. Ameboid movement. Amoeboid movement; Amoeba. AMEBOID MOVEMENT 59. Figure 25. Amoeba proteus. Rate of movement of the surface layer as compared with the rate of movement of the ameba. The pseudopod on the right vv^as extended to stage 5; from then on it was retracted, as indicated by the outHnes. Length of the arneba, 400 microns. retract. The particle moved times as fast as the ameba from I to 4. But from 4 to 7 the particle moved only times as fast as the ameba. In the earlier stages the outer layer was pulled toward the tip of both pseudopods, in the later stages only toward one,
. Ameboid movement. Amoeboid movement; Amoeba. AMEBOID MOVEMENT 59. Figure 25. Amoeba proteus. Rate of movement of the surface layer as compared with the rate of movement of the ameba. The pseudopod on the right vv^as extended to stage 5; from then on it was retracted, as indicated by the outHnes. Length of the arneba, 400 microns. retract. The particle moved times as fast as the ameba from I to 4. But from 4 to 7 the particle moved only times as fast as the ameba. In the earlier stages the outer layer was pulled toward the tip of both pseudopods, in the later stages only toward one, and in this lies the explanation for a more rapid movement of the particles in the earlier, and a slower movement in the later stages. This effect was also observed in discoides, but the fact that the particle in the later stages moved only wery little faster than the ameba is due to a narrow anterior edge and to the formation of ectoplasm in the ridges over the surface of the ameba. The effect of ridge formation on the movement of particles attached to the surface film is well seen when an ameba has two forward moving regions opposite each other. Under such conditions particles located equidistant or nearly so between such regions, move only very slowly or not at all, the pull upon the film being nearly or quite equal. In a similar manner the ridges which are constantly form- ing on a proteus are continually competing with the anterior end. 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 Schaeffer, Asa A. (Asa Arthur), b. 1883. Princeton : Princeton University Press
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