MERYCOCHCERUS 



155 



zygoma. The basicranial axis is not steep. The palate is wide and somewhat uparched, and the 

 palatonarial border is much nearer to a line along the front of the glenoid surfaces than it is to the 

 last molars. The glenoid surfaces are gently convex. The postglenoid process is transversely 

 short, anteroposterior^ narrow, and not deep. The paroccipital process is long and slender, extend- 

 ing nearly straight downward but somewhat outward as well. Index: 0.78. 



Mandible: The symphysis is long and strong and has a prominent tuberosity at the infero- 

 posterior termination. The symphysiodental angle is 43°. The chin has an approximately straight 

 line in contour. The coronoid process is blunt and scarcely higher than the condyle. The sigmoid 

 notch is very shallow and is wide open, while the condyle is thick, wide, and heavy. 



A.M.I4Z42 



Fig. 113. — Merycochcerus magnus Loomis. Skull, and superior and inferior dentition. HT. Cat. No. 14242 (skull), and 

 PT. Cat. No. 14238 (dentition), A.M.N.H. 2/5 nat. size. (After Loomis, 1924.) 



Foramina: The infraorbitals are above the anterior part of M 2 . The supraorbitals lie approxi- 

 mately 45 mm. apart and nearly on a line across the middle of the orbits. The posterior palatine 

 foramina are nearly opposite the middle of M 2 . 



Dentition: All the teeth are crowded, with the lower canine and the premolars overlapping. 

 The chief differences between this species and M. proprius, as shown in the tooth patterns, are that 

 the parastyles and mesostyles of the molars of the former are not rolled forward, Pi is more lenticu- 

 lar, P 2 is relatively longer, and the metastylid of M 3 is in line with the tooth row. The superior 

 molar-premolar index is 0.76, while that of the inferior is 0.70. 



Skeleton: The limb bones show the same characters as those of M. proprius, that is, they are 

 heavy and stocky, with very short and stubby feet. The phalanges exhibit the extreme in shortening. 



Discussion: Peterson (1906, pp. 63-64) figured and briefly described a skull and a pair of 

 lower jaws, both well preserved and with teeth, which he referred to Merycochoerus proprius with a 

 query. The skull is Cat. No. 1399 CM. and the mandible Cat. No. 1306 CM. They were not 



