484 SINCLAIR— ENTELODONTS FROM THE 



anterior and posterior cingula, extending round on the outer face of 

 the tooth. The enamel is rugose and there are numerous minor 

 vertical ridges and grooves above the base of the tooth, both ex- 

 ternally and internally. 



P4 is about as high as p2, 46^2 mm. anteroposteriorly by 27 

 wide, with a prominent heel supporting minor cuspules and mod- 

 erate cingulum continuous except for a gap internally. The enamel 

 is rugose and there is a single posterior mammillated cutting edge 

 at the outer angle of the crown. 



The molar crowns, although worn externally, show that the 

 cusps of the trigonids are much higher than the talonids. The 

 enamel is rugose where not smoothed by wear. Mi is of equal 

 width, front and rear; the other molars are wider in front. All 

 have medium-sized hypoconulids, rugose masses not well differenti- 

 ated from the posterior cingulum above which they rise. In all, the 

 entoconid is smaller than the hypoconid. Anterior and posterior 

 cingula are present, with strong remnants of external cingula at the 

 ends of the transverse valleys. In mj the tip of the anterointernal 

 cusp is bifid. The other molars are too worn to show it, if present. 

 The dimensions of the molars are as follows : 



Mf, anteroposteriorly 40.5 mm. 



MF, transversely 27.5 



Mi", anteroposteriorly 43.5 



M2, transversely (anteriorly) 36 



M3, anteroposteriorly 47 



M3, transversely (anteriorly) 36 



The lower jaw (Figs. 14, 15) has been shortened by crushing, 

 which has jammed together the molars and posterior premolars and 

 bent outward the posterior halves of the rami. The chin is at right 

 angles to the lower margin of the rami, is wide above, narrow below, 

 almost flat in front, and the anterior mental processes which are 

 small and extend but little below its lower border merely accentuate 

 slightly the corners of the great quadrangular chin (Fig. 14). The 

 symphyseal region is very wide (190 mm. across the swollen bases 

 of the canines, with a length of 144 mm. from the incisor border to 

 the junction of the rami), so wide that the canine and pi are well 



