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. Corals and coral islands. Coral reefs and islands; Corals. CORAL-MAKING ACTINOID POLYPS. 55 regularity that these hemispheres are perfectly symmetrical, even when enlarged to a diameter of ten or fifteen feet, A portion of the surface of one of these massive species, called Orbicella cavernosa, from the West Indies, is represented in the annexed figure. In the growth of these hemispheres, the enlargement takes place in the spaces between the polyps ; and. ORBICELLA CAVERNOSA. whenever these spaces begin to exceed the width usual to the species, a new mouth opens, commencing a new polyp ; and
. Corals and coral islands. Coral reefs and islands; Corals. CORAL-MAKING ACTINOID POLYPS. 55 regularity that these hemispheres are perfectly symmetrical, even when enlarged to a diameter of ten or fifteen feet, A portion of the surface of one of these massive species, called Orbicella cavernosa, from the West Indies, is represented in the annexed figure. In the growth of these hemispheres, the enlargement takes place in the spaces between the polyps ; and. ORBICELLA CAVERNOSA. whenever these spaces begin to exceed the width usual to the species, a new mouth opens, commencing a new polyp ; and thus the growth of the mass involves multiplication by buds. The small calicle near the centre of the figure is from one of the new interstitial buds. Species of Porites also grow into hemispheres and rude hil- lock-like forms, through the same method of budding, and some of the masses in the tropical Pacific have a diameter of even twenty feet. Myriads of living polyps are combined in a single such mass, for each is but a fifteenth or a twentieth of an inch in diameter. Often there is a lateral growth of the polyp and thereby of the zoophyte without much upward growth; and spreading leaves are thus made, and bowl-like shapes. Where there is lateral budding, the leaves have generally an edge of young polyps from the new buds that are there opening, as in the. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Dana, James Dwight, 1813-1895. New York : Dodd & Mead
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Keywords: ., bookcentury1800, bookdecade1870, bookpublishernewyo, bookyear1872