Snails belong to the mollusc tribe. The body size of the snails varies from less than 0.5 mm to over 90 cm. The body of a snail consists of head and foot as well as the back lying visceral sac, which is protected by the tissue layer of the coat. Cells in the coat form a hard shell, which resembles other mollusc shells in the basic structure, which is usually asymmetrically twisted to one side of the body.
