During this process the the velum is lost, the foot develops and the ctenidia develop.eval(ez_write_tag([[728,90],'earthlife_net-leader-4','ezslot_26',114,'0','0'])); Most bivalves live either partially or wholly buried in the substrate of the water body they live in, or firmly attached to a rocky or other solid substrate. Body is segmented. Bivalves include clams, oysters, mussels, scallops, and numerous other families of shells. All bivalves possess a large muscular foot. Another fish famous for its method of feeding on bivalves is the Harlequin Tuskfish (Choerodon fasciatus) made famous by David Attenborough’s Blue Planet ii video of one breaking open a small clam. Hello, my name is Billy and I'm here to tell you about my Class. The largest producer of commercially farmed bivalves is China. Pearl production is another important economic aspect of bivalve ecology. This is called “intracellular digestion” to distinguish it from the more usual form of digestion involving a soup of chemicals, enzymes and food particles in the stomach and intestines which is known as “extracellular digestion”.eval(ez_write_tag([[580,400],'earthlife_net-large-leaderboard-2','ezslot_13',109,'0','0'])); Many bivalves, especially fresh water ones separate the timing of their feeding (collecting food) and digestion. In filter feeders this involves an unusual organ called the crystalline style. The pedal ganglia are found at the base of the foot and the visceral ganglia are located below the posterior adductor muscle. 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