opposum, in zoology; a genus of quadrupeds belonging to the order of feræ, the characters of which are these: they have ten fore-teeth in the upper jaw, and eight in the under one. The dog-teeth are long; the tongue is somewhat ciliated; and they have a pocket formed by a duplicature of the skin of the belly, in which the dogs are included.

There are six species. 1. The marsupialis, with a long sharp-pointed nose; large, round, naked, and very thin ears; small, black, lively, eyes; long stiff hairs on each side the nose, and behind the eyes; the hind part of the neck and back covered with hair two inches long; the bottoms of a yellowish white, middle part black, ends whitish; the sides covered with hair of a dirty and dusky colour; the belly with soft, woolly, dirty white hair; the tail, for near three inches, clothed with long hairs like those on the back; the rest of the tail covered with small scales. The tail of this animal has a disagreeable appearance, looking like the body of a snake, and has the same prehensile quality with that of some monkeys; the body is round and pretty thick, the legs short: on the lower part of the belly of the female is a large pouch, in which the teats are lodged, and where the young shelter as soon as they are born. The length of the body is 16 or 17 inches; that of the tail 14.—This creature inhabits many parts of America and the East India. It is very destructive to poultry, and sucks the blood without eating the flesh; it feeds also on roots and wild fruits, and is very active in climbing trees. It hunts eagerly after birds and their nests; and will hang suspended from the branches of a tree by its tail; then, by swinging its body, it will fling itself among the trees that grow in the neighbourhood. It walks very slow; and when pursued and overtaken, will feign itself dead. It is not easily killed, being as tenacious of life as a cat. When the female is about to bring forth, she makes a thick nest of dry grass in some close bush at the foot of a tree; and brings four, five, or six, young at a time. As soon as the young are brought forth, they take shelter in the pouch or false belly; and fall into close to the teats, that they cannot be separated without difficulty. They are blind, naked, and very small, when new-born, and resemble fetuses: it is therefore necessary that they should continue in that false belly, till they attain proper strength and fight; and are prepared to undergo what may be called a second birth. After this they run into the pouch as into an asylum in time of danger; and the parent carries them about with her. During the time of this second gestation, the female shews an excessive attachment to her young, and will suffer any torture rather than allow this receptacle to be opened; for she has the power of opening or closing it by the assistance of some very strong muscles. The flesh of the old animal is very good, like that of a sucking pig: the hair is dyed by the Indian women, and woven into garters and girdles: the skin is very fetid.

2. The murina, hath the face and upper parts of the body of a tawny colour; the belly yellowish white; the tail slender, and covered with minute scales to the very rump: the length from the nose to the tail, about six inches and a half; the tail of the same length: the female wants the false belly of the former; but on the lower part the skin forms on each side a fold, between which the teats are lodged. It inhabits the hot parts of South America; agrees with the others in its food manners, and the prehensile power of its tail. It brings from 10 to 14 young ones at a time: they affix themselves to the teats as soon as they are born, and remain attached like inanimate things, till they attain growth and vigour to shift a little for themselves.

3. The Mexican opposum, is of an ash-colour on the head and upper parts of the body; the belly and legs whitish: the tail long and pretty thick, varied with brown and yellow; it is hairy near an inch from its origin, the rest naked: the length from the nose to the tail, about seven inches and a half; of the tail, more than 11.—It inhabits the mountains of Mexico,