Bryozoa, Or Moss Animals, a name proposed by Ehrenberg for so-called zoophytes having separate openings for the mouth and anus; they had previously been called polyzoa by Thompson. (See Polyzoa.) They have also been called molluscan zoophytes, ascidioid and tunicated polyps, ciliobranchiata, and anthoid mollusks. By modern systematists they have been generally regarded as an order of acephalous mollusks. They are of small size, growing in clusters and in delicate and beautiful ramifications on stones, shells, algce, and other submarine bodies; a few live only in fresh water. Though polyp-like in appearance, and some resembling corals in their moss-like aggregated cells, they present no radiated structure; the cells are either branched, reticulated, or in-crusting; they are found from the Silurian period to the present. Eschara, flustra, and retepora are characteristic genera. Prof. Morse has shown that the young brachiopod resembles the polyzoon in its ciliated appendages; and believes that both belong to the annelidan type of articulates, as Leuckart and Gegenbaur maintain, though having certain affinities to the mollusks, as Allmann has pointed out.