30 CO^CUYLl A— DITHYR A, 7. 



Turton, Conch. Diet. p. 245. 

 Mus. nost. From rocks at Teignniouth and Torbay. 



Shell nearly an inch long, and more than two and a half broad, 

 brownish or yellowish white, with sometimes a few purple broken 

 rays and zig-zag lines, generally of an oblong shape angularly 

 truncate at one end, sometimes rounded at both ends, or kidney- 

 shaped and indented : beaks nearer one end, a little prominent 

 aitd recurved, without any distinct heart-shaped impression under 

 them : inside white, glossy, with mostly a purple blotch at the 

 larger end ; the margin plain : hinge with three erect long and 

 somewhat recurved teeth in each valve, two ©f them cloven ; the 

 lower one in the right valve, and the upper one in the left valve 

 plain and much smaller than the others. 



The young shells are flattish, white variously marked with 

 purple blotches at the anterior end, and may be easily mistaken 

 for the young of Venus pullastra; but besides the difference of 

 the teeth, the latter are much more angular, and rough at the 

 anterior end. 



8. MYA—LINNE. 



Testa transversa, eequivalvis, lateribns hianlibus. Cardo 

 valvof sinistra! dente elevato transversiin dilatato, ralvd 

 dextrd muticd : lateralilms nullis. Ligamenium internum. 



