ioned in speaking of the divisions of the British fauna (p. 90).

The Arctic Hare (_Lepus variabilis_) is almost the only one of the
typical Arctic mammals which still inhabits the British Islands, and for
that reason it is to most of us more familiar than any of the preceding
species. Hares have been described from Greenland by the name of _Lepus
glacialis_, from the European Alps as _Lepus alpinus_, and under other
names from Arctic North America; but though slight differences in the
fur and even in the skull can be pointed out, there is no doubt that all
these are only varieties or races of what, in the British Islands, is
known as the Irish or the Scotch Mountain Hare, _Lepus variabilis_. In
the Arctic Regions this Hare remains white throughout the year, but in
Scandinavia and some other parts its fur becomes brown in the summer,
and in Ireland it frequently remains entirely brown during the whole
year, and never, or only in very rare cases, becomes entirely white in
winter. Besides Scandinavia, Scotland, and Ireland, it is found in
Northern Russia, and also in the Pyrenees, the Alps, and the Caucasus.
In Asia it occurs not only on the mainland of Siberia, but it has been
obtained on the Akita Mountains in Japan and on the Mioko San Mountain,
and also on the island of Saghalien. It had in former times a more
extensive range, and its remains have been discovered in England and in
a number of places on the continent of Europe. The peculiarity of its
range, which will be explained more fully directly, lies in the fact of
the occurrence of isolated colonies in the mountains of Europe, in
Ireland and Scotland, and in the mountains of Japan (Fig. 8). From a
distributional point of view, it is one of the most interesting species
of mammals, and its history throws a flood of light on the geographical
changes which have occurred in former times.

[Illustration: Fig. 8.--Map of the northern hemisphere, to show the
geographical distribution of the Arctic Hare (_Lepus variabilis_)
indicated in black.]

One more species must be mentioned, and that is the Banded Lemming
(_Cuniculus torquatus_), which occurs chiefly in Arctic America,
Northern Siberia, and Greenland. Though frequently mistaken for the
Scandinavian Lemming, there is a striking difference in the character of
the teeth, which has induced zoologists to put them into distinct
genera. The Arctic Lemming, moreover, is distinguished from the
Scandinavian by the absence