THE JURASSIC PERIOD 



725 



A less bizarre, but really greater evolution, was the contempo- 

 raneous differentiation of true birds. The remote ancestors of the 

 pterosaurs and the birds may have been closely allied, but there is 

 no evidence that the birds are descended from pterosaurs. The two 



ig. 497. The earliest known bird, Archceopteryx macrura. The long ver- 

 tebrated tail, the clawed digits of the fore limbs, and the toothed jaws 

 are ancestral features to be specially noted. (H. von Meyer.) 



