GEOLOGICAL SUCCESSION 7 . O 



of great size and adapted to every kind of life and food. The 

 latter part of this period, sometimes called the Quaternary, 

 : extends till the present day, and during it the mammals 

 still continue to be the prominent backboned animals ; but 

 one of them, man, has become by far the most important 

 inhabitant of the world, and, instead of merely being slowly 

 fitted to new conditions of life, now to a large extent controls 

 (the conditions, and changes them to suit his own convenience. 

 At the present day the different main sub-divisions of the 

 Mammalia are, as a rule, very distinctly marked off from one 



Fig. 1. 



Upper and lower dentition of pig, showing the presence of the full set of 

 44 teeth and the low-crowned bunodont cheek-teeth adapted for a soft, 

 mainly vegetable diet, c., canine ; '., incisors; m., molars; pm., pre- 

 molars. 



another. For instance, the Carnivora (flesh-eaters, e. g. } tiger, 

 bear) are now widely different from the Ungulata (hoofed- 

 animals, e. y. y horse and ox), each of these groups being fitted 

 for some special manner of life, and particularly for living on 

 some special kind of food. Thus, the principal character of 

 most of the Carnivora is the possession of sharp claws and 

 teeth for killing and devouring other animals; while, on the 

 other hand, the vegetarian Ungulata have teeth fitted for 



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