AVES 



279 



sub-class: Archceornithes. All other birds are placed in the sub-class 

 Neornithes, of which three divisions are distinguished: 



Division 1. Neornithes Odontolcce (toothed diving birds), repre- 

 sented by Hesperornis and Baptornis. 



FIG. 151. Hesperornis regalis. Restored skeleton. (From Parker and Haswell, 

 after Marsh.) 



Division 2. Neornithes Ratitce (running birds), exemplified by the 

 ostrich, and represented by both extinct and living species. 



Division 3. Neornithes Carinatce (keeled or flying birds), modern 

 birds mainly, with a few extinct species. 



