TRIBE CONCHACEA. 9:') 



\2.— Ch.f. 327, 8, 9.—E. t.2:>0.f. \.— Reeve. t.(:){.—W.t. 7./. 

 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.) 



Section. — Marine. 



Usually destitute of lateral teeth. 



CYPRINA. 



Shell equivalve, inequilateral, obliqneli/ heart-shaped, beahs ob- 

 liquely bent ; hiiuje with three unequal teeth, approximate at the 

 base, andsliyhtlii diverrjejit above; lateral tooth remote, anterior, 

 {sometimes obsolete) ; litjament external, and partly sunk be- 

 tween the beaks. 



C. IsLANDiCA.* Lam.. 2.—Turt. B.p. \35.—Bl. t. 70. hisf. 

 5.— Sow. G.— Reeve, t. G5. — Venus I. Lin. 1131.— Z>. p. 176. 

 —List. t. 272. f 108.— ir. t. 1 . f. W.— Ch.f. ZW.—Don. t. 3. 

 f. 77. Obliquely heart-shaped, thick, ponderous, white, Tinder a 

 coarse, brown, rather glossy cuticle, and striated irregularly and 

 concentrically ; beaks prominent, lunule obliterated : inside white, 

 and the margins very entire. Z^..3%.—N. Europe and N. Am- 

 erica." 



C. Triangularis. Turt. B. p. 136. t. 11./. 19, 20. Jenus 

 T. Mont. p. 577. t. 17. f. 3.—D.p. 173.— IF. t.7.f.S5.— 

 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 siuu- 

 lated. -I-. — England and Ireland. 



I C. Minima. T?<ri. i?. ;?. 137.— Venus M. Mont. p. \2\. t. 

 3./. 3.- D. p. \m.—Turt. D. p. 236.— TF. t. 7.f 17. Rounded, 

 with a triangular outhne 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. ^. . |. — Guernsey. 



CYTHEREA. 



Equivalve, inequilateral, stth-orbicular, trigonal or transverse ; 

 right valve with four primary teeth, of which three are divergent 



2 C. Tenuistria (Lam. C.) is a Venus Chinensis. 



