GEOGRAPHICAL DISTRIBUTION 419 



species are replaced by members of characteristic American 

 families. There are also a number of peculiar Nearctic genera, 

 but to give a list of them would serve no useful purposes. 

 Turkeys {Meleagris) are well represented, but also range south 

 into Central America. 



Nearctic Reptiles {Reptilia). — It need only be said that 

 poisonous Lizards {Helodernia) are characteristic, as also are 

 Rattlesnakes {Crotalus), though both range into the Neotropical 

 region, while Crocodiles and Alligators are represented in the 

 south of the United States. 



Nea^'ctic Amphibians {Amphibia). — The region is richer than 

 any other part of the world in Tailed Amphibians {Urodela), 

 and among the peculiar forms are the curious Mud - Eels 

 {Amphitmia) and Sirens (Siren). 



jVearctic Irishes (Pisces). — Several families and a consider- 

 able number of genera of freshwater fishes are native to this 

 region only, but their names would convey little meaning to 

 average European readers. 



Nearctic Freshivater Molluscs (Molhisca). — Wallace states 

 that the Nearctic region is richer in characteristic forms than 

 any other part of the world. 



Fauna of the Ethiopian Region. — We have seen that the 

 approximation in high latitudes of the great land-masses of the 

 Northern Hemisphere has led to a great deal in common be- 

 tween the faunas of the Pala;arctic and Nearctic regions, and 

 both of them are rather deficient as regards the presence of 

 peculiar forms known to the lay reader. This renders it rather 

 difficult to treat them in a popular manner; but there is no such 

 difficulty with regard to the southern regions which remain for 

 consideration, as all of them have well-marked characteristics, 

 and their more typical animals are familiar to everyone. In 

 varying degree they have been more or less isolated by physical 

 barriers for very long periods of time, and this isolation has 

 rendered possible the evolution of distinctive faunas. 



Ethiopian Mammals (Mammalia). — There is no lack of Apes 

 and Monkeys (Primates) belonging to genera not represented 

 elsewhere. Among the higher or man-like Apes the Gorilla 

 (Gorilla) and Chimpanzee (Anthropopithecus) are typical, while 

 of lower forms may be mentioned the Colobi (Colobtts) with 

 reduced thumbs, the Guenons (Cercopithectis), and a number of 



