378 GEOGRAPHICAL DISTRIBUTION OF ANIMALS. 



pachydermata, 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 articulated animals, 

 an immense variety of the most beautiful insects. The ma- 

 rine animals, as a whole, are equally superior to those of other 

 regions : the seas teem with crustaceans and numerous cepha- 

 lopods, together with an' infinite variety of gasteropods and 

 acephala. The echinoderms 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 surrounded with coral 

 reefs formed by those little animals. 



617. 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, 

 according as they are found on different continents. Thus, 

 the monkeys of America have flat and widely-separated nos- 

 trils, thirty-six teeth, and generally a long, prehensile tail. 

 The monkeys of the old world, on the contrary, have nostrils 

 close together, only thirty-two teeth, and not one of them has 

 a prehensile tail. 



618. But these differences, however important they may 

 appear at first glance, are subordinate to more important cha- 

 racters, which establish a certain general affinity between all 

 the faunas of the tropics. Such, for example, is the fact that 

 the quadrumana are limited, on all the continents, to the 

 warmest regions ; and never, or but rarely, penetrate into the 

 temperate zone. This limitation is a natural consequence of 

 the distribution of the palms ; for as these trees, which con- 

 stitute the ruling feature of the flora of the tropics, furnish, to 

 a great extent, the food of the monkeys on both continents, 

 we have only to trace the limits of the palms, to have a pretty 

 accurate indication of the extent of the tropical faunas on all 

 three continents. 



