Species: Starfish
A starfish does not have a real heart. Circulation takes place in three different points throughout the starfish. First, in the perivisceral coelom which is fancy for the empty space inside the starfish. The second place is in the legs of the starfish. The third takes place in the hemal channels. There are multiple hemal rings aiding in circulation. The rings are in the main part of the starfish and around its mouth. There is also a pulsating dorsal sac that acts as a heart except it lacks a one way valve system. Oxygen enters diffusion into the tube feet (or the legs), specifically, the papulae, which are little sacs all over the upper surface of the body.
A starfish does not have a real heart. Circulation takes place in three different points throughout the starfish. First, in the perivisceral coelom which is fancy for the empty space inside the starfish. The second place is in the legs of the starfish. The third takes place in the hemal channels. There are multiple hemal rings aiding in circulation. The rings are in the main part of the starfish and around its mouth. There is also a pulsating dorsal sac that acts as a heart except it lacks a one way valve system. Oxygen enters diffusion into the tube feet (or the legs), specifically, the papulae, which are little sacs all over the upper surface of the body.
http://www.madreporite.com/science/digest.htm