ELASMOBRANCHII. 



87 



eter, and surface of each with a depression. Length (width) 

 82 mm. 



Known from the type described above and a paratype. Both 

 are thought to be the upper dental plates, anteriorly abraded by 

 the attrition of food. Leidy suggested M. bisulcus may possibly 

 prove to be the lower jaw of this species, as it has a median deep 

 groove. The other example he describes has seven large median 

 transverse teeth in its dental plate. Although Hussakof has 



Fig. 42. — Myliobatis fastigiatus (Leidy). (Paratype.) Monmouth Co. 

 (Slack). 



listed an example of this species as typical and being in the 

 American Museum in New York, the original of Leidy' s figure 

 11 is in the Academy. Further, his example is said to be an upper 

 dental pavement with 11 median and several small lateral teeth. 

 Leidy states that this example has seven median teeth, together 

 with three small teeth of the first row of one side. 



Formation and locality. Known from the Eocene of Mon- 

 mouth County by the type (W. Cleburne) and one paratype (J. 

 H. Slack). 



