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The Sea Anemone, like the coral polyp, lives in the sea, but like the fresh water hydra, it deposits no limy support for its body. The anemone is much larger than the hydra and most coral polyps, many species attaining a height of several inches. It does not form colonies. When its arms are drawn in, it looks like a large knob of shiny but opaque jelly. Polyps used to be called zoophytes (plant-animals), because of their flower-like appearance (Figs. 50, 51).

Fig. 49.—Upright Cut through coral polyp × 4.

ms, mouth; mr, gullet; ls, ls, fleshy partitions (mesenteries) extending from outer body wall to gullet (to increase absorbing surface); s, s, shorter partitions; mb, fb, stony support (of lime, called coral); t, tentacles.

Fig. 50.—Sea Anemone.

Fig. 51.—Sea Anemones.