Cavy, a mammal of the order rodentia, family histricidae, subfamily caviina (Waterhouse), and genera dolichotis and cavia. This subfamily is exclusively South American; the molar teeth are (4-4)/4-4, without roots, those of the upper jaw converging and nearly meeting in front, incisors short; four toes on the fore feet, and only three on the hind, and without clavicles. The cavies have been generally associated with the agoutis, and classed under the section suo-ungulata of Illiger, erroneously in the opinion of Mr. Waterhouse, though the two groups approach each other in many respects. In some members of the subfamily, and probably in all, the fauces, or entrance to the throat, form a funnel-shaped cavity, opening backward into the pharynx by a small aperture capable of admitting only very finely chewed food; by the action of the muscles this conical cavity is made to pass over the epiglottis, preventing the entrance of the food into the windpipe; the stomach is simple, but the caecum is large and complicated.

The molar teeth of the upper jaw have the entering fold of enamel on the inner side, while in the lower it is on the outer side; the palatic portion of the skull in front of them is much contracted, and between them triangular, the posterior emargination being very deep, and exposing the anterior sphenoid bone; in the lower jaw a well marked ridge extends along the outer side from the first molar, at first horizontally backward, hut afterward curving upward to the condyloid portion, distinguishing them from all other rodents; the condyle is but little elevated above the crowns of the molars, and the coronoid process is extremely small, in this and other particulars resembling the tailless hares (lago-mys). The genus dolichotis (Desm.) is characterized by long limbs; ears half as long as the head, pointed, broad at the base; tail very short, and curved upward; metatarsus clothed with hairs anteriorly, posteriorly with the heel naked; molars small, the three front upper and the three posterior lower divided by folds of enamel into two equal lobes, the last upper and the front lower being three-lobed. The long legs, large ears, and distinct tail distinguish this from the genus cavia, of which the Guinea pig is a well known example.

The cavies approach the hares in their comparatively short incisor teeth, the imperfect condition of the palate before alluded to, the narrow bodies of the sphenoid bones, and the small brain cavity; the skull, however, is not so large in its facial portion, and is more depressed, with much smaller incisive openings. - Uniting the two groups of the true cavies and the hares, comes the typical species of the genus dolichotis, the Patagonian cavy(D. Patachoni-ca, Shaw). This animal is from 2 1/2 to 3 ft. in length, about 13 inches high at the shoulders, weighing from 20 to 36 lbs. when full grown. It inhabits the desert and gravelly plains of Patagonia, from about lat. 48 1/2° to 37 1/2° S., on the Atlantic coast, and extending into La Plata as far as Mendoza, 33 1/2° S. The fur is dense and crisp, gray on the upper parts of the head and body, yellowish rusty on the sides; chin, throat, and abdomen white; rump black, with a broad white band immediately above the tail; limbs rusty yellow, but grayish in front.

It lives in burrows, but wanders occasionally to great distances from home in parties of two or three; it runs much like the rabbit, though not very fast; it sel-dom squats like the bare, is very shy, and feeds by day; it produces two young at a birth, in its burrow; its flesh is white, but dry and tasteless. It has been generally mistaken by travellers for a hare, which it resembles in its legs, ears, and tail; the head is large, terminating in a blunt muzzle clothed with hairs; the upper lip is slightly notched; the mustaches are very long and black. - The genus cavia (Klein) is characterized by short limbs and ears, by feet naked beneath, and by molars nearly of equal size, each with two principal lobes. The genus presents two modifications of the molars: in one, the lobes arc nearly equal, and the hinder lobe of the upper series has no distinct indenting fold of enamel; for this P. Cuvier has instituted the genus cerodon, which Waterhouse retains as a subgenus; in the other (containing the Guinea pig), the hinder lobe is the larger, and in the upper series has a deep indenting fold of enamel on the outer side, and the corresponding half of the lower molar with a deep fold on the inner side.

The following species belong to the subgenus cerodon; those of cavia proper will be described under Guinea Pig. The rock cavy (C. rupestris, Pr. Max.) inhabits the rocky districts of the interior of Brazil, in the higher parts of the river courses. The nails are short, obtuse, and projecting from large fleshy pads; the soft fur is of a grayish color, with a rufous tint on the back; lower parts white, with a pale ochreous-yellow tint on the abdomen; fore legs whitish with a rufous tinge, hind legs chestnut red behind. The length is about 14 inches, and it stands higher than most cavies. Its flesh is much esteemed by the Indians. The rufousbrown cavy (C. flatidens, Brandt) is somewhat larger than the Guinea pig, but its head, ears, and fur are shorter; the incisors are yellow; the color above inclines to a yellowish brown, below to yellowish white; it inhabits Brazil. Some of its varieties are of a rich rufous-brown color. Spix's cavy (C Spixii, Wagler) inhabits Brazil from Rio de Janeiro to the Amazon; the general color is gray, with a tinge of brown on the back; the space between the eye and ear, a patch behind the ear, and the lower parts white; the incisors yellow. It is larger than the Guinea pig, with shorter and softer fur.

The Bolivian cavy (C. Boliviensis, Waterh.) inhabits the elevated regions of Bolivia; the incisors are orange yellow; general color of the fur gray, with a faint yellow tinge; throat, abdomen, and feet whitish. It rarely exceeds 10 inches in length. Some of the lofty plains of the Andes are so undermined by the burrows of these animals, that every step of a horse is attended with danger. It is very shy. The southern cavy (C. austral is, Is. Geoff.) is found in Patagonia from the straits of Magellan to lat. 30° S. The incisors are white; the fur soft and of a light grayish color; the eyes edged with white, and a spot of this color behind the ears. It is about 9 inches long, and is very tame; it lives in families, digging burrows in sandy hills overgrown with bushes; its food consists of seeds and green herbage, and it has been seen to ascend trees to feed on their fruits. It may be distinguished from all others of the group by the shortness of the head and the comparative length of the tarsi. - Numerous remains of fossil cavies have been found in the diluvial strata of Brazil; M. Lund has described four species from the caverns of that country.

Patagonian Cavy (Dolichotis Patachonica).

Patagonian Cavy (Dolichotis Patachonica).

Rock Cavy (Cerodon rupestris).

Rock Cavy (Cerodon rupestris).