Another lithophagous shell, taken from the genus Venus, from which it is
distinguished by the different disposition of the teeth, having three
primary in one of the valves at least.
Shell more or less irregular, sub-trigonal, striated or radiated,
equivalve, inequilateral, the anterior side shorter and rounded, the
posterior sub-truncated; summits well marked; hinge sub-regular, more or
less dissimilar, formed by slender, narrow, cardinal teeth, variable in
number on each valve, sometimes two on the right and three on the left,
and sometimes three on both; these teeth are small, contiguous,
parallel, and but little, if at all, divergent exterior; very weak.
Venerirupis perforans.
V. nucleus.
V. irus.
V. exotica.
V. distans.
V. crenata.
V. carditoides.
_V. perforans._ The perforating Venerirupis.
Sub-rhombic, transversely striated, wrinkled on the anterior side;
exterior brown, interior white, sometimes tinged with purple.
_V. irus._ The foliated Venerirupis. Pl. 7, fig. 2.
Species longitudinally striated; cardinal teeth two, sometimes three on
the right and three on the left.
FAMILY VIII.
NYMPHACEA. Ten genera.
This family is divided into N. Solenaria and N. Tellinaria, from their
resemblance to the Solen and the Tellina.
N. SOLENARIA. Three genera.