
ALA MOLLUSCA. 
dentibus apicalibus et lateralibus tenuibus instructus : intus incrassata, 
alba ; margine crenulato ; impressionibus profundis. 
Lucina lenticula, Gouup; Proceed. Boston Soc. Nat. Hist., iii. 256. 
June 1850. Expedition Shells, 83. 
SHELL small, rather solid, nearly circular, subequilateral, lenticular, 
moderately convex, the apex nearly central, slightly elevated, and a 
little inclined forwards, forming a very shallow anterior pit. The 
surface is rude and chalky, with concentric wave-strie, decussated by 
numerous fine, radiating lines, mostly denuded, but with remains of a 
dusky, thick epidermis at the margin. Hinge delicate, with minute, 
diverging cardinal teeth, and somewhat distant, sufficiently conspicu- 
ous lateral ones. Interior chalky white, incrassated within the pallial 
impression, which is deep, and jagged at the margin: edge delicately 
crenulated. 
Diameter two-fifths of an inch; breadth three-tenths of an inch. 
Probably from Rio Janeiro. 
This little shell has rather the aspect of an Astarte or Cyprina, and 
would be considered as such, were it not for its lateral hinge-teeth. 
Figures 528, 528 a, lateral and dorsal views of the shell; 528 d, the 
hinge. 
LucIna VEsIcuLa (Gould). 
Testa tenuis, sub-globosa, vix obliqua, pallidée flavescens, concentrice 
tenui-striata, radiatim obsolete striata: apicibus submedianis, elevatis, 
anteversis ; margine dorsali anticé excavato, demum sub-alato, postice 
rectiusculo, peripheria relicta circulart; cardine edentulo ; lgamento 
in fossam obliquam internam posito: cavositas flavescens, punctis 
nitidis notata. 
Lucina vesicula, Goutp ; Proceed. Boston Soc. Nat. Hist., ili. 256. 
June 1850. Expedition Shells, 82. 
