42 BIVALVES. — VENUS. 



ing tlie four following species : viz. V. literala, V. com- 

 pressa, V. scripta, and V. tigerlna. In some, the form is 

 very much inflated, gibbous, or swollen, as in the V. ver- 

 rucosa, V. fimbriata, and V. reticulata. 



Many of this genus are remarkable for their smoothness, 

 and the brilliant lustre of their surfaces, such as the V. 

 Erycina, V. maculata, V. Chione, &c. these at the same 

 time are distinguished for their high and rich coloring. 

 Others, again, have less of color and polish, but more of 

 carved work or reticulations, as the V. Paphia, V. reticu-* 

 lata, &c. and one species is even spinous, viz. V. Dione. 



In many specimens the exterior surface is covered with 

 longitudinal or transverse striae, sometimes with both, 

 which not unfrequently terminate in foliations near the 

 margins. 



The interior of the shells of this genus is often adorned 

 with rich coloring, as in the V. mercenaria or wampum 

 clam, which in fine specimens is of a rich purple. The 

 North American Indians make their wampum or money 

 of the shells of this species. 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 un- 

 frequently divergent at the tip. Tiie inner margin of the 

 shell is sometimes crenulated. 



Almost all parts of the world supply specimens of this 

 genus. The American, African, Eastern, and Western 

 Oceans abound with them. The Mediterranean, Caspian, 

 and Southern Seas likewise produce various species j as 

 also do the European and more northern oceans. 



Several species are found in a fossil state. 



