1870. J ^"^ [Cope. 



Clidastes cineriarum, Cope. 



The largest species of this genus as indicated by the zygosphen articu- 

 lation of the vertebrae. 



The locality where it was found is the same as the last, but the 

 specimens were taken from the gray bed, perhaps the same that produced 

 the Masmosaurus platynrus, Cope. They consist of vertebrae and ptery- 

 goid teeth. There are two anterior dorsals, three lumbars, and one caudal. 

 The articular faces of the caudals are broad vertical ovals. They increase 

 in width on the lumbars till on the last of these they assume the sub- 

 pentagonal form characteristic of man j' species, and which is still moi e 

 marked on the caudal. The centrum of the anterior dorsal is much com- 

 pressed ; inferiorly, slightly concave longitudinally, regularly and promi- 

 nently convex transversely. Conversely, the rims of the cup and ball are 

 strongly expanded, the latter with surrounding groove. The diapophyses 

 of the lumbars are of considerable length, exceeding in this respect those 

 of Mosasaurus we possess, where these parts are preserved. On the 

 median of the lumbars the inferior surface of the centrum iirst becomes 

 truncate or plane, and separated from that below the diapophyses, which 

 become slightly concave. The expansion of the ball becomes more ab- 

 rupt and striking on these vertebrae. The caudal is a little more com- 

 pressed than the lumbars, and presents the character of coossified chevron 

 bones. These are slender and longitudinally grooved. 



A single pterygoid tooth was found in the matrix on one of the dorsals. 

 The basis is short and much swollen ; the crown curved, acute, a little 

 compressed, and with an obtuse cutting edge posteriorly. 



Measurements. 

 Vertebi-aB, &c , from brown bed. 



M. 



Anterior dorsal, length centrum 0.0608 



" " depth articular ball 0.38 



" " width " " 088 



" " diameter behind diapophyses 029 



" " depth articular face for rib 022 



Lumbar, length centrum OG 



' ' depth ball 037 



" width 039 



" length remnant of diapophysis 04G 



" No. 2, length centrum 055 



" " width zygosphen 0182 



Caudal length centrum 041 



" depth cup 04 



" width 04 



" " basis diapophysis 0245 



'' " between chevron rami 0115 



Pterygoid tooth height crown 0125 



" " diameter pedestal 013 



