. Biology . inal division which is not different in any way from the divi-sion of Chilomonas. The daughter cells separate after division,and lead an independent existence. In some forms of flagel-lated protozoa, however, the cells after division do not separatecompletely but remain attached to each other in one way oranother {, by the basal ends as in Synura uvella (Fig. 23), thusforming aggregates of cells or individuals of a second order towhich the term colony is given. Sometimes the cells thusformed are embedded in a common jelly, the aggregate form-ing relatively large spherical masse
. Biology . inal division which is not different in any way from the divi-sion of Chilomonas. The daughter cells separate after division,and lead an independent existence. In some forms of flagel-lated protozoa, however, the cells after division do not separatecompletely but remain attached to each other in one way oranother {, by the basal ends as in Synura uvella (Fig. 23), thusforming aggregates of cells or individuals of a second order towhich the term colony is given. Sometimes the cells thusformed are embedded in a common jelly, the aggregate form-ing relatively large spherical masses (Fig. 24). Again they are FLAGELLATED PROTOZOA 59 limited to a certain number of cells, and this number alwaysreappears upon reproduction so that the multicellular individualis much more specific in nature, as in Gonium pectorale wherethe individual always consists of i6 cells (Fig. 25). These colony forms are of peculiar interest in that they havemany features in common with the higher animals and plants,. Fig. 25.—Gonium pectorale, a colony of flagellated protozoa consisting of sixteencells arranged in a flat plate, three on a side and four in the center. Each cellcarries two flagella. Photograph from a preparation. but the cells are not differentiated for the performance of differ-ent functions, each one acting for itself rather than for the ag-gregate as a whole. They represent, therefore, a phase incomplexity of form and function intermediate between the uni-cellular organisms (protozoa, protophyta) and the multicellular(metazoa and metaphyta). 60 ORGANISMS OF ONE CELL rff/cHocrsrs 5 MlCRONUCLEUS. MACRONUCLBUS GASTRIC VACUOLE ^ C. A Ciliated Protozoon, Paramecium caudatum An infusion of vegetable or animal matter becomes the feed-ing ground not only of bacteria and flagellated protozoa, butalso, after some considerable time, of ciliated protozoa as the fact that all of these organisms appear in such infu-sions, the term Infusoriawas formerly employed
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