Characterisitcs

Gastropods and bivalves brains are composed of ganglia. Cephalopods have the most complex nervous system of invertebrates as a whole. Therefore the cephalopod's brain is of various sections of other mollusks.

Gas exchange in mollusks in though paired gills.

The body cavity,a coelom,is much reduced, being restricted to small cavities around the heart and a few other organs.