64 



teeth on each valve, and even appears to have but 

 one, very large, on the left valve, the other projecting 

 but slightly. Shell orbicular, transverse, equivalve, 

 subinequilateral, and closed. Hinge with two strong 

 divergent teeth on the right valve, and two very une- 

 qual on the other. Ligament external, and placed on 

 the longest side. 



Sowerby, in his Genera of Shells, properly calls 

 this genus Astarte, several species having been describ- 

 ed under that name previous to La Marck's adopting 

 that of Crassina. 



Crassina Danmonicnsis. 



CYCLAS. 



T ELLIN A CORNEA. Linn. 



Lister, Conch, tab. \b§,fig. 14. 

 Shells of this genus are small, of a very convex oval 

 form; valves thin, and always without three primary 

 teeth on either of them; apices never eroded or decor- 

 ticated: some species are so thin and fragile, as to be 

 transparent, the valves smooth, or transversely stri- 

 ated. Shell transverse, equivalve; apices protuberant; 



