in zoology, a genus of quadrupeds, belonging to the order of glires; the generic character of which is, that the fore-teeth of the lower jaws are subulated. There are 21 species.

1. The porcellus, or guiney-pig, has no tail; there are four toes on the fore-feet, and three on the hind ones. This animal makes a grunting noise, is very restless, and stamps with its hind-feet when teased. It loves heat, and feeds upon various vegetables. The female has two dugs. The colour is very various. It is a native of Brazil.

2. The aguti has a short tail, four toes on the fore-feet, three on the hind ones, and a yellowish belly. It is a native of Brazil, Surinam, and Guinea.

3. The leporinus has the same characters with the former, only the belly is white. It is found in Java and Sumatra.

4. The citellus has a short tail, an ash-coloured body, and no ears. It is found in Bohemia, &c., below ground.

5. The lemmus, has a short tail, five toes on both fore and hind-feet, and the body is variegated with green and yellow. They are found in the Lapland mountains under little hillocks, and feed solely on vegetables.

6. The paca, has a short tail, five toes on each foot, and there are three yellowish lines on each side. It is a native of Brazil.

7. The marmota has a short hairy tail, round ears, and gibbous cheeks. It digs deep holes in the earth with amazing quickness; sleeps profoundly during the winter; lifts its food to its mouth with the fore-feet; often sits erect; it is easily tamed, and is found in Switzerland.

8. The monax has a hairy tail, an ash-coloured body, roundish ears, and four toes on the fore feet and five on the hind ones. It is a native of America.

9. The cricetus has a tail of moderate length, round ears, a black belly, and reddish sides, with three white spots. This animal digs deep caverns in the earth, divided into many different cells, in which it deposits and preserves large quantities of fruits and grains. The female brings forth five young ones twice in the year, each of which lives in a separate cell. They are hunted for food, for their skins, and even for the quantity of grain found in their cells. It is a native of Germany.

10. The terretris has a hairy tail, with four toes on the fore feet, and five on the hind ones, and ears shorter than the hair. This animal, which is about half the size of a rat, digs in the gardens like a mole, and eats the bark off the roots of trees, &c. It swims in ditches, and devours young ducks in the ponds. It is a native of Europe.

11. The amphibious has a long hairy tail, with palmed feet. It digs in the banks of ditches and under the roots of trees, and feeds upon vegetables. It is found both in Europe and Africa.

12. The rattus, or rat, has a long naked tail, four toes on the fore-feet, and five on the hind ones, and a claw on the large toe. This animal infests the houses everywhere through Europe, and is devoured by cats and other animals of the same class. It is reported by several authors, that rats were originally transported from America in a ship belonging to Antwerp.

13. The musculus, or common mouse, has a long naked tail, four toes on the fore-feet and five on the hind ones, but has no claw on the large toe. This animal is a native of Europe, feeds upon grain and fish of all kinds.

14. The avellanarius has a long hairy tail, a reddish body, a white throat, and the hind toes have no claws. It frequents the woods of Europe, feeds upon nuts, which it lays up in the earth, and sleeps during winter.

15. The quercinus has a long hairy tail, with a black ring under the eyes. It is a native of the south of Europe.

16. The gregarius has a tail about one third of the length of its body, and somewhat hairy; the body is of a greyish colour, and the legs are white. It is a native of Germany. 17. The sylvaticus has a tail of a middling length, four toes on the fore feet, and five on the hind ones; the body is grey, interspersed with black hairs, and the belly is white. It is found in the gardens and woods of Europe. 18. The striatus has four toes on the fore-feet, and five on the hind ones; it has longitudinal streaks on the body, with white spots. It is a native of India. 19. The longipes has a long covered tail, four toes on the fore feet, five on the hind ones, and very long thighs. It is found in the torrid zone. 20. The jaculus has a long fleecy tail, with very long thighs, and short fore-legs. It walks on its hind-feet only, and has a jumping motion. It is found in Arabia, Egypt, &c. 21. The volans has a long hairy tail, four toes on the fore feet and five on the hind ones, and the skin from the ears to the tail is extended like wings, by which it is enabled to fly. It is a native of Virginia and Mexico.