Elementary text-book of zoology, tr Elementary text-book of zoology, tr. and ed. by Adam Sedgwick, with the assistance of F. G. Heathcote elementarytextbo01clau Year: 1892-1893 1&2 TEOTOZOA. ever, be broad, lobed, or finger-like processes by means of which a quick and flowing motion can be imparted to the body mass. A tougher, clear homogeneous external layer (Exoplasni) is usually to be distinguished as the peripheral boundary from a more fluid and more granular internal mass (Endopktsm). During motion the former is projected in processes into which the granules of the latter stream more or
Elementary text-book of zoology, tr Elementary text-book of zoology, tr. and ed. by Adam Sedgwick, with the assistance of F. G. Heathcote elementarytextbo01clau Year: 1892-1893 1&2 TEOTOZOA. ever, be broad, lobed, or finger-like processes by means of which a quick and flowing motion can be imparted to the body mass. A tougher, clear homogeneous external layer (Exoplasni) is usually to be distinguished as the peripheral boundary from a more fluid and more granular internal mass (Endopktsm). During motion the former is projected in processes into which the granules of the latter stream more or less quickly. In the stiffer pseudopodia streams of granules are observable, slow but regular, passing from the base to the extremity and vice rersd. The explanation of these movements is to be sought in the contractility of the surrounding portions of sarcode (fig. 120). A pulsating space, the contractile vacuole, is not unfreqently to be found in the sarcode, , Difflugia, Actinophrys, Arcella (fig. 121). Nuclei are also usually present in the sarcode, by which the morpho- logical value of the Rhizopod body as cell or as cell aggregate is placed beyond all doubt. There are also forms in the protoplasm of which no traee of a cell nucleus has been found. In such either the protoplasm of the nucleus is not yet differentiated as a separate structure Monera of E. Haeckel), or we have to do with a transient, non- nucleated stage in the life-history. V J^'T,.-:--v;:'/ The sarcode usually secretes sili- Ki '' cious or calcareous structures, either as fine spicula and hollow spines which are directed from the centre \i to the periphery in regular order Pl°- 1C1rffmta IVf ?f TaV'^y' and number, or as lattice-work podia (after Fr. E. Schultze). N, Nu- cleus. PP. pulsating vacuole. chambers (Itadiolariu), which often bear points and spines, or finally as single and many chambered shells with finely perforated walls (Foraminifera) and one larger opening. Through this last (fig. 123
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