16 GEOLOGICAL SURVEY OF TEXAS. 



This species differs from the P. appalachianus in its straighter form, 

 and the shorter crenate portion of its anterior cutting edge, both points 

 of approach to the genus Clepsysaurus. Its peculiar sculpture distin- 

 guishes it from any of the species of either genus which are known. The 

 dimensions are about those of the P. appalachianus. 



The basal part of a larger tooth, probably of this species, was ob- 

 tained bj' Mr. Cummins at the same time and place. Its diameters are as 

 follows : 



Mm. 



Anteroposterior 28 



Transverse 23 



From Paloduro Canyon. 



PAL^OCTONUS DUMBLIANUS, CopC. 



Sp. nov. Plate 11, Figures 4-6. 



Numerous teeth found at the same time and place by Mr. Cummins be- 

 long to a species distinct from the preceding, and one more like the P. 

 appalachianus. The canine-like tooth has an inward curvature, and the 

 anterior cutting edge is not curved within the anterior convexity of the 

 crown at the base, but continues as its most prominent line. The enamel 

 is not plicate. It differs from corresponding teeth of P. appalachianus 

 in the greater convexity of the internal face. Enamel minutely striate. 



The posterior teeth, which agree in relative dimensions with the anterior 

 one just described, differ in character from those of the P. appalachianus 

 in several respects. Their internal face is more convex; there is no longi- 

 tudinal angle dividing the external face into two unequal facets, and there 

 is a shallow gi-oove near the base on both sides of both of the cutting edges. 

 These four grooves are present in two such teeth out of eight, which I 

 think correspond in their posterior position with those typical of the P. 

 appalachianus. In two others, probably from a more anterior position, 

 there are three such grooves. In two others there are but two, while in 

 two others, whose narrow form indicates the most anterior position, a 

 trace of but one groove, the anterior external, remains. 



The teeth of this species obtained are smaller than the types of either 

 of the other species, but they indicate a reptile of large size. 



Measurements . 



Mm. 



Diameters of canine-like tooth 5 anteroposterior 20 



( transverse 17 



Diameters of more posterior tooth i anteroposterior 22 



{ transverse 14 



Diameters of a superior tooth i anteroposterior 22 



( transverse 14 



longitudinal 30 



Diameters of a posterior tooth ^ anteroposterior 22 



transverse. ,,,,,....,..,.., 15 



