the brittle extremity of the branches, lest they should break with him in passing from one tree to another; but as soon as the wind arises, the branches of the neighbouring trees become interwoven, and then the sloth seizes hold of them and pursues his journey in safety. There is seldom an entire day of calm in these forests. The tradewind generally sets in about ten o'clock in the morning, and thus the sloth may set off after breakfast, and get a considerable way before dinner. The sloth does not hang head downwards like the vampire. When asleep he supports himself from a branch parallel to the earth. He first seizes the branch with one arm and then with the other, and after that brings up both his legs one by one to the same branch; so that all four are in a line; he seems perfectly at rest in this position. Now had he a long tail he would not know what to do with it; were he to draw it up within his legs it would interfere with them; and were he to let it hang down, it would become the sport of the winds. Thus his deficiency of tail is a benefit to him; it is merely an apology for

a tail, scarcely exceeding an inch and a half in length.

"There is a singularity in his hair, different from that of all other animals; it is thick and coarse at the extremity, and gradually tapers to the root, where it becomes fine as the spider's web. His fur has so much the hue of the moss which grows on the branches of the trees, that it is very difficult to make him out, when he is at rest. He is a scarce and solitary animal, and being good food is never allowed to escape destruction by the Indians, though it is said his piteous moans make the tiger relent and turn out of the way. Do not, then, level your gun at him, or pierce him with a poisoned arrow; he has never hurt one living creature. A few leaves, and those of the commonest and coarsest kind, are all he asks for his support. His looks, his gestures, his cries, all conspire to entreat you to take pity on him. These are the only weapons of defence which nature hath given him."

The sloth is exceedingly tenacious of life. It has been seen to move its legs even after the heart has been taken from the body. The Indians use

arrows tipped with the wourali poison in its destruction. The flesh is so much relished by them that they are in continual pursuit of it. These animals are always most active during the night, at which time they utter a plaintive cry, resembling the word Ai, which is the origin of the name they bear among the Europeans settled in America. Mr. Bingley says, that in this cry "they ascend and descend in perfect tune through six successive musical intervals." When the Spaniards first arrived in America, and heard this unusual noise, they fancied they were near some nation the people of which had been instructed in European music.

The Ai, or common sloth, is an inhabitant of South America. There are two distinct species, and three or four varieties. The common sloth is about the size of the domestic cat; it has a short round head covered with coarse, shaggy hair, which, growing much like that of the human species, gives to the animal a very grotesque appearance, the face being somewhat like that of a monkey, of a yellowish colour, covered with very short hair. On the other parts of the body the hair is long

and shaggy, and forms a kind of mantle to shelter the animal from both cold and heat. The eyes are small, black, and round, and the ears concealed in the long hair of the head. It has generally been supposed that the neck of the sloth, though very short, has nine vertebræ, or joints, belonging to it; whereas all other quadrupeds, even those with the longest necks, as the giraffe and camel, have but seven. Mr. Thomas Bell* has, however, proved by the careful investigation of a full-grown skeleton, and of a young specimen preserved in spirits, that the sloth does not differ from other quadrupeds in this respect. In fact, that the joints generally considered as the eighth and ninth of the neck are really the first and second of the back-bone. This uncommon arrangement is peculiarly adapted to the singular habit of the animal, which hangs from the under surface of boughs, with its head downwards. Suspended in this way, as we have before observed, it moves, rests, and sleeps. It is obvious that in this situation the only means by which it could look towards the ground must be by possess

* Transactions of Zoological Society, August 13, 1833.

ing a more than usual capability of turning the neck. To give this greater facility, the upper joints of the back-bone adjoining the neck are of a different form from those of other quadrupeds, and so admirably constructed as to enable the sloth to move them uniformly with the neck-joints, and thus to turn its head with ease and comfort. Mr. Bell remarks, "that he found with feelings of no ordinary satisfaction that the rule which assigns seven cervical vertebræ (bones of the neck) to the whole of the mammalia is left without a single exception." We cannot here forbear quoting the following remark from the "Penny Cyclopædia :" Every modification of nature is adapted to a wise and useful end. Deformity and imperfection appear only when from our own imperfect knowledge we fail to discover the adaptation of organic structure to the habits and economy of particular beings."

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The arm and fore arm of the sloth, taken together, are nearly twice as long as the leg and thigh. The feet are each furnished with three enormous claws, so sharp and crooked that they readily seize