New Zealand in its endemic plants is much more closely related to
Australia, the nearest mainland, than to any other region: and this is what
might have been expected; but it is also plainly related to South America,
which, although the next nearest continent, is so enormously remote, that
the fact becomes an anomaly. But this difficulty almost disappears on the
view that both New Zealand, South America, and other southern lands were
long ago partially stocked from a nearly intermediate though distant point,
namely from the antarctic islands, when they were clothed with vegetation,
before the commencement of the Glacial period. The affinity, which, though
feeble, I am assured by Dr. Hooker is real, between the flora of the
south-western corner of Australia and of the Cape of Good {400} Hope, is a
far more remarkable case, and is at present inexplicable: but this affinity
is confined to the plants, and will, I do not doubt, be some day explained.

The law which causes the inhabitants of an archipelago, though specifically
distinct, to be closely allied to those of the nearest continent, we
sometimes see displayed on a small scale, yet in a most interesting manner,
within the limits of the same archipelago. Thus the several islands of the
Galapagos Archipelago are tenanted, as I have elsewhere shown, in a quite
marvellous manner, by very closely related species; so that the inhabitants
of each separate island, though mostly distinct, are related in an
incomparably closer degree to each other than to the inhabitants of any
other part of the world. And this is just what might have been expected on
my view, for the islands are situated so near each other that they would
almost certainly receive immigrants from the same original source, or from
each other. But this dissimilarity between the endemic inhabitants of the
islands may be used as an argument against my views; for it may be asked,
how has it happened in the several islands situated within sight of each
other, having the same geological nature, the same height, climate, &c.,
that many of the immigrants should have been differently modified, though
only in a small degree. This long appeared to me a great difficulty: but it
arises in chief part from the deeply-seated error of considering the
physical conditions of a country as the most important for its inhabitants;
whereas it cannot, I think, be disputed that the nature of the other
inhabitants, with which each has to c