What Is a Radula?

The radula is a special structure used by many mollusks to scrape food off rocks, to feed off of plants or create depressions in rocks that the mollusk uses for habitat. The radula has many rows of tiny teeth that are replaced as they wear down. Each row of teeth consists of marginal teeth, one or more lateral teeth and a median tooth. 

One animal that has a radula is the common periwinkle, which uses its radula to scrape algae off rocks for food.

The limpet is a marine invertebrate that uses its radula to create a "home" by boring a shallow hole into a rock.