84 



THE COMMON FROG. 



[chap, 



upon the first appearance of vertebrate limbs, differen- 

 tiated in a fashion which thenceforward becomes 

 universal. 



The bones of the wrist in the frog, again, present a 

 nearer resemblance to those in man than do those of 

 most reptiles, and this is still more the case in some 

 other members of the froof's class, e.s:. Salamandra 



Fig. 



Fig. 



Fig. 48. — Skeleton of anterior extremity of an eft. 

 Fig. 49. — Skeleton of posterior extremity of the same. 



and other Efts. Nevertheless, there are certain 

 reptiles, and, strange to say, they are once more 

 Chelonians, which agree in this resemblance — as may 

 be seen in the hand of the tortoise — Chclydra 

 serpentina. 



The bones of the fingers show, moreover, a greater 

 likeness, in certain respects, to those of beasts than to 

 those of reptiles. No finger has a greater number of 



