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.

(FIGURE 11. SKULL, of natural size, of Half-lop Rabbit, showing the
different direction of the auditory meatus on the two sides, and the
consequent general distortion of the skull. The left ear of the animal (or
right side of figure) lopped forwards.)

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 larger and larger ears. The influence of
the external ear on the bony meatus is well shown in the skulls (I have