Molluscs: Feeding mechanisms
Molluscs have a variety of different feeding mechanisms. The bivalve molluscs can filter-feed fine particles form the water. Some of the single-shelled molluscs (limpets) possess a ribbon-shaped tongue or radula, covered with rasping teeth, which enables the animal to scrape algae from the rock. Whelks have a radula on a stalk that can extend beyond the shell and be used to bore into the shells of other molluscs. Through these holes that they have bored they poke the tip of the radula and suck out the flesh of the victim. The cone-shells also have a stalked radula which is modified into type of harpoon with which they secure their prey before injecting it with poison. In still more active carnivores the heavy shell is reduced in size and may even be lost as has occurred in the sea-slugs which have an upper surface covered with tentacles. One species of sea-slug actively hunts jelly fish and ingests these animals stinging cells which it then concentrates in the tentacles and uses them for protection.
TRANSVERSE VIEW OF THE BUCCAL CAVITY WITH THE RADULA.