1913] Zoo-Geography 15 



Bears, deer, and insectivorous mammalia occur throughout 

 practically its entire extent, tailed amphibians (salamanders) 

 are found throughout its temperate regions and here alone. 



It appears to me to fall into three natural divisions : — 



1. A71 Arctic Region, comprising the circumpolar regions 

 as far south as the northern limit of the growth of trees. 



2. An Eurasian Region, (equivalent to Sclater's Palsearctiii 

 Realm, with its Arctic portion deducted), comprising Europe, 

 north Africa, and Asia, north of the Indian Realm. 



3. A North American Region (equivalent to Sclater's iJ^e- 

 arctic Realm less Arctic I^orth America), comprising all JSTorth 

 America south of the Arctic regions and north of the ISTeo-trop- 

 ical realm. 



The Arctic Region is characterized by the scantiness of its 

 fauna which is circumpolar for the most part, its most promi- 

 nent mammalian components being the polar bear, Arctic fox, 

 Arctic wolf, Arctic hares, reindeer, and musk ox, the last being 

 American only. 



The Eurasian Region possesses the following forms not found 

 in ISTorth America, though mainly in other regions, in Insecti- 

 vora, the hedgehogs, in Ungulata, the true oxen and buffaloes, 

 the pigs, wild goats, and several species of antelopes. In reptiles 

 it possesses true viperine serpents, and in birds, true flycatchers 

 (Muscicapidse), bustards (Otidae), old-world warblers (Sylvii- 

 dse), true larks (Alaudidae) and wagtails (Motacillidse), the 

 last three families being also very sparingly represented in 

 America. 



The North American Region lacks the above mentioned Eu- 

 rasian forms and possesses the following peculiar ones : prong- 

 horn antelope, skunks, o'possum, raccoon, star-nosed mole, mole 

 shrews, and perhaps a few other mammals. Hoofed animals 

 are comparatively poorly represented, there being, except 

 the various deer, only the prong-horn, rocky mountain sheep, 

 rocky mountain goat, and American bison, the last now nearly 

 extinct. Among birds the wood warblers, tanagers, mocking 

 thrushes, new world vultures, tyrant fly catchers and humming- 

 birds distinguish it from the Eurasian region, but all of them 



