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FOOTNOTES:
[1] Wilson (’00) describes it as Pelomyxa, but it has much closer affinities with Amoeba. It is in fact perhaps the closest relative of Amoeba proteus. Ectoplasm formation, and especially the formation of ectoplasmic ridges in carolinensis, is exactly like that in proteus.
[2] This is shown by the fact that after this ameba has taken on a spherical shape due to some disturbance in the water, the number of small ridgeless pseudopods thrown out upon resuming movement, is about the same as in dubia; but after ridges begin to form, the number of pseudopods decreases.
[3] That is, resemblances in nuclear division stages are not correlated with corresponding degrees of resemblance in somatic characters. It is not generally held that the shape or size or number of chromosomes is correlated with any external characters. It is the presence of hypothetical factors or genes which are held to be correlated with somatic characters and their number or arrangement in a chromosome is not in any way related to their character.
[4] It is possible that Gruber was led to suggest a gelatinous composition for the layer in question on the strength of assertions made by several writers that amebas secrete mucus. It is true that amebas may be displaced by threads of mucus hanging to glass needles which has collected on the needles while manipulating the amebas in the culture medium, but that is not to be taken as evidence that the mucus is secreted by the amebas. Ameba cultures are always full of gelatinous material formed by bacteria. I have not thus far been able to convince myself that amebas actually secrete mucus.
[5] According to Ewart (’03) the viscosity of streaming protoplasm in plant cells lies between η = .04 and η = .2. But the velocity of streaming endoplasm in ameba is considerably slower than that in the plant cells which formed the basis for Ewart’s calculations. In comparison, we may estimate the viscosity of the endoplasm of ameba as η = .1 dynes per sq. cm. The velocity of streaming endoplasm, as ascertained by observations on Amoeba dubia (in which the endoplasm flows usually rapidly) is 1/880 cm. per second.
Now, given a unit mass of endoplasm moving at a given instant with a 1 velocity of 1/880 cm. per second against viscosity of η = .1 dynes per sq. how far will the unit mass travel before coming to rest?