Gas Exchange & Excretion

Ciliary flow of fluid over the gastrodermis and epidermis facilitates the excretion of ammonia, and gas exchange with the surrounding water through the tentacles and oral disc via diffusion. (Ruppert, 2004) Anemones also rely heavily on water currents to carry enough oxygen over their tentacles and oral disc so they can receive adequate amounts. C. polypus’ commensalism with Dardanus sp. aids the anemone in this way by allowing it to access a greater volume of water. 

Figure 1: Dardanus sp. with C. polypus residing on shell. (Murawski, 2013)