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PROCEEDINGS OF THE NATIONAL MUSEUM 



much-reduced last molar; (3) widening of the intermediate teeth 

 with sharp transverse cutting edges; (4) progressive reduction of 

 anterior teeth to those having simple crowns. In view of these 

 suggested affinities, the present genus is tentatively assigned to the 

 family Polyglyphanodontidae. 3 



Attention is called to the possibility that Coniosaurus crassus* from 

 the Cretaceous Chalk of Sussex, England, may eventually find a resting 

 place in this same family. This suggestion is made on the basis of its 

 small size, reduced posterior molar, a tendency of intermediate teeth 

 to widen transversely, and a reduction in size of the anterior teeth. 



PARAGLYPHANODON UTAHENSIS Gilmore 



Type. — U.S.N.M. No. 15668, consisting of a jaw bone containing 8 

 posterior teeth. In the original description it was identified as a left 

 maxillary, but in the light of new materials it quite certainly repre- 



Figure 6. — Right dentary of Paraglyphanodon utahensis Gilmore: A, Superior view of 

 dentition; B, lateral view of the dentary. X5. U.S.N.M. No. 15668 (type). (After 

 Gilmore.) 



sents a right dentary. This specimen was found in the lower part 

 of the North Horn formation, Upper Cretaceous, in close proximity to 

 the paratype of Polyglyphanodon sternbergi (U.S.N.M. No. 15816). 



Description. — The anterior end of the type dentary is missing, but 

 the lost part left its impression on the small block of matrix in which 

 it is preserved, and this impression gives evidence that there were prob- 

 ably 11 teeth in the complete dentary series. These occupied a space 

 11.5 mm. long. The teeth increase in size from front to back, with 

 a much-reduced posterior tooth as in Polyglyphanodon. The teeth 

 are subacrodont, anchylosed to the sides of shallow alveolar depressions. 



Viewed laterally the teeth are short and stout, with subacute, equi- 

 lateral, triangular crowns, the apex being centrally placed (see fig. 6, B) . 

 Viewed from above, however, the heterodont nature of the teeth (fig. 6, 



3 Gilmore, Charles W., Proc. U. S. Nat. Mus., vol. 92, p. 229, 1942. 



4 Owen, R., A monograph of the fossil Reptilia of the Cretaceous formations, pt. I, 

 p. 21, pi. 9, figs. 13-15, 1851. Paleontographica] Society, London. 



