possession, the males had generally the largest eye-wattles; Mr.
Esquilant also believes in this rule, but Mr. H. Weir, a first-rate judge,
entertains some doubt on the subject. Hale Pouters distend their crops to a
much greater size than do the females; I have, however, seen a hen in the
possession of Mr. Evans which pouted excellently; but this is an unusual
circumstance. Mr. Harrison Weir, a successful breeder of prize {162}
Fantails, informs me that his cock birds often have a greater number of
tail-feathers than the hens. Mr. Eaton asserts[306] that, if a cock and hen
Tumbler were of equal merit, the hen would be worth double the money; and
as pigeons always pair, so that an equal number of both sexes is necessary
for reproduction, this seems to show that high merit is rarer in the female
than in the male. In the development of the frill in Turbits, of the hood
in Jacobins, of the tuft in Trumpeters, of tumbling in Tumblers, there is
no difference between the males and females. I may here add a rather
different case, namely, the existence in France[307] of a wine-coloured
variety of the Pouter, in which the male is generally chequered with black,
whilst the female is never so chequered. Dr. Chapuis also remarks[308] that
in certain light-coloured pigeons the males have their feathers striated
with black, and these striae increase in size at each moult, so that the
male ultimately becomes spotted with black. With Carriers, the wattle, both
on the beak and round the eyes, and with Barbs that round the eyes, goes on
increasing with age. This augmentation of character with advancing age, and
more especially the difference between the males and females in the
above-mentioned several respects, are highly remarkable facts, for there is
no sensible difference at any age between the two sexes in the aboriginal
rock-pigeon; and rarely any such difference throughout the whole family of
the Columbidae.[309]

[Illustration: Fig. 24.--Skulls of Pigeons, viewed laterally, of natural
size. A. Wild Rock-pigeon, _Columba livia_. B. Short-faced Tumbler. C.
English Carrier. D. Bagadotten Carrier.]

_Osteological Characters._

In the skeletons of the various breeds there is much variability; and
though certain differences occur frequently, and others rarely, in certain
breeds, yet none can be said to be absolutely characteristic of any breed.
Considering that strongly-marked domestic races have been formed chiefly by
man's power {163}