16 PROCEEDINGS OF THE NATIONAL MUSEUM vol.86 



neura stembergii, and the superior process of the premaxillary ex- 

 tends much farther posteriorly between the nasals. The maxil- 

 lary is less triangular and more rounded anteriorly. The precoro- 

 noidal part of the dentary is shorter than the postcoronoidal portion. 

 Also, the most anterior process of the coronoid terminates slightly 

 behind the last tooth.'' 



When direct comparison of the original skulls of R. sterribergii and 

 R. hatcheHi is made, the supposed difference in the facial and oc- 

 cipital angles of the skulls largely disappears, as may be clearly 

 seen by comparing figures 2 and 3. The steeper premaxillary region 

 in R. sterribergii makes the nose of this species much blunter than in 

 R. hatcherii and R. minutus. 



The other characters used by Walker for differentiating R. stern- 

 hergii are as stated by him and effectually distinguish the species. 



Family ANGUIDAE 

 Genus GLYPTOSAURUS Marsh 



GLYPTOSAUBUS GIGANTEUS Gilmore 



FiGUBE 4; Pl-vte 1 



Olyptosaurus giganteus Gilmobh; Mem. Nat. Acad. Sci., vol. 22, p. 119, pi. 14, 

 fig. 1, 1928. 



The acquisition by the United States National Museum of two 

 well-preserved specimens referable to the little-known Glypfosaur>/s 

 gigant£us is of interest in contributing to a better understanding 

 of this species. The type specimen, Carnegie Museum no. 1471, con- 

 sists of the frontal portion of the skull, covered on its superior 

 surface vrith osseous dermal scutes. Although this fragmentary 

 specimen displayed minor distinctive characteristics, its large size 

 was the principal distinguishing feature. 



The most complete specimen, U.S.N.M. no. 13869, consists of the 

 almost complete skull and lower jaws to which is attached, in situ, 

 a considerable portion of the dermal scuta that form the protective 

 armor of the neck and the forward portion of the body (see pi. 1). 

 In this latter respect it is the most complete specimen of a Ghjpto- 

 saurus that has yet been discovered and the first to give an adequate 

 conception of the arrangement of the dermal scuta on the anterior 

 part of the animal. 



The second specimen, U.S.N.M. no. 13861, consists of a nearly 

 complete skull with the articulated ramus of the right side. Both 

 of these specimens were collected in 1935 by George F. Sternberg 

 from the Brule formation (Oreodon beds) of the Oligocene, about 

 8 miles southeast of Douglas, Converse County, Wyo. 



