222 

 Lucina continued. 



columbella. . suborbicular ; transversely sulcated on the side ; 

 base projecting with deep grooves, bowed obliquely. . 

 Touraine. 



Donax. 



retusa. . wedge-form, flat, blunt forwards ; fine transverse striae, 



margins entire. . 1 inch wide. . Parnes. 

 incompleta. . ovato -triangular ; smooth, round on the foreside ; 



two hinge teeth, no lateral ones. . small. . Beynes. 

 tellinella. . ovato -oblong, finely striated transversely ; remote 



lateral teeth ; margins entire. . small. . Grignon. 

 nitida. . ovato-oblong, smooth, polished ; two lateral teeth. . 



small. 

 lunulata. . orbiculato-ovate, flat ; blunt at the foreside, the 



striae very fine. . f inch. . Houdau. 

 obliqua. . longitudinal, ovately oblique, smooth ; margins entire ; 



one tooth on one valve and two on the other ; vestiges 



only of lateral ones. 



Cyprina. 



gigas. . large, cordato-rotund, with fine remote striae ; large 

 opening beneath the beaks ; lateral teeth obsolete. . 5j 

 inches. . Italy. 



islandica. . cordate ; striated transversely ; retains epidermis ; 

 foreside rather angular ; no posterior depression. . Sienna. 

 Italy. 



Piedmontana. . round, thin ; transversely grooved ; posterior 

 opening oblong ; lateral tooth obsolete. . 2 inches. . 

 environs de Turin. 



corrugata. . ovato-cordate ; grooved transversely, with intersti- 

 tial vertical striae ; impression posterior. . 4 inches. . Italy. 



tridacnoides. . transversely ovate ; corrugated, striae vertical ; 

 plicated on the upper surface. 



tenuistra. . longitudinally ovate, thick brown, white within, 

 transverse concentric striae, border crenated ; no posterior 

 opening, with an isolated tooth as in cytherea concentrica. 



islandicoides. . roundish ; longer than wide ; cordated, striae 

 transversely upwards ; foreside not angulated ; no poste- 

 rior opening. 



umbonaria. . rounded and cordate, subantiquated ; delicately 

 striated transversely; base tumid; no opening beneath 

 the beaks. 



Venus angulata, Sowerby. 



Cytherea. 



erycinoides. . rather depressed, white spotted with brown, transverse 



grooves, very obtuse. . Bourdeaux. 

 Analogue, cedo nulli ? 



multilamella. . inequilateral, distinct, transverse grooves.. 

 Montmarin. 



