50 BIVALVES. — VENUS. 



other genera of Bivalves : and it is in all probability from 

 this very circumstance that it has obtained the title it bears. 

 It contains no less than one hundred and fifteen spe- 

 cies; and among these the variety in formation and colour- 

 ing is almost infinite : many of its species have the frontal 

 margins of their shells somewhat flattened, and not unfre- 

 quently with the lips incumbent. The elongated, com- 

 pressed, angular, and orbicular forms, find a place in this 

 genus, as may be observed on inspecting the four follow- 

 ing species: viz. V. literftta, V. compressa, and V. tigrina. 

 In some, the form is very much inflated, gibbous, or savoI- 

 len, as in the V. verrucosa, V. fimbriata, and V. reticu- 

 lata. 



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 distingviished for their high and rich colouring. 

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

 carved word 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 colouring, 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 scarcely any exception, con- 

 tains three teeth, all approximate or close to each other ; 

 besides these three, there is a lateral tooth, not unfrequent- 

 ly divergent at the tip. The inner margin of the shell is 

 sometimes crenulated. 



