CONCHYLIX—DITHYRA. 14. 49 



Turton, British Fauna, p. 147. 

 Wood, Conch, p. 98. 

 Dillvoyn, Descript. Catal. p, 45. 

 Turton, Conch. Diet. p. 101. 

 Mus. nost. From rocks in Torbay. 



Shell from half an inch to an inch in diameter, very variable 

 in shape, orbicular, oblong, or kidney-form, with the margin 

 variously indented, rarely entire : but all the varieties may be 

 known by the projecting teeth. 



Anatina testd convexd oblongd, anguUs bints transversis, latere aictica 

 antico truncato, umbonibus terminalibus, cochlearibus rotun- 

 dato-protensis. 

 Shell convex oblong, with two transverse angles, truncate at 

 the hinder end, the beaks terminal, and the teeth rounded and 

 projecting inwards. 



Ta6. «os#. 4, fig. T and 8. 

 Mya arctica. Ltinn. Syst. Nat. p. 1113. 



Gmelin, Syst. p. 3220. 

 Turton, Linn. Syst. p. 177. 

 Wood, Conch, p. 93. 

 Turton, Conch. Diet. p. 104'. 

 Mus.nost. From a mass of Sertularia, in Dublin bay. 



SMfh^lir'aniiicKiaH^ knil'rjmi^'iifbV^tH^if'tilf^&^qlihftKM^if 

 an inch broad, with the beaks prominent and close to the hinder 

 end, from which ran two transverse ridges, one along the back 

 margin, and the other obliquely to the angle of the front margifl'J 



H 



