380 University Geological Survey of Kansas. 



tion of several conspicuous striae, which extend backward along 

 the middle of the side. 



The articular fits into a deep emargination in the dentary, 

 and rises almost vertically from the cotylus. The bone is thin 

 throughout, and is covered with rows of bony tubercles. The 

 cotylus is very small, indicating a very weak articulation with 

 the quadrate. 



Length of dentary 76 . mm. 



Depth, at coronoid. 25 . 5 " 



Length of articular 60 . " 



Length of first large tooth 16.5 " 



DERCETIDiE.* 



HoplopleuridcB Pictet and Humbert. 



LEPTECODON. 

 Leptecodon rectus. Plate LXXIII. 



Leptecodon rectus Williston, Kans. Univ. Quart., vol. viiia, p. 113. 



Slender and elongate ; head elongate, the jaws slender, the 

 anterior extremity in the specimen wanting. The hind end of 

 the mandibles is represented by an impression situated below 

 the posterior end of the skull. Teeth numerous, small, pointed, 

 slender. The orbit is situated posteriorly ; is of moderate size 

 and round. Scapular arch strong, the large opercular space in 

 front showing indications of the thin opercular bones. Verte- 

 brae about forty-five in number, elongate, more than three times 

 as long as deep, much constricted in the middle. Pectoral fins 

 small, composed of seven or eight rays. Ventral fin very small, 

 situated about the middle of the vertebral column ; caudal fin 

 small, the rays feeble, evidently cartilaginous, the outline in- 

 dicated on the stone ; the shape of the fin is regular apparently, 

 the angles produced. Other fins wanting or not preserved. 

 The side of the body, as preserved, shows three longitudinal 

 rows of large, firmly united scutes, apparently of the same 

 number in each series as the vertebrae. The scutes are in the 



* By S. W. Williston. 



