vature of the beak. So it is indeed in many breeds:
thus I had two strains of black Barbs, which evidently differed in the
curvature of the upper mandible. In width of mouth I have found a great
difference in two Swallows. In Fantails of first-rate merit I have seen
some birds with much longer and thinner necks than in others. Other
analogous facts could be given. We have seen that the oil-gland is
aborted in all Fantails (with the exception of the sub-race from Java),
and, I may add, so hereditary is this tendency to abortion, that some,
although not all, of the mongrels from the Fantail and Pouter had no
oil-gland; in one Swallow out of many which I have examined, and in two
Nuns, there was no oil-gland.

The number of the scutellae on the toes often varies in the same breed,
and sometimes even differs on the two feet of the same individual; the
Shetland rock-pigeon has fifteen on the middle, and six on the hinder
toe; whereas I have seen a Runt with sixteen on the middle and eight on
the hind toe; and a short-faced Tumbler with only twelve and five on
these same toes. The rock-pigeon has no sensible amount of skin between
its toes; but I possessed a Spot and a Nun with the skin extending for
a space of a quarter of an inch from the fork, between the two _inner_
toes. On the other hand, as will hereafter be more fully shown, pigeons
with feathered feet very generally have the bases of their _outer_ toes
connected by skin. I had a red Tumbler, which had a coo unlike that of
its fellows, approaching in tone to that of the Laugher: this bird had
the habit, to a degree which I never saw equalled in any other pigeon,
of often walking with its wings raised and arched in an elegant manner.
I need say nothing on the great variability, in almost every breed, in
size of body, in colour, in the feathering of the feet, and in the
feathers on the back of the head being reversed. But I may mention a
remarkable Tumbler[302] exhibited at the Crystal Palace, which had an
irregular crest of feathers on its head, somewhat like the tuft on the
head of the Polish fowl. Mr. Bult reared by accident a hen Jacobin with
the feathers on the thigh so long as to reach the ground, and a cock
having, but in a lesser degree, the same peculiarity: from these two
birds he bred others similarly characterised, which were exhib