adeira. C. Large Lop-eared Rabbit.]

[Illustration: Fig. 10.--Occipital Foramen, of natural size, in--A.
Wild Rabbit; B. Large Lop-eared Rabbit.]

In all the skulls of the large lop-eared rabbits, the bony auditory
meatus is conspicuously larger than in the wild rabbit. In a skull 4.3
inches in length, and which barely exceeded in breadth the skull of a
wild rabbit (which was 3.15 inches in length), the longer diameter of
the meatus was exactly twice as great. The orifice is more compressed,
and its margin on the side nearest the skull stands up higher than the
outer side. The whole meatus is directed more forwards. As in breeding
lop-eared rabbits the length of the ears, and their consequent lopping
and lying flat on the face, are the chief points of excellence, there
can hardly be a doubt that the great change in the size, form, and
direction of the bony meatus, relatively to this same part in the wild
rabbit, is due to the continued selection of individuals having {119}
larger and larger ears. The influence of the external ear on the bony
meatus is well shown in the skulls (I have examined three) of half-lops
(see fig. 5), in which one ear stands upright, and the other and longer
ear hangs down; for in these skulls there was a plain difference in the
form and direction of the bony meatus on the two sides. But it is a
much more interesting fact, that the changed direction and increased
size of the bony meatus have slightly affected on the same side the
structure of the whole skull. I here give a drawing of the skull of a
half-lop; and it may be observed that the suture between the parietal
and frontal bones does not run strictly at right angles to the
longitudinal axis of the skull; the left frontal bone projects beyond
the right one; both the posterior and anterior margins of the left
zygomatic arch on the side of the lopping ear stand a little in advance
of the corresponding bones on the opposite side. Even the lower jaw is
affected, and the condyles are not quite symmetrical, that on the left
standing a little in advance of that on the right. This seems to me a
remarkable case of correlation of growth. Who would have surmised that
by keeping an animal during many generations under confinement, and so
leading to the disuse of the muscles of the ears, and by continually
selecting indi