APTERYGES. — CASUARII. 375 



Older APTERYGES. 



The order Apterygcs contains only one suborder. 



Suborder XXXIII. APTERYGES. 



Keel of sternum obsolete ; basipterygoid processes present ; hallux 

 present. 



There are three species of Kiwi, all of them peculiar to New 

 Zealand. 



Order RATIT-ffi. 



Keel of sternum obsolete ; basipterygoid processes very large, and 

 placed on the basisphenoid rather than on its rostrum ; hallux absent. 

 The order Ratitse contains three suborders. 



Suborder XXXIV. RHE^. 



Keel of sternum obsolete ; length of humerus more than the com- 

 bined length of six dorsal vertebrae ; hallux absent ; second, third, 

 and fourth digits present and directed forwards ; basipterygoid pro- 

 cesses present, and articulating with the pterygoids as near the 

 quadrates as possible. 



There are three species of Rhea, all of them peculiar to the Neo- 

 tropical Region. 



Suborder XXXV. CASUARII. 



Keel of sternum obsolete ; vomer coalesced with the maxillo-pala- 

 tines in front ; length of humerus less than the combined length of 

 three dorsal vertebrae. 



There are a dozen species of Emu and Cassowary, which are only 

 known from the Australian Region. 



