. Zoology : for students and general readers . Zoology. HYDRO ID CORALS. 57 Hydractinia echinata (Fig. 37) forms masses (each called a hydrophyton) encrusting shells. In Clava the reproductive buds remain permanently at- tached. It grows in pink masses on Fucoids, about half an inch high, and is very common on our shores. It is repre- sented in fresh water by Cordylophora lacustris Allman, which lives attached to rocks and plants in Europe and this country. Here comes in the group of Hydroids represented by 3fillepora and Stylaster, which were formerly considered to be Anthozoan corals. By the
. Zoology : for students and general readers . Zoology. HYDRO ID CORALS. 57 Hydractinia echinata (Fig. 37) forms masses (each called a hydrophyton) encrusting shells. In Clava the reproductive buds remain permanently at- tached. It grows in pink masses on Fucoids, about half an inch high, and is very common on our shores. It is repre- sented in fresh water by Cordylophora lacustris Allman, which lives attached to rocks and plants in Europe and this country. Here comes in the group of Hydroids represented by 3fillepora and Stylaster, which were formerly considered to be Anthozoan corals. By the researches of L. Agassiz in 1859, and H. M. Moseley in 1876, Millepora, which had been confounded with the coral polyps, has been proved to be a Hydroid allied, as Agas- siz stated, to Hydracti- nia. Like that Hydroid, it forms a calcareous encrusting mass, but of much greater extent, a considerable proportion of the coral in the Flori- da reefs being formed by the Millepora. Our American species is Mil- lepora alcicornis Linn., while our description is taken from Moseley's account of Millepora nodosa Esper. (Fig. 38). Its generic name is de- rived from the numerous pores or calicles dotting its surface and arranged in irregular circular groups, consisting of a central calicle, or cup-like hollow, with from five to eight smaller calicles arranged around it. The mass of the coral, or hydrophyton, consists of fibres (or trabeculaj) of lime, forming a spongy mass, traversed in all directions by tor- tuous canals which " form regular branching systems with main trunks, giving oS numerous branches, from which arise secondary branches, and from these again smaller. Fit;. 38.—Millepora nodosa. a, nutritive b, reproductive zooid ; c, iast^o-cell; d. zooid ; the eame coiled up in its cell; e, a third form. ep: )il(. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illus
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Keywords: ., bookcentury1800, bookdecade1870, booksubjectzoology, bookyear1879
