GEOGRAPHICAL DISTRIBUTION OF ANIMALS. 501 



end we proposed in touching on this subject, it only remains 

 for us to take a view (coup d'ail) of the results brought about 

 by the different circumstances of which we have just spoken, 

 that is to say, of the actual condition of the geographic dis- 

 tribution of animated beings. When we compare the various 

 regions of the globe with each other in the relation of their 

 zoological population, one is struck at first with the extreme 

 inequality observable in the number of species. In a certain 

 country, for example, we meet with an extreme diversity in 

 the forms and the structure of the animals composing its 

 fauna, whilst elsewhere there reigns in this respect a great 

 uniformity ; and it is easy to observe a certain relation be- 

 tween the different degrees of zoological richness and the 

 elevation, more or less considerable, of the temperature. In 

 fact, the number of species, as well marine as terrestrial, aug- 

 ments in general in proportion as we descend from the poles 

 towards the equator. The more remote polar regions offer to 

 the traveller only a few insects, and in its icy seas the fishes 

 and the mollusca themselves are but little varied ; in tem- 

 perate climates the fauna becomes more numerous in species; 

 but it is in the tropical regions that nature shows herself 

 most prodigal in this respect, and the zoologist cannot see 

 without astonishment the endless diversity of animals which 

 are accumulated there. 



It is remarkable also that there exists a singular coin- 

 cidence between the elevation of the temperature in different 

 zoological regions, and the degree of organic perfection of the 

 animals inhabiting them. It is in the hottest climates that 

 we find the animals which most approach man, and those 

 which in each great zoological division possess the orga- 

 nization the most complex, and the faculties most developed; 

 whilst in the polar regions we meet only with beings occu- 

 pying a rank but little elevated in the zoological series. The 

 apes, for example, are limited to the hottest parts of the 

 two continents ; it is the same with the parroquets amongst 

 birds ; the crocodiles and the tortues (turtles and tortoises) 

 amongst reptiles, and of land-crabs amongst the Crustacea, 

 all animals the most perfect in their respective classes. 



It is also in hot countries that we find the terrestrial the 

 most remarkable for the beauty of their colours, the size of 

 their bodies, and the singularity of their forms. 



Finally, there seems to exist a certain relation between the 

 climate and the tendency of nature to produce such or such 



