MAZATLAN BIVALVES 101 
Gasteropod and then deserted, has made a coating over the 
hole inside. 
146. ? Lucina — , sp. ind, 
Tablet 475 contains a fragment of a pinkish shell with very 
smooth angular ribs. 
Hab.—Mazatlan ; in shell washings; L’pool Col. 
147. Luctna P EBURNEA, Reeve. 
Conch. Icon. Lucina, sp. 49, pl. 8, f. 49. 
Tablet 476 contains a young valve of exquisite beauty which 
may belong to this species, unless indeed it be a Strigilla lenti- 
eula. It is of glossy white, and so transparent as to shew the 
muscular impressions outside, and the external markings within. 
Suborbicular, with umbo very projecting between two concave 
margins and nearly central. Surface covered with very crowd- 
ed concentric strie, which at the margin shew a tendency to 
commence divarication. It is ‘06 across. 
Hab.—St. Elena and Panama, in sandy mud, 11 fm. Cuming.— 
? Mazatlan; one valve in Spondylus washings; L’pool Col. 
148. Lucina ————., sp. ind. 
Tablet 477 contains a fragment of a thin, globose species, 
with very numerous sharp concentric ridges ; interstices de- 
cussated by very fine radiating strie. 
Hab.—Mazatlan ; fragments of two specimens in shell wash- 
ings ; L’pool Col. 
Genus ?FIMBRIA, Meg. 
Fimbria, Megerle v. Mihlfeld, 1811, Entwurf &ce. p. 52. 
Corbis, Cuv. 1817, Régne An. vol. iii. p. 147. 
Idothea, Schwm. 1817, Essat. 
149. ? Fimpria — 
Tablet 478 contains one of two tiny valves which seem to 
belong to this genus, having the teeth of Cardium, with con- 
sJun., sp. ind. 
