Elementary text-book of zoology (1884) Elementary text-book of zoology elementarytextbo0201clau Year: 1884 ECTOPROCTA. 71) Sub-order 2. Stelniatopoda (Gymnolaemata). Bryozoa with discoidal lophopfipre, tentacles in a closed circle; mouth without epistome. The Stelniatopoda are, with the exception of the Paludicettidce, all marine forms. They are always without the epiglottis-like epistonie, and possess a complete circle of less numerous tentacles, which arise from a round buccal disc (fig. 547). In many forms, as in Alcyonidium gelatinosum, Membranipora pilosa, a flask-shaped ciliated canal i
Elementary text-book of zoology (1884) Elementary text-book of zoology elementarytextbo0201clau Year: 1884 ECTOPROCTA. 71) Sub-order 2. Stelniatopoda (Gymnolaemata). Bryozoa with discoidal lophopfipre, tentacles in a closed circle; mouth without epistome. The Stelniatopoda are, with the exception of the Paludicettidce, all marine forms. They are always without the epiglottis-like epistonie, and possess a complete circle of less numerous tentacles, which arise from a round buccal disc (fig. 547). In many forms, as in Alcyonidium gelatinosum, Membranipora pilosa, a flask-shaped ciliated canal in the body cavity has been observed; it opens to the exterior near the tentacles, and probably corresponds to the nephridia of segmented worms. Statoblasts are only rarely present. The eggs visually give rise to ciliated larvje. The colonies are for the most part polymorphic, being often composed of root- and stem-cells, with vibracula and avicularia. The ectocysts are sometimes horny, L sometimes incrustetl with cal- careous matter, and present great variety of form. Tribe 1. Cyclostomata. The orifices of the cells wide and terminal, without movable ap. pendages. Most of the species are fossil. The living species inhabit the Northern Seas. Fam. Crisiadae. Colonies erect PIG. ;3.—Phimatella rejifim, slightly magnified _and jointed. C risia corn uta Lam., (aftei, Allumil) Lp> Loljhul,hore. DI aiiIUeutun 'Mediterranean and North Sea; canal. C. eburncii L. Fani. Tubuliporidae. The zooecia disposed in continuous rows. Idninnrn atlantica Furl;.. Phalaitydla palmata Wood, Arctic Ocean. Tribe 2. Ctenostomata. Apertures of the cells terminal; when the tentacular sheath is retracted they are closed by a circle of spines as by an operculum. Stem-cells and root-filaments frequently occur Fam. Alcyonidiidae. Zooecia united to form gelatinous stocks of irregular form. Alfijiiitidhnn yrlattnoxum L., Northern Seas. Fam. Vesicularidae. Ihe zooecia project as free tubes on the branch
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