324 PALAEONTOLOGY. 



canines -f:|, molars f :f , the latter marked with five crescents, 

 formed by concealed plates of enamel. (Fig. 236.) We know 

 one extinct genus, Hippotherium, from the miocene stage at 

 Eppelsheim. Fossil species of the genus Equus (fig. 226) 

 have been found in the sub-apennine stage of Europe, Asia, 

 and the Pampas, and in the caverns of South America. 

 The horse was unknown in that continent before its con- 

 quest by the Spaniards. 



2nd Family. The OEDINAEY PACHYDEEMATA is com- 

 posed of a group of extinct, and a group of existing genera. 

 The extinct are Choeropotamus, which has molars -:. Two 

 species have been found in the eocene stage of Paris, and 

 of the Isle of Wight ; and three others in the falunian 

 stage of France and Asia. 



Hyracotherium, so named in consequence of its structural 

 affinities in the size of the orbits, &c., with the Hyraoc, was 

 found in the London clay and the lacustrine eocene sand 

 at Kyson. 



Anthracofherium ; molars ^ allied to the hogs by the 

 molars of the lower jaw, and to the Anoploiherium by the 

 molars of the upper jaw ; also to the tapirs, by the form of 

 its canine teeth. Its name is derived from the locality where 

 it was first found among the anthracite of Cadibona (near 

 Savone, Piedmont) ; we know five species three are eocene, 

 and two belong to the miocene stage of Eppelsheim and 

 Sansan. 



Lophiodon is allied to the tapirs ; its name is derived from 

 the pointed eminences on its molar teeth. This genus is 

 characteristic of the miocene stage: eleven species have been 

 obtained in France and Germany. Some of the species are 



FIG. 227. 



found in the eocene, but the great majority lived in the 

 middle ages of the tertiary period. 



