. A manual of elementary zoology . Zoology. PL A TYHELMTNTHES 211 movement by contraction of its muscles. The eggs are set free by its rupture. If, as may happen in various circum- stances, they are now swallowed by a pig, or, as occasionally, by man, their shells are dissolved in the alimentary canal and a little spherical six-hooked embryo or onchosphere is set free from each. This bores its way from the intestine of the pig into its blood vessels and is carried to the muscles and other organs, where it loses its hooks, increases in size,. Fig. 130.—A proglottis of Tania solium with the repr
. A manual of elementary zoology . Zoology. PL A TYHELMTNTHES 211 movement by contraction of its muscles. The eggs are set free by its rupture. If, as may happen in various circum- stances, they are now swallowed by a pig, or, as occasionally, by man, their shells are dissolved in the alimentary canal and a little spherical six-hooked embryo or onchosphere is set free from each. This bores its way from the intestine of the pig into its blood vessels and is carried to the muscles and other organs, where it loses its hooks, increases in size,. Fig. 130.—A proglottis of Tania solium with the reproductive organs at the stage of complete development. , Cirrus sac ; excr., excretory canals \, genital opening; , nerve cord; ov., ovary; , shell gland; testes; , vas deferens; ut., uterus ; vag-., vagina; , yolk gland. and becomes a bladder-worm or cysticercus. The wall of this becomes tucked in at one spot, forming a pouch, on the inner wall of which the suckers and hooks of the future head appear. No further change takes place unless the flesh of a pig infested with such bladder-worms (known as "measly" pork) be eaten raw or "underdone" by man. When this happens, the stimulus of the new surroundings causes the head to be turned inside out. The bladder is digested, but the head fixes itself and begins to bud off. 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 Borradaile, L. A. (Lancelot Alexander), 1872-1945. London : H. Frowde, Hodder & Stoughton
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Keywords: ., bookcentury1900, bookdecade1920, booksubjectzoology, bookyear1920
