T90 VESTIGES OF THE 



we discover that, in most instances, the plants of one 

 region have thriven when transplanted to another of 

 parallel clime. This would show that parity of con- 

 ditions does not lead to a parity of productions so exact 

 as to include identity of species, or even genera. Be- 

 sides the various isolated regions here enumerated, there 

 are some others indicated by naturalists as exhibiting 

 a vegetation equally peculiar. Some of these are 

 isolated by mountains, or the interposition of sandy 

 wastes. For example, the temperate region of the elder 

 continent is divided about the centre of Asia, and the 

 east of that line is different from the west. So also is 

 the same region divided in North America by the Rocky 

 Mountains. Abyssinia and Nubia constitute another 

 distinct botanical region. De Candolle enumerates in 

 all twenty well-marked portions of the earth's surface 

 w^iich are peculiar with respect to vegetation ; a number 

 which would be greatly increased if remote islands and 

 isolated mountain ranges were to be included. 



When we come to the zoology, we find precisely 

 similar results, excepting that man (with, perhaps, some 

 of the less conspicuous forms of being) is viniversal, and 

 that several tribes, as the bear and dog, appear to have 

 passed by the land connexion from the Arctic regions of 

 the eastern to those of the western hemisphere. " With 

 these exceptions," says Dr. Prichard, "and without any 

 others, as far as zoological researches have yet gone, it 

 may be asserted that no individual species are common 

 to distant regions. In parallel climates, analogous 

 species replace each other; sometimes, but not fre- 

 quently, the same genus is found in two separate 

 continents; but the species wliicli are natives of one 

 region are not identical with corresponding races indi- 

 genous in the opposite hemisphere. 



