UPPER CRETACEOUS LIZARDS — GILMORE 213 



The mandible is represented by the posterior half of the right ramus 

 and the nearly complete left ramus. This ramus has been freed from 

 the matrix, and although it gives a good idea of the jaw as a whole 

 the complete coalescence of sutures makes it impossible to determine the 

 detailed structure of the jaw. 



The dentition is represented by 15 teeth, 6 posterior teeth in the left 

 ramus, 4 in the right ramus, 3 in the left maxilla, and 2 in the remnant 

 of the right maxilla. Comparison of upper and lower teeth fails to 

 disclose differences that would distinguish one from the other (see 

 figs. 8 and 9). 



Figure 8. — Posterior teeth of left dentary of Paraglyphanodon gazini, crown view. 

 Most posterior tooth on the right. X5. U.S.N. M. No. 16580 (type). 



In the general plan of the subacrodont dentition the teeth of Par- 

 aglyphanodon gazini follow those of the genotype in having the 

 anterior teeth reduced and having a small tooth at the posterior end 

 of the series; also there is a similarity in cusp pattern of the larger 

 teeth, in having a sharp transverse cutting edge with an outer cutting 

 edge at right angles to it, though they differ much in other details. 



At the present time it is upon characters found in the lower dentition 

 that reliance is placed for distinguishing the present specimen from 

 the type of Paraglyphanodon utaliensis. The more important of these 

 differences are as follows : Crowns of larger teeth wider transversely 



Figure 9. — Teeth of left maxillary of Paraglyphanodon gazini, crown view. Small 

 tooth in front. X 5. U.S.N.M. No. 16580 (type). 



and narrower anteroposteriorly, with a relatively longer transverse 

 cutting edge ; posterior tooth with a well-developed cusp on the inner 

 side ; enumerated from the posterior end of the series, the second and 

 third are subequal in size with a reduced fourth, whereas in P. utaliensis 

 the second, third, and fourth are subequal with a much reduced fifth 

 tooth. Crowns of fourth and fifth subequal in size, with well- 

 developed transverse cutting edge whereas in P. utahensis the crown 

 of the fifth tooth is about half the size of the fourth and both have 

 incipient inner cusps; the crown of the sixth tooth is more robust than 

 P. utahensis. The teeth throughout the series are larger and more 

 widely spaced. The six posterior teeth in the left ramus occupy a 

 longitudinal space of 8.6 mm. 



