ROTCHE. NATATORES. MERGULUS. 431 



coasts of the United States. With us it is only recognised 

 as a winter visitant, although a few may probably breed 

 upon the extreme rocky islands of the north of Scotland. 

 Its occurrence in England is rare, and the greater number 

 of specimens hitherto obtained have been found after severe 

 storms, in a dead or dying state. It scarcely ever quits the 

 ocean, except for the purpose of reproduction; swimming 

 and diving there with as much facility as the rest of the Al- 

 cadte. Its flight is rapid, but at a low elevation ; its wings 

 being small and narrow in proportion to the weight of the 

 body. In its affinities it stands nearly intermediate between 

 the Auks and the Guillemots; the bill being much shorter, 

 stronger, and more convex than that of the latter, and not 

 having the compressed shape, and distinct transverse lateral 

 furrows which particularize that of the Auks. Like the last 

 mentioned genera, it is subject to a double moult, and that 

 indicative of the breeding season is analogous to the change 

 ascertained to take place in the Foolish Guillemot and the 

 Razor-Bill. 



PLATE 81. Fig. 1. represents this bird of the natural size, 



in the summer plumage. 



Crown of the head, nape of the neck, dorsal plumage, General 

 wings and tail, glossy velvet-black. Sides of the head, t i on> 

 throat, neck, and upper part of the breast, pitch-black. Summer 

 Side-edges of the long scapulars and tips of the second- 

 aries white. Under plumage white. The flanks having 

 the inner webs of the feathers black. Legs and toes 

 blackish-brown, with a tinge of red. Bill black ; from 

 the forehead to the tip five-eighths of an inch long, thick,, 

 and convex ; with both the mandibles notched, and with 

 two faint transverse furrows upon the upper one. 



Fig. 2. The bird in winter plumage ; which is common to Winter 

 both old and young, and differs from that of the summer 

 in having the throat, the fore part and sides of the neck, 



