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 Porto Santo rabbit, on the other hand,
the head relatively to the length of body is about a quarter of an inch too
long.

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
could 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 we
shall presently more fully see, has not increased relatively with the size
of body. As the brain has not increased, the bony case enclosing it has not
increased, and this has evidently affected through correlation the breadth
of the entire skull from end to end.

(FIGURE 6. SKULL OF WILD RABBIT, of natural size.

FIGURE 7. SKULL OF LARGE LOP-EARED RABBIT, of natural size.