A SYSTEMATIC CLASSIFICATION FOR THE BIRDS OF 



THE WORLD 



By Alexander Wetmoee 



Assistant Secretary, Smithsoman Institution 



Since preparing a classification of North American birds ^ in 

 collaboration with the late W. deW. Miller, of the American Museum 

 of Natural History, for use in the fourth edition of the official Check- 

 list of the American Ornithologists' Union, now in course of publica- 

 tion, the writer has continued investigations in this interesting sub- 

 ject, with the result that he here offers an arrangement of the known 

 birds of the world, living and fossil, in accordance with his present 

 understanding of their relationships. The work of Hans Gadow has 

 been taken as a starting point, and such changes have been incorpo- 

 rated as seem justified from personal research or from the investi- 

 gations of others. In general, only such variations from the current 

 order have been accepted as seem to be firmly established. Where 

 doubt seems to attach to any proposition, the older classification has 

 been followed; so the following scheme presents a conservative 

 arrangement so far as possible. The list is complete for all cate- 

 gories down to families. Attempt has been made to follow a definite 

 terminology for the various groups, so that there may be no mis- 

 understanding of their proper rank. 



Class Aves. 



Subclass Archaeornithes. 



Order Archaeopterygiformes. 



Family Archaeopterygidae, Archaeopteryx, Archaeor- 

 nis (fossil). 

 Subclass Neornithes. 



Superorder Odontognathae. 

 Order Hesperornithiformes. 



Family Hesperornithidae, Hesperorrhis, Hargeria (fos- 

 sil). 

 Baptornithidae, Baptornis (fossil). 

 Enaliornithidae,^ Enaliornis (fossil). 

 Order Ichthyornithiformes. 



Family Ichthyornithidae, IchtTvyornis (fossil). 



1 See Auk, 1926, 337-346. 

 ^ Position provisional. 



No. 2821.— Proceedings U. S. National Museum, Vol. 76. Art. 24 



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