Snails
The main difference between slugs and snails is the equipment the snail comes with; his shell, which grows along with his body. Most snails are gray, but the shells can range from white to brown or almost black, and be mottled or striped. The snail's head has two pairs of tentacles; a large pair holding his eyes and a smaller pair beneath for smelling. His mouth is below the lower tentacles, and the slime gland is beneath the mouth. The snail's shell holds his visceral hump, where the organs are located. The shell joins the snail's body, providing him refuge when he's disturbed.