Solidago subsect. Radulae

The radula (US: ; pl.: radulae or radulas) is an anatomical structure found only in most mollusks, serving as their primary feeding tool. Often compared to a tongue, this minutely toothed, chitinous ribbon typically functions by scraping or cutting food before it enters the esophagus. Mollusks in every class possess a radula, except for bivalves, which instead employ waving cilia to draw in minute organisms for feeding.

The radula typically functions as a rasping organ to scrape food particles. However, its form and use have diversified significantly; it is modified for drilling holes in prey shells (e.g., in Muricidae), transformed into venomous harpoons (e.g., in Conidae using conotoxins), or reduced/lost in fluid feeders (such as in the Pyramidellidae where the highly specialized, needle-like radula is called a stylet).