107 
short; beaks almost lateral, inclining to the shorter 
side ; hinge toothless, lateral, linear ; cartilage sub- 
internal, situated in a marginal groove ; scar single, 
sublateral, elongated und hatchet-shaped. 
M. RuomsBeEa. Berkely in Z. J. 3. p. 229. €. 18.7. 
1,.—Thin, rhombic, gibbous, with transverse subcrenu- 
lated folds which are posteriorly obscure, and longitu- 
dinal ribs; umbones incurved, slightly prominent. 
Length 0,17. Weymouth, rare. 
M. Mopiouvs. Turt. B. p. 199. ¢.15.f. 3.—ARoaA 
M. Lan. 1158.—Pen. 4. p. 238. t. 69.—Da Cos. p. 
219. ¢. 15. f. 5.—Don. 1. ¢. 23.—Inn. T. 8. p. 107. 
—Dor, Cat. p. 40. t. 12. f. 5.—D. p. 314.—Turt. D. 
p. LLL.—E#. ¢. 219. f. 1.—M. Vurearis. F. p. 412. 
—Oblong, smooth, long, thick, coarse, covered witha 
blackish skin, anteriorly obliquely dilated, the beaks 
tumid and obtusely angular ; when half grown thinner, 
of a horn color and usually clothed more or less with 
long leaf-like filaments which are entire on both their 
edges. (M. Barpatus. Lin. 1156.—Ch. f. 749.— 
Pen. 4. p. 238, t. 67. f. 2.—Don. 2. ¢. 70.) 4 or 5. 
Common. 
M. Grppsit. Turt. B. p. 200.—F. p. 413.—Leach. 
