117} 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.

In all the skulls of the large lop-eared rabbits, the supra-orbital
plates or processes of the frontal bones ere much broader than in the
wild rabbit, and they generally project more upwards. In the zygomatic
arch the posterior or projecting point of the malar-bone is broader and
blunter; and in the specimen, fig. 8, it is so in a remarkable degree.
This point approaches nearer to the auditory meatus than in the wild
rabbit, as may be best seen in fig. 8; but this circumstance mainly
depends on the changed direction of the meatus. The inter-parietal bone
(see fig. 9) differs much in shape in the several skulls; generally it
is more oval, or has a greater width in the line of the longitudinal
axis of the skull, than in the wild rabbit. The {118} posterior margin
of "the square raised platform" [271] of the occiput, instead of being
truncated, or projecting slightly as in the wild rabbit, is in most
lop-eared rabbits pointed, as in fig. 9, C. The paramastoids relatively
to the size of the skull are generally much thicker than in the wild
rabbit.

The occipital foramen (fig. 10) presents some remarkable differences:
in the wild rabbit, the lower edge between the condyles is considerably
and almost angularly hollowed out, and the upper edge is deeply and
squarely notched; hence the longitudinal axis exceeds the transverse
axis. In the skulls of the lop-eared rabbits the transverse axis
exceeds the longitudinal; for in none of these skulls was the lower
edge between the condyles so deeply hollowed out; in five of them there
was no upper square notch, in three there was a trace of the notch, and
in two alone it was well developed. These differences in the shape of
the foramen are remarkable, considering that it gives passage to so
important a structure as the spinal marrow, though apparently the
outline of the latter is not affected by the shape of the passage.

[Illustration: Fig. 9.--Posterior end of Skull, of natural size,
showing the inter-parietal bone. A. Wild Rabbit. B. Feral Rabbit from
island of P. Santo, near M