Echinodermata
Echinodermata is a phylum composed of marine animals. The animals in the Echinodermata phylum are animals that live in a marine environment and generally have five points on their physical bodies. For example, starfish and sand dollars are Echinodermata animals. All Echinodermata animals animals live in salt water; none live in fresh water animals. There are over 70,000 different species in the Echinodermata phylum.
Starfish do not have a circulatory system. Rather, starfish have a hemal system. The hemal system channels form rings around the mouth closer to the top of the starfish. Circulation occurs in three places throughout the body: the perivisceral coelom, the water vascular and the hemal system.
Sea Urchin also do not have circulatory systems. Sea Urchins have a network of water-filled canals. These are known as the water vascular system to help them move and feed. Additionally, they have three largely-independent fluid systems. The large, filled coelom that is surrounding the internal organs acts as the major medium for internal transport within the Sea Urchin. Circulatory currents set up by the ciliated cells of the coelomic lining distribute nutrients from the stomach to the body wall.
Starfish do not have a circulatory system. Rather, starfish have a hemal system. The hemal system channels form rings around the mouth closer to the top of the starfish. Circulation occurs in three places throughout the body: the perivisceral coelom, the water vascular and the hemal system.
Sea Urchin also do not have circulatory systems. Sea Urchins have a network of water-filled canals. These are known as the water vascular system to help them move and feed. Additionally, they have three largely-independent fluid systems. The large, filled coelom that is surrounding the internal organs acts as the major medium for internal transport within the Sea Urchin. Circulatory currents set up by the ciliated cells of the coelomic lining distribute nutrients from the stomach to the body wall.