, a
departure from the principle laid down by him. It is this, both
hybrids, the mule and the hinny take after the male parents in all
their external characters save one, which is _size_. In this respect
they both follow the female parents, the mule being in all respects a
larger and finer animal than its sire, the ass; the hinny being in all
respects a smaller and inferior animal to its sire, the horse, the
body and barrel of the mule being large and round, those of the hinny
being flat and narrow; both animals being in these particulars the
reverse of their respective sires, but both resembling their female
parents.

In explanation of this seeming exception is adduced a well known
principle in physiology, which is, that the whole bony framework is
moulded in adaptation to the softer structures immediately related to
it; the muscles covering it in the case of the limbs; and to the
viscera in that of the great cavities which it assists in forming.
Accordingly, in perfect accordance with the views above expressed, the
_general_ size and form which must be mainly that of the _trunk_, will
be determined by the size and character of the viscera of the chest
and abdomen, and will therefore accord with that of the female parents
by whom the viscera in question are chiefly furnished.

The foregoing are the most important of Mr. Orton's statements. He
gives, however, numerous additional illustrations from among beasts,
birds and fishes, of which we quote only the following:

"The mule and the hinny have been selected and placed first, because
they afford the most conclusive evidence and are the most familiar.
Equally conclusive, though perhaps less striking instances, may be
drawn from other sources. Thus, it has been observed that when the
Ancon or Otter sheep were allowed to breed with common ewes, the cross
is not a medium between the two breeds, but that the offspring retains
in a great measure the short and twisted legs of the sire."

Buffon made a cross between the male goat and the ewe; the resulting
hybrid in all the instances, which were many, were strongly
characteristic of the male parent, more particularly in the hair and
length of leg. Curious enough, the number of teats in some of the
cases corresponded with those of the goat.

A cross between the male wolf and a bitch illustrates the same law;
the offspring having a markedly wolfish aspect; skin, color, ears and
tail. On the other hand, a cross between the