- Norwegian: sjøpølser
The relationship with the other echinoderms is perhaps not that obvious. In stead of a protecting shell, the sea cucumbers only have small shell fragments in the skin. Five double rows of tube feet run from the mouth along the elongated, cylindrical body. Some species use tentacles, to catch food which is processed in a channel running from the mouth in one end to the anus in the other end of the body. Sea cucumbers feed on decaying animals or plants found on the seabed. Some live partially buried in the sea floor.
Together with the sea urchins they constitute the subphylum Echinozoa. Two orders are presented here:
- The members of the order Dendrochirotida have relatively large tentacles around the mouth from which they lick of any particles that may stick to them. Many of them have "respiratory trees", just inside the anus. Water is pumped in and out through anus into the trees. This contributes to the gas exchange. A majority of the species are at least partially buried.
- The species included in Aspidochirotida have "respiratory trees" too. However, the tentacles are very short. Their tactic is usually to crawl around on the seabed searching for food, rather than staying partially buried on one place and pick up whatever comes along.