48 ON THE REVOLUTIONS OF 



Certainly naturalists have not yet traversed every continent, and do 

 not even know all the quadrupeds which inhabit the countries over 

 which they have travelled. New species of this class are from time to 

 time discovered ; and those who have not attentively examined all the 

 circumstances of these discoveries, might believe also that the unknown 

 quadrupeds whose bones are found in our layers have remained con- 

 cealed to the present time in some islands not yet discovered, or in 

 some of the vast deserts which occupy the middle of Asia, Africa, the 

 two Americas, and New Holland. 



Little probability of finding new Species of great Quadrupeds. 



However, if we examine what species of quadrupeds have been re- 

 cently found, and in what circumstances they have been discovered, 

 we shall see that there is but little hope of ever finding those that we 

 have only seen as fossils. 



Islands of moderate extent, situated at a distance from extensive 

 continents have very few quadrupeds, and those very small ; when 

 they have large ones, it is because they have been brought from else- 

 where. Bougainville and Cook found only dogs in the South Sea 

 Islands ; and the largest species of the West-India Islands was the 

 agouti. 



In fact, large territories such as Asia, Africa, the two Americas, and 

 New Holland, have large quadrupeds, and generally species peculiar 

 to each of them ; so that wherever it has been found that the situa- 

 tion of these lands has kept them isolated from the rest of the world, 

 a class of quadrupeds has been there found entirely different from any 

 elsewhere existing. Thus, when the Spaniards first overran South 

 America, they did not find one of the quadrupeds common to Europe, 

 Asia, or Africa. The puma, the jaguar, the tapir, the cabiai, the lama, 

 the vicuna, sloths, armadilloes, opossums, and all the species of mon- 

 keys, were to them entirely strange, and beings of which they had no 

 idea. The same phenomenon occurred in our time, when the first 

 survey of the coast of New Holland and the adjacent islands took 

 place. The different kangaroos, phascolomys, dasyurus, and perameles, 

 the flying phalangers, the ornithorynchi, and echidnas, have been found 

 to astonish naturalists by their strange conformations, which broke 

 through all rules and overthrew all systems. 



If then there remained any extensive continent to discover, we 

 might hope to find new species, amongst which, some might be found 

 more or less resembling those of which the bowels of the earth have 

 presented us with the relics ; but it is sufficient to cast a glance over 

 the mass of the world, and see the numerous directions in which navi- 



