BIRDS. Y7 



less, only a rudimentary humerus persisting. Some of 

 these toothed birds were about as large as a pigeon; one 

 was about three feet in height. 



SUBCLASS III. ORNITHURJE (Modern Birds). 



In all living birds teeth are lacking and the tail is re- 

 duced ; and, excepting a few forms, all have well-developed 

 wings. The recent subdivisions of the subclass are based 



FIG. 30. South American Ostrich or Nandu (Rhea americana). From Liitkeru 



upon characters not readily grasped by elementary students, 

 so we must content ourselves with a classification founded 



