i:iKl> OF -ViAINK. 147 



lence of the species of one of the faume will result in determining 

 the area to which that region belongs. 



It is of the utmost importance to note the fact that these life 

 areas do not regularly blend with one another, but the points of 

 their iutergradation may be compared to the meeting of the water 

 and land along the irregular, indented coast of Maine. The 

 irregularity of these life areas and the mapping out of their various 

 spurs and projections are of the utmost importance to the farmer. 

 By utilizing the northern projections of a more southern fauna he 

 is able to grow its indigenous plants just so much nearer to a 

 northern market, while some dozens of miles to the eastward his 

 neighbor may be utilizing a southward extension of a colder life 

 area to grow boreal plants so much nearer to a southern market. 

 In general the southern extensions of the colder areas will be found 

 along the higher mountain ranges, while the northern branches of 

 the warm areas are in the lowlands. 



With these explanations we will proceed to an enumeration of 

 the various primary and secondary areas. The entire world has 

 been divided into eight primary life areas, termed Realms, as fol- 

 lows : 



(1) The Arctic Realm extends across the northern continents, 

 reaching from the northern limit of forest growth to the pole. It 

 is remarkable for the paucity and specific identity of the forms of 

 life occurring throughout it. 



(2) The North Temperate Realm extends from the northern 

 limit of forest growth south to the palm tree belt. 



(3) The American Tropical Realm includes tropical America. 



(4) The Indo-African Realm consists of all Africa, except the 

 northern portion, and tropical Asia with its islands. 



(5) The South American Temperate Realm includes temperate 

 South America. 



(6) The Australian Realm embraces Australia and the islands 

 of Oceanica adjacent thereto. 



(7) The Lemnriau Realm is confined to the island of Mada- 

 gascar. 



(8) The Antarctic Realm occupies the same position in the 

 south as does the Arctic in the north, and the species inhabiting it 

 are likewise few and of general distribution. The birds are mainly 

 pelagic. 



