26 Annals of the Carnegie Museum. 



lower ; the muzzle heavier j the nasals longer ; the infraorbital fora- 

 men placed further forward ; the mandible deeper, with the angle 

 more strongly produced downward and not so strongly produced 

 behind the condyle. The limbs are also shorter and comparatively 

 lighter than those in Mesoreodon chelonyx, as is indicated by the 

 fragments of the limbs found with the paratype (No. 1323). 



Measurements. 



Type. Paraiype. 



(No. 1325.) (No. 1323. ) 



mm. mm. 



Distance from anterior border of orbit to the incisors 123 



Transverse diameter of muzzle at base of canine 60 



Antero-posterior diameter of premolars 60 



Antero-posterior diameter of molars -!• and £ 44 



Antero-posterior diameter of M^ 30 



Vertical diameter of mandible at P- f ... .! 34 32 



Vertical diameter of mandible at anterior part of M- 3 - 42 



Length of premolar series 59 56 



Length of molar series 70 



Antero-posterior diameter of M 3 34 



Promerycochoerus carrikeri, 6 sp. nov. 



(Plate IX ) 



(Type. No. 1080 Carnegie Museum Catalogue of Vertebrate Fossils. ) 



This species is found in the upper Monroe Creek beds and is most 

 nearly allied to Promerycochoerus chelydra Cope. The skull is brachy- 

 cephalic. The dentition, of the usual merycoidodont type, is If, C^, 

 PJ, Mf. On direct comparison the skull of P. chelydra is seen to 

 differ from the series in the Carnegie Museum collection by a number 

 of important characters. In P. chelydra the zygomatic arch is less 

 robust and does not extend below the horizontal line of the dentition, 

 the superior border of the premaxillary is more oblique, the frontal 

 region is less convex, the vertical diameter of the cranium is less, the 

 tympanic bulla is smaller and differently shaped, the posterior nares 

 are located further back, the postglenoid process is smaller and more 

 widely separated from the paroccipital process, the dentition is relatively 

 somewhat shorter, and the type specimen is of smaller size than the 

 average sized skulls of Promerycochoerus carrikeri. Among the more 



6 In recognition of Mr. M. A. Carriker, Jr., who pointed out the locality of the 

 specimens to the writer. 



