Figure 7: Morphology of a typical cephalopod.

The head has highly developed sense organs - the eyes and the tentacles. The funnel is formed by the posterior part of the foot, and water filling the mantle cavity may be forcibly ejected here, which facilitates active locomotion. The cephalopod's muscular foot enables the animal's power of movement. The mantle is a sheet of tissue that covers the body and secretes a calcareous shell with an organic matrix; and the primary function of the gills is respiratory exchange.