g as a respirator or boa for
the mouth and a muff for the paws. Our Arctic travellers have remarked,
that it is a peculiarly cleanly animal, and its vigilance is extreme. It
is almost impossible to come on it unawares, for even when appearing to
be soundly asleep, it opens its eyes on the slightest noise being made.
During the day it appears to be listless, but no sooner has the night
set in than it is in motion, and it continues very active until morning.
The young migrate to the southward in the autumn, and sometimes collect
in great numbers on the shores of Hudson's Bay. Mr Graham noticed that
they came there in November and left in April.

[Illustration: Arctic Fox. (Canis Lagopus.)]

Sir James Ross found a fox's burrow on the sandy margin of a lake in the
month of July. It had several passages, each opening into a common cell,
beyond which was an inner nest, in which the young, six in number, were
found. These had the dusky, lead-coloured livery worn by the parents in
summer; and though four of them were kept alive till the following
winter, they never acquired the pure white coats of the old fox, but
retained the dusky colour on the face and sides of the body. The parents
had kept a good larder for their progeny, as the outer cell and the
several passages leading to it contained many lemmings and ermines, and
the bones of fish, ducks, and hares, in great quantities. Sir John
Richardson[115] observed them to live in villages, twenty or thirty
burrows being constructed close to each other. A pair were kept by Sir
James Ross for the express purpose of watching the changes which take
place in the colour of their fur. He noticed that they threw off their
winter dress during the first week in June, and that this change took
place a few days earlier in the female than in the male. About the end
of September the brown fur of the summer gradually became of an ash
colour, and by the middle of October it was perfectly white. It
continued to increase in thickness until the end of November.[116] A
variety of a blackish-brown colour is occasionally met with, but this is
rare: such specimens, Ross remarks, must have extreme difficulty in
surprising their prey in a country whose surface is of an unvaried
white, and must also be much more exposed to the persecutions of their
enemies. The food of this fox is various, but seems to consist
principally of lemmings and of birds and their eggs. He eats, too, the
berries of the _Empetru