172 GEOGRAPHICAL DISTRIBUTION OF ANIMALS. 



434. TROPICAL FAUNAS. The tropical faunas are dis- 

 tinguished, on all the continents, by the immense variety of 

 animals which they comprise, not less than by the brilliancy 

 of their coverings. All the principal types of animals are 

 represented, and all contain numerous genera and species. 

 We need only refer to the tribe of humming-birds, which 

 numbers not less than 300 species. But what is very im- 

 portant is, that here are concentrated the most perfect, 

 and also the oddest types of all the classes of the Animal 

 Kingdom. The tropical region is the only one occupied by 

 the Quadrumana, the herbivorous bats, the great pachyder- 

 mata, such as the elephant, the hippopotamus, and the tapir, 

 and the whole family of Edentata. Here also are found the 

 largest of the cat tribe, the lion and tiger. Among the 

 Birds we may mention the parrots and toucans, as essen- 

 tially tropical ; among the Reptiles, the largest crocodiles, 

 and gigantic tortoises ; and finally, among the articu- 

 lated animals, an immense variety of the most beautiful 

 insects. The marine animals, as a whole, are equally 

 superior to those of other regions ; the seas teem with 

 crustaceans and numerous cephalopods, together with an 

 infinite variety of gasteropods and acephala. The Echi- 

 noderms there attain a magnitude and variety elsewhere 

 unknown ; and lastly, the Polyps there display an activity 

 of which the other zones present no example. Whole 

 groups of islands are covered with coral reefs formed by 

 those little animals. 



435. The variety of the tropical fauna is further enriched 

 by the circumstance that each continent furnishes new and 

 peculiar forms. Sometimes whole types are limited to one 

 continent, as the sloth, the toucans, and the humming-birds to 

 America, the giraffe and hippopotamus to Africa ; and again, 

 animals of the same group have different characteristics, ac- 



