182 CONCHYLIA— DiTHFi^^. U. 



Shell somewhat globular and pouderous, a little truncate on the an- 

 terior side, with 21 ribs, the anterior ones tubercular and the hin- 

 der ones somewhat scaly, and together with the interstices rough 

 with wrinkled strioe. 

 Cardiura tuberculatum. Linn Syst. Nat. p. 1 122. 



Gmelin, Syst p. 3248. 



Turton, Linn Syst. iv. p. 202. 



Pennant, Brit. Zool. iv. p. 188. 



Donovan British Slu'lls, iii. tab. 107, fig. 2. 



Montagu, Test. Brit. p. 568. 



Linn. Trans, viii. p. 64. 



Turton, British Fauna, p. 152. 



Wood, Conch, p. 210, tab. 50. fig. 1, 2. 



Dorset Catal. p. 31, tab. 2. fig. 2. 



Dillwyn, Descript. Catal. p. 117. 



Turton, Conch Diet. p. 28, iig. 12. 



Chemnitz, vi. p. 179, tab. 17, fig. 173. 

 Pectunculus major. Lister, Conch, tab. 329, fig. 166. 

 Mus. nost. On the western coasts • 



Shell growing to the size of the last, from which it differs in the 

 following particulars, and by which they may be easily distinguished. 



It is more solid and ponderous, of a more globular shape, and 

 running in a nearly straight line on the cartilage side from the 

 beaks ; the ribs are narrower, and the grooves are deeper, both 

 marked with strong irregular transverse striae : the cartilage side 

 is clothed with rather sharp tubercles which never extend into 



