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 extreme- 

 ly narrow, towards the end erect and flat, the edges inflected, the dorsal out- 

 line concave, the tip decurved. Nostrils medial marginal, linear, short, con- 

 cealed 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. 



