through one and expelled through the other with microalgae and zooplankton being filtered out as the water passes through the gills. Respiration takes place at the same time. Cilia then waft the food particles to the mouth. Spawning usually takes place in summer. Gametes are passed out of the exhalent siphon and fertilisation takes place externally. After hatching, eggs develop into veliger larvae which are planktonic. After 16 to 21 days these undergo metamorphosis into a pediveliger stage and settle out onto a soft substrate such as sand. There they become juveniles and start burrowing. Uses Cyrtopleura costata is used as food in Cuba and Puerto Rico. It is a fast-growing species, and it has been investigated for possible use in commercial aquaculture. Under optimal conditions it was found that the larvae were ready to undergo metamorphosis after 12 days, and settlement could be triggered by use of a dilute solution of epinephrine. The clams could reach a marketable size of within 6 months. References Pholadidae Molluscs described in 1758 Taxa named by Carl Linnaeus