latent state in the female, so that the male offspring should not be
deteriorated, will be best appreciated as follows: the male of
Soemmerring s pheasant has a tail thirty-seven inches in length, whilst
that of the female is only eight inches; the tail of the male common
pheasant is about twenty inches, and that of the female twelve inches
long. Now if the female Soemmerring pheasant with her SHORT tail were
crossed with the male common pheasant, there can be no doubt that the
male hybrid offspring would have a much LONGER tail than that of the
pure offspring of the common pheasant. On the other hand, if the female
common pheasant, with a tail much longer than that of the female
Soemmerring pheasant, were crossed with the male of the latter, the
male hybrid offspring would have a much SHORTER tail than that of the
pure offspring of Soemmerring s pheasant. (3. Temminck says that the
tail of the female Phasianus Soemmerringii is only six inches long,
Planches coloriees, vol. v. 1838, pp. 487 and 488: the measurements
above given were made for me by Mr. Sclater. For the common pheasant,
see Macgillivray, History of British Birds, vol. i. pp. 118-121.)
Our fancier, in order to make his new breed with the males of a
pale-blue tint, and the females unchanged, would have to continue
selecting the males during many generations; and each stage of paleness
would have to be fixed in the males, and rendered latent in the
females. The task would be an extremely difficult one, and has never
been tried, but might possibly be successfully carried out. The chief
obstacle would be the early and complete loss of the pale-blue tint,
from the necessity of reiterated crosses with the slaty female, the
latter not having at first any LATENT tendency to produce pale-blue
offspring.
On the other hand, if one or two males were to vary ever so slightly in
paleness, and the variations were from the first limited in their
transmission to the male sex, the task of making a new breed of the
desired kind would be easy, for such males would simply have to be
selected and matched with ordinary females. An analogous case has
actually occurred, for there are breeds of the pigeon in Belgium (4.
Dr. Chapuis, Le Pigeon Voyageur Belge, 1865, p. 87.) in which the
males alone are marked with black striae. So again Mr. Tegetmeier has
recently shewn (5. The Field, Sept. 1872.) that dragons not rarely
produce silver-coloured birds, which are almost always hens; and he
himself has bred ten such females. It is on the other hand a very
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