and throat is continuous with that 

 of the sides of the head as far as the anriculars ; further on it merely extends 

 as a point along the middle of the throat, being separated from the black of 

 the sides of the nape by a large white area, an extension to the anriculars of 

 the white which is the color of the whole under parts except the sides under 

 the wings, as already described. 



Length 9-50 to 10-50; extent 16-75 to 18-25; wing 5-50; tail 1-60; bill 

 along culmen -60, along rictus 1-20, along gonys -40, depth at base -30, width 

 •20; tarsus 1-00 ; middle toe and claw 1-25, outer do. 1-15, inner do. 1-00. 



Younger. — Bill and feet as above described. " Iris brown," (label). Upper 

 parts as in the adult, but darker, the plumbeous being obscured by dusky, 

 especially on the wing and tail coverts, and lower back. Forehead, crown, 

 nape, and back of neck, sooty black, entirely unrelieved by white streaks, 

 or with only traces of the latter on the sides of the occiput. Eyelids some- 

 times largely white. No black on the throat or chin ; traces of it in a dusky 

 mottling about the base of the bill. White of under parts extending on sides 

 of head below and behind nearly to the eyes, and far around on the sides of 

 the nape, so that only a median nuchal line is left blackish. Sides of body 

 under the wings not pure black, but merely dusky plumbeous, and this not 

 continuous on the feathers over the flanks, these being in some part white, 

 producing a white and plumbeous variegation. The line of this dusky plum- 

 beous hardly extends in front of the wings to the sides of the neck. Under 

 parts white, as before, the bases of the inner webs of the primaries rather more 

 white than in the adult. 



1868.] 



