ls, true
greyhounds having been kept by savages: they are the product of
long-continued civilization.

The number of breeds and sub-breeds of the dog is great: Youatt, for
instance, describes twelve kinds of greyhounds. I will not attempt to
enumerate or describe the varieties, for we cannot discriminate how
much of their difference is due to variation, and how much to descent
from different aboriginal stocks. But it may be worth while briefly to
mention some points. Commencing with the skull, Cuvier has admitted[57]
that in form the differences are "plus fortes que celles d'aucunes
especes sauvages d'un meme genre naturel." The proportions of the
different bones; the curvature of the lower jaw, the position of the
condyles with respect to the plane of the teeth (on which F. Cuvier
founded his classification), and in mastiffs the shape of its posterior
branch; the shape of the zygomatic arch, and of the temporal fossae; the
position of the occiput--all vary considerably.[58] The dog has
properly six pairs of molar teeth in the upper jaw, and seven in the
lower; but several naturalists have seen not rarely an additional pair
in the upper jaw;[59] and Professor Gervais says that there are dogs
"qui ont sept paires de dents superieures et huit inferieures.". De
Blainville[60] has given full particulars on the frequency of these
deviations in the number of the teeth, and has shown that it is not
always the same tooth which is supernumerary. In short-muzzled races,
according to H. Mueller,[61] the molar teeth stand obliquely, whilst in
long-muzzled races they are placed longitudinally, with open spaces
between them. The naked, so-called Egyptian or Turkish dog is extremely
deficient in its {35} teeth,[62]--sometimes having none except one
molar on each side; but this, though characteristic of the breed, must
be considered as a monstrosity. M. Girard,[63] who seems to have
attended closely to the subject, says that the period of the appearance
of the permanent teeth differs in different dogs, being earlier in
large dogs; thus the mastiff assumes its adult teeth in four or five
months, whilst in the spaniel the period is sometimes more than seven
or eight months.

With respect to minor differences little need be said. Isidore Geoffroy
has shown[64] that in size some dogs are six times as long (the