366 E.-L. Troxell — Entelodonts in Marsh Collection. 



Like the skull, the lower jaws indicate a slender animal. 

 The premolar teeth are thin transversely, though ex- 

 tended antero-posteriorly. The anterior mental tubercle 

 is entirely behind the canine and has its backward edge 

 near the beginning of the symphysis. It is small and com- 

 pressed parallel with the chin border, and extends only 

 a little way from the ramus ; the chin is rounded in front 

 and the small tubercle under the anterior root of P 4 has a 

 rather sharp point which curves almost imperceptibly up- 

 ward. 



The large mental foramen lies under the anterior root 

 of P 1 and just above the mental tubercle ; another lies be- 

 low the middle of P 2 and between them are two small fora- 

 mina practically on the same line. The coronoid process 

 is narrow transversely, but forms a rather large angle 

 antero-posteriorly. It is only slightly out of the line of 

 the teeth. The nearness of the masseteric fossa makes 

 the process more slender. 



The lower canine is shorter but not more slender than 

 that above; it curves upward, then slightly inward and 

 backward. The enamel covers the teeth low. 



P-t is separated from d 7.5 mm. and from P 2 6 mm. It 

 is large relative to much larger species, stands high on its 

 two roots, slopes slightly backward, and is set straight in 

 the ramus. P 2 is very large, though compressed, is long 

 and narrow and stands high on its roots. It is consider- 

 ably recurved and has cutting edges and cingula anterior 

 and posterior. P 3 is about 3 mm. from P 4 ; the crown 

 itself is high, narrow, and long antero-posteriorly. The 

 slender point is recurved and from it there extend ridges 

 down to the cingula both front and back. There is no 

 shelf, but a wide roughened area slopes to the posterior 

 side. Its diameter antero-posteriorly is 29 mm. and 

 transversely 12.3 mm. P 4 has an antero-posterior diam- 

 eter of 28.8 mm. and a transverse one of 12.8 mm. It is 

 also long and narrow, but not high. It is especially wide 

 posteriorly where the heel forms a broad shelf. In the 

 middle and anterior it is narrow. The protocone stands 

 almost erect and the roots are not large. 



On one of the first lower molars, the enamel is com- 

 pletely worn away, on the other, half of the tooth is 

 sheared off on the outer side. This wearing away ex- 

 teriorly gives a valuable hint as to the motion of the jaws 

 and bears out the general observation that the lower 

 molars grind inward in the process of mastication. 



