320 CHARADRIIFORMES Sane 
ranges from the Gulf of St. Lawrence and Iceland to the Arctic 
Seas of both worlds in summer, moving further south in winter ; 
the North Pacific race being denominated U. arra. Descriptions 
of the colonies of Guillemots in the icy seas, and of the smaller but 
equally crowded stations in Britain, have been too frequently 
given to need repetition here; but it may be mentioned that 
during incubation, which lasts about a month, the parent holds 
the egg between its thighs, and not unfrequently carries it off 
foto) 
Fig. 64.—Great Auk. Alca impennis. x %. (After Hancock.) 
a ledge, when suddenly scared. On flat-topped stacks these eggs 
(p. 316) often lie in the closest juxtaposition. 
In Alcea the black bill is deep and highly compressed, with a 
curved culmen; and shews oblique or transverse grooves, which are 
wanting in the young. A. torda, the Razorbill, less common in 
Britain than the Guillemot, ranges from Jan Mayen and Greenland 
to Maine and Brittany, visiting North Carolina and the Canaries 
in some winters. It is greenish-black with brown throat-region 
and white lower parts, a white line stretching from the top of the 
