PART II 



THE PARTS OF ANIMALS AND HOW THEY 

 ARE USED 



CHAPTER IV 

 THE GRASSHOPPER AND THE SNAIL 



An animal's body composed of parts. — The body of 

 every animal, except the very simplest ones, is composed 

 of a few or many parts, each part having some special 

 use or thing to do. A dog has its body made up of head, 

 trunk, legs, and tail — the head comprising skull with 

 brain inside, jaws with teeth, tongue, eyes, ears, etc.; 

 the trunk comprising a host of internal parts, as the back- 

 bone, heart, lungs, stomach, intestines, etc., and the legs 

 in turn composed of a series of bones to which are attached 

 muscles, among which run nerves and blood-vessels, the 

 whole being covered with a hairy skin. The study of the 

 parts, external and internal, of an animal is called anat- 

 omy, and the study of the uses or functions of the parts is 

 called pJiysiology. In earlier years anatomy and physi- 

 ology were studied wholly separately, as they still some- 

 times are. But we know that the things animals do, and 

 the ways in which they do them, depend upon the parts 

 of the body and upon the special character of these parts. 

 We know also that these parts are specially developed 

 and fitted to do certain things or perform certain functions 



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