THE MIOCENE OF EUROPE, ASIA, AND NORTH AMERICA 247 



In the coastal rivers there swarmed at this time sirenians (Metaxytherium) , 

 also originally from Africa. From Asia there appeared the first of the 

 antelopes {Prutragocerus). From Asia or from eastern Europe there ap- 

 peared two entirely new phyla of rhinoceroses hitherto unrepresented in 

 western Europe and unknown, namely, the excessively bulky and short- 

 limhed teleocerine and the slender-limbed dicerorhine forms, the former 

 destined to flourish and die out in Europe during the Miocene period, the 

 latter destined to survive in the existing and rather primitive two-horned 

 rhinoceros {Dicer orkinus) of Sumatra. In this phylum, to which we shall 

 make frequent reference, the grinders are short, the horns are small and 

 placed in tandem on the frontals and nasals. Probably from Asia also, 

 there entered Europe the first of the higher primates, or anthropoid apes 

 (Pliopitheciis) . From Asia also entered the first horned cervuline deer, or 

 muntjacs. Of this Lower Miocene invading fauna the mastodons and 

 teleocerine rhinoceroses alone reached North America. Distinctive also is 

 the reappearance in Europe of horses in the Anchitherium stage either of 

 north Asiatic or of North American origin. 



The most characteristic of the larger forms of hoofed mammals which 

 by the Middle Miocene become common to the New and Old Worlds are 

 the following: 



Primitive mastodons with four large tusks (new). 



Chalicotheres, forest-living. 



Teleocerine, or short-footed rhinoceroses, single-horned (new). 



Aceratheres, large, hornless, tetradactyl rhinoceroses. 



Tapirs. 



Anchitheres. 



Mingled with the new and strange invaders, some of the descendants 

 of the great groups of Oligocene mammals continue their evolution both 

 in Europe and North America, but certain 

 of the most characteristic Oligocene types 

 have passed their flourishing period and 

 are in their last stages. These passing- 

 forms are the diceratheres, the anthra- 

 cotheres, the enteledonts, which die out 

 either at the close of the Oligocene or 

 very early in the Miocene. Of all the 

 mammals with bunoselenodont grinding 

 teeth (see Fig. 122) the chalicotheres , ^/,°- 125- — Restoration of the head 



, of Dmotherium, Miocene of turope 



alone survive and are among the most (X^\). After Gregory, 

 highly distinctive forms of the Miocene. 



During the Lower and Middle IVIiocene the greater diversity of the 

 American life as observed in the Oligocene continues. This is because we 

 know the fauna of the drier regions in North America at this period, while 



