CHAP. XVII.] 
MAMMALIA. 
211 
Maryland to Florida ; and an extinct genus, Prorastomus , in some 
Tertiary deposits in the Island of Jamaica. 
In Post-pliocene deposits in Siberia, remains of Bytina have 
been found ; while several species of the extinct genus Hali- 
therium, perhaps intermediate between Manatus and Halicore, 
have been found in the older Pliocene and Upper Miocene of 
France and Germany. 
Order VIL—UNGULATA. 
Family 43. — EQUIDZE. (1 Genus, 8 Species.) 
General Distribution. 
Neotropical 
Sub-regions. 
NE ARCTIC 
Sub-regions. 
I’AL/E ARCTIC 
Sub-regions. 
Ethiopian 
Sub-regions. 
Oriental 
Sub-regions. 
Australian 
Sub-regions, 
1.2 
1 
1 1 . 2 . 3 - 
1 
Living 
- 2.3 - 
Extinct 
| 1 . 2 . 3 . 4 - 
Species. 
1 . 2.3 - 
■ Species. 
j 1 - 3 - 
The Horses, Asses, and Zebras form a highly specialized group 
now confined to the Ethiopian and Paliearctic regions, but during 
the middle and later tertiaries having a very extensive range. 
The zebras (3 species) inhabit the greater part of the Ethiopian 
region, while the asses (4 species) are characteristic of the deserts 
of the Palsearctic region from North Africa and Syria to Western 
India, Mongolia, and Manchuria. The domestic horse is not 
known in a wild state, but its remains are found in recent de- 
posits from Britain to the Altai Mountains, so that its disappear- 
ance is probably due to human agency. 
Extinct Equidce . — Extinct forms of this family are very 
numerous. The genus Eguus occurs in Post-pliocene and Plio- 
cene deposits in Europe, North America, and South America. 
In North America the species are most numerous. An allied 
genus Hipparion, having rudimentary lateral toes, is represented 
