Cope.] ^" [Nov. 5, 1839. 



more compressed and curved, and differs mucli in the small posterior 



area, and very long anterior outer crest. 



In. Lin. 



Total length mandible (restored) " • • ■ 6 6 



Depth at extremity 9 



'• ' ' anterior crest 1 6 



'• " posterior " 3 5 



Length posterior outer area 7 



" anterior " " 1 7.5 



" " " " with crest 2 6 



" inner area 2 10.5 



From the upper cretaceous green-sand bed at Hornerstown, IST. J. Dis- 

 covered and f)resented to the writer by Jno. Meirs, proprietor of the ex- 

 cavations at that place. 



ISCHYODUS SOLIDULUS, GopC, Sp. TIOV. 



ISTo distinct external crests, and no anterior outer dentinal area. The 



posterior outer dentinal area is very small, and looks inwards from^ 



the gradual elevation of the outer superior margin. The inner area is 



very large and undivided, and is accompanied on the inner margin by a 



slender column, which issues in the i)Osterior corner of the symphyseal 



plane. The terminal area of the beak instead of having the usual narrow 



oblique form, is the round extremity of a narrow column. Inner and 



outer margins, anterior to the large area, of equal elevation, regularly 



curved outwards without angulation. 



In. Lin, 



Length (restored) 2 6.5 



' ' to end inner area 1 9 



" " " posterior outer 10.5 



" of " " 2.5 



" . " inner 1 9 



Depth at " 9.2 



" " posterior 1 2 



" " beak 4.5 



This species is nearest the I. divaricatus m. It differs in many re- 

 spects, among which are the absence of anterior outer area, and of pro- 

 minence of the inner lip, and the great reduction of the terminal column. 

 Its lack of dental development allies it to the Leptomylus m. Size, 

 small. 

 From the same locality and donor as the I. laterigerus. 

 Pristis attenuatds. Cope. 



Tooth slender, width at base less than one-sixth length, thick and 

 straight. Posterior face straight, with a wide groove, anterior curved 

 backwards, obtuse with a faint median longitudinal groove. Posterior 

 face at the tip of the tooth, oblique. No striae. 

 Length 26.7 lines ; width 4.5 lines ; depth at base 3 lines. 

 This species is much more slender than the P. agassizii Gibbes, the only 

 species which resembles it. Found by Prof. W. C. Kerr, State Geolo- 

 gist of North Carolina, at Flower's marl pit, Duplin Co., N. C. 



