206 THE STORY OP THE EARTH AND MAN. 



that of birds, which, they rivalled in energy and 

 intelligence. Some of them were larger than the 

 largest modern birds of prey, others were like pigeons 

 and snipes in size. Specimens in the Cambridge 

 Museum indicate one species twenty feet in the 

 expanse of its wings. Cope has recently described an 

 equally gigantic species from the Mesozoic of Western 

 America, and fragments of much larger species are 

 said to exist.* Imagine such a creature, a flying 

 dragon, with vast skinny wings, its body, perhaps, 

 covered with scales, both wings and feet armed with 

 strong claws, and with long jaws furnished with 

 sharp teeth. Nothing can be conceived more strange 

 and frightful. Some of them had the hind limbs 

 long, like wading birds. Some had short, legs, 

 adapted perhaps for perching. They could probably 

 fold up their wings, and walk on all fours. Their 

 skeleton, like that of birds, was very light, yet strong ; 

 and the hollow bones have pores, which show that, as 

 in birds, air could be introduced into them from the 

 lungs. This proves a circulation resembling that of 

 birds, and warm blood. Indeed, in many respects, 

 these creatures bridge over the space between the 

 birds and the reptiles. "That they lived/' says 

 Seeley, " exclusively upon land or in the air is im- 

 probable, considering the circumstances under which 

 their remains are found. It is likely that they 

 haunted the sea-shores ; and while sometimes rowing 

 themselves over the water with their powerful wirgs t 

 * Seeley : " Ornithosauria" 



