er from each
other in the most trifling respects. As several of the reasons which have
led me to this belief are in some degree applicable in other cases, I will
here briefly give them. If the several breeds are not varieties, and have
not proceeded from the rock-pigeon, they must have descended from at least
seven or eight aboriginal stocks; for it is impossible to make the present
domestic breeds by the crossing of any lesser number: how, for instance,
could a pouter be produced by crossing two breeds unless one of the
parent-stocks possessed the characteristic enormous crop? The supposed
aboriginal stocks must all have been rock-pigeons, that is, not breeding or
willingly perching on trees. But besides C. livia, with its geographical
sub-species, only two or three other species of rock-pigeons are known; and
these have not any of the characters of the domestic breeds. Hence the
supposed aboriginal stocks must either still exist in the countries where
they were originally domesticated, and yet be unknown to ornithologists;
and this, considering their size, habits, and remarkable characters, seems
very improbable; or they must have become extinct in the wild state. But
birds breeding on precipices, and good fliers, are unlikely to be
exterminated; and the common rock-pigeon, which has the same habits with
the domestic breeds, has not been exterminated {24} even on several of the
smaller British islets, or on the shores of the Mediterranean. Hence the
supposed extermination of so many species having similar habits with the
rock-pigeon seems to me a very rash assumption. Moreover, the several
above-named domesticated breeds have been transported to all parts of the
world, and, therefore, some of them must have been carried back again into
their native country; but not one has ever become wild or feral, though the
dovecot-pigeon, which is the rock-pigeon in a very slightly altered state,
has become feral in several places. Again, all recent experience shows that
it is most difficult to get any wild animal to breed freely under
domestication; yet on the hypothesis of the multiple origin of our pigeons,
it must be assumed that at least seven or eight species were so thoroughly
domesticated in ancient times by half-civilized man, as to be quite
prolific under confinement.

An argument, as it seems to me, of great weight, and applicable in several
other cases, is, that the above-specified breeds, though agreeing generally
in c