Nervous System and Behavior
The nervous system of molluscs shows a wide range of complexity. The relatively simple behaviors of gastropods, bivalves,and chitons do not call for a well-developedbrain. Chitons have a nervous systemmuch like that of flatworms. Rather than a single brain, gastropods and bivalveshave a set of
ganglia,
or “local brains,”clusters of nerve cells located in severalparts of the body.Complexity of the nervous systemreaches its highest point in cephalopods,not just for molluscs but for all inverte-brates. The separate local brains of othermolluscs are fused into a single large