Peterson : Miocene Beds of Nebraska and Wyoming. 39 



over the back part of I*. P± is similar to that in Merychyus elegans, 

 and as in that species, the protocone is shifted partly, by wear, to the 

 anterior portion of the crown. The second premolar is very convex 

 externally ; the base is slightly corrugated, but there is no true cingu- 

 lum. Except the usual small excavation at the antero-internal base, 

 the tooth is so much worn that all the characters of the grinding face 

 are entirely lost. The external face of P^ is slightly concave antero- 



Fig. 8. Palate view of skull of Merychyus harrisonensis. \ nat. size. Type. 

 No. 1 341. 



posteriorly, and there is a decided cingulum ; the tooth is much worn. 

 PA has a strong cingulum internally, while externally there is no cin- 

 gulum The external and internal cingula on M^ are only faintly 

 indicated. M* has a long postero-external heel ; the tooth is longer 



than broad. 



Measurements. 



mm. 



Greatest length of the skull * 9 



Distance from premaxillary to postorbital process of frontal 107 



Distance from postorbital process of frontal to the inion »£ 



Distance from the premaxillary to the occipital condyles 17° 



Length of the alveolar border of the maxillary 9 



Distance from posterior end of alveolar border to occipital condyle 82 



Greatest transverse diameter of the brain cavity 54 



Transverse diameter of frontals between orbits /° 



Transverse diameter of occipital condyles ^5 



Vertical diameter of occipital condyles 



Antero-posterior diameter of tympanic bulla -•> 



Transverse diameter of tympanic bulla 



