Starfish
Starfish/Sea Stars are probably the most well known type of Echinodermata today. It has a different way of respiring than others. It occurs through the tube feet, and through the dots on the body surface called papillae. They reach through the muscular body wall and then to the water they are in. Oxygen from the water goes into and through the starfishes' body by the fluid in the main body cavity. Like the Brittle Stars, the Hemal System (a series of sinuses and vessels) may and usually does play a role in a starfish's respiration.
Starfish Respiration
Respiration occurs mainly through the tube feet and through the papulae that dot the body surface. Oxygen from the water is distributed through the body mainly by the fluid in the main body cavity; the hemal system may also play a minor role.