508 



SKELETON OF BATS AND PTERODACTYLS. 



elongated in the wading birds, and the four separate toes, by 

 the spread of which the body is firmly supported, though 

 resting only on two feet. 



Fig. 25!. SKELETON OF BAT. (References as in Fig. 229.) 



669. In the Bat (fig. 251), however, the plan is very dif- 

 ferent. We have here no long stiif feathers, by the projection 

 of which from the limb itself the surface may be increased to 

 almost any extent ; but the wing is formed by an expansion 



Fig. 252. SKELETON OF PTERODACTYLS. 



of soft and delicate skin over a framework of bones, which 

 must consequently be made to support it to its very edge. 



