e climate, there is a wide difference with the nearer part of the S.
American coast, we see that the inhabitants have been formed on the same
closely allied type. On the other hand, these islands, as far as their
physical conditions are concerned, resemble closely the Cape de Verde
volcanic group, and yet how wholly unlike are the productions of these
two archipelagoes. The Cape de Verde{357} group, to which may be added
the Canary Islands, are allied in their inhabitants (of which many are
peculiar species) to the coast of Africa and southern Europe, in
precisely the same manner as the Galapagos Archipelago is allied to
America. We here clearly see that mere geographical proximity affects,
more than any relation of adaptation, the character of species. How many
islands in the Pacific exist far more like in their physical conditions
to Juan Fernandez than this island is to the coast of Chile, distant 300
miles; why then, except from mere proximity, should this island alone be
tenanted by two very peculiar species of humming-birds--that form of
birds which is so exclusively American? Innumerable other similar cases
might be adduced.

{353} For the general problem of Oceanic Islands, see _Origin_, Ed.
i. p. 388, vi. p. 541.

{354} This is an illustration of the general theory of barriers
(_Origin_, Ed. i. p. 347, vi. p. 494). At i. p. 391, vi. p. 544 the
question is discussed from the point of view of means of transport.
Between the lines, above the words "with that land," the author
wrote "Cause, formerly joined, no one doubts after Lyell."

{355} _Origin_, Ed. i. p. 390, vi. p. 543.

{356} See _Origin_, Ed. i. p. 397, vi. p. 552.

{357} The Cape de Verde and Galapagos Archipelagoes are compared in
the _Origin_, Ed. i. p. 398, vi. p. 553. See also _Journal of
Researches_, 1860, p. 393.

The Galapagos Archipelago offers another, even more remarkable, example
of the class of facts we are here considering. Most of its genera are,
as we have said, American, many of them are mundane, or found
everywhere, and some are quite or nearly confined to this archipelago.
The islands are of absolutely similar composition, and exposed to the
same climate; most of them are in sight of each other; and yet several
of the islands are inhabited, each by peculiar species (or in some cases
perhaps only varieties) of some of the genera characterising the
archipelago. So that the