From the great number of bones and teeth of animals of the extinct elephantine genus, to which the name of Mastodon was given by Cuvier (from the structure of the crowns of the teeth), that have of late years been brought to England, and are dispersed in our public and private collections, the intelligent reader must be familiar with the forms, characters, and gigantic proportions, of that stupendous tribe of animals which once ranged through the primeval forests not only of America, but also of some parts of Europe. From a perfect skeleton lately set up in the British Museum (in the same room with that of the Megatherium), a correct idea may be obtained of this peculiar type of mammalian structure. From this specimen it appears that the great Mastodon of the Ohio was not unlike the elephant In its general outline, though somewhat longer and thicker. It had a trunk or proboscis, tusks which curved upward, and four molar teeth in each jaw, but no incisors. But another remarkable peculiarity, and which entirely separates the Mastodon from the Elephant, is that the young animal had a pair of tusks, placed horizontally in the lower jaw, and of these tusks one only became developed, and that in the adult male: both were early shed in the female. In the midst of a collection of Mastodon bones imbedded in mud, a mass of small branches, grass, and leaves, in a half bruised state, and a species of reed common in Virginia, were discovered; the whole appeared to have been enveloped in a sac, probably the stomach of the animal. In another instance traces of the proboscis were observed. The tusks are composed of ivory, and vary somewhat in the direction and degree of their curvature. The bones of this colossal quadruped are found remarkably fresh and well preserved, and are generally impregnated with iron. No living instance of this creature is on record, and there can be no doubt that its race has long since been extinct.