. Animal biology. Zoology; Biology. PHYLUM PLATYHELMINTHES 167 Xc/Ar Ov/Wucf IJ-f-erus 5heJ/ row of hooks (Fig. 79). The proglottids represent individuals, and the whole forms a colony, of which the section forming the scolex and neck is the parent and in which new individuals are constantly being produced by transverse constriction at the end of the neck. The proglottids are carried farther and farther away from the point of origin as younger individuals are produced and gradually become mature, with fully developed sex organs. After the egg cells are fertilized they develop in the uterus. Al
. Animal biology. Zoology; Biology. PHYLUM PLATYHELMINTHES 167 Xc/Ar Ov/Wucf IJ-f-erus 5heJ/ row of hooks (Fig. 79). The proglottids represent individuals, and the whole forms a colony, of which the section forming the scolex and neck is the parent and in which new individuals are constantly being produced by transverse constriction at the end of the neck. The proglottids are carried farther and farther away from the point of origin as younger individuals are produced and gradually become mature, with fully developed sex organs. After the egg cells are fertilized they develop in the uterus. All other organs except the uterus disappear and finally the gravid proglottid becomes practically a sac of eggs, each egg containing an embryo. Ultimately these ripe proglottids are cast off and are passed out of the body of the animal containing the parasite with the feces. In the relation of the members of a tapeworm colony to each other there is a perfect correspondence to the relation of the individuals in a strobila. The scolex and neck corre- spond to the scyphystoma and the proglottids to the gradually develop- ing ephyrae, both being cast off when mature. New proglottids are devel- oped where the neck ends, in the same ^'y H. w. Manter.) The egg cells are ... , 1 1 1 1 a> formed in the ovary and passed into the fashion as new ephyrae are budded ott oviduct, where they are fertilized by from the SCVphvstoma. sperm cells from the seminal receptacle The effects of parasitism are carried much farther than in the flukes. Hooks may be added to the suckers as. Fig. 77.—Diagrammatic sketch showing relationships of female organs in Clonorchis sinensis. (From a sketch and provided with yolk and shell-form- ing material from the yolk gland. They then go on past the shell gland, the secretion of which hardens the shells, and into the uterus. The sperm cells organs of attachment, and the in the seminal receptacle have come ,.,, « ,, . ,. from another animal. In this case it is
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