. Text book of zoology. Zoology. 148 Platy helminths. of a pharynx and a simple sao-shaped gut. The redias break thi-ough the maternal body-wall and wander about in the Snail, consuming its liver. In these, eggs are again formed, which become "cerearise," with a branched alimentai-y canal and a caudal appendage. They escape through an opening in the maternal tissues, and later from the body of the Snail also. The cercaria swims actively for some time in the water, then it attaches itself to some plant, loses its tail, and secretes a mucous-substance which hardens into a cyst round th
. Text book of zoology. Zoology. 148 Platy helminths. of a pharynx and a simple sao-shaped gut. The redias break thi-ough the maternal body-wall and wander about in the Snail, consuming its liver. In these, eggs are again formed, which become "cerearise," with a branched alimentai-y canal and a caudal appendage. They escape through an opening in the maternal tissues, and later from the body of the Snail also. The cercaria swims actively for some time in the water, then it attaches itself to some plant, loses its tail, and secretes a mucous-substance which hardens into a cyst round the body. If it be swallowed with the food by a Sheep or an Ox, the capsule. Fig. 104. Distomum hepaticum. 1 newly hatched larva, t boringf papilla, o e-o. 2 the same (young sporocyst of the first generation), after it has entered the snail and lost its ciliated coat, h ovnm. 3 adnlt sporocyst of the first generation. 4 redia of the second generation. / Limb-like projection, Tij—Tij eeroarise developing within the redia, le oercaria-embryo, m month, ia gut, v genital aperture. 5 cercaria, Ku glands, whose secretion forms the capsule. Si—52 suckers, ta gut. All the figures are eiilarged.—After Thomas ; 4 slightly altered. is dissolved by the gastric juice, and the young Trematode wanders into the liver, where it attains sexual maturity (the hermaphrodite generation). Encysted Liver-flukes are found not only on water, but also on land plants, for the Snail frequently leaves the water and wanders about in the adjacent meadows. 2. Lewcochloridiwm paradoxum is a parthenogenetic trematode, parasitic in Suceinea amphibia, a Gastropod inhabiting damp places. This peculiar form has the appearance of a sac with numerous branches, some of which attain a very great development, forming thick, brightly coloured rods, which push their way into the tentacles of the Snail, and expand them enormously. Different insect- eating Birds tear the " rods " out of the Snail, which may go
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Keywords: ., bookcentury1800, bookdecade1890, booksubjectzoology, bookyear1896
