OF THE UNITED STATES. 305 



DONAX, Lin. 



Species. 



1. D. ^variabilis. Shell triangular; anterior mar- 

 gin obliquely truncated, cordate, suture a little con- 

 vex ; posterior hinge margin nearly rectilinear, su- 

 ture indented ; base a little prominent, beyond a re- 

 gular curve, near the middle ; valves longitudinally 

 striated with numerous, equal, parallel, regular, im- 

 pressed lines, hardly visible to the unassisted eye, 

 and obsolete on the posterior margin ; basal edge 

 within crenate. 



Length half an inch. 



Width nine-tenths of an inch. 



Thickness seven-twentieths of an inch. 



Inhabits the coasts of Georgia and East Florida. 



Cabinet of the Academy and Philadelphia Mu- 

 seum. 



Varies very much in colour and is a very pretty 

 shell. Its usual varieties are red, white, yellow, or 

 elegantly radiated with dilated reddish -brown lines, 

 upon a white or yellow ground ; lines are purpures- 

 cent within the shell. A very common shell; I found 

 it more particularly numerous on the beach of Cum- 

 berland island, where, in favourable situations, at the 

 recess of the tide, it may be taken up in handfuls, 

 without any intermixture of sand. It is very distinct 

 from .D. rugosa, but approaches much nearer to 

 D. trunculus, from which it is distinguished by being 



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