662 ZOOLOGY. 



forms. Indeed, at almost any point in temperate North 

 America the fauna is found to consist of three elements — ■ 

 I.e., mainly a temperate, with a certain percentage of boreal 

 or subarctic and of southern or semi-tropical forms ; and if 

 the point be situated near some lofty range of mountains, a 

 fourth element — i.e., a purely arctic or alpine feature — is 

 superadded. The earth's surface may then be mapped out 

 into general and special divisions. First, a tropical, tem- 

 perate, and arctic or circumpolar fauna or realm, and, sec- 

 ondly, each continent may form a smaller subdivision or spe- 

 cific centre — i.e., the Europeo-Asiatic, the African, the Aus- 

 tralian, and the South and Xorth American regions, for 

 each of these continental divisions have been peopled with 

 animals which have been from the earliest geological times 

 the original possessors of the soil, though they may have 

 adopted members of each other's faunae. 



Confining ourselves to the Xorth American Continent, 

 let us examine the distribution of life on its surface. We 

 shall have to throw out the arctic regions, which belong 

 with the arctic regions of Europe and Asia, to a distinct 

 circumpolar fauna or realm, and then map out the rest of 

 the continent into five provinces — i.e., the Canadian, the 

 Alleghanian, the Central or Rocky Mountains, the Pacific 

 or Californian, and the Mexican ; all of these provinces are 

 bounded by natural geological limits and differ in tempera- 

 ture and moisture. While the cougar, or Felis ccyncolor, is 

 common to each one of them, and the bison and black bear 

 range throughout the Canadian, Alleghanian, and Central 

 provinces, there is a certain percentage of animals which 

 are confined to each province ; and on closer examination, 

 each province, especially on the Atlantic and Pacific coasts, 

 will be found capable of minuter subdivision into more lo- 

 cal iaxms or faunidw. 



It will also be found that the animals, especially the 

 insects, of the Atlantic province have certain elements 

 reminding us of Xortheastern Asia, while on the Pacific 

 slope — i.e., the Californian province, a few insects, shells, 

 and Crustacea, as well as the birds, remind us of European 

 types, which are wholly wanting east of the Eocky :Moun- 

 tains. 



