the skull
of the wild, 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 in any respect 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.

As some of the largest lop-eared rabbits of which I prepared skeletons
were coloured almost like hares, and as these latter animals and
rabbits have, as it is affirmed, been recently crossed in France, it
might be thought that some of the above-described characters had been
derived from a cross at a remote period with the hare. Consequently I
examined skulls of the hare, but no light could thus be thrown on the
peculiarities of the skulls of the larger rabbits. It is, however, an
interesting fact, as illustrating the law that varieties of one species
often assume the characters of other species of the same genus, that I
found, on comparing the skulls of ten species of hares in the British
Museum, that they differed from each other chiefly in the very same
points in which domestic rabbits vary,--namely, in general proportions,
in the form and size of the supra-orbital plates, in the form of the
free end of the malar bone, and in the line of suture separating the
occipital and frontal bones. Moreover two eminently variable characters
in the domestic rabbit, namely, the outline of the occipital foramen
and the shape of the "raised platform" of the occiput, were likewise
variable in two instances in the same species of hare.

_Vertebrae._--The number is uniform in all the skeletons which I have
examined, with two exceptions, namely, in one of the small feral Porto
Santo rabbits and in one of the largest lop-eared kinds; both of these
had as usual seven cervical, twelve dorsal with ribs, but, instead of
seven lumbar, both had eight lumbar vertebrae. This is remarkable, as
Gervais gives {121} seven as the number for the whole genus Lepus. The
caudal vertebrae