. Elementary zoology. Zoology. AMOEBA AND PARAMECIUM 35 a fixed shape to the body, are all specializations which make Paramoecium more complex than Amoeba. But the whole body is still composed of a single cell, and there is, as in Amoeba, no differentiation of the body-substance into different tissues, and no arrangement of body-parts as systems of organs. Par amoecium may occasionally be found reproducing. This process takes place very much as in Amoeba. The animal remains dormant for a while, the micronucleus then divides, the macronucleus elongates and finally divides in two, the proto- pla
. Elementary zoology. Zoology. AMOEBA AND PARAMECIUM 35 a fixed shape to the body, are all specializations which make Paramoecium more complex than Amoeba. But the whole body is still composed of a single cell, and there is, as in Amoeba, no differentiation of the body-substance into different tissues, and no arrangement of body-parts as systems of organs. Par amoecium may occasionally be found reproducing. This process takes place very much as in Amoeba. The animal remains dormant for a while, the micronucleus then divides, the macronucleus elongates and finally divides in two, the proto- plasm of the body becomes con- stricted into two parts, each part massing itself about thewithdrawn halves of the macro- and micro- nuclei, and lastly the whole breaks into two smaller organisms which grow to be like the original. After multiplication or reproduc- tion has gone on in this way for numerous generations (about one hundred), a fusion of two Para- moecia seems necessary before further divisions take place. This process of fusion, called conjuga- tion, may be noted at some sea- sons. Two Paramcvcia unite with their buccal grooves together, part of the macronucleus and micronucleus of each passes over to the other, and the mixed elements fuse together to form a new macro- and micronucleus in each half. The conjugating Paramoecia now separate, and each divides to form two new Fig. 6. — Paramceciuj?i sp. ; buccal groove at right. (From life.). Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Kellogg, Vernon L. (Vernon Lyman), 1867-1937. New York : H. Holt and company
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Keywords: ., bookcentury1900, bookdecade1900, booksubjectzoology, bookyear1902
