98 



LUCINID^. 



Family LUCINID^, Gray. 



Shells more or less orbicular, compressed, surface sculptured; 

 animals with no protruding siphons, branchias coalescing into one 

 leaflet, pallial impression entire. 



Genus L,UCI]\A, Brug. 1792. 



Shell rounded, beaks small ; two diverging cardinal teeth, one 

 of which is bifid, and usually two marginal teeth, one of them near 

 the cardinal teeth in each valve ; there is sometimes a posterior 

 angle, but never a fold, as in Tcllina ; pallial impression without 

 a sinus. Animal with the mantle freely open in front, fringed ; no 

 protruding siphons ; foot long and tubular. 



Fig. 404. 



Lucina filosa. 



Shell orbicular, compressed ; surface with numerous remote, concentric, lam- 

 inated strife ; lunule depressed-lanceolate ; lateral teeth wanting. 



Lticina rarlula, GouLU, Inv. Mass. 1st ed. 69. — De Kat, Nat. Hist. New York, 214. 

 Lucina radula? Mighels, Best Journ. Nat. Hist. iv. 318. 

 Lucina Ji/osa, Stimpson, Shells of New England, 17. 



Shell white, thick, orbicular, regularly but moderately convex ; 

 hinge-margin straight ; beaks small, pointed, slightly prominent, 



inclining forwards over a small, 

 indented, smooth, lanceolate lu- 

 nule ; on each side of the hinge 

 runs a shallow oblique furrow, 

 which, terminating in the mar- 

 gin, causes a slight undulation. 

 Surface covered with remote, con- 

 centric, lamellar ridges, in the 

 intervals of which are several 

 rounded, thread-like strige, and 

 often minute radiating lines ; in- 

 terior chalky-white, except around 

 the margin, where it is polished ; 

 with radiating lines, most apparent near the margin. Hinge 

 straight, without marginal teeth, and with a single cardinal tooth 

 in the left valve, and two small, diverging ones in the right. An- 



L. Jilosa. 



