cies. Moreover, its
presence in Ireland in the plain as well as in the mountains, clearly
points to the fact that, in the British Islands at any rate, the Arctic
Hare was the first comer, and that subsequently the European Hare
invaded these countries. It probably found Ireland then no longer
accessible, having since become separated from England. Again and again
do we find the statement repeated, that the presence of the Arctic Hare
in Europe is a clear proof of the former prevalence in our continent of
an Arctic climate. But if so, why should this Hare at present live and
thrive in Ireland, which has a particularly mild climate in winter, and
be absent from so many continental stations where the temperature more
resembles that of its native home? If we suppose that the European Hare
migrated to Europe from the east, after the Arctic Hare had become
established in Western Europe, and drove the latter into the mountains
or northward whenever the two came into contact, we should have, it
seems to me, a better explanation of the range presented by the two
species. I was formerly of opinion that the European Hare had come with
the Siberian animals from Siberia, but it appears to me more likely now,
that it reached our continent with the Oriental migrants, and only then
joined the Siberians in Eastern Europe.

The evidence in favour of a former land-connection between Scandinavia
and Greenland, rests on many other facts besides those already brought
forward. That some form of land-connection formerly existed between
Europe and Greenland is now indeed almost universally accepted. That it
was situated more to the south between Scotland and Greenland is a
supposition which has been actively supported by many leading
authorities, but it seems to me that if such a land-bridge existed, it
must have been in very early Tertiary times, whilst the northern one,
such as I have indicated, may have originated later and persisted until
a recent geological date.

The distribution of few groups of animals is now better known than that
of the larger butterflies and moths (_Macro-lepidoptera_); even those
of Siberia have been fairly well investigated. The interesting facts
obtainable from their distribution are therefore of special value. No
less than 243 species of _Lepidoptera_ are mentioned by Moeschler as
being common to North America and Europe. It is extremely probable that
a fair number of these have either migrated direct from Ameri