The radula is a structure found in most moluscs (except bivalves) and used for feeding. The radula can be very different on different species, some using combining it with acid to bore holes in shell-fish, some including sharp teeth on it.
Some species might have more than one hundred thousand teeth on their radula, and these are replaced as they wear down, sometimes as fast as 5 rows in a single day!
Mucus on the radula makes food particles stick to it, which are then transferred to the oesophagus before digestion.