THE DISTRIBUTION OF ANIMALS 





the Sahara should resemble that of Europe rather than thai 

 southern Africa; the desert, however, forms a mosl tive 



barrier to the migration of animals and so serves as a natural 

 boundary for the two faunas, while the .Mediterranean has not 

 always been the barrier that it appears to-day, for Europe and 

 Africa were probably connected during the Pleistocene. The 

 characteristics of the Palaearctic fauna are difficult to define in a 

 general way, for they are characteristics of genera and species 

 rather than of larger groups. 



The Nearctic region consists of North America as far south 

 as the northern portion of Mexico, and Greenland. The fauna 

 is so much like the Palaearctic fauna that the two regions are 

 sometimes considered as one, under the term Holarctic. Main- 

 birds are common to the two regions, several Ungulata, as oxen, 

 elk, and deer, a number of rodents, such as hares, beavers, and 

 squirrels, and Carnivora, foxes, wild cats, and bears. But the 

 Nearctic possesses a number of animals which are entirely 

 absent from the Palaearctic fauna, such as some fresh-water 

 fishes, a number of tailed Amphibia, rattlesnakes, and some 

 genera of Lacertilia, and many birds and mammals ; of the last 

 the opossum and raccoon are conspicuous examples. 



The Ethiopian region consists of all Africa south of the 

 tropic of Cancer, and the southern portion of Arabia, as well as 

 Madagascar and a number of small islands off the coast of 

 Africa. In Africa we find a number of fresh-water fishes not 

 found elsewhere, notably one of the Dipnoi, Protopterus, and a 

 number of reptiles and birds; the African ostrich is found in 

 Arabia also. Distinctively Ethiopian are the aard-vark( Edentata ), 

 the zebra, very many antelopes, some species of the rhinocei 

 the hippopotamus, and the African elephant, and also numerous 

 Primates, such as lemurs, baboons, the gorilla, and the chim- 

 panzee. Native deer, oxen, and bears are unknown. The fauna 

 of Madagascar differs considerably from that of Africa in lack- 

 ing nearly all of the above mammals except the lemurs, which are 

 very abundant. 



The Oriental region comprises India, Burmah, Siam, the 

 southeastern portion of China, and a number of the East Indies. 

 notably Sumatra, Java, Borneo, and the Philippines. The south- 

 eastern boundary of this region is an imaginary line, called Wal- 



