, in which some members have not a tuft of
feathers on their heads, we may suspect that reversion to some
extremely remote form has come into action.

Several breeds of the fowl have either spangled or pencilled feathers;
and these cannot be derived from the parent-species, the _Gallus
bankiva_; though of course it is possible that an early progenitor of
this species may have been spangled, and a still earlier or a later
progenitor may have been pencilled. But as many gallinaceous birds are
spangled or pencilled, it is a more probable view that the several
domestic breeds of the fowl have acquired this kind of plumage from all
the members of the family inheriting a tendency to vary in a like
manner. The same principle may account for the ewes in certain breeds
of sheep being hornless, like the females of some other hollow-horned
ruminants; it may account for certain domestic cats having
slightly-tufted ears, like those of the lynx; and for the skulls of
domestic rabbits often differing from each {351} other in the same
characters by which the skulls of the various species of the genus
Lepus differ.

I will only allude to one other case, already discussed. Now that we
know that the wild parent of the ass has striped legs, we may feel
confident that the occasional appearance of stripes on the legs of the
domestic ass is due to direct reversion; but this will not account for
the lower end of the shoulder-stripe being sometimes angularly bent or
slightly forked. So, again, when we see dun and other coloured horses
with stripes on the spine, shoulders, and legs, we are led, from
reasons formerly given, to believe that they reappear from direct
reversion to the wild parent-horse. But when horses have two or three
shoulder-stripes with one of them occasionally forked at the lower end,
or when they have stripes on their faces, or as foals are faintly
striped over nearly their whole bodies, with the stripes angularly bent
one under the other on the forehead, or irregularly branched in other
parts, it would be rash to attribute such diversified characters to the
reappearance of those proper to the aboriginal wild horse. As three
African species of the genus are much striped, and as we have seen that
the crossing of the unstriped species often leads to the hybrid
offspring being conspicuously