20 



BIVALVES CARDIUM. 



sticcs, or spaces between these ribs, are (in perfect spe- 

 cimens) of a fine dark-brown color, which gives the shell 

 a great boldness of character. 



A great part of this genus inhabit the European and 

 Northern seas; however, many are collected from the 

 American, African, and Indian oceans; the Mediterra- 

 nean, likewise, produces some of the species, and thf 

 mouths of rivers, as the Tees, Thames, &c. &c. also sup- 

 ply specimens, though rarely. One species is mentioned 

 as sometimes being found in a fossil state, viz. Cardiiun 

 Lithocardium. 



CARDIUM. 



Costatum. 



Cardissa. 



Roseum. 



Retusum. 



Hemicardium. 



Lithocardium. 



Lhieatum. 



*Medium. 



*Aculeatum. 



*Echinatum. 



*Ciliare. 



Ciliatum. 



*Tuberculatum. 



Isocardia. 



Fragum. 



Unedo. 



Muricatum. 



Ma«num. 



Flavum. 



*Leevigatuni. 



Serratum. 



*Edule. 



Islandicum. 



Groenlandicum. 



Rusticum. 



Glaucum. 



Pectinatum. 



Virgineum. 



Trilaterum. 



Auricula. 



Triste. 



IMonstrosum. 



Lima. 



Ringens. 



Papyraceum. 



j^lolicum. 

 Oblongura. 

 Crassum. 

 Latum. 

 *PygmaBum. 

 Maculatum. 

 Flexuosum. 

 *Fluviatile. 

 Gaditanum. 

 Brasilense. 

 Amboinense. 

 Squamosum. 

 Cancellatum. 

 Rubiginosum. 

 Albidum. 

 Virescens. 

 Fasciatum. 



