Nemertean, from Halstead, 1965.
Most nemerteans are predators, but some are scavengers and others are herbivorous .
They are often found in and among seaweeds, rocks, mussle and barnacle beds, or buried in mud, sand, or gravel substrates. Some nemerteans actively track prey by following their chemical trails, - common prey items are polychaetes , snails , small crustaceans , and mollusks . A few species of Nemerteans are parasitic . The proboscis is used to capture prey, - in the armed forms it may have piercing barbs or stylets , which may contain a toxin used to help subdue the prey. There are only about 900 species of Nemerteans .