558 F. B. Loomis — New Mosasaior from the Ft. Pierre. 



usual. The total length of the skull from the snout to the 

 occipital condyle is 510 mm . 



The premaxillse are fused to each other and to the nasals, 

 and are characteristically short and blunt, making a very short 

 rostrum in front of the four teeth, which they carry. On the 

 ventral surface there originates a median carina just behind 



Fig. 1. 



Fig. 1. Top view of the skull of the cotype. 1/6 nat. size. /, frontal ; 

 j, jugal ; I, lacrymal ; mx, maxilla ; n, nasal ; p, parietal ; pf, prefrontal ; 

 pmx, praemaxilla ; psq, presquamosal ; q, quadrate. 



the teeth, which does not project between them, but is con- 

 tinued backward onto the vomers. Between the nares the 

 fused nasals make a moderately wide septum, which however 

 in the middle of the span is narrowed for a short distance to 

 about 10 mm . 



The vomers are wide and fill in the anterior part of the 

 space between the maxillae. The sutures about the vomer are 

 not clear, but the species is peculiar in that the palatal vacuity 



