Mollusca: The Body Wall

All mollusks possess a flexible body wall, which surrounds a body cavity containing the internal organs. The wall, which varies greatly in shape in different species, is usually folded to form a structure called the mantle, which is attached at the top of the body and surrounds it like a tent; the shell is formed on the outside of the mantle. On the underside of the body the wall is usually stretched out to form a thickened mass called the foot. The wall is covered by an outer epidermis and an underlying dermis. The epidermis usually contains gland cells that secrete mucus, which in mollusks has a variety of important uses, such as locomotion, food entrapment, and prevention of water loss. Muscle tissue is found in the body wall, and is particularly plentiful in the foot, which is used for locomotion in most mollusks (although some swim and some are sedentary), and in the mantle in species with reduced shells.

Sections in this article:

• Introduction
• Class Cephalopoda
• Class Scaphopoda
• Class Bivalvia
• Class Gastropoda
• Class Monoplacophora
• Class Polyplacophora
• Class Aplacophora
• Reproduction
• Circulatory and Nervous Systems
• Respiration
• The Digestive Tract
• The Shell
• The Body Wall
• Anatomical Features

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