GENERAL PHYSIOLOGY 



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while rotating at the same time on its long axis. In these sudden 

 darts, it strikes a Paramecium or other cihate purely at random, 

 the proboscis with seizing organ is buried in the victim which 

 is then swallowed whole (Figs. 88, C, and 89, 1-6). Lionotus 

 j'asciola, Sixdhidium spathula and other gymnostomatous ciliates 

 capture living organisms in a similar way (Fig. 90) while less 

 spectacular methods are employed by Frontonia leucas, Ophryo- 

 glena flora, Prorodon nireiis, etc., in swallowing diatoms, desmids 

 and other relativeh' stationarv organisms. 





A 



Y\a. 88. — Types of food getting. A, Raphidiophrys elega?is (after Penard) ; B, 

 Oicomonas termo (after Biitschli) ; C, Didinium nas^itum (after Blitschli) ; /, Food 

 particles; in C, Paramecium is captured and eaten. 



A special type of food-getting, illustrated by the Rhizopoda, may 

 be interpreted in some cases as the result of physical properties of 

 semifluid bodies. Hhinnbler has made the most exhaustive studies 

 of food ingestion in these forms and distinguishes four types, viz: 

 Ingestion by (1) "circumvallation," (2) "circumfluence," (3) "invag- 

 ination" and (4) "importation," Food taking by "circumvallation" 

 is illustrated by Amoeba profeus 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 (Schaeft'er, 

 1917) produced by a moving object (even a moving needle point 

 according to Verworn 1889), walls of protoplasm flow out on either 



