368 



GEOGRAPHICAL ZOOLOGY. 



[part IV. 



extend into the South Temperate zone, have six families, with one 

 peculiar to them ; while the Oriental region, which is wholly 

 tropical, possesses the five cosmopolitan families only. 



There are about 78 genera and 552 species of Anseres, giving 

 69 species to a family, a high number compared with the 

 Waders, and due to there being only one very small family, the 

 Colymbidae. The distribution of the Anseres, being more deter- 

 mined by temperature than by barriers, the great regions which 

 are so well indicated by the genera and families of most other 

 orders of birds, hardly limit these, except in the case of the 

 senera of Anatidse. 



Order X.—STEUTHI0NE8. 



Family 126.— STRUTHIONID^. (2 Genera, 4 Species.) 



General Distributiun. 



The Ostriches consist of two genera, sometimes formed into 

 distinct famiHes. Struthio (2 sp.) inhabits the desert regions of 

 North, East, and South Africa, as well as Arabia and Syria. It 

 therefore just enters the Paloearctic region. Rhea (3 sp.) inhabits 

 Temperate South America, from Patagonia to the confines of 

 lirazil. 



Family 127.— CASUAEIID^. (2 Genera, 11 Species.> 



General Distribution. 



The Cassowaries and Emeus are confined to the Australian 

 region. The Emeus, Dromceus (2 sp.), are found only on the 



