242 THE HAUNTS OF LITE 



that they were adepts, since the breastbone has 

 only a slight keel for the fixing on of the 

 wing-muscles; and we know that in birds a 

 prominent keel is associated with highly de- 

 veloped flying power, whereas the running 

 birds like the ostrich have no keel at all. 

 On the other hand, the Flying Dragons 

 show, as flying birds do, a solidifying of the 

 middle part of the backbone, giving the 

 wings a firm fulcrum against which to work. 

 It is probably quite safe to say that the 

 Pterodactyls represent a "lost race"; they 

 certainly were not the ancestors of birds. It 

 may be, however, that the ancestors of the 

 Pterodactyls and the ancestors of our birds 

 were related to one another. 



THE FLIGHT OF BIRDS 



The third solution was a triumphant one: it 

 gave birds their mastery of the air. There 

 seems no doubt that birds sprang from an 

 extinct stock of Dinosaur reptiles which had 

 become bipeds; and it is highly probable that 

 they were to begin with swift runners that 

 flapped their scaly fore-limbs and took long, 

 skimming leaps along the ground. When 



