Rorcue. 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- 
cade. 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 beg 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 ef 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. 
Prate 81. Fig. 1. represents this bird of the natural size, 
in the summer plumage. 
Crown of the head, nape of the neck, dorsal plumage, 
wings and tail, glossy velvet-black. Sides of the head, 
throat, neck, and upper part of the breast, pitch-black. 
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 
both old and young, and differs from that of the summer 
in having the throat, the fore part and sides of the neck, 
General 
descrip- 
tion. 
Summer 
Plumage. 
Winter 
Plumage, 
