. The cell; outlines of general anatomy and physiology. r on their whole ventral surfaces are in contact, their mouthopenings being opposite to one another (Fig. 148 I, o). An ir-regular thickening develops over a small area in the neighbourhoodof these latter, if conjugation lasts for any considerable the nuclear apparatus, including both the chief nucleusand the paranucleus, has undergone fundamental changes. The chief nucleus becomes somewhat enlarged, its surface beingat first covered with protuberances and depressions (Fig. 148 II—IV, k); these protuberances extend themse
. The cell; outlines of general anatomy and physiology. r on their whole ventral surfaces are in contact, their mouthopenings being opposite to one another (Fig. 148 I, o). An ir-regular thickening develops over a small area in the neighbourhoodof these latter, if conjugation lasts for any considerable the nuclear apparatus, including both the chief nucleusand the paranucleus, has undergone fundamental changes. The chief nucleus becomes somewhat enlarged, its surface beingat first covered with protuberances and depressions (Fig. 148 II—IV, k); these protuberances extend themselves into longer pro-cesses, which later on become separated off, and then graduallysplit up into still smaller pieces (V, VI, k). Thus the whole chiefnucleus becomes broken up into several small segments, whichdistribute themselves all over the body of the Infusorian (VII),and finally become dissolved and absorbed. In a word, the mainnucleus, having played its part, becomes completely disintegrated?during and after conjugation. 268 I. THE CELLI. Fig. 148.—Conjugation of Paramecium (R. Hertwig, Zooh, Fig. 141): nl: paranuclei; fcnuclei of conjugating animals. I The paranucleus transforms itself into a spindle ; in left-hand animal the sickle-stage, in right-hand animal the spindle-stage, are represented. IISecond division of paranucleus into chief spindle (marked 1 in left, and 5 in right) andsubsidiary spindles (2, 3, 4 in left, and 6, 7, 8 in right). Ill Subsidiary spindles show de-generation (2, 3, 4 in left, 6, 7, 8 in right), the chief spindles divide into male and femalespindles (1 into 1 m and lioin left, and 5 into 5 m and 5 w in right). IV Transmigration ofmale spindles nearly completed (fertilisation). One end remains in the mother animal,whilst the other has united itself with the female spindle of the other animal (1 m with5 u-, and 5 m with 1 w). The main chief nucleus has become converted into The primary division spindle resulting from the unio
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Keywords: ., bookcentury1800, bookdecade1890, bookidcelloutlines, bookyear1895
