488 SINCLAIR— ENTELODONTS FROM THE 



Troxell have been largely obliterated by wear, but traces remain. 

 If there ever was a heel, it has been lost by abrasion. The anterior 

 notch in p4, absence of which was noted by Troxell, is but slightly 

 indicated, and the tooth is a little smaller in anteroposterior diameter 

 than in his specimen (28.5 mm. anteropost. by 34.5 trans, as compared 



Fig. 19. Megachcrrus sygomaticus Troxell. No. 11 156. Skull and lower 

 jaws as seen from above, about thirteen one-hundredths natural size. Drawn 

 from photograph and the specimen. 



with 31 by 34). M2 is slightly different in dimensions (42 ant.-post. 

 by 47 mm. trans, anteriorly as compared with 40 by 42.5 in the Yale 

 specimen). In all other respects, so far as I can judge, there is the 

 closest agreement, and I do not hesitate to identify our specimen as 

 M egachcsrus sygomaticus, perhaps an old male as inferred from the 

 thicker cheek flanges and signs of injury. 



