CARINATE BIRDS l£ 



these are accordingly to be regarded as higher in the 

 scale of evolution. The natural order, therefore, is 

 to work upwards from the lowest, or more primitive, 

 types to the highest, or latest evolved forms. The 

 lowest of all, the Ostrich tribe, have already been con- 

 sidered, and we proceed now to a brief study of the 

 higher forms of bird life. 



