NATURAL SCIENCES OF PHILADELPHIA. 55 



Mergulus alle, Vieillot, Analyse, 1816, p. 66. Id., Gal. Ois. 1825, p. 236, pi. 

 295. Gould, Birds Eur. v, 1837, pi. 402. Macgillivray, Hist. Brit. Birds, ii, 

 1852, p. 341. Bonaparte, Coniptes Rendus, 1856, xlii, p. 774. Cassin, 

 Baird's B. N. A. 1858, p. 918. Boardman, Pr. Bost. Soc. N. H. Sept. 1862, 

 p. 131. Verrill, Proc. Essex Inst, iii, 1863, p. 160. Samuels, Ornith. and 

 Ool. of New England, 1867, p. 570. 

 Arctica alle, Gray, Gen. Birds, iii, 1849, p. 644. 

 Alcac.lce, Gmeliu, S. N. i, pt. ii, 1788, p 544, No. 5. 



Alca Candida, Briinnich, Orn. Bor. 1764, p. 26, No. 107. In pure white plu- 

 mage ; probably albino. 

 Mergulus arcticus, Brehm 



E: ropean and American coasts of the North Atlantic. On the United States 

 coast, in winter, south to New Jersey. Numerous specimens in Mus. Acad. 

 Philada., Smiths. Inst., Bost. Soc. Nat. Hist., Essex Inst., Gab. G. N.Lawrence, 

 author's Cab., etc. 



Adult, summer plumage. — Head and neck all around, and entire upper parts 

 glossy black, with a beautiful metallic lustre of a shade of blue, when in high- 

 est piumage ; scapulars edged with white ; shafts and inner webs of primaries 

 brown, lighter at base; secondaries tipped with white; under surfaces of the 

 wings brownish-gray; under parts from the breast pure white, with a few 

 elongated feathers of the sides' and flanks varied with black on the outer webs ; 

 bill black ; legs and feet posteriorly blackish, anteriorly flesh-colored (dull 

 j'ellowish in the dried state). 



Adult in winter. — As before ; the white of the under parts extending on the 

 neck and throat to the bill, on the sides of the head to the level of the rictus, 

 on the sides of the nape over the auriculars (where it is somewhat marbled 

 with black), or even to the middle of the nape, more or less confluent with 

 that of the other side 



Young, first winter. — Recognizable by its smaller and weaker bill, by the 

 duller and more brownish black of the upper parts, almost wanting in gloss, 

 and by the greater extension of the white upon the sides of the hind head and 

 neck. The scapulars and coverts are conspicuously marked with white, as in 

 the adult, The feet are mostly dusky. 



Length 8*50 ; wing 4-75 ; tail 1-50 ; tarsus -80 ; middle toe and claw 1-20, 

 outer do. 1-15, inner do. -85; bill along culmen -50, rictus TOO, gonys -20; its 

 depth at base -35, its width at same point about the same. 



When in mature plumage, this is a very beautiful species. No other Alci- 

 dine has such lustre of the dorsal plumage, traces of which are even found in 

 adult winter specimens. In the latter the extent of the black upon the throat 

 is indicated by a dusky clouding of the bases of the feathers of the parts. The 

 species is ordinarily subject to only moderate variation in size or colors. The 

 condition of albinism has been described. 



The first chronicles of this species are of great antiquity. It appears to have 

 shared for a time with Uria giylle the soubriquet of " Columba groenlandica." 

 Since its description as Alca alle by Linnieus, it has been the basis of very few 

 synonyms. Alca Candida of Briinnich is this species in the albino state. Mer- 

 gulus niclanoleucus, Ray, is adopted by many authors. Mr. G. R. Gray adopts 

 Moehring's generic appellation. 



SYNTHLIBORHAMPHUS, Brandt. 



Alca, Gmelin, S. N. i, 1788, p. 554, and of the older authors, in part. 



Uria, Pallas, Zoog. R -A. ii, 1811, and of some authors, in part. 



Fratercula, Stephens, Shaw's Gen. Zool. xiii, 1825, in part. 



Synlhlihorhamphus, Brandt, Bull Acad. St. Petersb. ii, 1837. (Type Alca anti- 



qua, Gm.) Subgenus oi' Brac/n/rhamphus, Brandt. 

 Mergulus, Vigors, Zool. Voy. Blossom, 1839, in part. 



1868.] 



