which it found lying dead on the prairies. The other American species are more local in their distribution; four of them occur in Mexico, and one of these is only known from that country. Of the Old World species the best known is the SISEL, or SUSLIK (_Spermophilus citillus_), which is abundant in Central and Eastern Europe and in Siberia. Several other species are known from Asia Minor, Siberia, and Central Asia. The BARKING SQUIRRELS, or PRAIRIE DOGS, of which two species (_Cynomys ludovicianus_, _see_ figure on p. 81, and _C. columbianus_) are found in the United States of America, are of a stouter form than the Spermophiles, and have the ears and tail short. The claws are well developed on all the toes of the fore feet, the cheek-pouches are shallow, and the two rows of grinding teeth converge towards the back of the mouth. These animals are peculiar to North America, where the former inhabits the prairies east of the Rocky Mountains, and the latter is found on the plains of the Columbia river, and in other parts of the western territories as far south as New Mexico. The best known of the two species is the _Cynomys ludovicianus_, to which the name of the PRAIRIE DOG was first applied: this name being given to it from a fancied resemblance of its voice to the barking of a small Dog. It measures about a foot in length, and its tail is about four inches long. Its colour on the upper surface is reddish-brown, variegated with grey, and with a few scattered black hairs; the tail is flattened, and brownish-black towards the end, and the lower surface is brownish or yellowish-white. These animals live together in great societies, especially upon those portions of the prairies where the so-called buffalo-grass (_Sesleria dactyloides_) grows most luxuriantly, this grass and succulent roots constituting their chief food. They live in burrows, which they dig in the ground at a distance of twelve or fifteen feet apart; a hard-beaten path runs from burrow to burrow, and would seem to give evidence of the sociable disposition of the animals; and at the mouth of every burrow there is a little hillock, formed by the earth thrown out of it, which serves the occupant as a watch-tower. These burrows are usually so numerous upon favourable pieces of ground that the space occupied by them is quite populous, and presents a scene of considerable animation when the inhabitants are out in the pursuit of their business or their pleasure, and hence they are in common parlance spoken of as “towns” or “villages.” Their curious appearance is heightened by the almost constant presence in them of numerous small Owls, of the species known as the Burrowing Owl (_Athene cunicularia_), a widely-spread species, which in some places digs its own subterranean habitation, but on these prairies saves itself the trouble by taking possession of the deserted abodes of the Prairie Dogs. These birds are diurnal in their habits, and are to be seen mixed up with the Prairie