Like the Mole, this animal lives in burrows, which it makes in all directions in the ground, throwing out as it proceeds heaps of earth, which exactly resemble ordinary mole-hills. To enable it to perform these labours the claws of the fore feet are exceedingly powerful; and to adapt it the better to its subterranean existence, the eyes are very small, and the external ears are wanting. Its digging operations have generally the same object as those of the Mole--namely, the search for food. The tunnel is carried along not far from the surface of the ground, and the roots of any plants that lie in its course are bitten off and devoured by the little miner. Besides the runs, the Pouched Rat digs himself a convenient dwelling in the shape of a chamber hollowed out under the roots of a tree, access to which is gained by a somewhat spiral descending passage. This chamber, which is usually at a depth of four or five feet, is comfortably lined with soft grass, and the nest in which the female brings forth her young is a cavity of the same kind, but surrounded by circular passages, from which, like that of the Mole, other passages branch off. One of these, according to Gesner, leads from the nest to a large store-chamber filled with nuts, seeds, and roots, among which the potato was found to play an important part. These provisions are carried to the store-house in the great cheek-pouches, which the animal is said to fill by the aid of its tongue, and to empty with the fore paws. This Pouched Rat does much damage in cultivated ground by attacking the roots of both plants and trees, sometimes destroying a great number of the latter in a few days. The female produces from five to seven young at the end of March or the beginning of April. The other species of _Geomys_ closely resemble this in their habits. Of the second genus belonging to this sub-family (_Thomomys_) Dr. Coues admits only two species, one of which, however, occurs under three named forms. They may be distinguished from the species of _Geomys_ by their having the upper incisors plain, without grooves. The NORTHERN POCKET GOPHER (_Thomomys talpoides_), with its sub-species, ranges over nearly the whole of North America from the Hudson’s Bay Territory to California and New Mexico. The three forms are for the most part in accordance with geographical distribution. A small species (_Thomomys clusius_) has been obtained in the Rocky Mountains.