156 Annals of the Carnegie Museum. 



I. Promerycochoerus carrikeri Peterson. 



Annals of the Carnegie Museum, Vol. IV, pp. 26-29; Pis. IX 

 and X (1907). 



Type: Skeleton, complete except as to the caudal region. (C. M. 

 Cat. Vert. Foss, No. 1080). 



Paratypes: Greater portion of skeleton C. M. Cat. Vert. Foss., 

 No. 1081, Skeletons Nos. 1078 and 1079, illustrated on Plate XXXIII. 



Horizon: Lower Miocene (Upper Monroe Creek beds). 



Locality: Head of \\'arbonnet Creek, Sioux County, Nebraska. 



Generic Characters: [.l^ established by Douglass and MattheiJ\. 

 Premolar scries not reduced in length (Douglass). Molars of subequal 

 size, the last a little larger. Skull elongate [or short].^ Occiput narrow, 

 produced backwards. Mastoid plates moderate in size. Zygomatic 

 process of squamosal very wide, with a thickened, rounded margin ending 

 bluntly at posterior edge (Matthew). 



Specific Characters: Extreme downward thrust of the zygomatic 

 arch and great elevation of the occiput; transverse diameter of the skull 

 nearly as great as the antero-posterior; sagittal crest and temporal ridges 

 very prominent; tympanic bulla- of comparatively large size; body heavy; 

 limbs short. Animals someivhat larger than Sus scrofa. 



Detailed Osteological Description of Promerycochcerus Car- 

 rikeri. 



THE cranial region. 

 (Plate XXXVIII). 



Owing to the early fusion of the sutures in the skull of this species 

 a study of each individual segment is not possible. 



The skull of Promerycocha-rus carrikeri is more nearly similar to 

 that of P. chelydra Cope. P. hollandi Douglass, and P. vantasselensis 

 Peterson than any other species of this genus. The skull, as in the 

 species mentioned, has the transverse very nearly as great as the 

 antero-posterior diameter. The occiput is high with its posterior 

 face greatly convex supero-inferiorly and concave laterally. The 

 lambdoidal crests diverge very suddenly from the top of the occiput 

 and again rapidly contract lower down, gi\ing a fan-shaped outline 

 to the upper part of the occipital plate. Superiorly the post-temporal 



^ Amendment justified by additional knowledge derived from recently described 

 species. 



