SUBORDER D 



ARTIODACTYLA 



181 



the exception of the last) of most genera with three cusps in either half of the tooth, 



inner cusps y -shaped, the others frequently conical. Inferior molars with conical inner 



cusps and V-shaped exterior cusps. Anterior 



inner cusps double. Anterior part of the 



inferior molars a little higher than the 



posterior. Premolars simple and elongated. 



Manus and pes tetradactyl. Lateral meta- 



podials shorter and slender. Skull similar 



to that of Tragidus. 



This family differs from all artio- 

 dactyls in the presence of six cusps in 



m^ 771^ nv, jp^ p.^ fv^ jv, c i, 4 v, 



Diplobune quercyiFUhol. Oligocene (Bohnerz) ; Eselsberg, Ulm. J, Cheek teeth of upper jaw. i3, C, Right 

 ramus of lower jaw, and dentition from upper aspect. %. j)^ Pore foot. E, Hind foot. 1/4. 



the upper molars, notwithstanding the resemblance to the primitive Siiidae, 

 Anthracotheriidae and Tragulidae. 



The Dichohimidae begin in Europe in the oldest Eocene and become extinct 

 in the Middle Oligocene. In North America they are confined to the Eocene. 



Dichohune (Microchoerus Wood, Hyopotamus Riitimeyer) (Fig. 248). Superior 

 series of the teeth closed. Superior molars with mesostyle, all cusps nearly 

 conical, premolars simple. Upper Eocene, D. leporinum Cuvier. 



Mouillacitherium Filhol (Necrolemur, Hyopsodus Eiitimeyer). AVithout pro- 

 toconules in the superior molars. Eocene. M. cartieri Eiitimeyer. 



Meniscodon Eiitimeyer (Phenacodus, Protogonia Eiitimeyer). Of moderate 

 size. Superior molars without mesostyle and with large parastyle. Middle 

 Eocene ; Egerkingen. M. europaeus Eiitimeyer. 



