ers. Mr. Darwin gives instances which he
observed himself. He crossed some white fantails with some black barbs,
and the mongrels were black, brown, or mottled. He also crossed a barb
with a spot, which is a white bird with a red tail and red spot on the
forehead, and the mongrel offspring were dusky and mottled. On now
crossing these two sets of mongrels with each other, he obtained a bird
of a beautiful blue colour, with the barred and white edged tail, and
double-banded wings, so as almost exactly to resemble a wild
rock-pigeon. This bird was descended in the second generation from a
pure white and pure black bird, both of which when unmixed breed their
kind remarkably true. These facts, well known to experienced
pigeon-fanciers, together with the habits of the birds, which all like
to nest in holes, or dovecots, not in trees like the great majority of
wild pigeons, have led to the general belief in the single origin of all
the different kinds.

In order to afford some idea of the great differences which exist among
domesticated pigeons, it will be well to give a brief abstract of Mr.
Darwin's account of them. He divides them into eleven distinct races,
most of which have several sub-races.

RACE I. _Pouters_.--These are especially distinguished by the enormously
enlarged crop, which can be so inflated in some birds as almost to
conceal the beak. They are very long in the body and legs and stand
almost upright, so as to present a very distinct appearance. Their
skeleton has become modified, the ribs being broader and the vertebrae
more numerous than in other pigeons.

RACE II. _Carriers_.--These are large, long-necked birds, with a long
pointed beak, and the eyes surrounded with a naked carunculated skin or
wattle, which is also largely developed at the base of the beak. The
opening of the mouth is unusually wide. There are several sub-races, one
being called Dragons.

RACE III. _Runts_.--These are very large-bodied, long-beaked pigeons,
with naked skin round the eyes. The wings are usually very long, the
legs long, and the feet large, and the skin of the neck is often red.
There are several sub-races, and these differ very much, forming a
series of links between the wild rock-pigeon and the carrier.

RACE IV. _Barbs_.--These are remarkable for their very short and thick
beak, so unlike that of most pigeons that fanciers compare it with that
of a bullfinch. They have also a naked carunculated skin round the eyes