heir pure parents.

_Sixthly._--Excluding certain important characteristic differences, the
chief races agree most closely both with each other and with _C. livia_ in
all other respects. As previously observed, all are eminently sociable; all
dislike to perch or roost, and refuse to build in trees; all lay two eggs,
and this is not a universal rule with the Columbidae; all, as far as I can
hear, require the same time for hatching their eggs; all can endure the
same great range of climate; all prefer the same food, and are passionately
fond of salt; all exhibit (with the asserted exception of the finnikin and
turner, which do not differ much in any other character) the same peculiar
gestures when courting the females; and all (with the exception of
trumpeters and laughers, which likewise do not differ much in any other
character) coo in the same peculiar manner, unlike the voice of any other
wild pigeon. All the coloured breeds display the same peculiar metallic
tints on the breast, a character far from general with pigeons. Each race
presents nearly the same range of variation in colour; and in most of the
races we have the same singular correlation between the development of down
in the young and the future colour of plumage. All have the proportional
length of their toes, and of their primary wing-feathers, nearly the
same,--characters which are apt to differ in the several members of the
Columbidae. In those races which present some remarkable deviation of
structure, such as in the tail of fantails, crop of pouters, beak of
carriers and tumblers, &c., the other parts remain nearly unaltered. Now
every naturalist will admit that it would be scarcely possible to pick out
a dozen natural species in any Family, which should agree closely in habits
and in general structure, and yet should differ greatly in a few {195}
characters alone. This fact is explicable through the doctrine of natural
selection; for each successive modification of structure in each natural
species is preserved, solely because it is of service; and such
modifications when largely accumulated imply a great change in the habits
of life, and this will almost certainly lead to other changes of structure
throughout the whole organisation. On the other hand, if the several races
of the pigeon have been produced by man through selection and variation, we
can readily understand how it is that they should still all resemble each
other in habits and in those man