ivith Descriptions of Neiv Species. 223 



.reeled, and the longest leg lying close to and parallel with 

 the sagittal plane. The inferior view shows a rather 

 abrupt anterior termination of the malar portion of the 

 zygoma above the middle of M-. The basicranial axis 

 is not steep. The bullae are large, ovoidal, and extend 

 downward below the glenoid tubercles, which are com- 

 pressed antero-posteriorly and stout. 



The basicranial foramina resemble those of Eporeodon, 

 rather than Oreodon {Merycoidodon). The condylar 

 foramen is normal and separated from the foramen 

 lacerum posterius by a ridge from the paroccipital pro- 

 cess. This latter foramen is relatively much larger 

 than in Oreodon {Merycoidodon) . The foramen lacerum 

 medium is also large and occupies a position corre- 

 sponding to that in Eporeodon. The foramen ovale is 

 large and oval-shaped. It is located much farther anter- 

 iorly to the bullae than in Oreodon (Merycoidodon). But 

 one- specimen, No. 10154, of this collection shows a fora- 

 men rotundum, and in this one it is so small that it could 

 not have been functional, and I consider it justifiable to 

 consider that this foramen is not present in the John Day 

 Promerycochoeri, any more than it is in Eporeodon. The 

 paramastoid processes are broad and plate-like. The 

 canine is flat posteriorly and rounded anteriorly, but that 

 of P. macrostegus is more oblong-square, with the long 

 diameter transverse to the sagittal plane. 



The orbits are nearly round. The lacrymal fossae are 

 usually very shallow and wide, although confined to the 

 lacrymal bone. This is, however, subject to slight varia- 

 tion. The malar beneath the orbit is very nearly flat, 

 while beneath the lacrymal fossa it is concave and then 

 convex from above downward. The depth below the 

 orbit varies from 35 to 43 mm. The anterior ridge of the 

 zygoma is prolonged forward and upward in the maxillary 

 beyond the infra- orbital foramen, which is above P^. The 

 posterior or squamous portion of the zygoma does not 

 rise as high as the sagittal crest, and its general form, 

 including the postorbital bridge, is that of a fairly wide 

 U. The external edge is not so heavy nor so rugose as 

 is that of P. macrostegus. The superior surface of the 

 skull slopes more steeply from the sagittal crest than in 

 the latter species. The posterior half of the lacrymal 

 fossa is sometimes quite rugose ; the anterior very 

 smooth. The nasals extend up to a point on the sagittal 



