42 PROCEEDINGS OF THE NATIONAL MUSEUM. vol. 37. 



It will be observed that of the seven identified species of reptiles, 

 only two {Ghjptops ornatus and Cwlurus fragilis) have been 

 recognized as occurring at other levels. 



In this paper, which may be considered preliminary, I only wish 

 to call attention to what appears to be a most interesting Morrison 

 fauna. In a later communication, however, I hope to be able to 

 present a more detailed account of this fauna. 



EXPLANATION OF PLATE 11. 



Fig. 1. Left dentary of Opisthias varus. Cat. No. 28G0 U.S.N.M. X2. Ex- 

 ternal view. Froui a photograpli. 



2. Left dentary of Sphcnodon punciatum. Cat. No. 29429 U.S.N.M.. Nat. 



size. "S'iewed from the outer side. 



3. Anterior portion of riglit upper mandible of undetermined animal from 



Quarry 9, Como, Wyo. Cat. No. 0133 U.S.N.M. X 2. Oblique ex- 

 ternal view. 



4. Portion of left dentary of undetermined reptile?. Cat. No. G134 U.S.N.M. 



X 2. External view. 



