. The Protozoa. Protozoa. 92 THE PROTOZOA disintegrated, the digestible portions being transformed into a sort of chyle which is distributed throughout the protoplasm. The gastric vacuole with its undigested residue is gradually left behind like a loaded contractile vacuole, until finally it is expelled to the outside (Arnceba). The Sarcodina, apparently, digest mainly proteids, some forms of starch, and fats remaining unchanged (Meissner, '88; Green- wood, '80; Stole, '00). G. Reproduction The Sarcodina reproduce mainly by simple division or spore-for- mation, either in the free state while a
. The Protozoa. Protozoa. 92 THE PROTOZOA disintegrated, the digestible portions being transformed into a sort of chyle which is distributed throughout the protoplasm. The gastric vacuole with its undigested residue is gradually left behind like a loaded contractile vacuole, until finally it is expelled to the outside (Arnceba). The Sarcodina, apparently, digest mainly proteids, some forms of starch, and fats remaining unchanged (Meissner, '88; Green- wood, '80; Stole, '00). G. Reproduction The Sarcodina reproduce mainly by simple division or spore-for- mation, either in the free state while active, or when quiet in the encysted state. The simplest form, consisting of a mere bipartition of the protoplasm and of the essential body-contents, occurs when the body is so large that it becomes unwieldy and it divides from sheer inertia. A well-known example is that of the division of Arnceba polypodia {Dactylospkcera, F. E. Schultze). Here, as in all cell-divi- sions, the nucleus divides first, the body then separating into two parts. Simple division becomes more complicated when the organism is. Fig. 51.—Microgrotnia sociatts Hert. [HERTWIG.] Division takes place within the shell, and one of the daughter-individuals migrates, forming a new shell. provided with an outer coating or test, although in the simplest of such cases, where the coating is flexible and plastic, as in Vampyrella, the process involves only the partition of the outer membrane. When the outer covering becomes hard and firm by impregnation with chi- tinous, silicious, calcareous, or horny materials, the operation is more complicated. The organism, while still within the shell, may divide by longitudinal division, one of the daughter-individuals then migrat- ing from the parent shell and, after a longer or shorter time, settling down and secreting a new shell for itself, the other daughfer-indi-. Please note that these images are extracted from scanned page images that may have been digitally enhanced
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