The sides of rocks may contain numerous chitonous or calcified tubes of polychaete. These must be removed with a pocketknife or chisel and hammer, or else the entire rock mush be collected. The fouling organisms on pilling and floats are also likely hiding places for polychaete worms. Commensals may also be taken from around the tube feet of starfishes. The biological dredge, orange-peel bucket, or other bottom samplers (Chapter 1) are useful for collecting deep-water species. Fouling organisms such as kelp holdfasts may be quickly examined by submerging them in a bucket of very weak formalin solution. Worms and other organisms will become irritated, leave their hiding places, and sink to the bottom of the bucket.