the
blue colour and various marks occasionally appearing in all the breeds,
both when kept pure and when crossed; the mongrel offspring being perfectly
fertile;--from these several reasons, taken together, I can feel no doubt
that all our domestic breeds have descended from the Columba livia with its
geographical sub-species.

In favour of this view, I may add, firstly, that C. livia, or the
rock-pigeon, has been found capable of domestication in Europe and in
India; and that it agrees in habits and in a great number of points of
structure with all the domestic breeds. Secondly, although an English
carrier or short-faced tumbler differs immensely in certain characters from
the rock-pigeon, yet by comparing the several sub-breeds of these
varieties, more especially those brought from distant countries, we can
make an almost perfect series between the extremes of structure. Thirdly,
those characters which are mainly distinctive of each breed, for instance
the wattle and length of beak of the carrier, the shortness of that of the
tumbler, and the number of tail-feathers in the fantail, are in each breed
eminently variable; and the explanation of this fact will be obvious when
we come to treat of selection. Fourthly, pigeons have been watched, and
tended with the utmost care, and loved by many people. They have been
domesticated for thousands of years in several quarters of the world; the
earliest known record of pigeons is in the fifth AEgyptian dynasty, about
3000 B.C., as was pointed out to me by Professor Lepsius; but Mr. Birch
informs me that pigeons are given in a bill {28} of fare in the previous
dynasty. In the time of the Romans, as we hear from Pliny, immense prices
were given for pigeons; "nay, they are come to this pass, that they can
reckon up their pedigree and race." Pigeons were much valued by Akber Khan
in India, about the year 1600; never less than 20,000 pigeons were taken
with the court. "The monarchs of Iran and Turan sent him some very rare
birds;" and, continues the courtly historian, "His Majesty by crossing the
breeds, which method was never practised before, has improved them
astonishingly." About this same period the Dutch were as eager about
pigeons as were the old Romans. The paramount importance of these
considerations in explaining the immense amount of variation which pigeons
have undergone, will be obvious when we treat of Selection. We shall then,
also, see how it is that the breeds so ofte