196 EASTERN ARCTOG^A. [CHAP. 



Chalicomys, Cricetus, and Myoxus are survivors from the Oligocene; 

 but porcupines (Hystrix] are new comers. Picas of the existing 

 genus Lagomys are likewise to the fore ; and it is a question 

 whether those distinguished by the name of Myolagus might not 

 be included under the same title. 



A marked approximation to the modern type is likewise the 

 characteristic feature of the ungulates of the European Miocene ; 

 although in this group living genera still remain in the minority. 

 The pigs (Sutda) include, for instance, the genus Hyotherium, in 

 which the molar teeth are tuberculated and of the general type of 

 those of some of the living members of the family ; and also the 

 more aberrant Listriodon, characterised by the presence of a pair 

 of transverse ridges on each of the teeth of the same series. A 

 species of the existing West African genus Dorcatherium alone 

 represents the chevrotains (Tragulidte) ; while we have forerunners 

 of the deer (Cervidce) in the extinct Pal&omeryx and Dicroceros, 

 both characterised by the simple structure of their antlers ; and 

 Protragoceros a generalised type of antelope marks the first 

 appearance of the hollow-horned ruminants (Bovida], which now 

 form such a numerous and characteristic group in the fauna of 

 Eastern Arctogaea. Perissodactyle ungulates are less numerous. 

 Anchitheriiim, to some of whose distinctive characters allusion has 

 been made above, constitutes the representative of the equine line 

 at this stage ; and tapirs and rhinoceroses belonging to the 

 existing genera were likewise common. Some of the latter were, 

 however, still hornless, and in none was more than a single horn 

 developed. The aberrant ChalicotheriidcB^ forming the last family 

 of this section of the order, and characterised by the extraordinary 

 resemblance presented by their claws and toes to those of eden- 

 tates, are here represented by the gigantic Macrotherium. Finally 

 the Miocene is notable as being the stage at which proboscideans 

 first made their appearance on the scene in Europe. In this group 

 we have species of Mastodon, which, as already explained, includes 

 the ancestors of the modern elephants ; and likewise one of the 

 more aberrant Dinotherium. 



Compared with the Oligocene, the loss of so many antiquated 

 types, coupled with the appearance of proboscideans and man-like 

 apes, and the general modern facies of all the mammals of the: 



