30 



scarcely probable that it belongs to either genus. It is flat, and has a 

 narrow, straight, inguinal margin at right angles to the fine suture with 

 the hyosternal. The suture with the postabdomial is partially gom- 

 phosial. Surface dense, polished, marked externally with a reticulate 

 sculpture of narrow ridges separating larger and smaller areas wider than 

 themselves. Marginal edge thinner. 



M. 



Length of hyposternal fore and aft 025. 



Thickness of hyposternal at front 004. 



Pits in .010 m six. 



Lignite Cretaceous of Colorado. 



ADOCUS, Cope. 



Proceedings Academy of Natural Sciences, Philadelphia, 1868, 235. Proceedings Amer- 

 ican Philosophical Society, 1870, November. 



Adocus(s) lixeolatus, Sp. nov. 



Established on a number of fragments from different exposures of the 

 lignite beds, primarily on a vertebral and sternal bone from the same 

 locality as the preceding specimen. As the diagnostic portions of this 

 specimen are wanting, it is referred to this genus provisionally, and 

 because the structure and sculpture of the parts resemble most nearly 

 known species of it from the Cretaceous greensand of New Jersey. 



The sternal bone is flat, and presents the wide and transverse sutures 

 forming the usual right angle, and of a rather coarse character of a 

 medium serrate keel with pits on each side for the reception of corres- 

 ponding pits. The vertebral bone is rather thick, and is shallowly 

 emarginate in front. The sculpture consists of delicate obscure parallel 

 lines which are more or less interrupted and occasionally joined, so as 

 to inclose faintly-marked areolae. 



M. 



Width of vertebral bone in front 0135 



Greatest of vertebral bone 0280 



Thickness of vertebral bone , 0070 



Thickness of sternal bone 0080 



From lignite of Colorado, and mouth of Big Horn Eiver, Montana. 



COMPSEMYS, Leidy. 



CoMPSEMYS VICTUS, Lcidv. Proceedings Academy Iifatural Sciences, 

 Philadelphia, 1856, p. 312. 

 Lignite of Long Lake, ]:?I"ebraska ; Cretaceous of Colorado. 



CoMPSEMYS OBSCURUS, Leidy, Cope. 



Extinct Batrachia, &c., p. 124. Emys ohscurus, Leidy. Proceedings 

 Academy, 1856, 812. 



Lignite of Long Lake, Nebraska. 



PYTHONOMOEPHA. 



The reptiles of this order are the most abundant in the marine Creta- 

 ceous of Kansas, or the Niobrara Group of Dr. Hayden. Material ac- 

 quired since my first account confirms the idea there maintained that 



