ELASMOBRANCHII. 



89 



clearly three-ribbed in section as this one. Myliobatis obesus is 

 somewhat similar, but much wider, with more curvature of teeth 

 and biserial laterals. Each tooth is both wider (longer) and 

 deeper than in most of the described species. 



Formation and locality. Known from the Eocene [Shark 

 River marl K.] of Farming-dale in Monmouth County. I have 

 not examined any specimens. 



Myliobatis magister (Leidy). 



Dental plate depressed in form, thick, composed of six median 

 teeth, and apparently no traces of lateral teeth. Enamel surface 

 convex, with slight median concave longitudinal depression, so 



Myliobatis magister (Leidy). Vincentown (Bryan) 



that surface is double convex with each side sloping down 

 strongly convex. Basal surface presents convex surface sloping 

 each side from median longitudinal convexity. Transverse 

 median sutures nearly horizontally straight, or curving slightly 

 posteriorly each side. Vertical diameter of median teeth about 

 4% of horizontal diameter (imperfect) and their surfaces almost 

 entirely smooth. Length (width) about 60 mm. (damaged). 



