86 



CRETACEOUS AND TERTIARY FISH. 



Dental plate arched in form, composed of nine median teeth and 

 a row of about four lateral teeth on each side. Enamel surface 

 convex, with strong median and lesser convex transverse lateral 

 convexity, so that surface is undulated. Basal surface presents 

 concave surface sloping each side from median range, though lat- 

 ter with convex surface and not sharply defined. Transverse 



Fig. 41. — Myliobatis fastigiatus (Leidy). (Type.) Monmouth Co. (Cleburne). 



median sutures backward in median convexity and forward on 

 concave depressions. Vertical diameter of median teeth about 

 one-seventh horizontal diameter, their surfaces with feeble ver- 

 tical wrinkles in concave depressions and on lateral depressions, 

 otherwise nearly smooth. Lateral small teeth rather hexagonal, 

 horizontal diameter about three-fifths to two-thirds vertical diam- 



