r
fish are not despised in times of scarcity. Its fur throughout the year
is coloured white, though in old bears it assumes a more yellowish hue.

[Illustration: Fig. 7.--The Musk-Ox (_Ovibos moschatus_). (From Flower &
Lydekker's _Mammals_, p. 358. London: Adam & Chas. Black.)]

Another large mammal, perhaps less well known, is the Musk-Ox (_Ovibos
moschatus_, Fig. 7), which resembles in size the smaller varieties of
Oxen, but in structure and habits is closely allied to the Sheep. As is
implied by the specific name, it exhales a musky odour; this does not,
however, appear to be due to the secretion of a special gland, as is the
case in other animals with a similar smell. The skin is covered with
long brown thickly-matted hair, interspersed with white. It is confined
to the most northerly parts of North America and the American Arctic
islands, and to North Greenland. Though not now living in the Old World,
it seems formerly to have been abundant in Siberia, and, as we shall
learn later on, it was one of the species which took part in the great
Siberian invasion of Europe. Its remains have been found not only in
Germany and France, but also in the south of England.

The Polar Fox (_Canis lagopus_) occurs throughout the Polar Regions, and
on islands where even the Reindeer and the Musk-Ox are unknown. Beyond
the Polar Circle, its range extends into Northern Asia, to the extreme
north of North America, and the mountains of Scandinavia. Like its
congeners, it had in pleistocene times a more southerly extension, and
fossil remains have been met with in various parts of continental Europe
and in England.

The Stoat (_Mustela erminea_), which is known and much valued in
commerce under the name of Ermine, was formerly believed to occur only
in Arctic America and the northern parts of the Old World, but in more
recent years it has been discovered in a number of the northern
islands, such as Saghalien, in the islands of the Behring Straits, the
Aleutian islands, and also in Greenland and Spitsbergen. In Europe, it
is found as far south as the Arctic Hare, or perhaps even farther, and
it flourishes in the Alps up to a height of 9000 feet. It offers a
parallel to the Arctic Hare in the fact that in some countries, such as
Ireland, it only rarely turns white in winter. The Irish form of the
Stoat differs so much from the English, that Messrs. Thomas and
Barrett-Hamilton are of opinion that it is specifically distinct, as I
ment