^7 



CHAM A squamosa. 

 TAB. CCCXLVIil. 



Spec, Char. Attached by the right valve ; 

 nearly orbicular, siibglobose, imbricated ; 

 lamellae undivided, somewhat erect, ante- 

 riorly produced, and adpressed ; posterior 

 part of the right valve obsoletely costated ; 

 left valve rather convex ; smooth witliin. 



SvN. Chama squamosa. Brander, 8G and 87. 



Distinguishable from Chama lamellosa of Lamarck, 

 who has referred to Brander for his shell, by its undi- 

 vided and not even lobed lamellae. 



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 ri^fht or 

 the left hand, and the definition become more intelligible. 



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. 



