VENUS- VENUS. 169 



of the beaks towards the areola, at once deter- 

 mine a shell to be a Venus, but these marks are 

 sometimes wanting ; in a few species there are 

 four cardinal teeth in each valve, and this is the 

 distinguishing mark of the genus separated from 

 this, under the name Cytherae. Those Veneres 

 which have only two teeth in each valve, belong 

 to the modern genus Crassina. 



The Venus is diffused over every part of the 

 world, and in many countries affords to animals 

 and birds a nutritious food. It is curious to 

 observe the contrivances by which the sea-fowl 

 endeavour to procure the mollusks of this and 

 other genera ; they have been seen to take ad- 

 vantage of a moment, when the shell is open, to 

 drop a pebble between its valves, which being 

 thus prevented from closing, the inmate is left ex- 

 posed to their attacks. Sometimes when they find 

 the shell so hard as to resist all their efforts to 

 break it with their beaks, they ascend to some 

 lofty eminence, and letting it drop upon rough or 

 craggy rocks, it is crushed in the fall, and the 

 animal thus becomes their prey. The mollusk of 

 the Venus has two siphons formed by the mantle, 

 and a lamellar foot. 



. VENUS Mercenaria. 



MONEY VENUS. 



Specific Character. Shell ponderous, oblique- 



