VEETEBRATA 



85 



distributed in areas, those of the wings 

 much differentiated ; (4) Euornithes. 



Ischium coossified with ilium posteriorly ; 

 no teeth; feathers universally distrib- 

 uted and not differentiated on wings; (5) Impennes. 



The Ratitse are the ostriches and their allies ; the Odon- 

 tolcEE and Odontotormse are toothed birds ; the Impennes 

 are the penguins, and the Euornithes are the remaining, or 

 typical birds. The geological distribution of these tribes 

 is as follows : 



The RatiTvE includes the following orders : 



Sternum without keel ; clavicles ; wings rudi- 



mental ; Struthiones.. 



Sternum without keel ; no clavicles ; wings 



rudimental ; Apteryges.. 



Sternum with keel ; clavicles ; wings rudi- 



meutal ; , Gastornithes.. 



Sternum with keel ; clavicles ; wings func- 

 tional ; Crypturi.. 



