of the tusks, such as are found in no other living or fossil animal.
The form of the molar teeth, Pl. 2. C. Fig. 3, approaches, as we have stated, most nearly to that of the molar teeth in Tapirs; but a remarkable deviation from the character of Tapirs, as well as of every other quadruped, consists in the presence of two enormous tusks, placed at the anterior extremity of the lower jaw, and curved downwards, like the tusks in the upper jaw of the Walrus. (Pl. 2. C. 1. 2.)
I shall confine my present remarks to this peculiarity in the position of the tusks, and endeavour to show how far these organs illustrate the habits of the extinct animals in which they are found. It is mechanically impossible that a lower jaw, nearly four feet long, loaded with such heavy tusks at its extremity, could have been otherwise than cumbrous and inconvenient to a quadruped living on dry land. No such disadvantage would have attended this structure in a large animal destined to live in water; and the aquatic habits of the family of Tapirs, to which the Dinotherium was most nearly allied, render it probable that, like them, it was an inhabitant of fresh water lakes and rivers. To an animal of such habits, the weight of the tusks sustained in water would have been no source of inconvenience; and, if we suppose them to have been employed, as instruments for raking and grubbing up by the roots large aquatic vegetables from the bottom, they would, under such service, combine the mechanical powers of the pick-axe with those of the horse-harrow of modern husbandry. The weight of the head, placed above these downward tusks, would add to their efficiency for the service here supposed, as the power of the harrow is increased by being loaded. with weights.
The tusks of the Dinotherium may also have been applied with mechanical advantage to hook the head of the animal to the bank. with the nostrils sustained above the water, so as to breathe securely during sleep, whilst the body remained floating, at perfect ease, beneath the surface: the animal
