DESCRIPTIONS OF FOSSIL LIZARDS GILMORE 23 



derms, which probably covered much of the surface, as in the related 

 Glyptosaurus, Melanosaurus^ and Peltosaurus. This bone is per- 

 forated by the usual row of foramina. 



The precise number of teeth in the maxillary cannot be determined 

 from this specimen. There is evidence of 13, but at least 3 more 

 would be required to fill the space hidden by the overlapping of 

 the dentary upon the anterior alveolar border. The teeth are pleu- 

 rodont, robust, and extend well below the parapet of the maxillary. 

 The apices are bluntly wedged-shaped, with the cutting edge run- 

 ning longitudinal. The outer beveled surface is much shorter than 

 the inner slope. Anterior and posterior sides of the teeth are flat- 

 tened and closely placed in the series (see fig. 6). In a 10-milli- 

 meter space there are 12 teeth, whereas in Melanosaurus maxirrms, 

 also from the "Wasatch, 4^4 teeth occupy an equal space. The related 

 Peltosaurus is intermediate in this respect, having 8 teeth in a 

 10-millimeter space. The crowns are parallel-wrinkled, usually at 

 right angles to the cutting edge. The right maxillary has a greatest 

 length of 14.3 mm. Except that the maxillary teeth become smaller 

 at the ends of the series, all seem to be very similar. 



FiQDRD 7. — Two dermal scutes of f Xestopa piercei: Type (U.S.N.M. no. 13807). Five 



times natural size. 



The few anterior teeth of the dentary that are present appear 

 slenderer and extend relatively higher about the parapet than in 

 the maxillary series. 



The few dermal scutes found with this specimen are keelless, but 

 it may be that all these pertain to the underparts of the skull and 

 neck, and these are usually without carinae. With the exception of 

 the narrow smooth band on the anterior end, for the overlap of the 

 next adjoining scute, the dorsal surfaces are sculptured by a series 

 of pits sparsely placed and without regular arrangement, as shown 

 in figure 7. 



One of the scutes has a beveled lateral edge, a condition previously 

 observed ^ only in the genus Xestops. The presence of this type of 

 scutellation and close resemblances of the dentition to that of Xestops 

 vagans strongly suggest that the affinities of this new species lie in 

 the genus Xestops, to which it is now provisionally referred. 



» Mem. Nat. Acad. Sci., vol. 22, p. 145, 1928. 



