CONCHYLI A— D/THYl?^. 38. 165 



Dorset Catal. p. 35, tab. 1, fig, 14. 



Dlllwyn, Descript. Catal. p. 191. 



Turton, Conch. Diet. p. 240. 



Chemnitz, vii. p. 6, tab. 37, fig. 390, 391. 

 Pectunculus magnus. Lister, Conch, tab. 337, fig. 174. 

 Mus. most. From Guernsea. 



Shell nearly an inch in diameter, flattish and rounded in the out- 

 line, strongly decussate, yellowish-white, with generally a crimson 

 or purple tinge about the margin near the beaks which are small and 

 pointed : inside smooth, glossy white. 



38. ARCA— L/iViVE. 



Testa transversa, suboequivalvis, inoEquilateralis ; umbonibus remotis, 

 area transversa intermedia. Cardo rectilinearis, dentibus numerosis 

 obtusis alternatim insertis, exterioribus majoribus : lateralibus nullis. 

 Ligamentum externum. 



Shell transverse, mostly equivalve, inequilateral, with the beaks re- 

 mote and separated by a transverse area. Hinge in a straight 

 line, with numerous obtuse teeth alternately closing together, 

 gradually enlarging from the centre : lateral teeth none. Liga- 

 ment external 



