Elements of comparative anatomy (1878) Elements of comparative anatomy elementsofcompar00gege Year: 1878 Fig. 22. An Amoeba figured at two different moments during move- ment, n Nucleus, i Ingested food. Some vacuoles may also be noted. / /, times tliu appearance of broad lobatc prolongations (Fig. 22) separated from one another 'by shallow depressions; sometimes they flow out as delicate, sometimes ;as wedge-shaped, currents, which divide in all kinds of ways at their periphery, and so form ramified processes. These changes are always within definite limits of form in the various divisions,
Elements of comparative anatomy (1878) Elements of comparative anatomy elementsofcompar00gege Year: 1878 Fig. 22. An Amoeba figured at two different moments during move- ment, n Nucleus, i Ingested food. Some vacuoles may also be noted. / /, times tliu appearance of broad lobatc prolongations (Fig. 22) separated from one another 'by shallow depressions; sometimes they flow out as delicate, sometimes ;as wedge-shaped, currents, which divide in all kinds of ways at their periphery, and so form ramified processes. These changes are always within definite limits of form in the various divisions, so that the form of the pseudopodia is the expression of the first differen- tiation of a definite morphological character of the protoplasm. The pseudopodia characterise the Rhizo- poda, the superficial protoplasm of which is able to emit them in every form of this group (Fig. 23). Neigh- bouring pseudopodia can unite with one another at any point and in various numbers (Fig. 23, x)} or may even become connected in a retiform manner. This character of the protoplasm is 'â¢â¢â¢â V\ }.'â¢;.:/..' Mi' â â â â¢'/,- ⢠/ n°t affected by in- ternal differentiation (skeletal organs, etc.). It is the expression of a stage in the lowest living material when it is not differentiated at its periphery. When the outer- most layer of the body is hardened, pseudopodia cannot be formed at every point. The chemico- physical changes iu the peripheral parts lead to the formation of something unlike the rest of the proto- plasm, which retains its indifferent character, and indeed still gives signs of its power of movement, but is restrained by the firmer cortical layer from any considerable exten- sion of itself. This stage is found in the Gregarime; characters which obtain in many of the Amoeba) exhibit intermediate steps towards it. A firm homogeneous membrane sometimes delicately striated, extends in these forms over the whole body, which is formed by a single cell. It passes
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