AREAS OF DISTRIBUTION. 77 



physical possibilities of dispersal, the climatic, nutritive, 

 and competitive conditions of diiferent areas, besides the 

 great changes of the earth's surface and of consequently 

 isolated evolution, explain in a general way why the fauna 

 of Europe is very different from that of South America, 

 or the fauna of Africa from that of Australia. 



In the course of our study we shall notice some of the 

 more striking facts of geographical distribution, meanwhile 

 we shall simply define the limits of the great regions into 

 which the earth is divided by zoologists. Schmarda, Murray, 

 Wallace, Sclater, and others have established these regions 

 mainly with reference to birds and mammals, but there is no 

 doubt that the divisions are in a general way consistent for 

 most animals. 



I shall simply quote a paragraph from Professor Angelo 

 Heilprin's work — The Geographical and Geological Distri- 

 bution of Animals (Internat. Sci. Series. London, 1887), a 

 most valuable book for the student, especially as it considers 

 distribution in space and time together. 



" By most naturalists the terrestrial portion of the earth's 

 surface is recognised as consisting of six primary zoological 

 regions, which correspond in considerable part with the 

 continental masses of geographers. These six regions are : 



" I. The Palcearctic, which comprises Europe, temperate 

 Asia (with Japan), and Africa north of the Atlas Moun- 

 tains ; also Iceland, and the numerous oceanic islands of the 

 North Atlantic : 



" 2 The Ethiopian, embracing all of Africa south of the 

 Atlas Mountains, the southern portion of the Arabian Pen- 

 insula, Madagascar, and the Mascarene Islands, and which, 

 consequently, nearly coincides with the Africa of geo- 

 graphers : 



" 3. The Oriental or Indian, which embraces India south 

 of the Himalaya, Farther India, Southern China, Sumatra, 

 Java, Bali, Borneo, and the Philippines : 



" 4. The Australian, comprising the continent of Aus- 

 tralia, with Papua or New Guinea, Celebes, Lobok, and the 

 numerous islands of the Pacific : 



" 5. The Nearctic, which embraces Greenland, and the 

 greater portion of the continent of North America (exclud- 

 ing Mexico) : 



