EVIDENCE FROM PALAEONTOLOGY 97 



formation of tooth-germs in certain embryo birds, 

 as was pointed out in Lecture III (see p. 71). The 

 joints of the backbone lack the characteristic fea- 

 tures of modern birds, and are much more reptilian 

 in structure. A very remarkable feature is the long, 

 lizard-like tail, com- 

 posed of many vertebrae, 

 to each of which a pair 

 of quill feathers is at- 

 tached. The hand is 

 most un-birdlike; its 

 four fingers are all sepa- 

 rate and free from one 

 another and are com- 

 pletely developed, with 

 the same number of 

 joints as the correspond- 

 ing fingers of a lizard, 

 and each one is pro- 

 vided With a Claw. FlG 6 R estoration of Archaopteryx, 

 There are feathers On Jurassic of Bavaria. (After An- 

 ., . ., j dreae). 



the wings, tail and 



legs, but the head, neck and body are mostly 



naked. We may well hope that the ancestors of 



Archceopteryx, fully intermediate between birds 



and reptiles, will yet be discovered in Triassic 



rocks. 



The ancestry of mammals is still a question of 

 much uncertainty and zoologists continue to debate 

 whether they were derived from reptiles or amphib- 



