This genus was taken from the Mactra, and is perfectly distinct, as it
wants the lateral teeth. It is called Lutricola by De Blainville, from
its lurking in sand or mud at the mouths of large rivers.
Shell inequilateral, orbicular, sub-triangular or transversely oval,
gaping at the extremities; hinge with one cardinal tooth folded in two,
or two teeth, one of which is plain, with an opposite hollow to receive
it; no lateral teeth; ligament interior and fixed in the hollow cavity
of the primary tooth.
Lutraria solenoides.
L. rugosa.
L. compressa.
L. piperata.
L. tellinoides.
L. elliptica.
L. papyracea.
L. plicatella.
L. crassiplica.
L. complanata.
L. candida.
_L. solenoides._ The Solen-like Lutraria.
Species oblong, sub-cylindrical, very gaping, two very strong cardinal
teeth; the spoonlike cavity of the ligament vertical.
_L. compressa._ The compressed Lutraria.
Species oval or orbicular, almost equilateral, very compressed, little
gaping; hinge similar; internal ligament inserted in the pit of a
vertical spoonlike cavity; two distinct tubes, without longitudinal
striæ.
_L. rugosa._ The rugged Lutraria.
Species ovate, closed at both ends; striæ from the summit to the base.
_L. elliptica._ The oval Lutraria.
Oblong oval, nearly smooth, having a few concentric striæ, and some
diagonal striæ at the ends of the valves; colour yellow or greenish
brown; inside white.