NATURAL SCIENCES OF PHILADELPHIA. 19 



Alca minor, Brisson, Ornitbologia, vi. 1760, p. 92, No. 3, pi. 8, fig. 2. 

 Alea glacialis et microrhyncha, Brehm. 



Hahitat. — European and American coasts of the Atlantic, from the higher 

 latitudes, in summer, to the 40°, or thereabouts, in winter. Very abundant. 

 Specimens in all the American museums, and most private collections. Breeds 

 in great numbers on the islands in the Gulf of St. Lawrence, and on the coasts 

 of Labrador and Newfoundland ; in Avinter strays south to New Jersey. Arctic 

 seas of both hemispheres. Rare, or accidental in the North Pacific. Japan ! 

 (Schlegel, Mus. Pays-Bas.) 



Adult, in summer. — Iris bluish. Mouth chrome yellow. Bill, feet and claws 

 black; the former with a conspicuous curved vertical white line occupying the 

 middle sulcus of both mandibles, continuous from one to the other. A straight, 

 narrow, very conspicuous white line from eye to base of culmen, composed of 

 a series of very short stiff setaceous feathers, sunk below the level of the others. 

 Secondaries narrowly but distinctly tipped with white. Head and neck all 

 around, and entire upper parts black ; this on the sides of the head, chin and 

 throat lustreless, velvety, tinged with fuliginous or brownish ; on the upper 

 parts glossy and more intense in color. Inner webs of primaries light brownish- 

 gray at base. Entire under parts from the throat, including under surfaces of 

 wings white. 



Adult in winter. — Upper parts lighter, duller, more brownish-black ; the white 

 of the under parts extending to the bill, and on the sides of the head and neck, 

 sometimes quite to the nape. 



Young, first luinter — Similar to the preceding ; smaller, the bill weaker, 

 shorter, less elevated, less decurved at the tip. the culmen, rictus f nd gonys 

 straighter, the sides of both mandibles smooth, except in the presence of one 

 sulcus ; bill brownish-black, the sulcus white. Legs and feet reddish or 

 brownish-black. 



Fledgelings. — Billvery small and slender; body clothed with smoky brown or 

 black down, lighter, or tending more or less to grayish-white below. 



The white stripe from the eyes to the bill is very variable, though present in 

 the great majority of individuals. It always exists in the adults in summer 

 plumage, bnt is sometimes absent in specimens, apparently perfectly adult, in 

 winter plumage. Its presence does not seem to be amenable to any very gene- 

 ral or constant law : since it may be very evident in very young birds, not yet 

 fully fledged, and again absent in apparently mature specimens, as just stated. 

 In winter specimens it is frequently interrupted and irregular, wanting the 

 sharpness of definition which it has in all cases of adult specimens in summer 

 vesture. 



Dimensions : Adult. — Length (average) 18-00, extent about 27-00,wing 7-75, tail 

 3-50, difference between outer and inner feathers 1-25 ; tarsus 1"25 ; middle toe 

 and claw 2-00, outer do. the same, inner do. 1-40 ; chord of culmen 1-30, its 

 curve 1-50 ; rictus 2-25 ; gonys -75 ; nostrils to tip -85; greatest depth of bill, 

 (just anterior to nostrils,) -90 ; greatest width of the corneous portion -30. 



rouw^r.— Length 15-00; extent 22-00; wing 7-00; tail 3-00; tarsus 1-00; 

 chord of culmen 1 00; rictus 1-75, gonys "60; greatest depth of bill -60; 

 greatest width -20. 



No one of the many synonyms of this species involves any doubtful point, 

 all being based upon the winter plumage, or upon the absence of the white 

 line, or upon an undeveloped condition of the bill. " Alca pica " was the 

 most firmly established of these, having held its ground until 1825 or there- 

 abouts. 



2. Subf\\mily PnALERiDiNiE. 

 FRATERCULA, Brisson. 



ilZca, Linnreus, Syst. Nat. 1744; and in part of subsequent editions ; and of 

 the older authors. 



1868.] 



