m to have been able to
cross the River Garonne, and we therefore find neither the Woodland
Reindeer nor any of the typical Siberian species represented in the
Pyrenean deposits.

[Illustration: Fig. 12.--Map of Europe, indicating the parts which were
probably submerged (shaded) at the commencement of the Glacial period.
The light portions represent, approximately, the extent of the land at
that time.]

The Woodland Reindeer persisted in continental Europe until
comparatively recent times, and it has since made its way into
Scandinavia across Northern Russia, and probably mingled with the older
stock of the Barren-ground form. In the same way, it may have come about
that in the English pleistocene deposits the remains of the two races
occur.

In a recent contribution to our knowledge of the deer tribe (_c_, p.
88), Mr. Lydekker suggests that the former division of the Reindeer
races into the two forms of Woodland and Barren-ground Caribou, no
longer holds good. He now recognises no less than six races, as
follows:--

1. Rangifer tarandus typicus.
2. " " spitzbergensis.
3. " " caribou.
4. " " terrae-novae.
5. " " groenlandicus.
6. " " arcticus.

I hardly think these can be considered of equal value; indeed, though
there may be differences between _R. groenlandicus_, _typicus_,
_arcticus_, and _spitzbergensis_, the antlers exhibit a certain much
closer relationship among one another than to _R. terrae-novae_ and
_caribou_. But the whole subject is by no means as well known as could
be wished, and a very careful comparative study of recent and fossil
remains of the Reindeer from various parts of the Old and New Worlds is
much needed to put our views on a firmer basis.

The presence of the Arctic Hare in Ireland and the absence of the common
European Hare (_Lepus europaeus_) can be explained in a somewhat similar
manner. The Arctic Hare is the older of the two species--corresponding
with the Barren-ground Reindeer--and the European Hare the newer one,
associating, like the Woodland Reindeer, in its westward migration with
Siberian animals, though probably of Oriental origin.

Let us once more refer back again to the map on page 137 indicating the
geographical distribution of the Arctic Hare. Its discontinuous range
and its isolated position in the Alps, Pyrenees, and the Japanese
mountains, all tend to show that it is an ancient spe