560 



Number of pairs of ambulacral pores.* 



Ant. lat. dors. amb. 8+10. 

 Post. lat. dors, amb. 13 + 8. 

 Loc. Petersbui-g. 



(^Family Cidarites.) 



2. Echinus Ruffinii Edw. Forbes^ 



[Feb. 26. 



1 



a. Echinus Ruffinii, viewed from above. 



b. Ditto, mouth. 



c. Ditto, a spinigerous tubercle. 



d. Ditto, ambulacra] plates and arrangement of pores. 



(a, h, natural size ; c, d, enlarged.) 

 Body subdepressed ; ambulacral and interambulacral plates with several 

 primary tubercles on each, closely ranged, having circles of secondary 

 tubercles surrounding their (broad) bases; rows of pores very oblique, 

 three pair of pores in each row, the uppermost distant from the other two. 

 Beneath concave, mouth broad, widely notched, opposite each avenue. 

 Anus narrow. 



Lat. 1 unc. ; Alt. ■^. ; Lat. apert. ^^. 

 The primary tubercles, being very numerous and of almost equal size, 

 give the testa a very granulated appearance. 

 Loc. Williamsburg, Virginia. 

 3. Spines of an Echinus from James River. Virginia. 



Ridges fine, numerous ; interstices apparently smooth, broader than the 

 ridges. 



Fish. 



The remains of fish consist chiefly of teeth of the shark family, 

 all belonging to existing genera. 



1. Carcharias megalodon. Evergreen, James River. 



2. Lamna xiphodoii. Evergreen, precisely like specimens I have seen from 



Touraine. 



3. L. hastalis ( Oxyrhina"). Evergreen, Virginia, like a specimen from Martha's 



Vineyard, and in the molasse of Switzerland. 



4. L. cuspidata. James River, also common to the molasse, 



5. Carcharias productus. Evergreen, also from the miocene of Malta. 



Several other shark's teeth, and the ossicles of the ears of fishes, which 

 I found in the miocene strata of Petersburg, Virginia, were very analo- 

 gous to European miocene fossils. 



* In another specimen the number was found to be — I 



Ant. lat. dors. amb. 8+13. I 



Post. lat. dors. amb. 11+11. 

 And four pair additional on each side of the ovarian holes. 



