. The Protozoa. Protozoa. 68 THE PROTOZOA akoff ('88) describes three, Penard ('90) no less than four in Euglypha, and Rhumbler ('98) the latter number in Cyplwderia. Schewiakoff ('88), apparently on very good grounds, maintained that certain spe- cific functions characterize each of these zones, indicating, in a general way, a regional differentiation and division of physiological labor. To the outer zone, which corresponds to the ectoplasm of Amoeba, he ascribed a locomotor function, this being the seat of pseudopodia for- mation ; to the second zone, which contains the nucleus, the function
. The Protozoa. Protozoa. 68 THE PROTOZOA akoff ('88) describes three, Penard ('90) no less than four in Euglypha, and Rhumbler ('98) the latter number in Cyplwderia. Schewiakoff ('88), apparently on very good grounds, maintained that certain spe- cific functions characterize each of these zones, indicating, in a general way, a regional differentiation and division of physiological labor. To the outer zone, which corresponds to the ectoplasm of Amoeba, he ascribed a locomotor function, this being the seat of pseudopodia for- mation ; to the second zone, which contains the nucleus, the function of assimilation, and to the third zone a reproductive function. Penard and Rhumbler separate Schewiakoff's second zone into two on account of certain structural differences. According to these observers the. Fig. â $2. â Actinophrys sol Ehr. [BiJTSCHLI after GRENACHER.] The axial filaments (a) extend through the endoplasm to the membrane of the nucleus; c, a. contractile vacuole in the ectoplasm; gt an ingested food particle in a gastric vacuole. outermost zone is distinctly vacuolated, the second contains food-par- ticles in the process of digestion, the third, granules which represent waste matter not determined, and the fourth, excretory granules. The appearance of the protoplasm in Heliozoa or Radiolaria is quite different from that of the Rhizopoda. Ectoplasm and endoplasm can be distinguished, but unlike the hyaline ectoplasm of Amoeba, the outer plasm of Heliozoa is made up of vacuoles much larger than those of the endoplasm, the walls of these vacuoles being distinctly granular (Fig. 32). The extremely vacuolated appearance, however, seems to be largely dependent upon the medium in which the 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 Calkins, Gary N. (Gary Nathan), b. 1869. New York,
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