WORMS - POLYCHAETA The polychaetes are divided into two major subclasses: the sedentary worms (Sedentaria), and the free-moving worms subclass (Errantia). All worms have repetitious body segments, each segment has separate but essentially similar systems. Each body segment has a pair of paropods (side feet) which can be used for locomotion but with free-moving worms also contain gills. The most known "bristleworms" also called fireworms have a hidden danger. The setae(white bristles) on their paropods are poisonous and can cause a burning pain when getting in touch with bare skin. Sedentary polychates live permanently in tubes, most known are the beautiful colored "christmas tree" worms. These particle feeders have a filtering mechanism called the radiole. Each branch(pinnule) from the radiole is lined with tiny hairs(cilia) which catch plankton and other particles out of the water and than transfer it direction the mouth. The radiole has eyespots which warns the tubeworm of shadow so he than again retract the radiole. This is why when divers or snorkelers go to have a close look, it disappears. It takes patience to come close to a christmas tree worm, approach it from the sides and not from the top. ength: cm. Distribution: known from Japan, Philippines and Indonesia. This worm has a segmented cylindrical body, head and tail. The palp which are shown on the photographs are extensions which are positioned at the mouth, are used to catch plankton, and then transport it towards the mouth. Sandy areas of coastal reefs.