48 



sides, pule brown with a few very obscure white rays ; 

 beaks prominent, incurved, from which there is a de- 

 pression to both extremities : inside pale with a tinge 

 of blush. l...2. Weymouth.fyc. 



M. GLAUCA. Gmel. 3260. D.p. 144. P.p. 428. 

 Mont. p. 571. Don. 4. t. 125. Pen. 4. p. 192. 

 Lin. T. 8. p. 6S.Turt. B. p. 74. M. HELVACEA. 

 Lam. 5.Ch.f. 232. M. NEAPOLITANA.PO&. t. 18. 

 f. 1, 2, 3. Oval, flattish, inequilateral, faint irregular 

 glaucous rays on a pale ground, finely striated trans- 

 versely ; beaks recurved, with a narrow gape under them. 

 2i...3K Very rare, Cornwall. 



M. FRAGILIS: Turt. B.p. 74. t. 4.f. \Q.An Ch. 

 f. 235. F.p. 428. Oval-oblong, compressed, nearly 

 equilateral and smooth, pale yellowish white, transparent, 

 angulated at the more produced side by a rib which 

 runs obliquely from the hinge to the margin; beaks 

 pointed with a depression under them on the shorter 

 side. If.. ..2. Guernsey, very rare. 



GENUS. LEPTON. TURTON. 



Flat, nearly orbicular, equivalve, inequilateral, a little 

 open at the sides, hinge of one valve with a single 

 tooth and a transverse linear lateral one on each 



