found, which have not been discovered in the intertropical parts of
Africa. On the Himalaya, and on the isolated mountain-ranges of the
peninsula of India, on the heights of Ceylon, and on the volcanic cones
of Java, many plants occur, either identically the same or representing
each other, and at the same time representing plants of Europe, not
found in the intervening hot lowlands. A list of the genera collected
on the loftier peaks of Java raises a picture of a collection made on a
hill in Europe! Still more striking is the fact that southern
Australian forms are clearly represented by plants growing on the
summits of the mountains of Borneo. Some of these Australian forms, as
I hear from Dr. Hooker, extend along the heights of the peninsula of
Malacca, and are thinly scattered, on the one hand over India and on
the other as far north as Japan.
On the southern mountains of Australia, Dr. F. Muller has discovered
several European species; other species, not introduced by man, occur
on the lowlands; and a long list can be given, as I am informed by Dr.
Hooker, of European genera, found in Australia, but not in the
intermediate torrid regions. In the admirable Introduction to the
Flora of New Zealand, by Dr. Hooker, analogous and striking facts are
given in regard to the plants of that large island. Hence we see that
throughout the world, the plants growing on the more lofty mountains,
and on the temperate lowlands of the northern and southern hemispheres,
are sometimes
identically the same; but they are much oftener specifically distinct,
though related to each other in a most remarkable manner.
This brief abstract applies to plants alone: some strictly analogous
facts could be given on the distribution of terrestrial animals. In
marine productions, similar cases occur; as an example, I may quote a
remark by the highest authority, Professor Dana, that it is certainly
a wonderful fact that New Zealand should have a closer resemblance in
its crustacea to Great Britain, its antipode, than to any other part of
the world. Sir J. Richardson, also, speaks of the reappearance on the
shores of New Zealand, Tasmania, etc., of northern forms of fish. Dr.
Hooker informs me that twenty-five species of Alg are common to New
Zealand and to Europe, but have not been found in the intermediate
tropical seas.
It should be observed that the northern species and forms found in the
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