This genus may be distinguished from the Solen by never having the
transverse oblong shape, or the edge of the valves parallel to the base.
Sanguinolaria occidens.
S. rosea.
S. livida.
S. rugosa.
_S. rosea._ The rosy Sanguinolaria.
Semi-orbicular, smooth, shining and convex; near the umbones of a
beautiful rose colour, which becomes paler as it descends; acute
transverse striæ.
_S. occidens._ The setting-sun Sanguinolaria. Pl. 7, fig. 4.
Oval, a little elongated, very compressed, slightly gaping, valves
elliptical, equally rounded at the two extremities, without mark of
posterior keel; summits slightly indicated; hinge formed by one or two
contiguous cardinal teeth on each valve; ligament projecting, convex;
margins not parallel.