. Text-book of zoology for schools and colleges. Zoology. ACTINOZOA. 91 processes, each of which bears numer- ous polypes. Closely allied to Virgu- laria is the " Cock's-comb " Pennatula (Fig. 28) ; but in this the lower end of the coenosarc is naked and fleshy, and the polype-bearing fringes are considerably longer, giving the whole organism very much the appearance of a feather. Another family of the Alcyonaria is represented by the so-called " Or- gan-pipe corals," of which Tubipora musica is a well-known example. In this there is a well-developed sclero- dermic coral co
. Text-book of zoology for schools and colleges. Zoology. ACTINOZOA. 91 processes, each of which bears numer- ous polypes. Closely allied to Virgu- laria is the " Cock's-comb " Pennatula (Fig. 28) ; but in this the lower end of the coenosarc is naked and fleshy, and the polype-bearing fringes are considerably longer, giving the whole organism very much the appearance of a feather. Another family of the Alcyonaria is represented by the so-called " Or- gan-pipe corals," of which Tubipora musica is a well-known example. In this there is a well-developed sclero- dermic coral consisting of numerous cylindrical tubes, which are not di- vided by vertical partitions (septa), but which are connected by strong transverse plates. The coral is bright red in color, and the polypes are usually bright green. The best known, however, of the Alcyonaria is the family Gorgonidw, represented by the sea-shrubs, fan-rm^!. The Cock's-' corals, and the red coral of commerce. comb (PmnaiuZa phospM- Af {• j-t ^ c lA ' £ "1 rea\ (AfterJohnson.) few of the members of this family live in temperate waters, but they attain their maximum in point of size and numbers in the seas of the tropics. In all the Gorgonidm the organism consists of a composite structure made up of numerous polypes united by a common flesh or coenosarc (Fig. 39, b), the whole supported by a central branched axis or coral. The coral varies in composition, be- ing sometimes calcareous—as in red coral—sometimes horny, and sometimes partly homy and partly calcareous, as in Isis (Fig. 29). In all cases, however, the corallum differs alto- gether from the sclerodermic corallum, which has been de- scribed as so characteristic of the reef-building corals. The coral in the present instance is always what is called " sclero- basic "—that is to say, it always forms an internal axis, covered by the ccenosarc with the polypes produced therefrom. It is, therefore, outside the polyp
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Keywords: ., bookcentury1800, bookdecade1880, booksubjectzoology, bookyear1884
