MAMMALIA OF EOCENE PERIOD. 81 
Mammalia of the Eocene Period, 
In tlie first great fresh- water formation of the 
Eocene period, nearly fifty extinct species of 
mammalia have been discovered by Cuvier ; the 
greater number of these belong to the following 
extinct genera, in the order Pachydermata,* viz. 
Palaeotherium, Anoplotherium, Lophiodon, An- 
thracotherium, Cheropotamus, Adapis (see Plates 
3 and 4). t 
* Cuvier's order Pachydermata, i. e. animals having thick 
skins, includes three subdivisions of Herbivora, of which the 
Elephant, Rhinoceros, and Horse are respectively examples. 
t PalcBotherium. 
The place of the genus Palaeotherium (see Plates 3 and 4) 
is intermediate between the rhinoceros, the horse, and tapir. 
Eleven or twelve species have already been discovered ; some as 
large as a rhinoceros, others varying from the size of a horse to 
that of a hog. The bones of the nose show that, like the tapir, 
they had a short fleshy trunk. These animals probably lived 
and died upon the margins of the then existing lakes and rivers, 
and their dead carcases may have been drifted to the bottom in 
seasons of flood. Some perhaps retired into the water to die. 
Anoplotherium. 
Five species of Anoplotherium (see Plates 3, 4) have been 
found in the gypsum of the neighbourhood of Paris. The 
largest (A. Commune) being of the size of a dwarf ass, with a 
thick tail, equal in length to its body, and resembling that of an 
otter; its probable use was to assist the animal in swimming. 
Another (A. Medium) was of a size and form more nearly 
approaching the light and graceful character of the Gazelle ; a 
third species was nearly of the size of a Hare. 
The posterior molar teeth in the genus Anoplotherium resemble 
those of the rhinoceros ; their feet are terminated by two large 
toes, like the ruminating animals, whilst the composition of their 
GEOL. G 
