rely terrestrial animals, and
leaving us without the number of species which our favourable climate
and varied surface entitle us to." The comparative zoological poverty of
Ireland he attributes to the fact that "the depth of the Irish Sea being
somewhat greater than that of the German Ocean, the connecting land
would there probably be of small extent and of less duration, thus
offering an additional barrier to migration."

Dr. Wallace's explanation of the origin of the British fauna is
disappointing after Forbes's careful study and critical inquiry into
its component elements. So great an authority on geographical
distribution might have given us more lucid statements of his views on a
variety of topics connected with this subject.

In speaking of the fauna of Ireland, Professor Leith Adams, Professor
Dawkins, and Mr. Alston are evidently only thinking of the mammals,
which form but a very small proportion of it. The first-mentioned
palaeontologist held that there was a land-communication between Scotland
and Ireland at the close of the Glacial period, by which the greater
portion of the mammals that had found their way to the former country
crossed to the latter (p. 100). And, he continues, the severance between
the two countries must have taken place before the slow-travelling Mole,
the Beaver, the forest-haunting Elk and the Roebuck had time to arrive.

Much in the same spirit are Mr. Alston's remarks on this subject (p. 5).
"The absence from the known fossil fauna of Scotland and Ireland of most
of the characteristic post-pliocene English animals, shows that the
northward migration of these forms was slow, gradually advancing as the
glacial conditions of the northern parts of our islands decreased in
intensity. Thus it is not difficult to suppose that the Hedgehog,
Ermine, Badger, Squirrel, and Mountain Hare may have found their way
through southern Scotland into Ireland long before they were able to
penetrate into the still sub-arctic regions of the Highlands.
Subsequently, when the improvement of the climate had continued, the
Shrews and Voles may well have found their way northward along the
comparatively genial coasts, before the larger beasts of prey could find
a sufficient stock of game."

That the Bear, Wolf, Stag, Horse, Mammoth, and Reindeer lived in Ireland
before the Glacial period is considered highly probable by Professor
Boyd Dawkins (_a_, p. 152).

Only the Butterflies are dealt with in Dr. Buch