TRIBE CONCHACEA. 109 
C. Lununaris.t1. Lam. 74.—Del. t. 9. f. 6. Sub-orbicular 
heart-shaped, longer than broad, transversely grooved, livid, rayed 
towards the margin: the lunule with a white triangular spot at its 
base: inside white. 14.--America? 
C. Cyenus. Lam. 77. Heart-shaped, tumid, uniform white 
within and without, with raised transverse stria which become 
smaller towards the margin; the beaks inclining towards the 
heart-shaped lunule. 12.—Mediterrenean. 
C. Dentaria. Lam. 78. Triangular broadly, transverse, pale 
fulvous with white rays, and the anterior side with a reddish-brown 
spot more apparent in the interior. 23}.—Rio Janeiro. 
C. Errossa. Nobis.in Z. P.1842. Oval, sub-cordiform, sub- 
equilateral, thick, glossy, convex, with strong rather distant trans- 
verse grooves, the intervening spaces flattened, pale livid variegated 
by darker zigzag veins ; lunule impressed and lanceolate : lozenge 
deeply excavated, the sides smooth, white with wavy transverse ches- 
nut bands : inner dise stained with purple ; inner margin dlstinctly 
erenated.. 4..17. 
C. Excavata. Nobis in Z. P.1842. Rounded ovate, sub- 
equilateral, posteriorly expanded, anteriorly narrowed by the much 
arcuated ventral margin sweeping obliquely upward to meet the 
posterior edge ; thick, smooth, glossy, pale fulvous, more or less 
distinctly marbled with livid angular markings : lunule lanceolate : 
lozenge very deeply excavated, the sides flattened, white with a few 
livid veins : inner dise with a pale crimson stain, inner margin 
finely crenulated. 1.. 14. 
C. Sotanprt. Gray in Ann. Phil.—C. Hyans. W. S. t. 2. 
Jf. 11. Elliptical-sub-cordiform, thick, very convex, sub-equilateral, 
smooth, polished, white with angular clouded livid purple markings, 
especially near the umbones: lunule and lozenge lanceolate, the 
former indistinct, the latter excavated: margin crenulated. 14.. 12. 
— China.— Akin with the two preceding to Donax Scripta. 
VENUS. 
Equivalve, inequilateral, transverse, or sub-orbicular ; hinge with 
three teeth in both valves, all approximate, the lateral ones 
divergent at their summits ; ligament external, concealing the 
lozenge. 
* Inner margin crenulated or toothed. 
Section A.— With lamellar strie. 
V. Purrpsra. Lin. Mantissa. p. 545.—Lam. 1. (eacluding 
var. 2.)\—D. p. 188.—Ch. f. 388, 9.—E. t. 278. f. 1.—Reeve. 
1C. Frexvosa. Lam. 72.—Macropon. 73.—Savuamosa. 75, 
and Carp1Lua, 76, belong to Venus. 
