Chap. 36 BIRDS — CONQUEST OF THE AIR 751 



have been found in Bavaria and none anywhere so perfect as the now famous 

 Archaeopteryx (Fig. 36.20). The skeleton is similar to that of the flying rep- 

 tiles of the same era. As a bird, Archaeopteryx is certified only by its feathers. 

 It was about the size of a large crow but more heavily built than a modern 

 bird. The skeleton is lizardlike; the vertebrae of the pelvic region are separate, 

 not fused as in birds and freely movable ones formed a long tail. Each tail 

 vertebra supports a pair of long feathers all of them forming an expanse that 

 was probably spread fan-wise in the air. The wings had free movable "fingers," 

 each with a claw, and on the jaws there were true teeth set in sockets. Ages 

 must have elapsed between the scaly flying reptiles and a feathered Archae- 

 opteryx, but there is no fossil record of a development of birds in that long 

 period. In fossil birds of the far later Tertiary Period (Eocene), the teeth are 

 missing and the tail is short. 



