CARDIUM. 



455 



Sub-gen. trachycardtum, Morch (Pectunculus, Mart., 



not Adanson). 



Shell oblong, oblique, sub-globose; valves with radiating, 

 squatnose ribs; hinder gape nai-row, and toothed on the hinder 

 edge. 



alternatum, Sow. 

 angulaturu, Lam. 

 arenicolum, Reeve. 

 assimile, Reeve. 

 Dupuchense, Reeve. 

 enode, Sow. 

 flavum, Linn. 

 foveolatum, Sow. 

 impolitum, Sow. 

 lacunosum, Reeve. 

 leucostomurn, Bow. 

 maculatum, Sow. 

 maculosum, Wood. 



muricatum, Linn. 

 nebulosum, Reeve. 

 oxygonuru, Sow. 

 Panamense, Sow. 

 procerum, Sow. 

 pulicarium, Reeve. 

 rubicundum, Reeve. 

 subelongatum, Sow. 

 subrugosum, Sow 

 unicolor, Sow. 

 variegatum, Sow. 

 vimineum, Martyn. 



Sub-gen. isocardta, Klein (Acanthocardia, Gray). 



Shell sub-globose, tumid ; valves with strong, spiny, radiating 

 ribs ; hinder gape nearly closed. 



aculeatum, Linn. 

 consors, Brod. and Sow. 

 Deshayesii, Payr. 

 echinatum, Linn. 

 erinaceum, Lam. 

 isocardia, Linn. 

 Mindauense, Reeve. 



multispinosum, Sow. 

 orbita, Brod. and S<nr. 

 paucicostatum, Sow. 

 pseudolima, Lam. 

 rastrum, Reeve. 

 rusticum, Linn. 

 tuberculatum, Linn. 



Sub-gen. ckrastoderma, Poli (Cerastes, Poli, not Hasselquist). 



Shell sub-cordate, convex behind; lunule simple; valves 

 closed, smooth or nearly smooth behind. Hinge with the 

 cardinal teeth well developed. 



"Raltiruni, Beck. 



Califomianum, Conr. 



