248 DESCRIPTION OF VERTEBRATE REMAINS, CHIEFLY 



and aft width, 3 lines ; tliickness, ^ lines ; thickness of crown, 2^ lines. The 

 differences from the former are such as are observed in intermediate teeth to the 

 worn and unworn teeth of the recent Zygohates Jussieu. 



Figures 28-33 represent three teeth, which from the difference in thickness 

 between their outer and inner ends, indicate a position in the series succeeding 

 the median one. The dull aspect of the triturating surface and the comparative 

 thinness of the crown show that they are all worn specimens. Their measurements 

 are as follow: — 



Breadth of crown . . . 12| lines. 11 lines. IQi lines. 



Width fore and aft ... 4^ " 4 " 21 " 



Thickness internally . . . 2 " li^ " * 1^5 " 



" externally ... ^i " 1 " ^ ' 



A small tooth, represented in figures 34, 35, resembles those of the third row 

 outwardly from the median series of the recent Z. Jussieu, except that it is broader 

 than usual in proportion to its fore and aft width. It is hexagonal, broader than 

 wide, and thicker internally than externally. Its dimensions are as follow: breadth, 

 5i lines; width, 3 lines; thickness of the crown internally, 2| lines; externally, 2 

 lines. The root is broken away. 



Another small tooth, represented in figures 36, 37, is unlike any with which I 

 am familiar, and perhaps pertains to a different species from the preceding. It is 

 from the outermost row of the dental series, and is about four times as broad as wide 

 fore and aft. The inner end is rectangular and thick, and the tooth thins away 

 outwardly to a sharp border. The outer end is rather abruptly curved backward. 

 The measurements are as follow: breadth, 8 lines ; width, 2 lines; thickness of 

 the crown internally, 2[ lines. The root is broken away. 



Prof. Emmons, in his Report of the North Carolina Geological Survey for 1858, 

 page 243, has represented several isolated median teeth, under the name of Trygon 

 carolinetisis, from the eocene marl of Craven Co., North Carolina. They resemble 

 specimens from Ashley Kiver attributed to Zygohates duhius, and perhaps pertain 

 to the same. 



CERATOPTERA. 



Ceratoptera unios. 

 Leidy: Proceedings Academy of Natural Sciences of Philadelphia, 1876, 86. 



Among the fossils of the Ashley phosphate beds, an interesting one recently 

 obtained is the specimen represented in figures 1, 2, Plate xxxiv. It appears to 



