y characters which man has not cared to
modify, whilst they differ to so prodigious a degree in those parts which
have struck his eye or pleased his fancy.

Besides the points above enumerated, in which all the domestic races
resemble _C. livia_ and each other, there is one which deserves special
notice. The wild rock-pigeon is of a slaty-blue colour; the wings are
crossed by two black bars; the croup varies in colour, being generally
white in the pigeon of Europe, and blue in that of India; the tail has a
black bar close to the end, and the outer webs of the outer tail-feathers
are edged with white, except near the tips. These combined characters are
not found in any wild pigeon besides _C. livia_. I have looked carefully
through the great collection of pigeons in the British Museum, and I find
that a dark bar at the end of the tail is common; that the white edging to
the outer tail-feathers is not rare; but that the white croup is extremely
rare, and the two black bars on the wings occur in no other pigeon,
excepting the alpine _C. leuconota_ and _C. rupestris_ of Asia. Now if we
turn to the domestic races, it is highly remarkable, as an eminent fancier,
Mr. Wicking, observed to me, that, whenever a blue bird appears in any
race, the wings almost invariably show the double black bars.[338] The
primary wing-feathers may be white or black, and the whole body may be
{196} of any colour, but if the wing-coverts alone are blue, the two black
bars surely appear. I have myself seen, or acquired trustworthy evidence,
as given below,[339] of blue birds with black bars on the wing, with the
croup either white or very pale or dark blue, with the tail having a
terminal black bar, and with the outer feathers externally edged with white
or very pale coloured, in the following races, which, as I carefully
observed in each case, appeared to be perfectly pure: namely, in Pouters,
Fantails, Tumblers, Jacobins, Turbits, Barbs, Carriers, Runts of three
distinct varieties, Trumpeters, Swallows, and in many other toy-pigeons,
which, as being closely allied to _C. livia_, are not worth enumerating.
Thus we see that, in purely-bred races of every kind known in Europe, blue
birds occasionally appear having all the marks which characterise _C.
livia_, and which concur in no other wild species. Mr. Blyth, also, has
made the same observation with respect to the various domestic races known
in India.

Certain variations in the plumage are equally