170 BIVALVES. 



liquely heart-shaped, slightly striated trans- 

 versely ; posterior depression cordiform ; inner 

 margin crenated ; the outside is greyish or 

 brownish, the inside is white, with a violet- 

 coloured spot at the anterior side; the length 

 is about two inches and three-quarters, the 

 breadth about three inches and a half. 



The Indians of North America cut these 

 shells into beads, some white and some black ; 

 of these they form their wampum, or treaty- 

 belts, which are symbolical of friendship. They 

 also string them together and use them for 

 money. The females cover the shoes they wear 

 in dancing with these shells, which in their 

 movements being struck together produce a 

 sound resembling the tinkling of the bells used 

 by the Israelitish women, and mentioned in 

 Isa. iii. 16. 



VENUS Dysera* 



RIBBED VENUS. 



Specific Character. Shell triangular, convex, 

 heart-shaped, marked with distinct concentric 

 raised ridges, which are closely cancellated ; f 

 the longitudinal striae are also crossed by fine 



* Plate VIII. figure 8. 



"T" Cancellated, crossed like the bars of a window, from 

 the Latin cancelli, lattice. 



