The gastropod shell is an animal shell which is part of the body of a gastropod or snail.
It is an external skeleton or exoskeleton, which serves not only for muscle attachment, but also for protection from predators and from mechanical damage.
In land snails the shell is an essential protection against the sun, and against drying out.
The gastropod shell has several layers, and is typically made of calcium carbonate precipitated out into an organic matrix.
It is secreted by a part of the molluscan body known as the mantle.
Not all gastropods have a shell, but the majority do.
The shell is in one piece, and is typically spirally coiled, although some groups, such as the various families of limpets, have simple cone-shaped shells as adults.