BRITISH BIRDS. 
ANSERES, 
GENUS XXXIII. 
ALCA AUK. 
This genus of birds is distinguished by 
the following characters: 
Bill toothless, short, compressed, convex, 
often transversely furrowed; lower man- 
dible gibbous near the base. 
Nostrils linear. 
Legs (mostly) three toed, 
Gmelin describes eleven species belong- 
ing to this genus. They principally 
inhabit the Arctic Seas ; are very stupid, 
remaining concealed during the night, 
nestle in rabbits' holes and fissures of the 
rocks; and lay only a single egg, which 
is very large in proportion to the size of 
the bird. They are pretty uniform in their 
colours, black above and white below. 
