DISTRIBUTION. 299 



the Reindeer, the South American Antelopes, and the North-American 

 Buffalo, the Seals, Whales, and Bats, but more especially the 

 Lemmings, which migrate in enormous herds from the northern 

 mountains southwards to the plains, are stopped by no obstacles on 

 their journey, and even cross rivers and arms of the sea. 



Th 2 intellectual faculties are more highly developed than in any 

 othei class of animals. The Mammalia possess the faculty of 

 discrimination and memory; they form ideas, judgments, and 

 conclusions; they exhibit affection and love to their benefactors, 

 dislike, hate, and anger to their enemies; each individual has a 

 definite character. Further, the intellectual faculties of Mammals 

 are capable of being developed and improved, but to a relatively 

 small extent on account of the absence of articulate speech. The 

 more docile and intelligent of the Mammalia have been chosen 

 by man as domestic animals, and in this capacity have played 

 an important and indispensable part in the history of civilisa- 

 tion (Dog, Horse). Instinct, however, always occupies an important 

 place in the life of Mammals. It leads many of them to construct 

 spacious passages and ingenious nests above or below the earth, in 

 which they rest and bring up their offspring. Almost all Mammals 

 make special places for their brood, which they often line with soft 

 materials ; some even construct true nests, like those of birds, of grass 

 and stalks on the earth. Many of those which inhabit subterranean 

 holes and passages store up winter-provisions, which they consume in 

 the sterile season, sometimes only in autumn and spring (winter- 

 sleepors.) 



Geographical distribution. Some orders, as the Rodents and 

 Bats, are represented in all parts of the world. Of the Cetacea 

 and Pinnipedia most species belong to the Polar regions. In 

 general, the Old and New Worlds have each their own fauna. 

 The mammalian fauna of Australia consists almost exclusively of 

 Marsupials. The oldest fossil remains (lower jaw) of Mammals are 

 found in the Trias (Keuper Sandstone and Oolite, Stonesfield 

 slate) and are probably Marsupial. But it is not until the tertiary 

 period that the mammalian fauna presents a rich development. 



