544 



Comparative Morphology of Chordates 



Fig. 419. Bennett's cassowary, Casuarius bennetti. (Courtesy, Knowlton and 

 Ridgway: "Birds of the World," New York, Henry Holt & Co., Inc.) 



Order 2. Struthioniformes : Ostriches (Struthio) of Africa 

 and Arabia; largest living birds; wings much reduced, flightless; no 

 carina on sternum; legs long and strong; only two toes (third and 

 fourth); no aftershafts (Fig. 420). 



Order 3. Rheiformes: South American ostrich (Rhea); 

 similar to African ostrich, but smaller and three-toed; wings less 

 reduced; no aftershafts. 



Order 4. Apterygiformes: Kiwi (Apteryx) of New Zealand (Fig. 

 421); slightly larger than common fowl; short neck; long, sharp bill; 

 thick coat of loose, fluffy plumage, no aftershafts; wings extremely 

 vestigial and buried under plumage ; no rectrices ; no carina on sternum ; 

 legs short and stout; four toes; eyes small and poorly developed; 

 olfactory organs highly developed; egg 5 inches or more in length; 

 ground-inhabiting, sometimes burrowing; nocturnal. 



[carinatae (p. 542) : Orders 5-20] 

 Order 5. Tinamiformes (Crypturiformes) : Tinamous (Tinamus) 



of Mexico and South America; resemble partridges; poor fliers, strong 

 runners (Fig. 422). 



in. neognathae: 



Order 6. Sphenisciformes: Penguins (Fig. 423); flightless; short 

 wings used as powerful swimming paddles; carina well developed; 

 Southern Hemisphere only. 



