IV. 



Zoological regions. — Holarctic realm. — Neotropical. — Ethiopian. — Oriental. — 

 Australian. — Polynesian. — Tyrrhenian, Sonoran, and Austro - Malaysian 

 transition regions. 



ZOOLOGICAL REGIONS. 



As an outcome of the laws governing distribution, and the 

 varying adaptabilities of animal organisms to overcoming the many 

 conditions of existence which present themselves on the surface of 

 the earth, it has resulted that different assemblages or groups of 

 animals have been thrown into different quarters of the habitable 

 globe, which may, accordingly, be said to be divided into a num- 

 ber of regions, of greater or less extent, each of which is character- 

 ised by its own particular fauna. To the more comprehensive of 

 such zoological divisions the term "region" or "realm" has been 

 applied by scientists. But just as the earth's surface taken collec- 

 tively may be divided into zoological regions, so may these be 

 again further subdivided into minor regions, these still further, and 

 so on, until we have, as generally recognised, "regions," "sub- 

 regions," "provinces," and "sub-provinces." 



By most naturalists the terrestrial portion of the earth's sur- 

 face is recognised as consisting of six primary zoological regions, 

 which correspond in considerable part with the continental masses 

 of geographers. These six regions are : 1. The Palaearctic, which 

 comprises Europe, temperate Asia (with Japan), and Africa north 

 of the Atlas Mountains; also, the numerous oceanic islands, with 

 Iceland, of the North Atlantic. 2. The Ethiopian, embracing all 

 of Africa south of the Atlas Mountains, the southern portion of 

 the Arabian Peninsula, Madagascar, and the Mascarene Islands, 

 and which, consequently, nearly coincides in its entirety with the 

 Africa of geographers. 3. The Indian or Oriental, which embraces 



