734 LECTUBfe LIX. 



orders, of which we shall only be able to take a very cursory view. The 

 first class, denominated mammalia, from the female's suckling its young, 

 comprehends all viviparous animals with warm blood. These, with very 

 few exceptions, have teeth fixed in their jaw bones; and from the form and 

 number of these teeth, the orders are distinguished, except that of cetaceous 

 fishes, which is known by the fins that are found in the place of feet. The 

 distinctions of the teeth are somewliat minute, but they appear to be con- 

 nected with the mode of life of the animal, and they are tolerably natural. 

 The first order, primates, contains man^ monkeys, and bats; the second, 

 bruta, among others, the elejihant, the rhinoceros, the ant cater, and the 

 ornithorhynchus, an extraordinary quadruped, lately discovered in New 

 Holland, with a bill like a duck, and sometimes teeth inserted behind it; 

 but there are some suspicions that the animal is oviparous. The order 

 ferae contains the seal, the dog, the cat, the lion, the tiger, the weasel, 

 and the mole, most of them beasts of prey; the opossum and the kan- 

 garoo also belong to this order, and the kangaroo feeds on vegetables, 

 although its teeth are like those of carnivorous animals. The fourth order, 

 glires, comprehends beavers, mice, s({uirrels, and hares, the fifth, pecora, 

 camels, goats, sheep, and horned cattle. The sixth order, belluae, contains 

 the horse, the hippopotamus, and the hog. The cetaceous fishes, or whales, 

 form the seventh and last order: they reside in the water, enveloped in a 

 thick clothing of fat, that is, of oily matter, deposited in cells, which enables 

 their blood to retain its temperature, notwithstanding the external contact 

 of a dense medium considerably colder. 



Birds are distinguished from quadrupeds, by their laying eggs; they are also 

 generally feathered, although some few are rather hairy; and instead of hands 

 or fore legs they have wings. Their eggs are covered by a calcarious shell; 

 and they consist of a white, or albumen, which nourishes the chick during 

 incubation, and a yolk, which is so suspended within it, as to preserve the 

 side on which the little rudiment of a chicken is situated, continually up- 

 permost, and next to the mother that is sitting on it. The yolk is in great 

 measure received into the abdomen of the chicken a little before the time of 

 its being hatched, and serves for its support, like the milk of a (juadruped, 

 and like the cotyledons of young plants, until the system is become sulfi- 



