26 



BIVALVES VENUS. 



In many specimens the exterior surfiice is covered with 

 longitudinal or transverse striae, sometimes with both, 

 which not unfrequcntly terminate in foliations near the 

 margins. 



The interior of the shells of this genus is often adorned 

 with rich coloring, as in the Venus Mercenaria or Wam- 

 pum Clam, which in fine specimensis of a rich purple. 

 It is from these shells that the North American Indians 

 make their wampum or money. The same shell, in a 

 fossil state, is often found in the Swedish mountains. 



The hinge of the Venus, with scarce any exception, 

 contains three teeth, all approximate or close to each 

 other; besides these three, there is a lateral tooth, not 

 mifrequently divergent at the tip, the inner margin of 

 the shell is sometimes crenulate. Some of the species, 

 though rarely, gape. 



Almost all parts of the world supply specimens of this 

 genus. The American, x\frican. Eastern, and Western 

 Oceansabound witli them. The Mediterranean, Caspian, 

 and Southern Seas likewise produce some species; as also 

 do the European and more northern oceans. 



Several species are found in a fossil state. 



VENUS. 



