76 



STUDIES IN ANIMAL LIFE. 



Fig. 17. MALE TBITON, OR WATEB-NEWT. 



mals the skeleton is found to be identical in plan. 

 Every bone in the body of a triton has its corre- 

 sponding bone in the body of a man or of a mouse ; 

 and every bone preserves the same connection with 

 other bones, no matter how unlike may be the va- 

 rious limbs in which we detect its presence. Thus, 

 widely as the arm of a man differs from the fin of 

 a whale, or the wing of a bird, or the wing of a bat, 

 or the leg of a horse, the same number of bones, 

 and the same connections of the bones, are found in 

 each. A fin is one modified form of the typical 

 limb ; an arm is another ; a wing another. That 

 which is true of the limbs is also true of all the 

 other organs; and it is on this ground that we 

 speak of the vertebrate type. From fish to man 



