PALEONTOLOGY. 



which the anterior are compressed. The posterior molars in 

 the upper jaw have square crowns, and those of the lower 

 jaw have double crescents. The extremities had two toes 

 developed like Ruminants ; some species had, besides, rudi- 

 mentary toes: the metacarpal and metatarsal bones re- 

 mained separate, and did not form a single canon bone as in 

 ruminants. Of the three species known, two, of the size of 

 a hog, and of an ass, are from the lacustrine eocene stage of 

 Montmartre and the Isle of Wight. The third is from the 

 sub-apennine of Asia. The other extinct genera, Potamo- 

 hippus, Charotherium, Elasmotherium, are from the newer 

 tertiary or sub-apennine stage. Hyotherium, Macrauckenia, 

 Chalicotherium, are from the miocene stage. 



Zipkodon and Adapis are from the lacustrine eocene stage, 

 and Toxodon is from the newer tertiary of the Pampas of 

 South America. 



TIG. 232. Hippopotamus amphibius. 



Fossil species of Sus and Tapirusare found in the miocene 

 si age of Eppelsheim, and Dicotyles in the caverns of Brazil. 



