NATATORES. URIA. 419 
Genus URIA, Briss. GUILLEMOT. 
GENERIC CHARACTERS. 
Bitt of mean length, strait, strong, compressed, pointed, 
and cultrated. Upper mandible slightly arched towards the 
tip. ‘lomia intracted. Angle of the lower mandible gently 
ascending. Commissure nearly strait. Nostrils basal, late- 
ral, concave, longitudinally cleft, and half covered by the 
feathers of the antie, or projecting side angles of the cra- 
nium. 
Wings short, narrow, and acute. Tail of twelve or four- 
teen feathers ; very short. 
Legs situated at the back part of the abdomen ; the tibize 
concealed within the integuments. ‘'Tarsi short and com- 
pressed. Feet of three toes, all directed forwards, and pal- 
mated; outer and middle toes of equal length, the inner one 
much shorter. Claws falcate, and sharp-pointed ; the mid- 
dle one the longest. 
In the form of the bill, in the birds of this genus, we 
trace a strong resemblance to that of the Divers, with which 
they were systematically associated by the earlier writers. 
They have, however, since been judiciously separated from 
the Colymbida, not only on account of the different form of 
the foot, but for the greater affinity they bear to the rest of 
the Alcade, in many other essential particulars. They are 
oceanic birds, and, unless from fortuitous circumstances, are 
never seen upon fresh water. They swim well, and dive 
with great ease ; are able to remain long beneath the surface, 
and reach to a great distance. In this way, indeed, they ob- 
tain their prey, which consists of fish and marine insects. 
From the shortness of their wings, their flight is confined to 
small distances, and near to the surface of the water ; it is, 
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