8 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 63 



Laterally the median portion unites with the squamosal by a 

 straight sutural edge that is directed forward and inward toward the 

 center of the skull. A triangular outward projection with an upper 

 striated surface at the anterior termination of the squamosal suture 

 represents a surface that was overlapped by the articulated squamos- 

 als (s.s., plate I ). A low. sharp, diagonally directed ridge apparently 

 indicates the posterior extent of the overlap of the squamosal. The 

 squamosals are missing, but those as in other primitive Ceratopsians 

 appear to have been short and broad. 



The rostral is missing from the type, but is present in a slightly 

 smaller individual (Cat. No. 7952, U. S. Nat. Alus.). (See fig. 2.) 

 In general aspect it resembles the rostral of Triceratops, but wdth a 



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Fig. 2. — Rostral of Brachyceratops )iioiitaiicnsis. Paratype : Cat. No. 7952 

 U. S. Nat. Mus., 14 nat. size. a. side view ; b, posterior view ; s. superior 

 process ; p, posterior processes. 



less curved anterior border. Externally the surfaces are pitted and 

 grooved and in life were doubtless covered by a horny sheath. 



The predentary except for its much smaller size is indistinguish- 

 able from that of Triceratops. It is to be distinguished from the 

 predentary of Monocloniiis dazvsoiii Lambe by the upward turned 

 apex of the anterior end. 



The dentary is stout, gradually narrowing vertically toward the 

 front, the anterior end being especially depressed and unusually 

 broad transversely, this end being nearly at right angles to the pos- 

 terior portion. Near the posterior end on the external surface a 

 stout coronoid process is developed, extending well above the dental 

 border. It is compressed transversely but widens antero-posteriorly 

 with a hooked forward process as in other primitive Ceratopsians. 

 Beginning at the base of this process, a low, broad ridge extends 



