Head- anterior part of the body, which contains mouth, eyes and tentacles and other sense organs. Foot-is ventral in position usually thick and muscular and generally forms the main locomotory organs. Visceral mass- on dorsal side contains digestive, circulatory and reproductive organ of the body and it forms a hump or dome.
Sense organs include eyes, statocysts and osphradia. Statocyst are organs for balancing. Osphradium is used to test chemical nature of water.