THE PLIOCENE OF EUROPE, ASIA, AND NORTH AMERICA 315 



enormously long straight tusks. The especially significant change is that 

 the lower tusks are sniall(>r and that the lower jaws are short or 'breviros- 

 tral.' As in North America these mastodons include two series provided 

 respectively with three- and four-crested intermediate molars; of the for- 

 mer 'trilophodont' type is the M. horsoni, of the latter ' tetralophodont ' 

 type is the M. arvernensis. It is noteworthy that these two species persist 



Fig. 153. 



Outline restoration of Mastodon arvernensis, the great Pliocene short-jawed 

 mastodon of Europe (X ^V). 



throughout the Pliocene and that M. horsoni is the more closely relat-ed to 

 the American Pleistocene mastodon {M. americanus), which is also tri- 

 lophodont. 



The tridactyl horse of the period (Hipparion crassum) is, like its prede- 

 cessors, a t^T^ical grazing form. There is some recent evidence that this 

 animal persists throughout the Pliocene.^ 



The Oriental and Indo-Malayan element of the fauna of Roussillon and 

 Montpellier includes the two kinds of monkeys, namely, Dolichopithecus 

 and Semnopithecus, which are related respectively to the macaques^ and 

 the langurs, both of Asia. We also find that the bear of the period (Ursus 

 minutus) is a small member of the Helardos group, ancestral to the arboreal 

 Malayan sun-bear. Similarly the tapir (T. arvernensis) is almost identical 

 wdth the recent Malayan tapir {T. indicus) now distributed in Sumatra and 

 Borneo. The two-horned rhinoceros {Dicerorhinus leptorhinus) receives its 

 specific name from the slender character of its nasal bones, which are without 

 the supporting septum characteristic of the Upper Pliocene species; it also 

 belongs in the same sub-family (see p. 272) with the existing rhinoceros of 

 Sumatra. The civet (Viverra) may be classed with the Indo-Malayan 

 group. Altogether Deperet finds ten species of animals in this fauna which 

 are of existing Indo-Malayan affinity. 



The existing African and west Asiatic element is represented by the 

 hy?enas (H. arvernensis), ancestral to the striped hyaena of north Africa and 

 southern Asia, by the caracals {Lynx brevirostris) allied to the southern or 



' Stehlin, Une Faune ;\ Hipparion i Perrier. Bull. Sac. Geol. France, Ser. 4, Vol. IV, 1904, 

 p. 44.3. 



- The Barbary ape (Macacus inuus) of Northern Africa and Gibraltar is an isolated sur- 

 vivor of these widespread Pliocene macaques. 



