To the Fauna of the Madagascar forests also belongs an extremely rare animal, few specimens of which have been brought into Europe. After some hesitation our naturalists have agreed to refer it to the order of Primates, although its general appearance and its system of dentition caused it at first to be taken for a kind of large squirrel; while, on the other hand, the form and disposition of its thin fingers, and the development of its nails, liken it to the sloths. This animal is the Aye-Aye, or _Cheiromys Madagascariensis_. The characters which have determined its annexations to the order of Primates are, principally, the presence of opposable thumbs on the hind-paws; the terminal position of the nostrils; the oblique direction of the eyes, and the absence of a vertical fissure on the upper lip. Its habits are not well known; but it is a burrowing animal, very slothful, and goes abroad at night. It has large flat ears, like a bat's, and a tail like a squirrel's; but its peculiarity is the middle toe or finger of the fore-foot, whose two last joints are very long, slender, and destitute of hair. From nose to tail it measures about eighteen inches, and its general colour is a pale ferruginous brown, mixed with gray. Sonnerat, who discovered the aye-aye in his expedition to Madagascar, at the close of the last century, succeeded in obtaining a couple of specimens, which he kept alive for two months. "I nourished them," he says, "upon cooked rice, and they make use, in eating, of the thin fingers of their fore-feet, just as the Chinese do of their chopsticks. They seemed always drowsy, resting with the head placed between the fore-paws, and it was only by shaking them several times we could get them to move." This torpid condition, however, was it the effect of confinement or of natural apathy? If due to the latter, it would be another point of approximation between the aye-aye and the sloths, which some naturalists have also inclined to rank among the Primates. Other authors have placed those latter quadrupeds in an order apart, under the name of "Tardigrades;" but most scientific zoologists now classify them with the Edentata, and form them into the family of Bradypes or Bradypidæ. Undoubtedly the sloth, or aï, is an animal of curious and uncouth appearance; in general conformation not unlike the bear, to which he also approaches in the form of his head, and in deficiency of tail, while his long rough hair, coarse and shaggy, like dry withered grass, recalls the fur of the ant-eater. The most singular peculiarity of his organization is the structure of the feet, whose strong crooked claws, to the number of three or more in each limb, are so linked together that they cannot be moved separately. [Illustration: CHEIROMYS, OR AYE-AYE OF MADAGASCAR.]