erable proportion of peculiar species. Owing to the comparatively
easy passage from the northern extremity of Japan through the island of
Saghalien to the mainland of Asia, a large number of temperate forms of
insects and birds are still able to enter the country, and thus diminish
the proportionate number of peculiar species. In the case of mammals this
is more difficult; and the large proportion of specific difference in their
case is a good indication of the comparatively remote epoch at which Japan
was finally separated from the continent. How long ago this separation took
place we cannot of course tell, but we may be sure it was much longer than
in the case of our own islands, and therefore probably in the earlier
portion of the Pliocene period.

FORMOSA.

Among recent continental islands there is probably none that surpasses in
interest and instructiveness the Chinese island named by the Portuguese,
Formosa, or "The Beautiful." Till quite recently it was a _terra incognita_
to naturalists, and we owe almost all our present knowledge of it to a
single man, the late Mr. Robert Swinhoe, who, in his official capacity as
one of our consuls in China, visited it several times between 1856 and
1866, besides residing on it for more than a year. During this period he
devoted all his spare time and energy to the study of natural history, more
especially of the two important groups, birds and mammals; and by employing
a large staff of native collectors and hunters, he obtained a very complete
knowledge of its fauna. In this case, too, we have the great advantage of a
very thorough knowledge of the adjacent parts of the continent, in great
part due to Mr. Swinhoe's own exertions during the twenty years of his
service in {401} that country. We possess, too, the further advantage of
having the whole of the available materials in these two classes collected
together by Mr. Swinhoe himself after full examination and comparison of
specimens; so that there is probably no part of the world (if we except
Europe, North America, and British India) of whose warm-blooded vertebrates
we possess fuller or more accurate knowledge than we do of those of the
coast districts of China and its islands.[95]

_Physical Features of Formosa._--The island of Formosa is nearly half the
size of Ireland, being 220 miles long, and from twenty to eighty miles
wide. It is traversed down its centre by a fine mountain range, which
reaches an altitude of abou