30 KANSAS UNIVERSITY QUARTERLY. 



rior parietal region is broad and transverse and nearly flat, the upper 

 orbital margins being as high as the intervening portion. The poste- 

 rior orbital process is more projecting. The temporal ridges meet 

 in a very obtuse angle, as much greater than a right angle as it is less 

 in Dicotyles. The transverse diameter of the brain cavity in front is 

 almost exactly the same as in the adult skull of D. toyquatus, indi- 

 cating a brain of relatively less capacity in the Platygonus. The 

 sagittal crest is longer in Platygonus, and the constriction in front of 

 the lateral wings of the occiput decidedly less; the tentorium seems 

 to be better developed. The ascending process of the squamosal, 

 over the external auditory meatus, is more nearly vertical, placed 

 nearer to the cranial wall, and with a more constricted and more 

 sinuous notch between it and the lateral occipital wings. The malar 

 is thicker, stouter and broader, and has the masseter ridge arching up 

 on its outer side to the base of the orbital process. Anteriorly, the 

 malar ridge is not continued on the side of the face, as is so conspic- 

 uously the case in the peccary, but ends in a convex surface above 

 the hind part of the infraorbital foramen. The side of the face is 

 thus much less deeply excavated and is broader than in Dicotyles. 

 The infraorbital foramen is situated a little further back and has two 

 small, deep fossae above it, the one a little in front, the other behind 

 it. 



In the lower jaw the condyles have a greater antero-posterior 

 diameter, being, on the inner side, almost as great as the transverse 

 diameter. The coronoid process is no stouter or higher, but is more 

 rounded, and is rather more inflected, with the fossa on the outer 

 side deeper and bounded by sharper and stouter ridges. The flange 

 at the angle is longer from before back, and the under margin of the 

 jaw is less concave in front of it. The inferior border of the body 

 of the jaw is straighter, and the depth below the teeth is relatively 

 less. The post- canine diastema, as in the upper jaw, is much longer, 

 the canines are more slender, not grooved on the sides, and relatively 

 not so long. The chin has a prominence in the middle, giving a 

 strongly convex and less receding profile. The incisors are much 

 smaller, and wholly lack, in all the specimens, the lateral one — there 

 being but two in the lower jaw. The projecting flange at the angle 

 of the jaw is turned outward in its anterior part, not inflected as in 

 Dicotyles. 



As a whole, the skull has the upper surface straightened, with a 

 gentle convexity over the nasal region. The orbits are situated fur- 

 ther back relatively, the chin is more rounded below, etc. 



