. The biology of the protozoa. Protozoa; Protozoa. B Fig. 140. — Adelina dimidiata A. Schn. .1, association of macrogametocyte and smaller microgametocyte. B, nuclear divisions in microgametocyte and formation of gametic nuclei. X 1400. (From Doflein after Shellack, Arbeit, aus d. kaiserlichen Gesundheitsamt, courtesy of J. Springer.) It is possible that the peculiar conditions existing in present-day ciliates may have resulted from conditions of pseudo-conjugation as illustrated by the present-day gregarines, and that originally, a group of gametes were formed which united to form zygotes out
. The biology of the protozoa. Protozoa; Protozoa. B Fig. 140. — Adelina dimidiata A. Schn. .1, association of macrogametocyte and smaller microgametocyte. B, nuclear divisions in microgametocyte and formation of gametic nuclei. X 1400. (From Doflein after Shellack, Arbeit, aus d. kaiserlichen Gesundheitsamt, courtesy of J. Springer.) It is possible that the peculiar conditions existing in present-day ciliates may have resulted from conditions of pseudo-conjugation as illustrated by the present-day gregarines, and that originally, a group of gametes were formed which united to form zygotes outside of the parent cells, or inside as in the case of Ophryocystis mesnili1 (Fig. 120, p. 281). On this hypothesis which has been very generally accepted by protozoologists, the fusing nuclei of conjugating ciliates are interpreted as the nuclei without cell bodies 1 Some of the parasitic ciliates suggest the gregarines in their conjugation phe- nomena. Thus in Balantidium coli, according to Brumpt (1909), two individuals come together and form a common enveloping cyst membrane within which the two cells now completely 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, Lea & Febiger
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