pale brown zones, but it is occasionally nearly white 

 and immaculate; in other specimens the ribs are 

 spotted. 



Besides the variety indicated by Mr. Say, which 

 is more compressed and variegated, another occurs 

 entirely black, with smaller ears, but of this I have 

 seen only a few inferior valves. A third beautiful 

 variety is represented in the smaller figure. It was 

 found on the coast of Rhode Island by Lieut. Brown 

 of Newport, and communicated to Mr. D. B. Smith 

 of this city. 



This shell is very common on the new Jersey coast, 

 where numbers may be observed scattered along the 

 beach, but Long Island Sound produces the largest 

 and most beautiful specimens. The animal is eaten, 

 and is comparable in flavour to the lobster. It is sold 

 in the New York market, but as an article of food is 

 scarcely known in Philadelphia. 



On the coast of Long Island, where the flats or 

 shoals extend to a considerable distance, and the wa- 

 ter is about two feet deep, immense numbers of the 

 young of this species may be observed swimming near 

 the surface, which they are enabled to do by opening 

 and closing the valves with great rapidity. My friend 

 William R. Clapp informs me that he has frequently 

 witnessed this interesting exhibition of activity, so 

 strongly contrasting with the habits of the Ostreadx, 

 and other bivalve shells which have not the power of 

 locomotion. 



Before Mr. Say described this shell as a distinct 

 species, it appears to have been confounded with P. 

 opercularisy a common shell on the coast of Great 

 Britain, but not hitherto found on this side the At- 



