Elementary text-book of zoology . elementarytextbo0101clau Year: 1884 204 PROTOZOA. 7! PF like the substance of a true cell nucleus, when undergoing division. The paranucleus too increases in size and becomes striated, and divides into a number of bodies by a single or re- peated division. Some of these bodies produced by the division of the nucleus and paranucleus disappear or are cast out, and others are employed in the formation of the new nucleus and paranucleus. The processes of regene- ration are for the most part not com- pleted until the conjugating animals ' have separated. Conjugati
Elementary text-book of zoology . elementarytextbo0101clau Year: 1884 204 PROTOZOA. 7! PF like the substance of a true cell nucleus, when undergoing division. The paranucleus too increases in size and becomes striated, and divides into a number of bodies by a single or re- peated division. Some of these bodies produced by the division of the nucleus and paranucleus disappear or are cast out, and others are employed in the formation of the new nucleus and paranucleus. The processes of regene- ration are for the most part not com- pleted until the conjugating animals ' have separated. Conjugation is probably followed by a repeated division (fig. 146). The mode of life of the Infusoria, which principally inhabit fresh water, is very various. Most of them lead an independent life, and take up larger or smaller bodies, even Rotifera, as nourishment. Some, as Amphilej)tus, select fixed Infusoria, as Epistylis and Carchesium, for their prey, and swallow them down as far as the origin of the stalk • they then, while fixed on the stalk, secrete a capsule, and divide up into two or more individuals, which pass out. Certain Infu- soria, as the mouthless Opalina, and many Bursa- ridse, are parasitic in the intestine and bladder of Vertebrates. To these belongs the 'Balantidium coli from the large intestine of Man (fig. 147). 1. Sub-order : Holotricha. - - Body uniformly covered with cilia, which are arranged in longitu- dinal rows, and are shorter than the body. Longer cilia are sometimes found in the region of the FIG. 146. — ParamtBcium Bursaria about one hour after conjugation (after Biitschli). », nucleolus ; N, nucleus; P V, contractile vacuole. Two of the nucleoli have become clear spheres.
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