AVES. 



407 



432. Classification of Aves. 



Subclass I. Saiirnrce (Tailed, Reptilian Birds). These are 

 extinct birds related to the extinct reptiles the dinosaurs in 

 having a vertebrated tail, and jaws bearing teeth. Each ver- 

 tebra of the tail possessed a pair of feathers, the tail thus hav- 

 ing a row of rectrices on either side. 



FIG. 208. 



FIG. 208. Ostrich (Struthio). From Wood's Natural History. 



Questions on the figure. Which of the types of feathers of ordi- 

 nary birds become the plumes in the ostrich? What is the real size of 

 the ostrich ? 



Archgeopteryx, of which two specimens have been found in 

 the lithographic quarries of Bavaria, represents the group and 

 was about the size of a crow (Fig. 206). 



Subclass II. Neornithes (Modern Birds). This group is 

 characterized by the reduction and fusion of the tail vertebrae 



