Geographical Regions 321 



In 1853 appeared L. K. Schmarda's^ two volumes, embracing the 

 whole subject. Various centres of creation being, according to him, 

 still traceable, he formed the hypothesis that these centres were 

 originally islands, which later became enlarged and joined together 

 to form the great continents, so that the original faunas could overlap 

 and mix whilst still remaining pure at their respective centres. After 

 devoting many chapters to the possible physical causes and modes of 

 dispersal, he divided the land into 21 realms which he shortly charac- 

 terises, e.g. Australia as the only country inhabited by marsupials, 

 monotremes and meliphagous birds. Ten main marine divisions 

 were diagnosed in a similar way. Although some of these realms 

 were not badly selected from the point of view of being applicable to 

 more than one class of animals, they were obviously too numerous for 

 general purposes, and this drawback was overcome, in 1857, by 

 P. L. Sclater'^. Starting with the idea, that "each species must have 

 been created within and over the geographical area, which it 

 now occupies," he concluded "that the most natural primary onto- 

 logical divisions of the Earth's surface " were those six regions, which 

 since their adoption by Wallace in his epoch-making work, have become 

 classical. Broadly speaking, these six regions are equivalent to the 

 great masses of laud; they are convenient terms for geogi-aphical 

 facts, especially since the Palaearctic region expresses the unity of 

 Europe with the bulk of Asia. Sclater further brigaded the regions of 

 the Old World as Palaeogaea and the two Americas as Neogaea, a 

 fundamental mistake, justifiable to a certain extent only since he 

 based his regions mauily upon the present distribution of the Passerine 

 birds. 



Unfortunately these six regions are not of equal value. The 

 Indian countries and the Ethiopian region (Afi'ica south of the 

 Sahara) are obviously nothing but the tropical, southern continua- 

 tions or appendages of one greater complex. Further, the gi*eat 

 eastern mass of land is so intimately connected with North America 

 that this continent has much more in common with Europe and Asia 

 than with South America. Therefore, instead of dividing the world 

 longitudinally as Sclater had done, Huxley, in 1868^, gave weighty 

 reasons for dividing it transversely. Accordingly he established 

 two primary divisions, Arctogaea or the North world in a wider 

 sense, comprising Sclater's Indian, African, Palaearctic and Xearctic 

 regions ; and Notogaea, the Southern world, which he divided into 



^ Dir gcographische Verbreitung der Thiere. Wien, 1853. 



* " On tlie general GeoRraphical Distribution of the members of the class Aves," Proc. 

 Linn. Soc. (Zuology), ii. 1858, pp. 130—145. 



* "On the classification and distribution of the Alectoromorphae and Hcteromorphae," 

 Proc. Zool. Soc. 1808, p. 294. 



i>. 21 



