ABSTRACT
Sea anemones are soft-bodied conspicuous members of the intertidal community. The gastrovascular cavity is partitioned by longitudinal, radiating mesenteries. Mesenteries or septa extending from the body wall to the stomodaeum are known as primary mesenteries. The muscular system is highly developed, particularly the gastrodermal musculature. Ectodermal muscles form longitudinal fibers in the tentacles and radial fibers in the oral disc, but the main musculature is endodermal. Histological and electrophysiological studies indicate that the nerves pass through the mesogloea from the ectoderm to the endodermal nerve net. The anemone creeps by gliding motions of the basal disc, which extends a turgid lobe in the direction of movement. It then engages in waving movements of the disc and column and retraction of the oral disc. Respiration is aerobic and its rate is directly dependent on the degree of expansion of the animal and to some extent on the oxygen content of the water.
