TRIBE NYMPHACEA. 75 
f- 65. Oval, thick, gibbous, with transverse undulated ribs and 
longitudinal striz : yellowish white, the margin crenulated : both 
muscular impressions somewhat lanceolate, the posterior the shorter 
and broader. 2..23.—Indian Ocean. Pacific Ocean? 
C. Sowers. Reeve. Z. P. 1841.—Reeve. t. 58. Trans- 
verse, tumid, gibbous, white or pink with obsolete rosy rays diverging 
from the umbones to the margin, transverse elevated rather distant 
ridges serrated at the sides, particularly posteriorly, and numerous 
radiating striz intervening: margin thickish, strongly crenulated, 
the umbones longitudinal, direct and minute ; lunule small and sub- 
cordate. 23..33.—Philippines.—The young are rather depressed 
and the rays ( frequently) more distinct. 
LUCINA. 
Suborbicular, inequilateral ; beaks small, pointed, and oblique ; 
hinge variable, sometimes with two divergent teeth, one of which 
is. bifid, (but changing or disappearing with age); two lateral 
teeth, the intermediate one obsolete; the posterior nearest the 
primary ones; two distinct muscular impressions widely sepa- 
rated, the posterior one prolonged. 
L. Jamaicensis. Lam. 1.—Sow. G. f. 3.—Reeve. t. 59. f. 3. 
—Venus J. D.p.193.—E. t. 284. f. 2.—W.t. 8.679. Sub- 
orbicular, thick, inflected with a longitudinal furrow at both extre- 
mities ; slightly ventricose, white or yellow with distant transverse 
membranaceous striz : interior usually yellowish or brownish, pos- 
terior depression minute. Diam. 13.—W. Indies. 
L. Pensytvanica. Lam, 2.—Venus P. Lin. 1134.—D. p. 
198:— Fi. t. 284: fo V.— Oh. 394; 5.— List... t. 305.2 138.—-B. t. 
5. f: 8.—W. t.8.f. 78. Sub-orbicular, inflected by a longitudinal 
furrow on the anterior side; ventricose, tumid, white within and 
without and marked with concentric membranaceous ridges : poste- 
rior depression large and heartshaped. Diam. 13.—W. Indies. 
L. Epentuta. Lam. 3.—Venus E. Lin. 1135.—D. p. 202. 
—Ch. f. 427, 8, 9.—H. t. 284. f. 3.— W. t. 8. f. 98. Orbicular 
ventricose, sub-globose, not thick, white, with fine concentric 
wrinkles : posterior depression ovate-acute and much sunken ; apri- 
cot yellow within, hinge toothless. 13..2.—W. Indies. 
L. Rapuua.* Lam. 5. Turt. B. p. 116.—Venus Spurtia. 
Gmel. 3284.--D. p. 194.—TrevimaR. Mont. t.2. f. 1, 2.—Ch. 
f. 399. ?’—Wood. Gt. C. t. 42. f. 4, 5.—W. t.4. f. 71. Orbicular, 
convex, dirty white, with numerous raised concentric thread-like 
strie, which in old specimens become irregular and indistinct to- 
wards the margin ; the interstices broad and shallow ; inside dull 
chalky white ; beaks central, a small lunule. Diam. 13.—ng- 
land. 
L. Divaricata.* Lam. 7.—TevtrnaD. Lin. 1120.—D. p. 
