OF THE UNITED STATES. 325 



which the anterior process and the basal cone are 

 firmly attached. 



Bruguiere in forms us that the galea is obtained 

 from great depths in the ocean only ; but I have 

 found the elongata in considerable numbers in inlets 

 of the bay of Charleston, on Gorgonia, which at the 

 recess of the tide was visible on the surface ol the 

 water. 



This species, like the galea, is often found coated 

 over with the conical envelope of the Gorgonia, and 

 the animal destroyed, probably by its encroachment. 



CGRONULA, Lam. 



Species. 



C. *dentulata. Shell depressed-conic ; base oval; 

 height equal to about one-third of the base ; valves 

 and interstices smooth, the anterior valve largest, 

 and the posterior one smallest ; operculum trans- 

 versely striated, the posterior pair of valves with a 

 submarginal impressed line, from which to the edge, 

 are drawn three or four other impressed lines. 



Found on the Clypeus of Limulus Polyphemus. 



Collection of the Academy and Philadelphia Mu- 

 seum. 



The posterior margins of the posterior valves of 

 the operculum, are divided by the impressed lines, 

 into three or four broad, flat, dentiform divisions, 

 which, however, but simply crenate the edge. 



