38 



PHOLADOMYA vii-ulosa. 

 TAB. DCXXX.— fig. I. 



Spec. Char. Transversely elongated, convex, rib- 

 bed ; ribs numerous (about 24), rounded, thin, 

 crossed by many irregular waves, obscure on 

 the anterior and wanting on the posterior slope; 

 beaks near the anterior extremity, which is 

 truncate ; section ovato- cuneiform. 



At least one-fourth wider than long, with the sides a little 

 flattened ; the ribs above 24, thin, and divided into small 

 tubercles by the concentric undulations. This shell has 

 long been known as found in the Bognor rocks, but I am 

 not aware that it has been discovered elsewhere. The 

 name has been given it by a society of gentlemen who meet 

 to study tertiary fossils. It is a very distinct species ; the 

 specimen figured is in Mr. Dixon's cabinet. 



PHOLADOMYA Dixoni. 

 TAB. DCXXX.— Jig. 2. 



Spec Char. Transversely oblong, gibbose, rib- 

 bed along the middle, concentrically waved ; 

 ribs few (about 12), slender ; beaks large, 

 placed near the truncated but not gaping an- 



