snails without shells. ... Like snails, slugs secrete a film of mucus to protect their delicate skin and to “grease” the surface on which they are traveling.
A snail is, in loose terms, a shelled gastropod. The name is most often applied to land snails, terrestrial pulmonate gastropod molluscs. ... When the word "snail" is used in this most general sense, it includes not just land snails but also numerous species of sea snails and freshwater snails.
