A shell of a singular form, resembling a pickaxe, found only in the
Indian and Australian Seas; there are two species, the white and the
black, both of which, when in fine preservation, are highly esteemed,
but the white is more rare and valuable.
Shell sub-nacreous, irregular, rugged, sub-equivalve, inequilateral,
generally auricled before and prolonged behind, so as to be in form like
a hammer; summit entirely anterior; between them and the inferior
auricle, an oblique cut or slope for the passage of the byssus; hinge
linear, elongated, without teeth; ligament simple, triangular, inserted
in a conical oblique cavity, partly exterior; one rather large
sub-central muscular impression.
Malleus albus.
M. vulgaris.
M. normalis.
M. vulsellatus.
M. anatinus.
M. decurtatus.
_M. vulgaris._ The common Malleus. Pl. 14, fig. 4.
Species with two earlike appendages; trilobate, colour blackish brown.
_M. albus._ The white Malleus.
Species trilobate; base of the lateral lobe prolonged, without a sinus;
the base and the pit of the ligament not distinct; colour white, with
transverse undulations.
_M. vulsellatus._ The tweezer Malleus.
Species slightly auricled.
_M. normalis._ The square Malleus.
Species without earlike appendages.