20 CLASS I. MAMMALIA. 



blance in structure and conformation, are placed together in 

 an ORDER ; whilst upon a similar principle, but more exten- 

 sive in its application, these orders are marshalled into sepa- 

 rate CLASSES. 



SECTION II. 

 Class I. Mammalia. 



THE Mammalia are placed at the head of the animal king- 

 dom. It is to this class that man, considered as an object of 

 nattfral history, properly belongs; and beside him, the an>- 

 mals of this class are distinguished for a more perfect bodily 

 structure, for more varied faculties, more delicate sensations, 

 a more elevated intelligence, and greater capability of im- 

 provement by imitation and education, than those of any 

 other. Man is arranged with them, because he nearly resem- 

 bles them in structure and organs, though raised in reality 

 far above them by the possession of superior intellectual, and 

 moral powers. 



There is a very considerable similarity in the anatomical 

 conformation of all the animals of this class. The greater 

 part of them are intended for motions confined to the surface 

 of the earth ; but a few are capable of mounting into the air, 

 as the bats; and others are adapted for a life confined to the 

 water, as the whales. But notwithstanding these differences 

 in their mode of life, their principal organs are nearly similar 

 in the general plan of their construction. We shall begin 

 therefore by a description of them as they exist in man, and 

 afterwards point out such important modifications as exist in 

 other animals which differ from him. 



The human body is divided into the head, trunk, and ex- 

 tremities. 



The head includes the cranium, or skull, and the face. 

 The skull is a large bony cavity, composed of several wide, 

 thin, and arched bones, united together by sutures. It con- 

 tains the brain, and gives passage to the spinal marrow, 

 through a hole situated in its lower part, where it proceeds 

 from the brain, and goes to the back-bone. The face is 

 formed of the upper and lower jaws, and of the organs of see- 

 ing, smelling, and tasting. The bones, which form the basis 

 of these organs, are very numerous and difficult to describe ; 

 they are united by sutures, and when taken together, give 



