Sea urchins belong to echinoderm animals, at present more than 940 species are known. You can see some of the tube feet attached to the rocks as it pulls itself along. Sea urchins are members of the phylum Echinodermata, which also includes sea stars, sea cucumbers, brittle stars, and crinoids.Like other echinoderms, they have five-fold symmetry (called pentamerism) and move by means of hundreds of tiny, transparent, adhesive "tube feet".The symmetry is not obvious in the living animal, but is easily visible in the dried test. Sea urchins move around on hundreds of sticky tube feet that allow them to crawl on rocks and sand. These feet are controlled by a water vascular system. Urchins can also move using their spines, which are controlled by strong muscles. Most sea urchins (particularly regular sea urchins) move using their tube feet. Diversity. Their moutha are genrally made up of five calcium carbonate teeth or jaws containing a fleshy tongue-like structure. Tube feet are extensions of a complex set of canals within each sea urchin — a water-vascular system. They do not have a brain. They move water in and out of their bodies to control their feet. they use their water vascular system. Sea stars move around the same way (to view a movie of how sea stars move (~1.6M), click here). When attacking, sea urchins will rise up and then drop on top of the player, releasing purple smoke. Keeping sea urchins in the home aquarium is no easy task but, if you prepare your tank properly and if you are careful in selecting a species, you can be successful in keeping sea urchins … Sea urchins are sensitive to touch, light, and chemicals in the water. they use their water vascular system. In a lot of places, sea urchins are overfished, but that certainly isn't the case off the coast of California, where there's such an overabundance of purple sea urchins that it has become an aquacultural concern. Sea Urchins are slow creatures, with move speeds just below that of the player, but after being attacked, they will travel at a medium speed, moving as fast as the player. Sea urchins can be found in warm waters, among corals, and also in the oceans, at a depth of up to 7 kilometers. Ali Bouzari is a biochemist and trained chef. See the answer to your question: How does a sea urchins move?. By changing the amount of water inside, the animal can extend or contract the feet to move about. Find information about Invertebrates at AskAllDay.com Every other section has holes through which the sea urchin can extend its tubed feet. The tube feet are part of the urchin's water vascular system. Sea urchins move using their tube feet and spines on the underside of their body. Purple Sea Urchin (Arbacia punctulata) A purple sea urchins pin cushion appearance comes from its round inner shell, called a “test.” The test is covered with pincers (pedicellariae), tube feet and purple spines that move on ball-and-socket joints.The spines spear food and protect an urchin from predators. Sea urchins move using their tube feet and spines on the underside of their body. Sea urchins hit all the taste pleasure points – salt, sweet and umami. How Sea Urchins Move This purple urchin moves along the bottom of the aquarium in much the same way it would in the ocean. Mainly sea urchins use their feet to hang on to the bottom while … By now you should have a basic understanding of what sea urchins are and what roles they can plan in the saltwater aquarium. Most sea urchins have five pairs of external gills, placed around the mouth. These are tube-like projections, extending from their body (from the star-shaped ambulacral regions), which end in sucker-like projections.