The _Primates_, which is the first order of the class MAMMALIA, have four parallel front, or cutting teeth, in each jaw; except in some species of bats, which have either two only, or none. They have one canine tooth on each side, in both jaws. The females have two pectoral mammae, or breasts. The two fore feet resemble hands, having fingers, generally furnished with flattened, oval nails. Their food is both animal and vegetable. The principal animals in this order are, man, the ape and lemur tribes, and the bats. 2nd. The _Bruta_ have no front teeth in either jaw: their feet are armed with strong, blunt, and hoof-like nails. Their form is, to appearance, clumsy, and their pace usually slow. Their food is principally vegetable. None of the animals of this order are found in Europe: they consist of the sloths, the ant-eaters, the rhinoceros, elephant, and manati. 3rd. The _Ferae_ have generally six front teeth, of a somewhat conical shape, both in the upper and under jaw: next to these, are strong and sharp canine teeth; and the grinders are formed into conical, or pointed processes. Their feet are divided into toes, which are armed with sharp, hooked claws. This tribe is predacious, living almost entirely upon animal food; and consists of the seal, dog, cat, weasel, otter, bear, opossum, kangaroo, mole, shrew, and hedgehog genera. 4th. _Glires_ are furnished with two remarkably large and long front teeth, both above and below, and are destitute of canine teeth. Their feet have claws, and are formed both for bounding and running. They feed on vegetables. The genera are, the porcupine, cavy, beaver, bat, marmot, squirrel, dormouse, jerboa, and hare. 5th. The _Pecora_ have several blunt, wedge-like front teeth, in the lower jaw, and none in the upper. Their feet are armed with cloven hoofs. They live on vegetable food, and all ruminate, or chew the cud. The genera are, the camel, musk, deer, giraffe, antelope, goat, sheep, and cow. 6th. _Belluae_ have obtuse front teeth. The feet are armed with hoofs; in some whole or rounded, in others obscurely lobed or sub-divided. They live on vegetable food. The genera are, the horse, hippopotamus, tapir, and hog. 7th. The _Cete_, or Whales, although they resemble fishes in external appearance, are ranged very properly amongst the Mammalia, having warm blood, similar lungs, teats, &c. Instead of feet, they are provided with pectoral fins, and a horizontally flattened tail, fitted for swimming. They have no hair. The teeth are in some species cartilaginous, and in others bony. Instead of nostrils, they have a tubular opening on the top of the head, through which they occasionally spout water. They live entirely in the sea; feeding on the soft marine animals and vegetables. The children carefully read over this paper, exclaiming: "It is almost exactly what you have told us before, papa, only here we have it all at one view."