(52 



GENUS. PSAMMOBIA. 

 Transverse, elliptical or oblong-ovate, compressed, 



slightly gaping at one side ; beaks prominent ; two 



cardinal teeth in the left valve and one in the oppo- 



site, no lateral teeth. 



P. TELLINELLA. Lam. 1. P. FLORIDA. Turt. B. 

 p. 86. t. 6./. 9. F.p. 437. Oblong, nearly smooth, 

 thin, subequilateral, anteriorly obtusely angulated, 

 posteriorly rounded, yellowish, with either red inter- 

 rupted rays or zones, but always with one small distinct 

 posterior ray, which only proceeds a short distance 

 from the beaks. $ . . . 0,83. W. Coasts of Ireland. 



P. COSTULATA. Turt. B.p.87. t. 6./ 8. F.pA37. 

 P. DISCORS. Philippi.p. 23. t. 3./. 8 Oval-oblong, 

 thin, slightly angular anteriorly where there are about 

 twelve fine oblique radiating ribs ; color varying from 

 pale yellow to deep purple and marked with crimson 

 blotches or stripes ; transven ely striated and minutely 

 so longitudinally ; beaks nearly central, a little promi- 

 nent, not inclining to either side : hinge with a single 

 cloven tooth in one valve locking into two in the other, 

 one of which is slightly cleft. i,..l. Dredged in 

 Torbay and the Channel. 



P. FRAGILIS. Turt. B.p. 88. t. 7./. 1 1,2. F.p, 

 TKLLINA F. LU. 1117, C*./ 5*4, Twt. 



