Marine snails are a type of mollusk that live in the ocean. They come in a variety of shapes and sizes, and can be found in both shallow and deep waters. Common types of marine snails include winkles, which have a spiral shell with six letters; whelks, which have a conical shell with five letters; conchs, which have a large, thick shell with five letters; and neritas, which have a flat, oval shell with six letters.