Beginners' zoology . in vessels of watercontaining suitable food but previously free from proto-zoans. ? The Slipper Animalcule or Paramecium Suggestions.—Stagnant water often contains the paramecium aswell as the amoeba; or they may be found in a dish of water con-taining hay or finely cut clover, after the dish has been allowed tostand in the sun for several days, A white film forming on thesurface is a sign of their presence. They may even be seen withthe unaided eye as tiny white particles by looking through the sideof the dish or jar. Use at first a i or ^ in. objective. Restricttheir mov
Beginners' zoology . in vessels of watercontaining suitable food but previously free from proto-zoans. ? The Slipper Animalcule or Paramecium Suggestions.—Stagnant water often contains the paramecium aswell as the amoeba; or they may be found in a dish of water con-taining hay or finely cut clover, after the dish has been allowed tostand in the sun for several days, A white film forming on thesurface is a sign of their presence. They may even be seen withthe unaided eye as tiny white particles by looking through the sideof the dish or jar. Use at first a i or ^ in. objective. Restricttheir movements by placing cotton fibres beneath the cover glass;then examine with ^ or ^ objective. Otherwise, study figures. Shape and Structure.—The Parameciums whole body,like the amoebas, is only one cell. It resembles a slipperin shape, but the pointed end is the hind end, they;w/^ endbeing rounded (Fig. 14). The paramecium is propelledby the rapid beating of numerous fine, threadlike append- 14 BEGINNERS ZOOLOGY. —r There isthe macro- ages on its surface, called cilia (Latin, eyelashes) (Figs.).The cilia, like the pseudopods of the amoeba, are merely prolongations of the cell protoplasm,but they are permanent. The sepa-ration between the outer ectoplasmand the interior granular cndoplasvtis more marked than in the amoeba(Fig. 14). Nucleus and Vacuolesa large nucleus callednucleus, and beside it asmaller one called themicronucleus. They arehard to see. About onethird of the way fromeach end is a clear, pul-sating space (bb. ) called the pulsat-ing vacuole. Thesespaces contract untilthey disappear, and thenreappear, gradually ex-panding. Tubes lead from the vacuoles which probablyserve to keep the contents of the cell in circulation. Feeding. — A depression, or groove, is seen on one side;this serves as a mouth (Figs.). A tube which serves as a gullet leads from themouth-groove to the in-terior of the cell. Themouth-groove is linedwith cilia which sweepfood particles
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Keywords: ., bookcentury1900, bookdecade1920, booksubjectzoology, bookyear1921
