1877.] LJO [Cope. 



prominent ridges. The interior is hollow, and the walls are composed of 

 a few concentric layers without external enamel or cementum. The solid 

 base to which it is attached is shallow, presenting smooth surface on the 

 opposite side, which is deeply impressed by a longitudinal groove at one 

 end. 



The characters of this species are pointed out at the place above quoted. 

 The measurements of a large specimen are : length .015 ; diameter of base, 

 long .008 ; short .005. 



I am not sure as to the part of the skeleton to which this body should be 

 referred. 



On Reptilian remains from the Dakota Beds of Colorado. 

 By E. D. Cope. 



(Meeting of American Philosophical Society, November 2, 1877.) 



Since the discovery of the huge saurian Ccmarasaurus supremus (Cope, 

 Paleontological Bulletin, No. 25, p. 5), Superintendent Lucas has explored 

 the horizon of the Dakota of the Eastern Rocky Mountains near the Ar- 

 kansas River for other indications of extinct life. His search has been re- 

 warded by the finding of several species of reptiles of interesting charac- 

 ter, which it is the object of the present paper to describe. 

 Caulodon diyersidens gen. et. sp. nov. 



This large saurian is represented by ten teeth found together, but sepa- 

 rated from the cranial bones, and in a more or less broken condition. I se- 

 lect four of these exhibiting the characters most clearby. 



Char. gen. Fang of the tooth of great length and hollow, and 

 contracted at the base. It is without excavation for successional tooth. 

 Crowns of the teeth of different forms in different portions of the jaw ; the 

 posterior are like the bowl of a spoon ; others have a similar form but 

 are more compressed, having double lateral ridges, while the crown of an- 

 other, supposed to be an incisor, is little wider than the root, and has the 

 section an oval with one side less convex than the other. All are coated with 

 an enamel-like layer of considerable thickness which extends on the fang 

 in some of the teeth. None of the crowns present cutting edges. 



The characters presented by these teeth are quite distinct from anything 

 hitherto found in North American Saurians. The absence of indication of 

 the successional teetli is remarkable, and in connection with the contrac- 

 tion of the base of the root, suggests that the mode of succession of teeth 

 approximated that exhibited by the Mammalia. 



Char, specif. — The roots of all the teeth- are cylindric. The crown 

 of the posterior tooth is convex on one (the external) side, and concave 

 on the other. The convexity is increased by a contraction of the ex- 

 ternal surface near and parallel to each border. The concavity is divided 

 by a longitudinal rib which disappears at the base. This edge of the 



