E. L. Troxell — Entelodonts in Marsh Collection, 443 



character is a sexual variation (which might apply also 

 to the jugal processes), or the supposition that they were 

 lost in Sinclair's specimen. 



The form of the dependent process from the jugal, 

 large, hanging directly in line with the orbit and swinging 

 strongly backward, and the close arrangement of the 

 teeth distinguish this specimen from all others, but bring 

 it nearest to Megachoerus zygomaticus (figs. 15, 16). 

 The end of the dependent lobe is much thickened and 

 widened ; anteriorly the edge is thin and is folded inward ; 

 this feature and the form of the slender anterior process 

 from the temporal resemble the corresponding parts of 

 A. crassum. 



The glenoid cavity is very narrow transversely and is 

 formed partly by the posterior process from the jugal. 

 The palate is well arched and the posterior narial opening 

 extends forward to a point even with M 2 . 



The upper rim of the orbit is exceptionally thick and 

 heavy but smooth. The frontals are smooth, though not 

 flat, and a fossa is seen just in front of the parietals as in 

 Dinohyus. Between the right frontal and the lachrymal 

 there is a deep round pit ; although the bottom is closed 

 now, it seems probable that there might have been a deep 

 wound, which afterward healed, received from the thrust 

 of an opponent's tusk or horn. 



The first incisors are very small, the third are large and 

 strong. The long canines are wide-spreading, slender 

 and unusually recurved. They are so long and so curved 

 that the points extend 50 mm. beyond the area of abrasion 

 and are practically unworn. 



A striking feature in this species, in both the upper and 

 the lower jaws, is the short diastemata. These, together 

 with the fact that the premolars are all double-rooted, 

 show the specimen to be very conservative in its evolution. 



P 1 is small and is situated postero-internal to the 

 canine. P 2 is somewhat larger, is functional, parallel- 

 sided and recurved; P 3 is large, 42x23 mm., has its sides 

 almost straight and had a roughened heel. P 4 is much 

 broader than long (32.5 X 29 mm.), has its posterior and 

 external sides straight, but anteriorly has the notch so 

 commonly seen outside of Megachoerus zygomaticus and 

 Entelodon magnus. 



M 1 has a long slope on its inner face, resembling M. lati- 

 dens (fig. 17), giving it the width of 38 mm. compared to 

 its length, 32 mm. This feature is found again in M 2 



