296 



OXYRHINA, Agassiz. 



OXYRHINA EXTENTA, Leidy. 



L. c, 11. 302, Tablo XVIII, figs. 23-25. 



Niobrara epocli of the Smoky Hill. 



OXYRUINA I 



A species with flat but narrower crown than the last, and with perfectly 

 smooth cementum ; the base of the latter being serrulate on the convex 

 side of the crown. No denticles. Crown with a lateral curvature. 



Common in the greensand, No. 4, New Jersey. 



OXYKHINA ? 



With crown flatter and broader than the last; frequently oblique, but 

 not curved, and not unfrequently with lateral denticles. Cementum smooth, 

 except a short distance from the base on the convex side striate-grooved. 



Common in the greensand, No. 4, New Jersey. 



OXYEIIINA ? 



A species with much narrower crown than the preceding species, and at 

 the same time flat, and with transversely-extended and shallow roots. Crown 

 oblique, but not curved ; cementum perfectly smooth. Lateral denticles 

 large, flat. 



Niobrara epoch of Ellis County, Kansas. Professor Mudge. 



LAMNA, Cuvier. 

 Lamna texana, Roemer. 



Kreidebildungeu voa Texas, 29, Plate I, fig. 7 ; Leidy, Report of the United States Geological 

 Survey of the Territories, I, pp. 304-305, Plate XVIII, figs. 46-50. 



With numerous specimens of this species before me, I can substantiate 

 the observations of Dr. Leidy that its teeth are generally without lateral 

 denticles, but must add that it occasionally possesses them. They are seen on 

 three individuals, undoubtedly from the greensand No. 4 of New Jersey, 

 which are associated with many others from the same locality without 

 denticles. 



V 



