EPORKODON 



85 



striction. The zygomata are not wide, although robust below the orbits, and the maximum expan- 

 sion is in advance of the glenoid surface. The nasal bones are moderately narrow and posteriorly 

 truncated, and extend forward to a point above the incisive border. The pars facialis of the lacrimal 

 bone is mediumly large, and the fossa is small but deep. The frontals are gently convex, except for 

 a narrow median concavity in front of the supraorbital foramina. The orbits are large, looking 

 mainly sidewise. The temporal ridges unite at a point about on a line above the bases of the paroc- 

 cipital processes. This produces a short, low sagittal crest, not more than a fifth of the length of 

 the skull. Most of the supraoccipital crest is broken away in both type specimens, but the remainder 

 indicates a moderate production aft, with the wings mediumly expanded. The brain case is well 

 developed and has a slight convexity along the parietosquamosal suture. The palate is narrow and 

 slightly vaulted, and the V-shaped palatonarial border lies well beyond the last molars. The basi- 

 cranial axis is steeper than that of many of the species. The bullse are broken away, but the basal 

 outline shows that they were large and triangular in section, with the anterior portion extending as 



12425 , TYPE 

 Y. P. M. 



Fig. 44. — Eporeodon parvus Thorpe. Skull and jaw. HT. Cat. No. 12425 Y.P.M. 1/2 nat. size. (After Thorpe, 1921.) 



/2J-2S , TYPE 

 Y. P. M. 



Fie. 45. — Eporeodon parvus Thorpe. Left half, superior view of skull. HT. Cat. No. 12425 Y.P.M. 1/2 nat. size. 



(After Thorpe, 1921.) 



far forward as the middle of the glenoid surface. The latter is very gently convex, while the post- 

 glenoid process is small and anteroposteriorly compressed. The paroccipital process is robust and 

 extends outward as well as downward. Index: 0.52. 



Mandible: The symphysiodental angle is about 50°, and the profile of the chin is very slightly 

 concave. The mental tubercle is very small. The angle is large, and the ascending ramus is deep. 

 The thin coronoid process rises but slightly above the condyle, which is transversely wide and inset 

 from the posterior mandibular margin. The sigmoid notch is small, and the masseteric fossa is 

 moderately large. 



Foramina: The infraorbitals lie above the posterior portion of P 3 , and the supraorbital foramina 

 are 11 mm. apart. 



Dentition: M 2 is square, instead of being wider than long. The superior premolars are 

 crowded. The superior molar-premolar index is 0.90 and that of the inferior series 0.72. 



