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DIVISION XI. CAMACEvE. 



GENERA. 



4. DicerAs. (1) Lam. 



Inequivalved, adherent; 1 very large, thick, 



beaks large, diverging, concave, sub-auricular 



conical, turned in irregu- tooth, projecting into 

 lar spires. Fig. 56. 



the largest valve. 



1. Chama. Lin. M. 



Irregular, inequivalved, 

 adherent ; beaks curved, 

 unequal. Fig. 60. 



1 thick, oblique, sub- 

 crenated tooth, fitting 

 into a hollow on the op- 

 posite valve. 



a. Beaks turning from left to right. 

 f. . . : . . right to left. 



hinges un- 



No tooth ; 

 dulated, sub - sinuated, 

 unequal. 



3. Etheria. Lam. M. 



Irregular, inequivalved, 

 adherent ; beaks short, as 

 if sunk into the base of 

 the valves ; shell foliated, 

 with irregular blisters (ap- 

 parently accidental) with- 

 in. Fig. 59. 



a. An oblong callosity in the base of the shell. 

 ft. No callosity 



Ligament exterior, 

 deeply inserted. (2) 



Ligament exterior, 

 twisted, partly penetra- 

 ting the shell : muscular 

 impressions distant, la- 



teral. 



oblong. 



(3) 



(1) I have only been able to procure the mould of a Dlceras to draw from ; 

 there is but one species known, and that in a fossil state. Cuvier does not see 

 any essential difference between it and the Chama. It is found at Mount Saleve, 

 and in the environs of St. Mihiel in Lorraine. Interior moulds of a smaller size 

 have been found at Clevre, near Ferle-Benard, in the department of Sarthe, and 

 in that of Calvados. 



(2) Almost all the Camacece adhere to rocks, corallines, and frequently to each 

 other. Foss. in the Green Sand, Kelloway Stone, at Piedmont, Angers, Plaisance, 

 Grignon . 



(3) This is a very rare shell, and is sold at a considerable price : the blisters 

 found on its inner surface, have never been satisfactorily explained. East- 

 Indies and Madagascar. 



B 



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