. A manual of elementary zoology . Zoology. PLATYHELMINTHES 209 appears to take place through the mucous membrane of the mouth. To the Platyhelminthes belong also the Tapeworms or Cestoda, of which Tcenia solium, found in man, Cestoda. 1 t 1 1 1 1 â is an example. In the adult state this worm may reach a length of many feet. It lives in the intestine, to whose wall it is attached by a head or scolex, provided with four suckers and a crown of hooks. Behind the head is a narrow neck, followed by a long chain of joints ox proglot- tides which it buds off. The younger of these, near the head, are
. A manual of elementary zoology . Zoology. PLATYHELMINTHES 209 appears to take place through the mucous membrane of the mouth. To the Platyhelminthes belong also the Tapeworms or Cestoda, of which Tcenia solium, found in man, Cestoda. 1 t 1 1 1 1 â is an example. In the adult state this worm may reach a length of many feet. It lives in the intestine, to whose wall it is attached by a head or scolex, provided with four suckers and a crown of hooks. Behind the head is a narrow neck, followed by a long chain of joints ox proglot- tides which it buds off. The younger of these, near the head, are small, but they grow larger as they are pushed farther from the head by the formation of new joints. The body is covered with a cuticle, under which lies a layer of «y«.. Fig. 128.âA turbellarian (Planariapolychroa) swimming.âFrom Shipley and MacBride. , Ciliated slit at side of head ; eye ; , genital opening ; »z., mouth, at end of outstretched pharynx ; , sheath into which pharynx can be withdrawn. very deep cells with longitudinal muscle fibres between them and a circular layer of muscle below them. Inside this is a mass of parenchyma like that of the fluke, in which are embedded the excretory, generative, and nervous systems. There is no alimentary canal, nutriment being absorbed through the surface of the body. The excretory system is of the same type as that of the fluke, with flame cells and a larger and a smaller main duct on each side, connected by a transverse vessel on the hinder side of each proglottis. In the last proglottis these vessels open by a median pore. The nervous system consists of a ring in the head with small forward nerves and two lateral nerve cords. The reproductive organs have the same general structure as in the liver fluke: they are shown in Fig. 129. A complete set of them is found in each proglottis. Apparently each. Please note that these images are extracted from scanned page images that may have been digitally
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Keywords: ., bookcentury1900, bookdecade1920, booksubjectzoology, bookyear1920
