M. caudigera.
M. discors. The discordant Modiola.
Shell elongated oval, very convex, narrowest at the anterior end; striated at the two extremities; summit oblique; exterior greenish; interior white, with sometimes a pink-tinge, and somewhat pearly; crenulated margin.
M. Papuana. The Papuan Modiola. Pl. [12], fig. 6.
Species smooth, more or less triangular; summit near the anterior extremity; byssus obsolete in adults.
M. sulcata. The furrowed Modiola.
Species striated longitudinally.
3. Pinna. The Wing Shell. Fifteen species.
This genus is the same as constituted by Linnæus; the shell is marine, generally very brittle and fragile, in form resembling an acute angled triangle; usually covered with longitudinal ribs and elevated transverse striæ; generally horn coloured.
This genus is remarkable for the production of an abundant byssus of a fine brown silky texture, which the Italians frequently fabricate into articles of dress, equal in appearance to the finest silk.