TRIBE CONCHACEA. 95 
13.—Ch. f. 327, 8, 9.—E. t. 250. f. 1.— Reeve. t. 64.—W.t. 7. f. 
48. Sub-equilateral, sub-triangular, ponderous, tumid at the elevated 
beaks, slopes concave, sub-rostrated, the ventral edge being slightly 
incurved anteriorly : cuticle olive, sometimes with dark narrow rays, 
smooth, shining: inside white. 3.—Africa. (Sierra Leone.) 
SecTtron.—MArIneE. 
Usually destitute of lateral teeth. 
CYPRINA. 
Shell equivalve, inequilateral, obliquely heart-shaped, beaks ob- 
liquely bent ; hinge with three unequal teeth, approximate at the 
base, and slightly divergent above ; lateral tooth remote, anterior, 
(sometimes obsolete) ; ligament external, and partly sunk be- 
tween the beaks. 
C. Isnanpica.* Lam. 2.—Turt. B. p. 135.—Bl. t. 70. bis. f. 
5.—Sow. G'.— Reeve. t. 65.—Venus I. Lin. 1131.—D. p. 176. 
—List. t. 272. f. 108.—W. t. 7. f. 41.—Ch. f. 341.—Don. t. 3. 
Jf. 77.  Obliquely heart-shaped, thick, ponderous, white, under a 
coarse, brown, rather glossy cuticle, and striated irregularly and 
concentrically ; beaks prominent, lunule obliterated : inside white, 
and the margins very entire. 31..33.—N. Hurope and N. Am- 
erica? 
C. Triancuraris. Turt. B. p. 136. ¢. 11. f. 19, 20.~ Venus 
T. Mont. p. 577. t. 17. f. 3.—D.p. 173.—W. t. 7. f. 35.— 
Turt. D.p. 238. Roundish with a triangular outline towards the 
beaks, which are produced and equally sloping on both sides, 
smooth, white: lunule lanceolate: three teeth and a curved lateral 
in one valve, two and a lateral in the other, palleal scar not sinu- 
lated. 4.—England and Ireland. 
+ C. Minima. Turt. B. p.137.—Venus M. Mont. p. 121. t. 
3. f. 3.—D. p. 166.—Turt. D. p. 236.—W.t.7.f.17. Rounded, 
with a triangular outline towards the beaks, compressed, with indi- 
stinct smooth narrow transverse ribs ; lurid flesh-coloured, speckled 
with minute livid dots, and when young the markings consist of 
four longitudinal rufous spots, two near the beaks, two at the mar- 
gin; these by age become obsolete ; beaks posterior, much recurved, 
the lunule lanceolate ; inside white, sometimes with purple under 
the umbones, margin entire. 3..3.— Guernsey. 
CYTHEREA. 
Liquivalve, inequilateral, sub-orbicular, trigonal or transverse ; 
right valve with four primary teeth, of which three are divergent 


2 C. Tenvistria (Lam. 6.) is a Venus CHINENSIS. 
