55 



The basal ridge at the anterior part of the tooth is very 

 strongly marked. 



Upper Jaw. The molars increase in size from first to last 

 with considerable regularity. The premolars are small, and, 

 as in Hyrachyiis, have one single internal cone, which is 

 joined by transverse ridges from the two outer cusps ; the 

 anterior accessory tubercle is well developed. The first 

 molar is considerably larger than the last premolar ; it is 

 much worn, and does not show anything more than that 

 there are two internal cones. The anterior conical buttress 

 is very largely developed throughout the true molar series. 

 The second and third molars resemble almost precisely the 

 corresponding teeth of Hyrac/iyus. Their shape, however, 

 is more nearly square than is usual in that genus. 



Measu rente n ts. 



UPPER JAW. 



M. 



Length of true molar series 036 



Length of last molar -0135 



Width of last molar -015 



Length of second molar -012 



Breadth of second molar -015 



Length of first molar -0105 



Breadth of first molar -012 



Length of last premolar . -009 



Breadth of last premolar -on 



Length of third premolar -008 



Breadth of third premolar -009 



LOWER JAW. 



Length of true molar series 042 



Length of last molar -018 



Breadth of last molar -009 



Length of second molar -013 



Breadth of second molar 008 



Length of first molar ... -012 



Breadth of first molar . . 008 



Length of third premolar -008 



Breadth of third premolar -005 



Diameter of canine at base -006 



Length of symphysis (about) -027 



Found at Henry's Fork. 



