kals, and owing on the other hand
to the great dissimilarity of the skulls of the several breeds of the
domestic dogs. It seems, however, that remains have been found in the {16}
later tertiary deposits more like those of a large dog than of a wolf,
which favours the belief of De Blainville that our dogs are the descendants
of a single extinct species. On the other hand, some authors go so far as
to assert that every chief domestic breed must have had its wild prototype.
This latter view is extremely improbable; it allows nothing for variation;
it passes over the almost monstrous character of some of the breeds; and it
almost necessarily assumes, that a large number of species have become
extinct since man domesticated the dog; whereas we plainly see that the
members of the dog-family are extirpated by human agency with much
difficulty; even so recently as 1710 the wolf existed in so small an island
as Ireland.

The reasons which have led various authors to infer that our dogs have
descended from more than one wild species are as follows.[6] Firstly, the
great difference between the several breeds; but this will appear of
comparatively little weight, after we shall have seen how great are the
differences between the several races of various domesticated animals which
certainly have descended from a single parent-form. Secondly, the more
important fact that, at the most anciently known historical periods,
several breeds of the dog existed, very unlike each other, and closely
resembling or identical with breeds still alive.

We will briefly run back through the historical records. The materials are
remarkably deficient between the fourteenth century and the Roman classical
period.[7] At this earlier period {17} various breeds, namely hounds,
house-dogs, lapdogs, &c., existed; but as Dr. Walther has remarked it is
impossible to recognise the greater number with any certainty. Youatt,
however, gives a drawing of a beautiful sculpture of two greyhound puppies
from the Villa of Antoninus. On an Assyrian monument, about 640 B.C., an
enormous mastiff[8] is figured; and according to Sir H. Rawlinson (as I was
informed at the British Museum), similar dogs are still imported into this
same country. I have looked through the magnificent works of Lepsius and
Rosellini, and on the monuments from the fourth to the twelfth dynasties
(_i.e._ from about 3400 B.C. to 2100 B.C.) several varieties of the dog are
represented; most of them ar