all these the skull is remarkably elongated in comparison with its
breadth. In a wild rabbit the length was 3.15 inches, in a large fancy
rabbit 4.30; whilst the breadth of the cranium enclosing the brain was
in both almost exactly the same. Even by taking as the standard of
comparison the widest part of the zygomatic arch, the skulls of the
lop-eared are proportionally to their breadth three-quarters of an inch
too long. The depth of the head has increased almost in the same
proportion with the length; it is the breadth alone which has not
increased. The parietal and occipital bones enclosing the brain are
less arched, both in a longitudinal and transverse line, than in the
wild rabbit, so that the shape of the cranium is somewhat different.
The surface is rougher, less cleanly sculptured, and the lines of
sutures are more prominent.

Although the skulls of the large lop-eared rabbits in comparison with
those of the wild rabbit are much elongated relatively to their
breadth, yet, relatively to the size of body, they are far from
elongated. The lop-eared rabbits which I examined were, though not fat,
more than twice as heavy as the wild specimens; but the skull was very
far from being twice as long. Even if we take the fairer standard of
the length of body, from the nose to the anus, the skull is not on an
average as long as it ought to be by a third of an inch. In the small
feral P. Santo rabbit, on the other hand, the head relatively to the
length of body is about a quarter of an inch too long.

[Illustration: Fig. 8.--Part of Zygomatic Arch, showing the projecting
end of the malar bone and the auditory meatus: of natural size. Upper
figure, Wild Rabbit. Lower figure, Lop-eared, hare-coloured Rabbit.]

This elongation of the skull relatively to its breadth, I find a
universal character, not only with the large lop-eared rabbits, but in
all the artificial breeds; as is well seen in the skull of the Angora.
I was at first much surprised at the fact, and could not imagine why
domestication should produce this uniform result; but the explanation
seems to lie in the circumstance that during a number of generations
the artificial races have been closely confined, and have had little
occasion to exert either their senses, or intellect, or voluntary
muscles; consequently the brain, as {