largest skulls of the lop-eared this line was plainly bowed inwards. In one
specimen there was an additional molar tooth on each side of the upper jaw,
between the molars and premolars; but these two teeth did not correspond in
size; and as no rodent has seven molars, this is merely a monstrosity,
though a curious one.

The five other skulls of common domestic rabbits, some of which approach in
size the above-described largest skulls, whilst the others exceed but
little those of the wild rabbit, are only worth notice as presenting a
perfect gradation in all the above-specified differences between the skulls
of the largest lop-eared and wild rabbits. In all, however, the supra-
orbital plates are rather larger, and in all the auditory meatus is larger,
in conformity with the increased size of the external ears, than in the
wild rabbit. The lower notch in the occipital foramen in some was not so
deep as in the wild rabbit, but in all five skulls the upper notch was well
developed.

The skull of the Angora rabbit, like the latter five skulls, is
intermediate in general proportions, and in most other characters, between
those of the largest lop-eared and wild rabbits. It presents only one
singular character: though considerably longer than the skull of the wild
rabbit, the breadth measured within the posterior supra-orbital fissures is
nearly a third less than in the wild. The skulls of the silver-grey, and
chinchilla and Himalayan rabbits are more elongated than in the wild, with
broader supra-orbital plates, but differ little in any other respect,
excepting that the upper and lower notches of the occipital foramen are not
so deep or so well developed. The skull of the Moscow rabbit scarcely
differs at all from that of the wild rabbit. In the Porto Santo feral
rabbits the supra-orbital plates are generally narrower and more pointed
than in our wild rabbits.