The subradular organ is a sensory organ below the grinding mouthparts of some molluscs, specifically the chitons. This organ is involved in chemoreception - that is, in judging the nature of food or the substratum. In this sense, it can be considered a 'smell' or 'taste' organ; food is sensed before each stroke of the radula.
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Subradular organ Wikipedia(Text) CC BY-SA