328 



COMPARATIVE ZOOLOGY. 



'•"■^ 



Fig. 305.- 



■Afi-icaii Ostrich {Sti'uthio caimlus). 



New Zealand {Bi- 

 nornis, or Moa). 

 This singular ge- 

 ographical distri- 

 bution, like that 

 of the Dipnoi and 

 Marsupials, shows 

 that the grpup was 

 once widely spread 

 over the earth, but 

 is now greatly re- 

 stricted in area. 



Subclass II. 

 Carinatae. 



Birds with a 

 keeled sternum, 

 and with devel- 



oped functional wings. 



A. Aquatic Birds. — Specially organized for swimming; 

 tlie body flattened, and cov- 

 ered with water-proof cloth- 

 ing — feathers and down ; the 

 legs short (the knees being 

 wholly withdrawn within the 

 skin of the body), and set far 

 apart and far back ; the feet 

 webbed, and hind-toe elevated 

 or absent. The legs are al- 

 ways feathered to the iieel at 

 least. Tliey are the only Birds 

 whose neck is sometimes 

 longer than the legs. 



1. Pygopodes, or Divers. — 

 lliese lowest oi tlie leathered tu). Falkland laUuds. 



