PDF - Wallace Online

216 GEOGRAPHICAL ZOOLOGY. [part IV.
Oregon, and Arkansas. Elotherium is said to be allied to the
peccary and hippopotamus. Hyopotamus, from the Miocene of
Dakota, is allied to Anthracotherium, and forms with it (accord-
ing to Dr. Leidy) a distinct family of ancestral swine.
It thus appears, that the swine were almost equally well re-
presented in North America and Europe, during Miocene and
Pliocene times, but by entirely distinct forms ; and it is a re-
markable fact that these hardy omnivorous animals, should, like
the horses, have entirely died out in North America, except a
few peccaries which have preserved themselves in the sub-tropical
parts and in the southern continent, to which they are compara-
tively recent emigrants. We can hardly have a more convincing
proof of the vast physical changes that have occurred in the
North American continent during the Pliocene and Post-pliocene
epochs, than the complete extinction of these, along with so
many other remarkable types of Mammalia.
According to M. Gaudry, the ancestors of all the swine, with
the hippopotami and extinct Anthracotherium, Merycopotamus,
and many allied forms,—are the Hyracotherium and Pliolophus,
both found only in the London clay belonging to the Lower
Eocene formation.
Neotropical
sub-kegions.
Family 48.—CAMELIDvE. (2 Genera, 6 Species).
Nearctic
Sub-regions.
1 - 2.3.4
General Distribution.
PaLvEARCTIC
SUB-KEGIONS.
Living Species.
2 .3
Ethiopian
Sub-regions.
Extinct Species.
- 3
Oriental
Sub-regions.
Australian
Sub-regions.
The Camels are an exceedingly restricted group, the majority
of the species now existing only in a state of domestication. The
genus Camelus (2 species), is a highly characteristic desert form