128 NATURE STUDIES. 



reptile thus acquired powers of flight, the develop- 

 ment of flight in the bird-stock, which was evolved 

 from the reptile, or conjointly with it, need cause us 

 no surprise. 



The Pterodactyls possessed the outermost finger 

 {seen in the illustration) enormously elongated, and 

 adapted to form the chief support of a wing-membrane 



Fig. 3. A. Skeleton of Pterodactyl ; B. Restoration of 

 Pterodactyl. 



which extended along the sides of the body and 

 between the hind limbs and tail also, as shown in B, 

 Fig. 3. It may be added that these reptiles had a 

 keel on the b reastbone like most living and extinct 

 birds, and whilst in some species the teeth were 

 developed, in others the jaws appear to have been 



