The geological place of the extinct Palæotherium seems to have been in the first great fresh-water formation of the Eocene period, where it is chiefly found with its allies, of which several species have been found and identified by Cuvier. Dr. Buckland is not singular in thinking that they lived and died on the margins of lakes and rivers, as the Rhinoceros and Tapir do now. He is also of opinion that some retired into the water to die, and that the dead carcases of others may have been drifted into the deeper parts in seasons of flood. The _Palæotherium_ varied greatly in size, some species being as large as the Rhinoceros, while others ranged between the size of the Horse and that of a Hog or a Roe. The smaller Palæotherium resembled the Tapir. Less in size than a Goat, with slim and light legs, it must have been very common in the north of France, where it would browse on the grass of the wild prairies. Another species, the _P. minimum_, scarcely exceeded the Hare in size, and it probably had all the lightness and agility of that animal. It lived among the bushy thickets of the environs of Paris, in Auvergne, and elsewhere. All these animals lived upon seeds and fruits, on the green twigs, or subterranean stems, and the succulent roots of the plants of the period. They generally frequented the neighbourhood of fresh water. [Illustration: Fig. 154.--Anoplotherium commune. One-twentieth natural size.] The _Anoplotherium_ (from ανοπλος, _defenceless_, θηριον, _animal_), had the posterior molar teeth analogous to those of the Rhinoceros, the feet terminating in two great toes, forming an equally divided hoof, like that of the Ox and other Ruminants, and the tarsus of the toes nearly like those of the Camel. It was about the size of the Ass; its head was light; but what would distinguish it most must have been an enormous tail of at least three feet in length, and very thick at its junction with the body. This tail evidently served it as a rudder and propeller when swimming in the lakes or rivers, which it frequented, not to seize fish (for it was strictly herbivorous), but in search of roots and stems of succulent aquatic plants. “Judging from its habits of swimming and diving,” says Cuvier, “the Anoplotherium would have the hair smooth, like the otter; perhaps its skin was even half naked. It is not likely either that it had long ears, which would be inconvenient in its aquatic kind of life; and I am inclined to think that, in this respect, it resembled the Hippopotamus and other quadrupeds which frequent the water much.” To this description Cuvier had nothing more to add. His memoir upon the _pachydermatous fossils_ of Montmartre is accompanied by a design in outline of _Anoplotherium commune_, which has been closely followed in Fig. 154.