They are deuterostomes, and are often found as separate sexes. Echinoderms have spiny skin, which is a part of an endoskeleton which supports the organ systems such as muscles. Tube feet are common in this phylum - these are tubes with a suction disk at the distal end. The are used for locomotion and food getting. The water vascular system moves the feet by filling them with water, then emptying them.
Echinoderms have a well-developed gut, while the nervous and circulatory systems are quite simple.
These organisms range from about half an inch to 3 feet in diameter, and move very slowly. These particular organisms feed on small microscopic particles as well as seaweed, and may graze the ocean floor. Some may be predators. The Echinoderms have amazing regenerative powers, able to produce a new star fish from one arm and a small portion of the central disk. Some, like the star fishes, eat in a rather odd manner.