Jim. 7, 1870.] '^ * J- [Cope. 



ON SOME REPTILIA OF THE CRETACEOUS FORMATION OF 

 THE UNITED STATES. 



POLYDECTES, Cope. 

 TliLs genus is indicated by one, i^erhaps more teeth, which resembles in 

 some resi3ects those of the Crocodilian genus Thecachampsa. Crown 

 of dense concentric dentinal layers, with small pulp cavity. Enamel with 

 two prominent ridges separating inner from outer aspects, but approxi- 

 mated on the inner face, which thus included, is but one-third the circum- 

 ference of the tooth. Ridges extending from tip to near base of crown, 

 with a sulcus along the inner side of each. Crown acuminate, a little 

 swollen at the base and above the middle. Section circular. 



POLYDECTES BITURGIDUS, CopC. 



Crown a slender cone slightly curved near the base. Middle jjortion 

 constricted, its surface iTiarked with narrow obscure facets. On the inner 

 face, a shallow groove within each of the bounding sulci, the two separ- 

 ated by an indistinct groove. The enamel is smooth and worn, and leaves 

 no traces of other sculpture. 



Lines. 



Length of crown 30 



Diameter at base of do 10 



' ' middle 6. 



" above do 6.5 



From the marl pits of James King, Sampson co., N. Ca. Discovered 

 by Prof. W. C. Kerr, Director of the Geological Survey of North Carolina. 



LiODON CONGROPS, Cope. 



Spec. nov. 



This species is indicated by a posterior cervical vertebra which presents 

 so many characters, as to render its exclusion from the present work 

 scarcely proper. In size it bears some relation to the Mosasaurus minor, 

 Gibbes, but is still smaller, and is separated at once by the round instead 

 of depressed articular faces. 



The posterior articvilar face is the round one; the anterior is slightly 

 depressed; and opposite the diapophyses and neural canal slightly flat- 

 tened, so as to give a slightly trilateral superior outline to the cup. It is 

 not excavated above as in the species of Clidastes. The hypapophysis is 

 broken, but its base is unusually long and wide. The infero-anterioi 

 limb of the short diapophysis descends to the edge of the cup, consider- 

 ably below its middle. The space it encloses with its superior ridge 

 which extends into the anterior zygapophysis, is reticulate striate. The 

 whole surface below is minutely striate; the striae become coarse as it ap- 

 proaches the ball. The latter is surrounded by a groove, and its margin 

 projects acutely beyond the adjacent surface of the centrum. The latter 

 is much contracted behind the ball, and the faces below the diapophyses 

 are concave. Bases of neurapophysis striate. Neural arch broken away 

 above. Neiiral caudal with an epapophysial ridge. 



