Birds of America
By John James Audubon, F. R. SS. L. & E.
GENUS II.--ALCA, Linn. AUK.
Bill as long as the head, feathered as far as the nostrils, beyond which it
is very high, exceedingly compressed, and obliquely furrowed on the sides; upper
mandible with the dorsal line decurved, the ridge extremely narrow, the sides
nearly flat, the nasal groove very large, and feathered, with its lower margin
very narrow, and convex, the edges sharp and inflected, the tip decurved, very
narrow, but obtuse; lower mandible with the angle very narrow, and having a
horny triangular appendage, the sides at first extremely narrow, towards the end
erect and flat, the edges inflected, the dorsal outline concave, the tip
decurved. Nostrils medial marginal, linear, short, concealed by the feathers.
Head large, ovate; neck short and thick; body full, rather depressed. Feet
placed far behind, short, stout; tibia bare for a short space; tarsus very
short, compressed, anteriorly scutellate; hind toe wanting; anterior toes of
moderate length, rather slender, scutellate, webbed, the outer slightly longer
than the middle. Claws rather small, arched, compressed, obtuse. Plumage
close, blended, very soft. Wings very short, narrow, acute, first quill
longest. Tail short, tapering, of twelve or fourteen feathers.