THE AUK: 



A QUARTERLY JOURNAL OF 

 ORNITHOLOGY. 



Vol. XXIX. July, 1912. No. 3. 



BIRD GENEALOGY.i 



BY CHARLES W. TOWNSEND, M. D. 



Arch.eopteryx had teeth in its jaws, separate hip bones, bi- 

 concave vertebrae, claws on its front limbs and a vertebrated tail, 

 all marks of the reptile, in which group it might still be placed 

 by some, were it not for the fact that the impression of the 

 feathers has been preserved to us and stamps its essential bird 

 nature. The links between birds and their reptilian predecessors 

 are very perfect. 



Now if birds are descended from reptiles, one may perhaps still 

 find some traces of this lowly origin in the infantile period of bird 

 life, just as there are various ear-marks of the savage of the jungle 

 in the infancy of the most gilded city dweller, not to mention the 

 transient and permanent reversions often found among adults of 

 the race. Thus the Hoatzin of the Orinoco when young, has 

 claws on the wings and scrambles about the branches in a truly 

 reptilian style, a mode of progression that, according to Beebe, is 

 still used by the adults. 



One need not go so far as the Orinoco, however, to find evidences 

 of the quadrupedal reptilian mode of progression in birds, as 

 witness the actions of young Herons before they learn to fly, when 

 with wings and legs they climb about their family tree almost as 

 gracefully, I dare say, as did some of the ancient winged reptiles. 



I Read before the Nuttall Ornithological Club, March 4, 1912. 

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