. The biology of the protozoa. Protozoa; Protozoa. lSli BIOLOGY OF THE PROTOZOA it strikes a Paramecium or other ciliate purely at random; the proboscis with seizing organ is buried in the victim which is then swallowed whole (Fig. 98, 1-6). Lionotus fasciola, Spathidium spathula and other gymnostomatous ciliates capture living organ- isms in a similar way (Fig. 99) while less spectacular methods are employed by Frontonia leucas, Ophryoglena flava, Prorodon niveus, etc., in swallowing diatoms, desmids and other relatively stationary organisms. A special type of food-getting, illustrated by the
. The biology of the protozoa. Protozoa; Protozoa. lSli BIOLOGY OF THE PROTOZOA it strikes a Paramecium or other ciliate purely at random; the proboscis with seizing organ is buried in the victim which is then swallowed whole (Fig. 98, 1-6). Lionotus fasciola, Spathidium spathula and other gymnostomatous ciliates capture living organ- isms in a similar way (Fig. 99) while less spectacular methods are employed by Frontonia leucas, Ophryoglena flava, Prorodon niveus, etc., in swallowing diatoms, desmids and other relatively stationary organisms. A special type of food-getting, illustrated by the Rhizopods, may be interpreted in some cases as the result of physical properties of semifluid bodies. Rhumbler has made the most exhaustive studies. >M Fig. 97.—Types of food getting. A, Acanthocystis (after Penard); B, Oicomonas termo (after Biitschli). of food ingestion in these forms and distinguishes four types, viz.: Ingestion by (1) "circumvallation," (2) "circumfluence," (3) "invag- ination" and (4) " ; Food-taking by " circumvallation" is illustrated by Amoeba yroteus and usually takes place at that por- tion of the body which, for the time being, is posterior. According to Hofer (1889), Schaeft'er (1917) and others, the body becomes anchored to the substratum by the secretion of an ectoplasmic gelatinous substance; then, through the physical stimulus (Schaeffer, 1917) produced by a moving object (even a moving needle point according to Verworn, 1889), walls of protoplasm flow out on either side of the object and meet around it, thus enclosing a rotifer, an. 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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