GQ CONCHYLIA— D/THFKJ. 22. 



Chama fusca. Lister, Conch, tab. 415. li^^ 259. 

 Mus. nost. On sandy and muddy .shores. 



Shell two inches and a half long, and four and a half broad, thin, 

 brittle, nearly equally rounded at both the ends, covered with a 

 greenish or brownish wrinkled skin which projects three or four 

 inches beyond the extremity of the shell, and covers the elongated 

 tube of suction : both the sides slope nearly equally from the hinge. 



Young shells are sometimes very much produced transversely, but 

 in all other respects similar. 



A singular variety, perhaps a distortion, is in our cabinet, in 

 which the valves are very unequal ; one of them being greatly con- 

 vex and larger, inclosing the other which is flat ; both of them fur- 

 nished with transverse plaits and striae, and on the inside of the 

 flat or smaller valve are raised laminar plates, especially under the 

 hinge : the cardinal margin runs in a nearly straight direction ; the 

 hinge is nearer to the more pointed end ; and it is barely an inch in 

 length and two in breadth. 



It may possibly be the Mactra planata of Chemnitz, iv. p. 238, 

 tab. 24, fig, 238 and 239, who describes it as being furnished with 

 unequal plaits both inside and outside, and very finely striated. It 

 was dredged up in Torbay. 



