AVES 



411 



flat breast bone (i.e., no keel) and with all the organs of flight 

 much reduced. The barbs of the feathers are not held together 

 by barbules, thus producing plumes. 



The Ratitas (order Cur sores or runners) are the lowest forms 

 of living birds and include the ostriches, emus, cassowaries, in 

 all of which the wings are reduced, and the Apteryx or wingless 

 bird of New Zealand (Fig. 210) in which they are very rudi- 



FlG. 211. 



FIG. 211. Ostrich (Struthio). From Wood's Natural History. 



Questions on the figure. Which of the types of feathers of ordinary birds 

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



mentary. The ostrich (Fig. 211) is the largest and most power- 

 ful of living birds. Ostriches are somewhat gregarious, and 

 frequent regions more or less desert. At mating time they 

 unite in pairs, the male assisting in incubating the eggs, which 

 are laid in holes in the sand. Ostrich culture is an important 



