CO. AM A squamosa. 

 TAB. CCCXLVIIl. 



Spiic. Char. Attached by the right valve ; 

 nearly orbicular, siibglobose, imbricated ; 

 lamellse undivided, somewhat erect, ante- 

 riorly produced, and adpressed ; posterior 

 |)art of the right vaive obsoletely costated ; 

 left valve rather convex ; smooth within. 



Syn. Chama squamosa. Srander, 8G and 87. 



T)ist;nguishable from Chama lamellosa of Lamarck, 

 ^vho has referred to Brander for his shell, by its luuli- 

 vided and not even lobed laraellee. 



In the section to which this species belongs the right 

 valve is the largest and the one attached to foreign sub- 

 stances : by considering this the two sections of the 

 genus made by Lamarck will be as readily recognised, 

 as by observing whether the beaks turn to the right or 

 the left hand, and the definition become more iatelligii)le. 



Extremely common at Barton, where perfect pairs are 

 often found : it seldom exceeds in size the specimens 

 figured ; it is consequently a smaller shell than C. lamel- 

 losa : I have small individuals from some part of France ; 

 I think the neighbourhood of Paris ; it is however rare 

 in that country. 



