INTRODUCTORY. [CHAP. 



Geographical Distribution it is, therefore, essential to discard such 

 misleading popular titles, and to speak of animals by their correct 

 names. 



Apart from the specific or generic distinctions between the 

 animals of one country and another, the observer 



Distributional 



Area and sta- will not fail to notice more or less well-marked 

 differences between those inhabiting different dis- 

 tricts of a single country ; such differences being most intensified 

 when a country presents great variation in its physical features. 

 An excellent instance of this is afforded by South America, where 

 there are the open grassy plains of the Argentine, the dense tropi- 

 cal forests of Paraguay and Brazil, and the snow-clad heights of 

 the Andes. In the former tract the traveller will meet with the 

 peculiar rodents known as viscachas, the Patagonian cavy, a species 

 of deer, numerous armadillos, and the rhea (miscalled the American 

 ostrich). In the Brazilian forests, on the other hand, he will find 

 monkeys, marmosets, tapirs, tree-porcupines, sloths, and anteaters, 

 together with certain armadillos which are for the most part speci- 

 fically or generically distinct from those of the pampas. If, on 

 the other hand, he ascend high on the Andes, he will leave 

 behind the animals of the forest, to be confronted with chinchillas, 

 guanacos and vicunas. Different, however, as are the animals of 

 these various districts, yet an acquaintance with their zoological 

 affinities will prove that many of them belong to closely allied 

 groups, some of which are met with in no other parts of the world. 

 This will serve to show that they belong to what is known as one 

 zoological province or region, and that the differences between the 

 faunas of different districts of that province are due to the physical 

 variations between its component districts. 



Perhaps this point may be still better illustrated by the cases 

 where the same species of animal is restricted to different districts 

 of one country or continent. For instance, the common squirrel 

 is only found in the wooded districts of Europe, and is entirely 

 absent from open plains. The chamois, again, is only met with 

 in the isolated mountain ranges of the Pyrenees, the Alps, and the 

 Caucasus ; while the Siberian ibex of the Altai reappears in Tibet 

 and the Himalaya, but is wanting in the intervening tracts. In 

 these instances Europe would be spoken of as the distributional 



