. An introduction to zoology : for the use of high schools . Fig. 150.—Female of Roti-fer. {Ilydatina senta). 224 HIGH SCHOOL ZOOLOGY. also to be recognised. The development is often complicatedby a metamoiphosis, and the creatures often pass through dif-ferent stages of their parasitic life in diiferent hosts, a phenom-enon known as Fig. 151.—Trichina spiralis. A, female; B, male; C, junction of oesophagus and intestine; D, encystedTrichina-larva between the fibres of muscular tissue. 10. Two orders of Nematelminthes are recognised, the Nematodes,which have generally a complete
. An introduction to zoology : for the use of high schools . Fig. 150.—Female of Roti-fer. {Ilydatina senta). 224 HIGH SCHOOL ZOOLOGY. also to be recognised. The development is often complicatedby a metamoiphosis, and the creatures often pass through dif-ferent stages of their parasitic life in diiferent hosts, a phenom-enon known as Fig. 151.—Trichina spiralis. A, female; B, male; C, junction of oesophagus and intestine; D, encystedTrichina-larva between the fibres of muscular tissue. 10. Two orders of Nematelminthes are recognised, the Nematodes,which have generally a complete intestine, and the Acanthocephali, whichhave none. To the former order there belong some free microscopic forms,which live in decaying matter in water, also some vegetable para-sites, like the wheat-worm fT^^feHc/ms^ and the beet-worm ^i/e^ercxZera^,but the bulk of the order are parasites, either during a part of theirlife (like the insect parasites Gordius and Mermls), or during the whole ofit. All groups of Vertebrates have special Nematode parasites, which liveiu the skin, or the eyes (Filaria), or iu the intestine (AscarisJ, or the HIGH SCHOOL ZOOLOGY. 225 muscles (Trichina), or the respiratory organs (Syngamus, Strongylus),or blood-vascular system (SclerostomumJ, and cause many seriousdiseases. One of the most dangerous of these to
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Keywords: ., bookcentury1800, bookdecade1880, booksubjectzoology, bookyear1889
