MAMMALIA. 



31 



Nothing is known of the direct ancestors of the American Table-case 

 peccaries (Dicotylidae). Iveniains of the typical Dicotylcs 7. 



from the caverns of IJrazil are exhihited in Table-case 7. 



Among earlier animals allied to the pigs, the large 

 Elotherium, from the Oligocene and ]\liocene of Europe and 

 North America, is especially remarkable. As shown l)y 

 remains in Pier-case 13, it had only two toes, with the 

 merest rudiment of the outer toes. Listriodon, from the 

 ]\Iiocene of Europe and India, has a skull like a pig, l)ut 

 grinding teeth with cross-ridges like those of a tapir (Tal de- 

 case 7). Hyotlicrlnm is provided with large upper canine 

 teeth (Table-case 7). Ckceropotamus is represented in the 

 same Case by jaws and teeth from the Upper Eocene of the 

 Isle of Wight and of France. 



In these early allies of the pigs the molar teeth are • 

 nearly square and l)ear regularly arranged cusps or ridges. 

 In some of them the tooth-cusps tend to Itectmie crescent- 

 shaped, and lience make an approaeli to the trenchant 

 cresceutic (" selenodont ") cusps of the teeth in the higher 

 Artiodactyla which chew the cud ("ruminants"). One 

 family, that of the Anthracotheriidse, witli niohir teeth in 

 this condition, arose in tlie U])])er 

 Eocene and was re})resented during 

 the Oligocene period by nuiny moder- 

 ately large species, which ranged 

 over the greater part of tlie northern 

 hemisphere. These were stoutly- 

 built animals, some probably much 

 resembling the ])igs in outward 

 aspect, others nu)re nearly allied to 

 the hippopotannis. All of them have 

 four or live separate toes. AnthrK- 

 cotheriwiii ("coal beast") itstdf, which 

 is well represented in Talile-case 7, 

 is so called hoxn the circumstance 

 that its remains were first discovered 

 in the lignite or lirown-coal of Savoy. 

 It is chieHy Ibund in tlie (Oligocene 

 of Europe, but also seems to occur 



in the c(jrres)»onding deposits in Dakota, U.S.A., while a 

 few teetli have lieen' assigned to it from the Lower Pliocene 

 Siwalik Formation of liulia. Tlie European A. magnum must 

 have been as large as a rhinoceros. Ancofhis or Hjiopotamus 

 is another genus, of which the delachcd teelh (Fig. 20) are 



Fig. 20.— Grinding surface 

 of third right upper true 

 molar tooth of Ancodus 

 [Hijopota niHfi] bou imis, 

 from the Oligocene of 

 Hempstead, Isle of Wight; 

 nat. size. (Table-case 7.) 



