the integument is reënforced by bony concretions, in others it is covered with imbricate scales, in others clothed with coarse hairs, and in others still perfectly nude. From all this it results that naturalists are greatly puzzled when they have to name the general characteristics of the order. Nevertheless, it may be said that these mammals bear in their skeleton and in the arrangement of their viscera certain signs of inferiority; that their salivary glands are highly developed, a fact accounted for by their insectivorous diet; and that in their circulatory system they present some peculiar features, certain interlacings of the blood-vessels which regulate the flow of the blood to the limbs, which latter usually move with extreme slowness. Furthermore, it may be added that, in Edentata with teeth, those organs have a peculiar aspect, being for the most part void of enamel, and, to all appearance, consisting of a number of cylinders standing side by side.
In the animal world as at present constituted the Edentata are all of medium or even small size; but in former geological epochs they attained very considerable dimensions, rivaling even the elephant. The megatherium, whose bones have been found in Buenos Ayres, was 412 metres (1434 feet) in length, and 212 metres (614 feet) in height; and the megalonyx and the mylodon, found in the same locality, were also of gigantic proportions. And it is curious to observe that America, where the remains of these great creatures are found, is still the continent which possesses the greatest abundance of animals belonging to this order. The Old World, on the other hand, possesses only a few species, and Australia none at all, the part of the Edentata being in that strange country played by the Monotremata, Echidna, and Ornithorhynchi.
Some species of the Edentata are well known to our readers. The armadillo and the pangolin are common in our zoölogical gardens; the ant-eater and the sloth are to be seen there too, though far more rarely. But besides these familiar species, there are others which, till recent times, were all unknown in menageries, and of which but a very imperfect idea could be formed from the stuffed specimens in the public collections. To this class belongs especially the orycteropus, or earth-hog, a curious sort of Edentate from tropical Africa, which several travelers, and among them Von Heuglin, had vainly tried to carry to Europe alive. Two or three months ago, however, the Paris Museum of Natural History was so fortunate as to secure an animal of this genus. It is quartered in the monkey-house, sheltered from the cold, and there, no doubt, it will be able to live for some time to come in captivity.
The traveler Kolbe, about the middle of the eighteenth century, was the first to publish some notices of the orycteropus, already known even at that time to the Dutch settlers under the name of aard-vark (earth-hog); a little later Camper procured the skull of one of these animals, and studied its osteological character; but to Étienne Geoffroy Saint-Hilaire belongs the credit of having clearly pointed out the essential
