A very rare little, large-eared, small-legged animal was found by Sir Thomas Mitchell on the banks of the River Murray, and its appearance was so remarkable that much attention was paid to its anatomy, whilst unfortunately nothing particular was learned regarding its natural history and habits. Subsequently the little creature, whose body is about nine inches and a half long, the tail measuring in addition about four inches, was found in the interior of the country near the Swan River. It is an active little animal, and a hunter of insects, but it will feed upon vegetable substances also. Mr. Gould states that, like the Perameles, to which it is allied in many parts of its construction, it forms a nest composed of leaves and other substances. The pouch is deep and runs upwards, and not like that of the Kangaroo, and there are eight teats. At first there was much discussion whether the animal had a tail, but there is no doubt about its possessing one when in the perfect condition. The slender fore limbs, no thicker than goose-quills, end in two very small digits, and they are provided with small, compressed, and but little curved nails. They have a small fleshy pad on their under surface, behind which is a smaller one. The hind legs are longer than the front ones, and are almost as slender. The foot is long, and at first sight appears to have only one large toe, for the others are very small and far removed from the end of the foot. The outer little toe has a small nail, and the inner toes, joined, are almost as small, but they have hollow nails. The greatly-developed toe has a conical and compressed nail, but beneath there is a large fleshy pad; the rest of the foot is hairy. Hence it appears that the heel is not put to the ground. The colour of the long, loose, soft fur is brown-grey above, and yellowish-white beneath, the limbs and the fore feet have a whitish tint, and the large toe is of a dirty white colour. So far as the skull and teeth are concerned, the little Chœropus greatly resembles the other kinds of Marsupials which are classified under the genus Perameles. Sir Thomas Mitchell noticed the broad head and very slender snout, which, he stated, resembled the narrow neck of a wide bottle, in the specimen which the natives took from a hollow tree after chasing it on the ground. In the construction of the skull and in the number of the teeth, this long-eared creature resembles the rest of the genus Perameles. In the upper jaw there are five incisor teeth on each side, and they are close, and the canine is small, and resembles a premolar, and is slightly distant from the incisors. The first premolar is separated from the canine by a space of one line and a half, and slightly from the second premolar; and the second and third premolars and the four molars form a continuous line. V.--THE DASYURUS FAMILY.--DASYURIDÆ.