1870 ] ^"-'- [Cope. 



M 



Length of radius 0. 108 



Width do. narrower extremity 064 



" " wider " 08 



" " medially 043 



This species cannot be confounded with the L. proriger, Cope, and L. 

 congrops, Cope, owing to its depressed vertebral centra ; from L. mitchillii, 

 DeKay, the equal and numerous i^terygoid teeth separate it at once. 



LlODON MUDGEI, Cope. 



I am not quite sure whether this species belongs to this genus or to 

 Mosasaurus. The characters of its quadrate bone, size, &c., induce me 

 to refer it provisionally to the former. 



Its determination rests on a series of specimens from the yellow chalk 

 at a point six miles south of Sheridan, Kansas. They consist of three 

 vortebrse and fragments of atlas, with numerous portions of cranium and 

 proximal extremity of scapula. 



The parts of cranhim preserved are the frontal bone without the 

 anterior extremity, and with the adjacent parietal almost complete, parts 

 of the basisphenoid, the suspensorium, the ossa quadrata, and the greater 

 part of the articular. The frontal is flat with thin edge, longitudinally 

 hollowed on each side of the median line, which is marked by a low but 

 acute keel. There is an abundance of foramina and delicate grooves on 

 the surface, and posteriorly elevated strife, which converge to the median 

 keel. The median square projection of the border of the parietal is in 

 advance of the lateral portion of the same, and not behind it as in CU~ 

 dastes propytlion. The fontanelle is large. A marked feature is that the 

 parietal crests unite into a low median ridge a short distance behind the 

 fontanelle and are not, as in CUdastes propython, separated by a horizontal 

 plane. The sutures of the bones forming the side of the brain- case are 

 very obscure. Nevertheless it appears that the descending margin of the 

 parietal does not descend to the front of the alisj^henoid, but is margined 

 inferiorly by the latter to the postorbital expansion. No part of the in- 

 ferior margin of the alisphenoid can reach the sphenoid, as it terminates 

 in a thin edge except for a short distance medially whei'e it is broken off. 



The infe.rior aspect of the parietal and frontal bones presents a furcate 

 keel corresponding to the divergent parietal crests, and a very large 

 funnel for the epiphysis of the brain. The olfactory groove is deep and 

 regular. 



The articular bone is characterized by the prominent longitudinal 

 crest which descends on the inner side, from the front of the glenoid 

 cavity to below the posterior attachment of the coronoid bone, where it 

 terminates in a thin edge. Also by the short distance between the 

 margin of the glenoid cavity (cotylus) to commencement (or end) of coro- 

 noid suture, indicating a shortening of the posterior part, at least, of the 

 cranium. The bone is continued forwards only immediately under the 

 coronoid (cfr L. idericus). 



