174 GEOGRAPHICAL DISTRIBUTION OF ANIMALS. 



peculiar species. It is in this zone that the Pentacrinus 

 caput-medusce. is found, the only representative, in the 

 existing creation, of a family so numerous in ancient 

 epochs, the Crinoidea with a jointed stem. 



The limits of the fauna of Central America cannot yet 

 be well defined from want of sufficient knowledge of the 

 animals which inhabit those regions. 



438. The tropical zone of Africa is distinguished by a 

 striking uniformity in the distribution of the animals, which 

 corresponds to the uniformity of the structure and contour 

 of that continent. Its most characteristic species are spread 

 over the whole extent of the tropics : thus, the giraffe is met 

 with from Upper Egypt to the Cape of Good Hope. The 

 hippopotamus is found at the same time in the Nile, the 

 Niger, and Orange River. This wide range is the more 

 significant as it also relates to herbivorous animals, and thus 

 supposes conditions of vegetation very similar, over wide 

 countries. Some forms are nevertheless circumscribed 

 within narrow districts ; and there are marked differences 

 between the animals of the eastern and western shores. 

 Among the remarkable species of the African torrid region 

 are the baboons, the African elephant, the crocodile of the 

 Nile, a vast number of Antelopes, and especially two spe- 

 cies of Ourang-outang, the Chimpanzee and the Engeena, 

 a large and remarkable animal, recently described by 

 Drs. Savage and Wyman. The fishes of the Nile have a 

 tropical character, as well as the animals of Arabia, which 

 are more allied to those of Africa than to those of Asia. 



439. The tropical fauna of Asia, comprising the two pe- 

 ninsulas of India and the isles of Sunda, is not less marked. 

 It is the country of the gibbons, the red ourang, the royal 

 tiger, the gavial, and a multitude of peculiar birds. Among 

 the fishes, the family of Chetodons is most numerously 

 represented. Here also are found those curious spiny 



