[90] _Arctomys Ludoviciana._ ORD.—This interesting and sprightly little animal has received the absurd and inappropriate name of Prairie dog, from a fancied resemblance of its warning cry to the hurried barking of a small dog. This sound may be imitated with the human voice, by the pronunciation of the syllable cheh, cheh, cheh, in a sibilated manner, and in rapid succession, by propelling the breath between the tip of the tongue and the roof of the mouth. The animal is of a light dirty reddish-brown colour above, which is intermixed with some gray, also a few black hairs. This coating of hair is of a dark lead colour next the skin, then bluish-white, then light reddish, then gray at the tip. The lower parts of the body are of a dirty white colour. The head is wide and depressed above, with large eyes; the iris is dark brown. The ears are short and truncated; the whiskers of moderate length and black; a few bristles project from the anterior portion of the superior orbit of the eye, and a few also from a wart on the cheek: the nose is somewhat sharp and compressed; the hair of the anterior legs, and that of the throat and neck, is not dusky at base. All the feet are five-toed, covered with very short hair, and armed with rather long black nails: the exterior one of the fore foot nearly attains the base of the next, and the middle one is half an inch in length: the thumb is armed with a conic nail, three-tenths of an inch in length; the tail is rather short, banded with brown near the tip, and the hair, excepting near the body, is not plumbeous at base.[91] The length of the animal, from the tip of the nose to the origin of the tail, is sixteen inches; of the tail, two inches and three-fourths; of the hair at its tip three-fourths of an inch. As particular districts, of limited extent, are, in general, occupied by the burrows of these animals, such assemblages of dwellings are denominated _Prairie dog villages_ by hunters and others who wander in these remote regions. These villages, like those of man, differ widely in the extent of surface which they occupy; some are confined to an area of a few acres, others are bounded by a circumference of many miles. Only one of these villages occurred between the Missouri and the Pawnee towns; thence to the Platte they were much more numerous. The entrance to the burrow is at the summit of the little mound of earth, brought up by the animal during the progress of the excavation below.