. Elementary text-book of zoology, tr. and ed. by Adam Sedgwick, with the assistance of F. G. Heathcote. . larger segments FIG. 306.—LarvEB of Polycheeta (after Busch). a, Larva of Nereia F, tentacle; Oc, eyes; PrW, prreoral circle of cilia: O, mouth; A, anus, b, Mesotrochal, larva of C/urtoptenis; Wp, circle of cilia. proceeding from the segmentation of the larger half. In the subsequent development a primitive streak makes its appearance in all embryos of Polychceta, sometimes, how- ever, not until the embryo has begun to lead a free life as larva. The ganglia become differentiated later int
. Elementary text-book of zoology, tr. and ed. by Adam Sedgwick, with the assistance of F. G. Heathcote. . larger segments FIG. 306.—LarvEB of Polycheeta (after Busch). a, Larva of Nereia F, tentacle; Oc, eyes; PrW, prreoral circle of cilia: O, mouth; A, anus, b, Mesotrochal, larva of C/urtoptenis; Wp, circle of cilia. proceeding from the segmentation of the larger half. In the subsequent development a primitive streak makes its appearance in all embryos of Polychceta, sometimes, how- ever, not until the embryo has begun to lead a free life as larva. The ganglia become differentiated later into the ventral chain. In the free-swimming larva? the cilia are rarely distributed over the whole surface of the body (Atrocha*). They are usually confined to special rows (ciliated rings); sometimes, as in Loven's larva, there is one row placed in front of the mouth at some distance from the * Compare E. Claparede and E. Metschnikoff, " Beitrii?* znr Entwiokclungs- geschichte der Chretopoden," Zeitschr. fur wiss. Zool., Tom. XIX., 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. London, Swan Sonnenschein & co.
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