. The biology of the Protozoa. Protozoa; Protozoa. 502 BIOLOGY OF THE PROTOZOA to Brandt (1885) and Borgert (1900) the same central capsular protoplasm gives rise to anisogametes in the form of two types of flagellated swarmers, but fusion of gametes has not been observed. A further stage in the manifestation of differentiation at times of maturity is shown })\' those Protozoa in which the form, character, and size of the fusing gametes are widely different. Here progres- sive differentiation has followed two general directions resulting, in one direction, in the formation of large, usually qu
. The biology of the Protozoa. Protozoa; Protozoa. 502 BIOLOGY OF THE PROTOZOA to Brandt (1885) and Borgert (1900) the same central capsular protoplasm gives rise to anisogametes in the form of two types of flagellated swarmers, but fusion of gametes has not been observed. A further stage in the manifestation of differentiation at times of maturity is shown })\' those Protozoa in which the form, character, and size of the fusing gametes are widely different. Here progres- sive differentiation has followed two general directions resulting, in one direction, in the formation of large, usually quiescent, food-stored cells the macrogametes, in the other direction, in. Fig. 210. -Epiatylis umheUaria: colony with mature macrogametes and micro- gametes and tlieir fusion (m) and (M). (After Greeff.) minute highly motile cells, the microgametes. In these cases furthermore the differences in the gametes may be followed back through the gametocytes for several generations so that cells destined to give rise to macrogametes or to microgametes may be distinguished at an early period. Examples of this type of anisogamy are practically limited to the Phytomonadida and the Coccidiomorpha. In theCiliata, however, there is a partial differentiation in this direction in the Vorticellida? where a larger and attached individual —the macrogamete—is scarcely distinguishable from \'egetative agamonts, while the micro-. 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 Calkins, Gary N. (Gary Nathan), b. 1869. Philadelphia, New York, Lea & Febiger
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