Animated coloured scanning electron micrograph (SEM) of Marine snail radula surface (Nerita polita). The radula is a tongue-like organ found in molluscs. Gastropods have elaborate radulas used primarily for gathering food. A gastropod radula is a toothed chitinous ribbon studded with longitudinal rows of chitinous and recurved teeth, the cuticula. It is used to rasp and scrape diatoms and other microscopic algae off rock surfaces and other substrata. The radula apparatus consists of two parts: 1) the odontophore (the cartilaginous base), with associated muscles; and 2) the radula itself, with its cuticula. The odontophore is movable and the radula itself is movable over the odontophore. Through this action the radula teeth are erected. The tip of the odontophore then scrapes the feeding surface, while the teeth cut and scoop up the food and convey the particles through the oesophagus to the digestive tract.