74 



FIRS7 LESSONS IN ZOOLOGY 



ing — the)' all make use of the same plan of levers, each 

 kind of animal, however, having it specially adapted 

 for its peculiar motions. To see this more clearly com- 



FiG. 43. — Bones ol fore limb of various backboned animals; A, horse; 

 B, bird; C, man; D, dog; £, fish; J^, reptile. 



pare the skeleton of the fin of a fish with the fore leg of 

 a lizard, the wing of a bird, the fore leg of a horse, the 

 fore leg of a dog, and the arm of man (fig. 43). 



If we carefully remove the skin from the side of a 

 fish such as a black bass or sunfish, there is shown 

 a mass of flesh (fig. 44). The great bulk of this is 

 one large muscle, the contraction of which makes the 



