Armadillos[20] are remarkable animals, with a covering of horny plates, not unlike a tortoise shell, but arranged in sections in a way that allows more freedom of motion. Some of the extinct species were of gigantic proportions. A fossil armadillo found near the La Plate was as large as a full grown rhinoceros. The Sloths are natives of South America. They are covered with long, coarse, gray-and-black hair, resembling the moss of the trees in which they live, for these animals are arboreal, while the other members of the order burrow. Ant-eaters, of which there are several varieties, are covered with spines like the hedge-hog. Even the long, rough tongue and palate are provided with the sharp little spines with which they spear and hold their prey. Their claws also are fitted for digging into the ant hills, where the food is obtained. They are very inferior mammals, but have their place, and are useful in destroying noxious insects. The giant ant-eater of South America is much the largest of the genus, and an animal of considerable strength. From its long, bill-like snout it thrusts out its longer tongue, and the frantic ants, disturbed in their quarters, on rushing out stick to it, and are rapidly swept into the mouth. When sleeping, it is coiled up under its immense bushy tail and looks more like a little heap of dried grass than an animal. [Illustration: THE ANT-EATER.] ORDER IV.—_Sirenia_[21] (sea cows), include the Manatee, found between the Amazon and Southern Florida, and the Dugong, of India. They are amphibious milk givers. In appearance and structure they are very unlike most mammals. Their forelimbs resemble fins, having fingers or toes. The hind legs are wanting, and the tail like that of a fish, but they suckle their young, sometimes supporting them for the purpose with their flippers. ORDER V.—_Cetacea_[22] (Whales). They are much the largest of mammals. They live entirely in the sea, and have in general a fish-like appearance. Their forelimbs are huge paddles, the others being only rudimentary. But they produce their young well developed, and nourish them with an abundance of rich, creamy milk. The amount of blood in a large whale must be immense, the great artery being a foot in diameter, every pulsation of the heart forces many gallons along the channels prepared for it. A single whale, captured in 1884 by the crew of a New London vessel, produced whalebone and oil worth $15,720, beside other products of considerable value. ORDER VI.—_Insectivora_ (insect eating). An order of small animals, having well developed teeth, the molars remarkable for their sharp cusps; and five-toed feet furnished with claws. The Mole, Hedge-hog and Shrew are examples. [Illustration: VARIETIES OF BATS.]