22 BIOLOGICAL SOCIETY OF WASHINGTON. 



mous ; Opisthocomidae, the hoazin ; Thinocoridae ; Cariamidae : 

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

 and Palamedeidae, or horned screamers. The Trochilidae, 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 Iguanidae 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 found nowhere else, and genera of the respective families 

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

 two realms. 



VI. THE AMPHIG^EAN 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 18 families of terrestrial mammals, two 

 of which (the Chinchillidae and Chlamyphoridae) are almost con 

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

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

 called families, of birds, three of which (the Chionididae, Thino 

 coridae, and Rheidae) scarcely or not at all encroach northwards ; 

 15 families of reptiles; n 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^EAN 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, and the Austro-Malayan Archi- 



