have made an equivocal species of this animal, the first under the name of _philandre_ of Brasil, and the second under that of _philander_. The true _taiibi_ of Marcgrave and Ray, is not therefore the _taiibi_ of Seba, the _philander_ of Linnæus, nor the Brasilian _philander_ of Brisson; nor are the two latter the _tlaquatzin_ of Hernandes. The _taiibi_ of Seba (supposing his existence) is a different animal from all those treated of by the above authors, and ought to have had a particular denomination, and not been confounded with the _taiibi_ of Marcgrave, which has nothing in common with him; besides, as the male opossum has no pouch, it is not surprising that they have been taken for different animals, as that the female is called carigueya, and the male taiibi. Edward Tyson dissected and described the female opossum with care; in the individual which served him for subject, the head was six inches, the body thirteen, and the tail twelve in length: the fore legs were six inches, and the hind legs four inches and a half in height: the body was fifteen or sixteen inches in circumference; the tail three inches round in the beginning, and only one inch towards the extremities; the head three inches betwixt the two ears, decreasing gradually to the nose; and was more like that of a pig than a fox; the sockets of the eyes are much inclined in the direction from the ears to the nose; the ears are rounded, and about an inch and a half long; the mouth was two inches and a half wide from one of the corners of the lip to the extremity of the snout; the tongue narrow, three inches long, and rough; his fore feet had five toes armed with crooked claws, but in the hind feet he had only four toes with claws, and the fifth toe, or thumb, was separated from the others, was placed lower, and had no claws. All his claws were without hair, and covered with a skin of a reddish colour, and very near an inch in length; his hind and fore paws were large, and he had fleshy callosities under all the toes. The tail was covered with hair for two or three inches from the beginning, and the rest of it with a smooth scaly skin to the end. These scales were whitish, almost hexagonal, and placed regularly, so that they did not encroach upon each other, but were divided by a skin browner than the scales. The ears were without hair, thin and membranous like the wings of a bat, and very open. The upper jaw longer than the under; the nostrils large, the eyes small, black, and lively; the neck short, the breast wide, and the whiskers like those of a cat: the hairs of the forehead whiter and shorter than those of the body; his colour a yellowish grey, intermixed with black on the back and sides, more brown on the belly, and still deeper on the legs. Under the belly of the female (_fig. 131._) is a skin two or three inches long, which forms a kind of pouch by a double fold thinly covered with hair on the inside, and which pouch contains the teats.