largely kept, that it is almost certain, if any degree of infertility
had existed between them, it would have been detected. On the other hand,
the four known species of Gallus when crossed with each other, or when
crossed, with the exception of _G. bankiva_, with the domestic fowl,
produce infertile hybrids.

Finally, we have not such good evidence with fowls as with pigeons, of all
the breeds having descended from a single primitive stock. In both cases
the argument of fertility must go for something; in both we have the
improbability of man having succeeded in ancient times in thoroughly
domesticating several supposed species,--most of these supposed species
being extremely abnormal as compared with their natural allies,--all being
now either unknown or extinct, though the parent-form of scarcely any other
domesticated bird has been lost. But in searching for the supposed
parent-stocks of the various breeds of the pigeon, we were enabled to
confine our search to species having peculiar habits of life; whilst with
fowls there is nothing in their habits in any marked manner distinct from
those of other gallinaceous birds. In the case of pigeons, I have shown
that purely-bred birds of every race and the crossed offspring of distinct
races frequently resemble, or revert to, the wild rock-pigeon in general
colour and in each characteristic mark. With fowls we have facts of a
similar nature, but less strongly pronounced, which we will now discuss.

* * * * *

_Reversion and Analogous Variation._--Purely-bred Game, Malay, Cochin,
Dorking, Bantam, and, as I hear from Mr. Tegetmeier, Silk fowls, may
frequently or occasionally be met with, which are almost identical in
plumage with the wild _G. bankiva_. This is a fact well deserving
attention, when we reflect that these breeds rank amongst the most
distinct. Fowls thus coloured are called by amateurs black-breasted reds.
Hamburghs properly have a very different plumage; nevertheless, as Mr.
Tegetmeier informs me, "the great difficulty in breeding cocks of the
golden-spangled variety is their tendency to have black breasts and red
backs." The males of white Bantams and {240} white Cochins, as they come to
maturity, often assume a yellowish or saffron tinge; and the longer neck
hackles of black bantam cocks,[388] when two or three years old, not
uncommonly become ruddy; these latter bantams occasionally "even moult
brassy winged, or actually red