22 BIOLOGICAL SOCIETY OF WASHINGTON. 



mous ; Opisthocomidie, the hoazin ; Thinocorid;^ ; Cariamidee : 

 Aramidae ; Psophiidse, or trumpeters ; Eurypygidie, or sun-bitterns ; 

 and Palamedeidffi, or horned screamers. The Trochilidte, or hum- 

 ming-birds, are especially noteworthy on account of their great 

 numbers. Six families of reptiles have also been claimed as pecu- 

 liar to the realm, and among the lizards the family of Iguanidse is 

 remarkably developed. Four families of amphibians and four of 

 fishes are also considered as restricted to the realm. The relation 

 between the fishes of South America and Africa is another feature 

 of special significance : there are three families shared between the 

 two, and fomid nowhere else, and genera of the respective families 

 are not distantly related, although none are actually common to the 

 two realms. 



VI. THE AMPHIG^AN REALM. 



The Temperate South American Realm may retain provisionally 

 the limits assigned to it by Mr. Allen, and as these have already 

 been specified when considering Mr. Allen's views, it is unnecessary 

 to repeat them here. Within its limits occur representatives of several 

 peculiar groups; there are i8 families of terrestrial mammals, two 

 of which (the Chinchillidee and Chlamyphoridse) are almost con- 

 fined to it, and two (Ursidae and Camelidse) are shared with the 

 northern realms without occurring in the contiguous realm ; 42 so- 

 called families of birds, three of which (the Chionidida3, Thino- 

 coridse, and Rheidse) scarcely or not at all encroach northwards; 

 15 families of reptiles ; 11 families of amphibians ; 5 families of 

 fishes, two of which are shared with New Zealand and Tasmania, 

 and scarcely extend into Tropical America ; and one family of 

 Myzonts, also shared with New Zealand and Tasmania. 



VII. THE AUSTROG^AN REALM. 



The Australian Realm is of all the most distinctly defined 

 by its fauna. As it will be here limited, it comprises Australia and 

 the immediately outlying islands, tmd the Austro-Malayan Archi- 



