46 



tooth in each valve, and an adjacent heart-shaped 

 cavity, two lateral compressed teeth situated near 

 the hinge and inserted; ligament internal and 

 placed in the pit of the hinge. 



* Lateral teeth striated. 



M. SOLIDA. Lin. 1126. D. p. 140. Lam. 23. 

 Pen. 4. p. 123. t: 66. f. 2.Ch. f. 229, 230. Don. 

 t. 61. Mont. p. 92. Lin. T. 8. p. 70. Dor. Cat. p. 

 32. t. 6. /. 6. Turt. C. D. p. 81. Da. Cos. t. 14. 

 f. 6. Sub-triangular, strong, opaque, sub-equilateral, 

 slightly depressed from the beaks at both extremities, 

 nearly smooth, with a few concentric antiquated ridges, 

 dull dirty white; inside glossy and white. H...l|. 

 Common. 



M: TRUVCATA. Mont. Sup. p. 34. Turt B. p. 68. 

 F.p. 427. M. SUBTRUNCATA. Don. t. 126. 

 M. CRASSATELLA. Lam. 33. Triangular, equilateral, 

 solid, depressed from the beaks at both extremities, so 

 that the sides almost form a rectangle at the prominent 

 beaks; convex, solid, opaque, dull yellowish white, 

 sub-angulated anteriorly, irregularly striated by the 

 lines of growth : umbones large and prominent, slopes 

 striated . H . . . H . Teignmouth and Scotland. 



