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.