(57 



170, F. p. 435. Ovate, thin, transparent, glossy, 

 white ; anteriorly contracted, posteriorly rounded ; one 

 of the valves obliquely striated, the other quite smooth ; 

 two cardinal and a single lateral tooth in one valve, only 

 single cardinal in the other. i...f . Common on sandy 

 coasts. 



T. SIMILIS. Sow. Brit. Mis. t. 75. Mont Ap. p. 

 157. Turt. C.D.p. 170. Turt. B. p. 102. F. p. 

 435. Oval, with both valves obliquely striated ; a 

 lateral tooth in each valve. Paignton sands, very 

 rare. 



T. DONACINA, Lin. 1118. D.p. 89. Lam. 27. 

 Mont. p. 58. t. 27. f. 3.Poli. 1. t. 15. /. [O.Pen. 

 4. p. 178. Lin. T. S. p. 50. t. I./. 7. Dor. Cat. p. 

 29. t. iZ.f.Zv. Wood. G. C.p. 161. t. 45. /. 5. 

 Turt. D. p. 170. F. p. 435. Turt. B. t. 8./. 4. p. 

 103. Oval-oblong, anteriorly very short and obtusely 

 cuneiform, posteriorly rounded ; the posterior dorsal 

 edge but little sloping ; yellowish with narrow red, often 

 interrupted rays, semi pellucid ; hinge in one valve with 

 a cloven cardinal tooth, an additional simple one and 

 lateral teeth on each side in the other. i...l. Guern- 

 sey, Devon, Dorset, not common. 



