Snail is not a biologically classified name, but generally refers to all terrestrial species of Gastropoda. In general, Western languages do not distinguish between aquatic snails and terrestrial snails. In Chinese, snails only refer to terrestrial species, while snails in a broad sense also include giant shield slugs. Snails are an animal that includes many different families and genera. Snails are mollusks, gastropods; they feed on plants and lay their eggs in the soil or on trees. It is more common in tropical islands, but some also live in cold regions. The arboreal species are brightly colored, while the ground-dwelling species usually have several close colors, usually with stripes. Agate snails in Africa are the largest, with more than 20 cm. Several species of the large snails in Europe are often used in delicacies, especially in France. Snails are the most common mollusks on land, and snails have high edible and medicinal value.