74 
54.—Pen. 4. p. 181.—Wood. G. C. p. 183. t. 42. f. 
4.5.—Turt. C. D. p. 175.—VENuts Boreatis. Don. 
4.¢. 130.—V. Spurtia. D. p. 194.—Lenticular, con- 
vex, dirty white, with numerous raised transverse thread- 
like striz (which become indistinct in old shells, 
towards the margin), the interstices broad and shallow ; 
inside dull chalky white; beaks central, pointed, and 
a little curved ; a small lunule; two teeth (one bifid) 
in each valve. 13. W, and Irish Coasts. 
L. Sinvosa. Lam. 17,—L. Fiexvosa. F. p. 442. 
—Gould. p. 52.—TeEiina F. Mont. p. 72,—Lin. 
T. 8. p. 56.—Wood. G.C. p. 188. #. 47. f. 7, 8.— 
D. p. 99.—Turt C. D. p. 177.—-Venus SINvosA. 
Don. t 42.f. 2.—Cryptopon F. Turt. B. p. 121. t. 
7. f. 9, 10.—Suborbicular, longer than broad, very con- 
vex, pure white, thin, pellucid, marked with minute 
irregular concentric wrinkles, and a longitudinal furrow 
extending from the apex parallel to the cartilage slope, 
and forming a deep incurvation in the margin at its 
termination: hinge with a single obscure penetrating 
cardinal tooth. #. S. Coasts. 
L. SpinrrFera.—Vewnus 8. Mont. p. 577. ¢.17. f. 1. 
—Lin. T. 8. p. 78.—D. p. 163.—Turt. C. D. p. 231. 
—Myrtera 8S. Turt. B. p. 133.—F. p. 443.—Oval 
