. The microscope and its revelations. d as Actiiw-K/>lin>riuni EicJiornii (fig. 574); the pseudopodia are longer andmore numerous ; there are generally a number instead of one con-tractile vacuole. and there is more than one nucleus. The axis of thepseudopodia may be seen to be clothed with a layer of soft sarcodederived from the super-ficial 01- cortical zone ofthe body. Several nuclei(//. it) are usually to beseen imbedded in theprotoplasmic ma>s. Thegeneral life-history ofthis type correspondswith that of the pre-ceding, but its mode ofreproduction presentssome marked peculiari-tie
. The microscope and its revelations. d as Actiiw-K/>lin>riuni EicJiornii (fig. 574); the pseudopodia are longer andmore numerous ; there are generally a number instead of one con-tractile vacuole. and there is more than one nucleus. The axis of thepseudopodia may be seen to be clothed with a layer of soft sarcodederived from the super-ficial 01- cortical zone ofthe body. Several nuclei(//. it) are usually to beseen imbedded in theprotoplasmic ma>s. Thegeneral life-history ofthis type correspondswith that of the pre-ceding, but its mode ofreproduction presentssome marked peculiari-ties. In many if not inall cases it first observed bvKolliker, with the con-jugation of two separateindividuals. The binarysegmentation is pre-ceded by a withdrawalof the pseudopodia. eventheir clearly definedaxis becoming indistinctand finally disappear-ing; the body becomesenveloped by a cleargelatinous- exudation,which forms a kind ofcyst ; and within thisthe process of binarysubdivision is repeatedlyperformed, until the. original single ma^s i> FIG. 576. — Clathrulina elcgans: A, completeorganism; B, swarm-spore showing nucleus, »,and two contractile vesicles near its opposite end. replaced by a sort ofmorula, each spherule of which shows the distinction between thecentral and cortical regions, the former including a single nucleus,whilst the latter is strengthened by siliceous deposit into a firminvestment. After remaining in this state during the winter theyoung Actinosphceria come forth in the spring without this siliceousinvestment, and gradually grow into the likeness of their 1 On the results of the artificial division of Actinosphferium see K. Brandt, T~< 1» rActinosphterium EirJinrnii, Halle aS., 1877; Gruber, Hrrirlite d. Nntiirf. (Irx. zuFreiburg ijB., lSS(i; Nnssbaum, Arch. f. M/lr. Aunt. xxvi. 742 MICROSCOPIC FORMS OF ANIMAL LIFE—PROTOZOA A large number of new and curious fresh-water forms of thitype are being frequently brought un
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Keywords: ., bookcentury1900, bookdecade1900, booksubjectmicrosc, bookyear1901
