CHAPTER IX. 



ON THE LAWS, ACCORDING TO WHICH, ANIMALS AND PLANTS 

 ARE DISTRIBUTED ON THE SURFACE OF THE GLOBE. 



When we examine the plants and animals in different 

 parts of the earth, we find that each great country on the 

 globe has its own flora and fauna. This diversity in their 

 vegetable productions is one of the causes of that particular 

 physiognomy which landscapes present in the different parts 

 of the earth. Thus the vegetation which covers the coun- 

 tries to the north, consisting of immense forests of pine, fir, 

 and birch, is very different from that of the more temperate 

 climates, where the forests are less abundant, and possess 

 more of variety in the species which compose them ; and 

 the plants of the temperate zone are not the same as that 

 of tropical countries, where the climacteric conditions are 

 favorable to the support and development of a continuous 

 vegetation which is never arrested. 



The geographical distribution of animals is intimately 

 associated with that of plants; for herbivorous animals 

 can exist only where there is an adequate supply of 

 vegetables suitable for their food; and the carnivorous 

 prey upon the herbivorous races. Hence it is that the fauna 

 of the different parts of the earth presents the same ever- 

 varying aspect as its flora. The animals of Oregon and 

 California, for example, are not the same as those of New 

 England; and in like manner the animals of temperate 

 Asia differ from those of Europe and the torrid regions of 

 Africa. Under the torrid zone, the animal as well as the 



