given: indeed it is an almost universal
rule that the endemic productions of islands are related to those of the
nearest continent, or of other near islands. The exceptions are few, and
most of them can be explained. Thus the plants of Kerguelen Land, though
standing nearer to Africa than to America, are related, and that very
closely, as we know from Dr. Hooker's account, to those of America: but
on the view that this island has been mainly stocked by seeds brought
with earth and stones on icebergs, drifted by the prevailing currents,
this anomaly disappears. 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 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 i