ch Lh, 
TRIBE MACTRACEA. 29 
—W, t.6.f.22.—M. Gieantea. Lam. 1.—H.t.259. f.1. Solid, 
oval, subtriangular, nearly smooth; under a thin whitish or yellowish 
epidermis, pale fulvous, opaque, the ventral edge little arcuated, 
slopes smooth ; hinge nearly but not quite central, the lateral teeth 
cross ribbed and elongated. 4.— New York. 
M. Srencuieri. Lam. 2.—Gmel. 3256.—D. p. 132.—Ch. f. 
199, 0, 1.—#. t. 252. f. 3.—Reeve. t. 42. f. 1.— Son. G. f. 1.— 
W.t 6. f.1. Triangular, smooth, both slopes flat, the anterior 
chiefly so, subdiaphanous, pale brownish ; beaks distant, separated 
by a transverse crescent-shaped gap, which contains the ligament. 
2..3.—Cape of Good Hope. 
M. Srriatrevta. Lam. 3.—E. t. 255. f. 2. Large, pellucid, 
convex, white, anterior slope obliquely striated, bounded by an 
obtuse angle ; beaks substriated ; lateral teeth short and smooth. — 
India. Larger but bearing some resemblance to the next. 
M. Striatuwa. LinH25.— D. p. 133.—Kn. 6. t. 34. f. 1.— 
M Carinata. Lam. 4.—E. t. 251. f. 1.—M. Avata. W.S. f. 7. 
Triangular, pellucid, white, convex; beaks smooth; hinge rather 
nearer the posterior than the anterior side which is bounded by an 
elevated plate with raised angles ; anterior lateral tooth small and 
close, the posterior elongated.— EH. Indies ? 
M. Guavuca.* Gmel. 3260.—D. p. 144.—W. t. 6. f. 30.—Ch. 
f. 232.—M. Hetvacea. Lam. 5.—NeEapourrana. Poli. t. 18. f. 
1, 2, 3. Triangularly oval, dirty white rayed with fulvous becoming 
by age of an obscurely rayed red colour, rather depressed, striated 
transversely ; beaks not quite central, smooth, and recurved, with 
a narrow gape beneath them. 2}..33.—Spain and Italy. 
M. Srutrorum. Lin. 1126.—D. p. 138.—Lam. 7.—Ch. f. 
224, 5.—Mont. p. 94.—Turt. B. p.72.—E. t. 256. f. 3.— Don. 
t. 106.—W. t. 6. f. 18.—Truiina Rapiata. Pen. 4. p. 87.t. 49. 
f. 30. Ovate triangular, thin, slightly depressed from the beaks at 
each extremity, subdiaphanous, nearly smooth, pale fulvous with 
obsolete white rays; beaks nearly central, and, as well as the interior, 
purplish red. 13..13.—Hurope, the Atlantic.? 
M. Granois. Lam. 6.—Gmel. no. 12.—D. p. 139.—E. t. 253. 
f.1.—Ch. f. 228.—W. t. 6. f. 19. Triangular, anteriorly the 
more produced and subrostrated, smooth, fawn colour with paler 
rays ; beaks tumid and violet-brown. 24..34.—Nemw Jersey ? 
M. Macutosa. Lam. 8.—M.Ornata? Gray in Mag. N. H. 
1837. ‘Triangularly oval, livid rufous, speckled with white, and 
marked with paler rays, smooth, subinequilateral ; beaks and sides 


2 The M. Cinerea* of Montagu, Pennant and Turton differs in being 
proportionately broader, of a pale drab with sometimes one or two 
obsolete white rays and never lilac internally. 
vee p.3% 
