CONCHYLIA— DITHYT?^. 39. 171 



The beaks appear to separate and become gradually more distant 

 at their points, as they advance in age, exhibiting the marks of their 

 annotination, or annual growth, by transverse lifles or wrinkles in 

 the hollow space between them, and not on the external surface, as 

 in most other bivalves. 



Pectunculus testa obliqud ineequilaterali, antici subangulatd. Giycymens. 



Shell oblique and inequilateral, a little angular at the anterior side. 



Tab. nost. 12, fig. 1 . 

 Area Glycymeris. Linn. Syst. Nat. p. 1143. 



Gmelin, Syst. p. 3313. 



Turton, Linn. Syst. iv. p. 256.] 



Pennant, Brit. Zool. iv. p. 216. 



Ldnn. Trans, viii. p. 93, tab. '3. fig. 3. 



Turton, British Fauna, p. 160. 



Dillwyn, Descript. Catal. p. 241. 



Turton, Conch. Diet. p. 7. 



Chemnitz, vii. p. 229, tab. 57, fig. 564. 

 Pectunculus maximus. Lister, Conch, tab. 240, fig. 77- 

 yius. nost. Western coasts and British Channel. 



Shell growing to more than three inches in diameter, rather con- 

 vex, but not so tumid as the Pectunculus pilosus, very finely decus- 

 sate, and when fresh clothed round the margin with a dark brown 

 silky skin, under which it is greyish-white with obscure longitudi- 

 nal reddish marks : the outline is oblique, with a slight angularity 

 At the produced side. 



z 2 



