Contraction of these muscles shortens the column and withdraws the tentacles and oral disk into the column. Anemones have circular muscles in the body wall of the column which pressurize the gastrovascular cavity. In addition, there are radial muscles in the septa. These run from pharynx to the body wall and open the pharynx and mouth when they contract. During contraction, the anemone opens the mouth and contracts the longitudinal muscles to expel the water from the gastrovascular cavity.
Anemones are hermaphroditic but each individual produces only one kind of gamete at any one time.
The gonads are longitudinal bands of gamete-producing tissue on the edges of the mesenteries just peripheral to the septal filaments and central to the longitudinal muscles. The gonads are usually located on the incomplete septa but are not always present. The organization of the muscular system of Metridium . Microscopical Anatomy of Invertebrates, vol. Wiley-Liss, New York.