197 



The distinguishing features of the species have been already pointed out. 



The premaxillary is an obliquely oval or subpentagona'l bone ; the suture, 

 with the maxillary, is not toothed, and the anterior or free edge is smooth, not 

 tubercular, as in two specimens of P. molossus. There are but two teeth, of 

 which the anterior is immense, and the second little more than half its diam- 

 eter. The maxillary is stout, and supports in front four very small teeth ; 

 then three very large, of which the median is largest. The teeth recom- 

 mence very small and are closely placed in the same line ; but, as the extremity 

 of the maxillary is lost, the number cannot be stated. 



The dentary is similar in form to that of the P. tnolovsus, but has rather 

 more numerous teeth. Counting from the front, there are two large, one 

 rather small ; two large, and eighteen small and medium following ; the 

 smallest from third to ninth, inclusive. None of the crowns are preserved, but 

 the alveoli are round, or nearly so. The large tooth of the premaxillary, if 

 proportioned as in P. molossus, must have projected m .0755, or three inches, 

 above the alveolus ; the fourth mandibular was but little smaller. 



Measurements of the jaws. 



m. 



Length of the premaxillary 0. 075 



Depth of the premaxillary 0. 09 



Depth of the maxillary at the coDdyle 0.08 



Thickness of the maxillary just hehind the condyle '- 0. 025 



Length of the dentary 0.25 



Depth of the dentary at the symphysis 0. 03 



The various portions of cranial bones preserved are much like those of P. 

 molossus, but stouter. The hyomandibular is nearly perfect ; it, is thin, but 

 has a convex rib extending to its acuminate extremity at the postero-inferior 

 angle of the metapterygoid and the superior extremity of the symplectic. 

 The preoperculum is attached by a thickened grooved margin, and is not 

 overlapped by the hyomandibular. It extends in a curved form round toward 

 the condyle of the inferior quadrate. Three elongate bones, closely appressed, 

 I suspect to be part of this bone, with the interoperculum and superior cera- 

 tohyal adherent. The last is rather narrow, and with smooth distal articular 

 surface, without suture. The superior branchihyals are a little like phalanges 

 of Mosasaurus in form, being subsimilar and expanded at the ends, and much 

 flattened. The parasphenoid is similar to that of P. molossus. The position 

 of the hyomandibular is vertical to the axis of the basioccipital, the superior 

 part directed forward. 



