120 



the merycqidodontim: 



Specific Characters: The skull length ranges from that of P. carrikeri to that of P. hol- 

 landi, but the width is narrower than either. The maximum expansion of the zygomatic arches lies 

 just in advance of the glenoid surface. The malar is medium in depth, and the convexity from the 

 anterior zygomatic pedicle is not especially prominent on the side of the long narrow muzzle. The 

 squamous portion of the zygoma is short and slender, extending forward no farther than a point 

 below the postorbital bar and rising aft to the crest, which is above the posterior of the glenoid 

 surface and about on a level with the middle of the orbit. The nasal bones are long and slender, 

 extending from a plane through the canines to their posteriorly pointed terminations in a plane 

 through the anterior third of the orbits. The -pars facialis of the lacrimal bone is oblong in shape and 

 bears a deep and moderately large fossa. The unreduced flat frontals rise very gently aft and have 

 but a slight decurvature above the orbits. The latter are situated well up on the side of the skull, 

 are nearly round in outline, and are medium-sized. The temporal ridges unite above the glenoid 



iil3i$wv 



A.M.I2964 



Fig. 79. — Promerycochoerus gregoryi Loomis. Skull, and crown view of superior and inferior dentition. HT. Cat. No. 



12964 A.M.N.H. 2/5 nat. size. (After Loomis, 1924.) 



surfaces to form a thin, high sagittal crest, less 

 occipital crest is well produced aft, and the wings 

 not much elongated and has no prominent lateral 

 directed upward and somewhat backward. The 

 the palatonarial border lies aft of the last molars, 

 notched. The glenoid articular surface is of the 

 sagittal plane. The postglenoid process is relati 

 teriorly and has a vertical external border. The 

 pressed, and extend downward as far as do the 

 slightly in advance of the postglenoid processes b 

 paroccipital processes are slender and compressed, 

 contact the bulke but are well separated from the 



than a fourth of the skull length. The supra- 



are not widespread. The brain case is narrow but 



ridge. The external auditory meatus is large and 



basicranial axis is steep. The palate is narrow, and 



The posterior palatal border is but very slightly 



normal proportions and somewhat oblique to the 



vely wide transversely and compressed anteropos- 



bullas are of moderate size, are transversely com- 



postglenoid processes. The bullae extend only 



ut considerably aft of their posterior bases. The 



with the greater diameter anteroposterior. They 



postglenoid processes. Index: 0.47 (holotype). 



Mandible: The symphysiodental angle is 45°, and the chin profile is straight, except for a 

 slight eversion of the incisor parapet. The mental tubercle is small. The inferior border of the 

 horizontal ramus is nearly straight, and the angle is not especially prominent. 



