. Elementary text-book of zoology. Zoology. 226 CCELENTERATA. than the preceding ones. After an interval four new folds appear, one on each side of the two primary mesenteries (tig. 170). The twelve gastrovascular chambers thus formed gradually become equal in size, and can be separated into two unpaired chambers situated in the median plane, and into five pairs placed symmetrically on either side of FIG. 170.—From tlie history of the development of Actinia mesembryamthermim (after Lacaze Duthiers). a, Larva with eight mesenteries and two coiled bands; O, mouth. I, Slightly more advanced


. Elementary text-book of zoology. Zoology. 226 CCELENTERATA. than the preceding ones. After an interval four new folds appear, one on each side of the two primary mesenteries (tig. 170). The twelve gastrovascular chambers thus formed gradually become equal in size, and can be separated into two unpaired chambers situated in the median plane, and into five pairs placed symmetrically on either side of FIG. 170.—From tlie history of the development of Actinia mesembryamthermim (after Lacaze Duthiers). a, Larva with eight mesenteries and two coiled bands; O, mouth. I, Slightly more advanced larva with the commencement of eight* tentacles, c, d, Young Actinia with twenty-four tentacles, two longitudinal sections at right angles to one anothei. e, Mouth and tentacles seen from the oral surface. The tentacles begin to develop before the appearance of the fifth and sixth pairs of mesenteries. They appear at the oral end of the gastrovascular chambers, and the tentacle of the anterior unpaired. 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 Claus, Carl, 1835-1899; Sedgwick, Adam, 1854-1913; Sinclair, F. G. (Frederick Granville), b. 1858. New York : Macmillan


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Keywords: ., bookcentury1800, bookdecade1880, booksubjectzoology, bookyear1884