TRIBE NYMPHACEA. 75 



f. 65. Oval, thick, gibbous, with transverse undulated ribs and 

 longitudinal stri«3 : yellowish white, the margin crenulated : both 

 muscular impressions somewhat lanceolate, the posterior the shorter 

 and broader. 2 . . 2^. — Indian Ocean. Pacific Ocean ? 



C. SowERBii. Reeve. Z. P. 1841. — Reeve, t. 58. Trans- 

 verse, tumid, gibbous, white or pink with obsolete rosy rays diverging 

 from the umboues to the margin, transverse elevated rather distant 

 ridges serrated at the sides, particularly posteriorly, and numerous 

 radiating strias intervening : margin thickish, strongly crenulated, 

 the umbones longitudinal, direct and minute ; lunule small and sub- 

 cordate. 2f . . ^\. — Pliilippines. — IVie yoxuuj are rather depressed 

 •and the rays {frequently) more distinct. 



LUCINA. 



Suborhicular, 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 intertnediate one obsolete ; the posterior nearest the 

 primai'y ones; two distinct imiscular impressions widely ^sepa- 

 rated, the jwsterior one prolonged. 



L. Jamaicensis. Lavi. 1. — Sow. G. f. 3. — Reeve, t. 59. f. 3. 

 —Venus J. I), p. 103.— E. t. 284. f. 2.—W. t. 8./. 79. Sub- 

 orbicular, thick, inflected with a longitudinal furrow at both extre- 

 mities ; slightly ventricose, white or yellow with distant transverse 

 membranaceous striae : interior usually yellowish or brownish, pos- 

 terior depression minute. Diam. 1|^. — W. Indies. 



L. Pensylvanica. Lam, 2. — Venus P. Lin. 1134. — P. p. 

 193.—^. t. 284. f. \.—Ch.f 394, 5. -List. t. 305./. 138.— i?. 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. ly. — JV. Indies. 



L. Edentula. Lam. 3. — Venus E. Lin. 1135. — P. p. 202. 

 — Ch.f. 427, 8, 9.—E. t. 284. f. 3.— TF. /. 8./. 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. 1|..2. — W. Indies. 



L. Radula.* Lam. 5. Tart. P. pi. 116. — Venus Spuria. 

 Gmel. 3284.~P.p. 194.— TellinaR. 3Iont. t.2. f. 1, 2.— Ch. 

 f 399. ?— TFoofZ. G. C. t. 42. f. 4, 5.— TF. t. 4./. 71. Orbicular, 

 convex, dirty white, with numerous raised concentric thread-like 

 stria?, 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. 1^. — P'fg- 

 land. 



L. Divaricata.* Lam. 7' — TellinaD. Lin. 1120. — P. jj. 



