CONCHYLIA— DITHFE^ 14. 45 



Shell four inches long, and twice as much broad, coarse, wrinkled 

 transversely in a laminar manner, of a yellowish or ochraceous color, 

 obliquely truncate at the anterior end, and irregular at the margin. 



14. A^AUm A.^LAMARCK. 



Testa transversa vel suborbicularis, inoEquivalvis, utrinque vel latere 

 antico hiante. Cardo dente dilatato concavo interne prominulo in 

 utrdque valvd : lateralibus nullis. Ligamentum externum, breve. 



Shell transverse or somewhat orbicular, inequivalve, open at the 

 anterior or both ends. Hinge with a dilated concave tooth pro- 

 jecting a little inwards in each valve : lateral teeth none. Liga 

 ment external, short. 



This is a very natural genus, and well merits the attention of 

 such conchologists as may have opportunities of examining carefully 

 the rocky parts of our coasts ; as we are inclined to think, that 

 some very distinct species may yet remain to be discovered. 



And for the purpose of clearer and more decided discrimination, 

 a careful examination of the teeth or spoon-shaped cavities, 

 may oflFer much facility ; some of them being placed in an oblique 



g2 



