ELASMOBRANCHIL 91 



Leidy notes that the above tooth at the median prominence is 

 no thicker than in the smaller of the dental plates described as 

 Myliobatis fas<tigiatus, while it is considerably broader. The 

 prominence appears as an exaggeration of the median ridge o" : 

 the dental plate of M. fastigiatus, due to the more abrupt depres- 

 sion of the sides of the crown. In this specimen the coronal emi- 

 nence is unsymmetrical. 



Formation and locality. Only the above-described tooth, said 

 to be from the Eocene [Manasquan ? K.] marl beds at Vincen- 

 town, in Burlington County (T. M. Bryan), and presented to 

 the Academy of Natural Sciences of Philadelphia. I have not 

 located this specimen. 



Myliobatis leidyi Hay. 



Myliobatis leidyi Hay, Amer. Nat. XXXIII, 1899, p. 785 (name based on 



Leidy). 

 Myliobates serratus (nee Meyer 1848) Leidy, Proc. Acad. Nat. Sci. Phila., 



1855, p. 239. Greensand of Burlington Co., N. J. 

 Leidy, Journ. Acad. Nat. Sci. Phila., (2) VIII, 1877, p. 239, PI. 32, fig. 5, 



(Pemberton Eocene, same example.) 



Dental plate depressed in form, composed of six median teeth 

 and a single series of lateral teeth on each side. Triturating sur- 



Fig. 46. — Myliobatis leidyi Hay. (From Leidy.) 



face of plate dull, but slightly impressed along median line, in- 

 clines forward and downward on first tooth, apparently as result 

 of wearing. Transverse sutures of median teeth gently curved 

 with convexity backward. Lateral teeth hexagonal, nearly broad 

 as fore and aft wide. Sutures generally, especially outer parts 



