316 HISTORICAL PALZONTOLOGY. 
The family of the Tapirs is represented, both in the Old 
and New Worlds, by species of the genus Zophiodon, some of 
which were quite diminutive in point of size, whilst others 
attained the dimensions of a horse. Nearly allied to this 
family, also, is the singular group of quadrupeds which Marsh 
has described from the Miocene strata of the United States 
under the name of Lrontotheride. ‘These extraordinary ani- 
mals, typified by Brontotherium (fig. 243) itself, agree with the 
fi 
Fig. 243.—Skull of Bronxtotherium ingens. Miocene Tertiary, United States. 
(4 \fter Marsh. ) 
existing Tapirs of South America and the Indian Archipelago 
in having the fore-feet four-toed, whilst the hind-feet are three- 
toed ; and a further point of resemblance is found in the fact 
(as shown by the form of the nasal bones) that the nose was 
long and flexible, forming a short movable proboscis or trunk, 
by means of which the animal was enabled to browse on 
shrubs or trees. They differ, however, from the Tapirs, not 
only in the apparent presence of a long tail, but also in the 
possession of a pair of very large “horn- -cores,” carried upon 
the nasal bones, indicating that the animal possessed horns of 
a similar structure to those of the “Hollow-horned” Rumin- 
ants (e.g., Sheep and Oxen). Brontotherium gigas is said to be 
nearly as large as an Elephant, whilst 2. zzgens appears to 
have attained dimensions still more gigantic. The well-known 
genus Zvtanotherium of the American Miocene would also 
appear to belong to this group. 
The family of the Horses (Zguide) appears under various 
forms in the Miocene, but the most important and best known 
of these is H/ifparion. In this genus the general conformation 
of the skeleton is extremely similar to ‘that of the existing 
Horses, and the external appearance of the animal must have 
been very much the same. The foot of Azpparion, however, 
