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Family Placunidae - windowpane shells
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Class |
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Bivalvia |
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No. of Species in Ref. |
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Environment |
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Fresh : No |
Brackish : No |
Marine : Yes |
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Remark |
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Shell thin and brittle, nearly equilateral, rounded to saddle-shaped, very compressed laterally; slightly inequivalve, right (lower) valve nearly flat or little concave, left (upper) valve weakly inflated. Umbones low, submedian. Outer surface smoothish, with slightly lamellate lines of growth and sometimes fine radiating threads. Periostracum inconpicuous. Ligament mostly internal, forming and inverted V-shaped structure under the umbones, attached to ridge-like nymphs in the right valve and to corresponding grooves in the left. Hinge line straightish, without teeth. Interior of shell subnacreous. A single, centrally situated, rounded (posterior) adductor muscle scar. Pallial obscure, without a sinus. Internal margins smooth. Gills of filibranchiate type. Foot long and narrow, cylindrical. Mantle widely open ventrally, with marginal tentacles. Suspension filter-feeding species, living unattached on the surface of muddy flats in shallow water, lying generally on the right valve. Sexes separate. Development with a free-swimming larval stage. Placunidae are extensively collected in the Indo-West Pacific, and cultivated in several areas, for their translucent shell, originally as a substitute of glass in glazing, now mainly for the manufacture of trays, lamp-shades and numerous decorative items. The flesh is often used for food by coastal populations (Ref. 348). |
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