Remarkable for the form of its shell, which resembles, when partially
expanded, a bird flying.
Shell foliaceous or not, thin and very fragile, always pearly,
sub-equivalve; form sub-regular, but rather variable; summit anterior;
valves oblique, the left one with a little notch, through which the
byssus passes; sometimes unequally and obliquely auricled; hinge linear,
toothless, or with two small rudimentary teeth; ligament more or less
exterior, placed in a narrow groove, sometimes enlarged towards the
summit; one very large posterior muscular impression; and one very small
anterior.
Avicula macroptera.
A. lotorium.
A. semi-sagitta.
A. heteroptera.
A. falcata.
A. crocea.
A. Tarentina.
A. Atlantica.
A. squamulosa.
A. papilionacea.
A. costellata.
A. physoides.
A. virens.
_A. macroptera._ The rounded Avicula. Pl. 14, fig. 3.
Species oval, oblique, the earlike appendages very developed, especially
the superior; one tooth at the hinge.
_A. Atlantica._ The Atlantic Avicula.
Obliquely curved, yellowish fawn colour, with dark reddish-brown stains;
interior pearly.