lainly barred across the
legs than is even the pure quagga. Lastly, and this is another most
remarkable case, a hybrid has been figured by Dr. Gray (and he informs
me that he knows of a second case) from the ass and the hemionus; and
this hybrid, though the ass only occasionally has stripes on his
legs and the hemionus has none and has not even a shoulder-stripe,
nevertheless had all four legs barred, and had three short
shoulder-stripes, like those on the dun Devonshire and Welsh ponies, and
even had some zebra-like stripes on the sides of its face. With respect
to this last fact, I was so convinced that not even a stripe of colour
appears from what is commonly called chance, that I was led solely
from the occurrence of the face-stripes on this hybrid from the ass and
hemionus to ask Colonel Poole whether such face-stripes ever occurred
in the eminently striped Kattywar breed of horses, and was, as we have
seen, answered in the affirmative.

What now are we to say to these several facts? We see several distinct
species of the horse genus becoming, by simple variation, striped on the
legs like a zebra, or striped on the shoulders like an ass. In the horse
we see this tendency strong whenever a dun tint appears--a tint which
approaches to that of the general colouring of the other species of the
genus. The appearance of the stripes is not accompanied by any change
of form, or by any other new character. We see this tendency to become
striped most strongly displayed in hybrids from between several of the
most distinct species. Now observe the case of the several breeds
of pigeons: they are descended from a pigeon (including two or three
sub-species or geographical races) of a bluish colour, with certain bars
and other marks; and when any breed assumes by simple variation a bluish
tint, these bars and other marks invariably reappear; but without any
other change of form or character. When the oldest and truest breeds of
various colours are crossed, we see a strong tendency for the blue tint
and bars and marks to reappear in the mongrels. I have stated that the
most probable hypothesis to account for the reappearance of very ancient
characters, is--that there is a TENDENCY in the young of each successive
generation to produce the long-lost character, and that this tendency,
from unknown causes, sometimes prevails. And we have just seen that in
several species of the horse genus the stripes are either plainer or
appear more