OP PLANTS AND ANIMiLS. 167 



a few star fishes and echini. We must not omit the 

 whales, which are, however, the lowest of all the mammalia. 

 This assemblage of animals is decidedly inferior to the 

 temperate and tropical faunas. 



We have already intimated that "elevation has the 

 same effect on temperature as an increase of distance from 

 the equator." Hence there is a remarkable similarity be- 

 tween the plants and animals which cover a hemisphere 

 from the equator to the poles, and those which clothe the 

 sides of a tropical mountain, from its warm and sunny base 

 to its cold and snowy summit. The species, genera, and 

 even the families of both plants and animals growing in 

 the country surrounding its base, may be entirely different 

 from the vegetable productions of Europe. But here, ele- 

 vation above the ocean level, acts in the same manner on 

 vegetation as an increase of distance from the equator. In 

 proportion as we ascend the mountain, the fauna and flora 

 gradually lose their tropical character, and assume the ap- 

 pearance of that without the tropics ; the climate becomes 

 cooler, until at length the tropical plants disappear, and 

 European genera, and even species analogous if not abso- 

 lutely identical with those of the temperate climates of 

 Europe, present themselves to the eye of the astonished 

 observer. As we approach the limits of perpetual snow, 

 the vegetation becomes wholly cryptogamous, and similar 

 to that of the arctic regions. 



M. Mirbel has therefore very properly compared the 

 terrestrial globe to two immense mountains, whose bases 

 are united at the equator, and whose summits are the 

 arctic regions around its northern and southern poles. 



