722 THE EOCENE FAUNA. 



a prolongation outwards and forwards. Intermediate tubercle not distinct. 

 External, anterior, and posterior cingula. The third superior premolar 

 diflfers much in form from that of 3£iodcenus tiirgidiis, although having the 

 same elemental parts. The external portion is extended anteroposteriorly, 

 and has a cutting edge, of which the posterior tubercle forms a lobe. The 

 internal tubercle is quite small, much less than in M. turgidus. A posterior 

 and a weak external cingulum. 



In the inferior true molars the external tubercles wear into crescents. 

 The crowns increase in size posteriorly. The fifth tubercle of the last 

 molar is rather small, but is well distinguished from the other cusps. The 

 internal median cusp is small, the external median large. The premolars 

 are not so much larger than the true molars in this as in the typical species 

 of the genus. The second and third are more elongate on the base than 

 the fourth. The latter is also less compressed than those that precede it. 

 It has a short wide heel, and a small anterior basal tubercle. In the second 

 and third premolars the posterior edge of the principal cusp is sharp, and 

 descends gradually to the posterior base of the crown. Both have small 

 acute anterior basal tubercles. The first inferior premolar is one-rooted, 

 and has a simple crown directed somewhat forwards. It is separated from 

 the second by a short space. The teeth anterior to this point are lost. 



Measurements. 



M. 

 Length posterior four superior molars .0182 



Diameters Pm.iv J ''"*'''^''P°«'<'"°'" ^^^ 



transverse .0042 



anteroposterior 0043 



transverse 0060 



Diameters M.iii^'''^t^''°P°«**'"°' 0''40 



( transverse OOCO 



Length of inferior molars 0330 



Length of inferior premolars 0192 



Length of inferior Pm. iii 005.1 



Length of inferior Pm. iv 0045 



Diameters M.i^ ''"*<='■"?•'"*"■'''•■ "^^^ 



< transverse 0033 



Diameters M. iii ^^°*'"'°P°"*^"°' 0"^2 



< transverse 0040 



Depth of ramus at Pm. i.. 0047 



Depth of ramus at M. ii 0090 



