truly-inherited sub-breeds, or species, as he would call them, could be
shown him.

Great as are the differences between the breeds of the pigeon, I am fully
convinced that the common opinion of naturalists is correct, namely, that
all are descended from the rock-pigeon (Columba livia), including under
this term several geographical races or sub-species, which differ 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, they did not
breed or willingly perch 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 improbable; or they must have become extinct in the wild
state. But birds breeding on precipices, and good flyers, are unlikely to
be exterminated; and the common rock-pigeon, which has the same habits with
the domestic breeds, has not been exterminated 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 a very rash assumption. Moreover, the several
above-named domesticated breeds have been transported to all parts of the