414 



DISTRIBUTION IN SPACE AND TIME 



II. Nearctic Region. — Practically equivalent to North 

 America. Sub- Regions: — i. Canadian; 2. Californian; 3. Rocky 

 Mountain; 4. Alleghany. 



III. Ethioi'Ian. — Africa south of the Sahara, south Arabia, 

 and Madagascar. Sub- Regions: — i. West African; 2. South 

 African ; 3. East African ; 4. Mascarene. 



IV. Oriental Region. — South Asia, the western part of the 

 East Indies, the Philippines, and Formosa. Sub- Regions: — i. 

 Indian; 2. Cingalese; 3. Indo-Chinese; 4. I ndo- Malayan. 



V. — Australian Region. — The eastern part of the East 

 Indies, Australia and adjacent islands. New Zealand, and Poly- 

 nesia. Sub- Regions: — i. Austro- Malayan; 2. Australian; 3. 

 Polynesian; 4. Novo-Zelanian. 



VI. Neotropical Region. — Central America, South America, 

 and the West Indies. Sub-Regions: — i. Me.\ican; 2. Chilian; 

 3. West Indian; 4. Brazilian. 



Chalmers Mitchell has devised the following ingenious way 

 of representing the regions and sub-regions in a diagrammatic 

 form, which readily lends itself to expressing the distribution of 

 any animal or group of animals, by simply leaving out the numbers 

 of those sub-regions in which that particular form or group does 

 not occur. 



Regions and Sub-Regions. 



Distribution of Crocodiles and 

 Alligators (Crocodilia). 



4 



VI 



I 3 



III 

 I 3 



IV 



1 3 



2 4 



Fauna of the Pal.earctic Region. — In spite of its great 

 size this region possesses comparatively few animals which are 

 found nowhere else. The number would be much larger if there 

 were not a good many species common to it and the Nearctic 

 Region. This is not very surprising when we remember the 



