vex side, whose junctions form the anterior and posterior edges 

 of the crown, as in the latter genus ; and like the latter, there is 

 no anterior cutting edge, but instead, a solid angle. But the pos- 

 terior edge is denticulate as in Lselaps, and the plicae or keels of 

 Paronychodon are here only recognizable in low angles. Some 

 light may be cast on the affinities of the latter genus by the dis- 

 covery of Zapsalis. 

 Zapsalis abradens, sp. nov. 



This reptile was apparently about the size of the Lselapts 

 Isewfrons. The best preserved tooth is that of a probably adult 

 animal, as it displays considerable attrition, especially on the 

 flat side. Here three worn lines indicate the former existence of 

 as many low longitudinal angles of the surface, of which the 

 median is basal and short. The convex side exhibits four low 

 angles of nearly equal length, all stopping short of the apex. 

 The facets between them, excepting the anterior two, are slightly 

 concave. The denticles are of moderate coarseness, measuring 



M. .00033. 



Measurements. m. 



Elevation of crown 0120 



( antero-posterior 0065 



Diameter of crown | transyerse 0030 



URONATJTES, Cope. 



Genus novum Sauropterygiarum. Cervical vertebrae, like the 

 dorsals and caudals, short and transverse, and distinct from each 

 other. Neural arches and transverse processes coossified at ma- 

 turity. Transverse processes of the cervicals simple and depressed. 

 Extremities plesiosauroid. 



This genus might be referred to Polycotylus, Cope, were it not 

 for the distinctness and greater abbreviation of the cervical ver- 

 tebrae. From Cimoliasawus, Leidy, it differs in the coossifica- 

 tion of the caudal diapophyses and the much greater abbreviation 

 of the cervical vertebrae. The centra are amphiplatyan in Cimo- 

 liasaurus, biconcave in Uronautes. From Pliosaurus, Owen, 

 which resembles the present form in the shortness of the cervical 

 vertebrae, the coossified transverse processes of the cervicals sepa- 

 rate it. The present is pre-eminently a short-necked genus of the 

 order. 



The remains on which it reposes are the cervical, dorsal, and 

 caudal vertebrae, with portions of limb and rib bones. 



