Taken by Lamarck from the Mytilus, as it differs by being more
transverse than longitudinal, and the beaks, instead of being terminal,
are placed beneath the apex.
Shell smooth, sub-transverse, equivalve, regular, sub-triangular, the
posterior side short; summits almost lateral; hinge lateral and linear,
without teeth; ligament partly interior, placed in a marginal furrow;
one sub-lateral elongated muscular impression in each valve.
Modiola Papuana.
M. tulipa.
M. albicosta.
M. vagina.
M. picta.
M. sulcata.
M. plicatula.
M. semifusca.
M. securis.
M. purpurata.
M. barbata.
M. Guyanensis.
M. Adriatica.
M. pulex.
M. discrepans.
M. discors.
M. trapezina.
M. cinnamomea.
M. silicula.
M. plicata.
M. semen.
M. lithophaga.
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.