AND BLACK-BILLED AUK. 
23 
and anxiously endeavouring to allure them from our reach. 
After the old ones have brought the young to sea, they 
almost immediately leave the land, and both young and old 
are then found in great numbers several miles off. The 
object of thus hurrying out to sea, seems to be to remove 
their young from their more numerous enemies, and to 
.place themselves in comparative safety in commencing the 
process of moulting. This is very complete, or at least 
leaves them during part of its progress without the power 
of flight, the old feathers being generally cast before the 
new are sufficiently long for this purpose. The Velvet 
Ducks in North America are annually killed in great num- 
bers during the moulting process, when they are incapable 
of flying; and the Auks and Guillemots would experience 
similar havoc, if instinct did not teach them to withdraw 
from the reach of their more formidable pursuers. After 
an absence of two or three weeks, they again approach the 
coast, and are found occasionally in parties of three or four 
individuals. 
The young are easily tamed, but I think rather difficult 
to rear. They display an unaccountable restlessness to- 
wards evening, incessantly moving about, and uttering a 
plaintive, piping sound. They do not seem to be able to 
exist long in situations where they have not the opportunity 
of diving, and this, perhaps, is the reason of their going so 
early to sea. The fact, at all events, seems certain, how- 
ever difficult it may be to assign a physiological reason for 
it. 
The thorax is very much elongated, and capable of great 
distension. The circulating system is much developed ; 
the heart and primary red vessels peculiarly capacious. 
The blood seems in greater quantity, and its colour is 
deeper than in land-birds,—- a fact I have remarked in most 
diving animalso The tenaciousness of life is very remark-- 
