the edge rounded at the bafe and runs into a fharp procefs 

 about half way up ; from whence it turns in a diagonal 

 line to cover the edge of the two fuperior valves : the 

 the whole fhell is much comprefTed; the anterior and 

 pofterior fides are nearly parallel to each other for rather 

 more than half way froni the bafe ; the upper part is 

 truncated obliquely to the front ; the apex turns a little 

 backward. 



The peduncle is large in proportion, cylindric, com- 

 pofed of many annulations of the fame colour as the fhell ; 

 is nearly of the fame length, and covered with fliort 

 hairs. 



This fpecies is rarely above five-eighths of an inch long 

 independant of the peduncle; and three-eighths broad. 

 It is a rare fhell, and (eldom met with on our coaft. 



We firfl; received it from Mr. Boys of Sandwich, and 

 fince found it on a fpecies of Gorgonia, to which it feems 

 to be particularly attached. Chemnitz mentions the 

 fame circumftance. Hitherto it has been only known as 

 a produftion of the Norwegian feas, and even there ac- 

 counted extremely rare. Ours M^ere idtk^n o^ Plymouth 

 by trawling. 



D 2 GEN. 



