. Elementary text-book of zoology. Zoology. COPEPODA. 431 the respimfor;/ function. Circulatory organs are either replaced by the regular oscillations of the intestinal canal (('//clojts, Achtheres), or there is present in the anterior part of the thorax above the intes- tine (Calanidoe) a short saccular heart, which may even be continued into a cephalic artery (Calanella) (fig. 53). Generative organs.—The C'opepoda are of separate sexes. Both kinds of genital. organs lie in the cephalothorax and in the thoracic segments, and open right and left on the basal segment of the abdomen. Sexual diff
. Elementary text-book of zoology. Zoology. COPEPODA. 431 the respimfor;/ function. Circulatory organs are either replaced by the regular oscillations of the intestinal canal (('//clojts, Achtheres), or there is present in the anterior part of the thorax above the intes- tine (Calanidoe) a short saccular heart, which may even be continued into a cephalic artery (Calanella) (fig. 53). Generative organs.—The C'opepoda are of separate sexes. Both kinds of genital. organs lie in the cephalothorax and in the thoracic segments, and open right and left on the basal segment of the abdomen. Sexual differences in the form and structure of the different parts of the body are almost uniformly found. These lead. FIG. 342.—Metamorphosis of Cyclops, a, Xauplius larva of Cyclops serrulntns after hatching. I, Older stage strongly magnified, c, V«ry young Cyclops form. AD, antennal plainU ; Ol, upper lip; JIf, mandibnlar foot; 3IJ, mandible ; MX, maxilla, JTj/', masilliped; F', F", first and second swimming feet; He, urinary concretions ; D, intestine; Ad, rectum; A, anus ; G, rudimentary genital organs. in certain parasitic Copepoda (Chondracanthidir, Lemceopodid'Ce) to an extremely striking dimorphism. The males are smaller and move with greater facility; the anterior antennae and the last pair of feet become accessory copulatory organs, the former serving to hold the female, the latter to affix the spermatophores. The sper- matophores are formed in the vas deferens by a mucous secretion which surrounds the seminal mass and hardens to a tough mem- brane. The females are larger than the males and often move. 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
