. Elementary text-book of zoology, general part and special part: protozoa to insecta. Animals. 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 di\asion. 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. Conjug
. Elementary text-book of zoology, general part and special part: protozoa to insecta. Animals. 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 di\asion. 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 Amjyhihjytus, select fixed Infvisoria, as Ejnstylis and 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 diAade up into two or more individuals, which pass out. Certain Infu- soria, as the mouthless Opalina, and many Bursa- ridfe, 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 mouth, but these do not form an adoral zone. Besides the parasitic Opalinae (^Oj)alina! ranarvm'), with- out mouth or anus, the following families belong to this group :— Fam. Trachelidse. Body of changeable shape prolonged into an anterior neck-like process. Mouth ventral, without longer cilia. Trachdius ovum Ehrbg., Amj)7iilrj>tu.^ fasci- cola Ehrbg. Fam. Colpodidse. Form of body definite. ^louth ventral, in a depression, Fig. 146. — Faramepcium Bursaria about one ho
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Keywords: ., bookcentury1800, bookdecade1890, booksubjectanimals, bookyear1892
