39 



lerior extremity, which is separated by a ridg-e 

 from the middle; jiosterior extremity produced, 

 rounded, g;aping ; section obovate. 



(Shell very gibbose, wider tlmn long, with prominent 

 beaks, and the anterior portion almost flat and without 

 ribs. Hitherto found only at Bognor: Mr. Dixon has 

 several specimens in his cabinet besides the one figured. 



PHOLADOMYA margaritacea. 



TAB. DCXXX.— ^g-. 3. 



Spec. Char. Subquadrate, very convex, ribbed; 

 ribs small, few (about 12\ extending over the 

 small anterior portion of the surface, which is 

 separated by an angle from the middle ; beaks 

 produced, pointed, placed near the anterior, 

 almost straight, truncated extremity ; section 

 elliptical. 



Syn. Cardita margaritacea, M. C. t. \7b.Jig.2k3. 

 Pholadomya margaritacea, M. C. General Index. 

 Morris, Cat. 98. 



1 vro new species of Pholadomya having been found in the 

 London Clay, it has become necessary to describe the P. 

 margaritacea with more precision ; and thus we have been 



