. The biology of cilia and flagella. Cilia and ciliary motion; Flagella (Microbiology). 136 MOVEMENT OF CILIA AND FLAGELLA It is a pity that Lowndes was not able to substitute for these diagrams an equally clear picture of the movement of a flagellum from his own observations. He can not be blamed for this, however, for the movements are evidently not simple, and two features in particular complicate the picture very considerably. The first is that the movements are three-dimensional in that the body of the organism rotates even though the flagellar beat may be more or less in a single plane.
. The biology of cilia and flagella. Cilia and ciliary motion; Flagella (Microbiology). 136 MOVEMENT OF CILIA AND FLAGELLA It is a pity that Lowndes was not able to substitute for these diagrams an equally clear picture of the movement of a flagellum from his own observations. He can not be blamed for this, however, for the movements are evidently not simple, and two features in particular complicate the picture very considerably. The first is that the movements are three-dimensional in that the body of the organism rotates even though the flagellar beat may be more or less in a single plane. Secondly, the flagellum projects from the anterior end of the body as the organism moves, and the movement of the water is bound to bend the flagellum back and distort the movement of bending waves propagated from the base of the flagellum to the Euglena viridis. Fig. 35. Movement of Euglena, showing two waves of con- traction passing along the flagellum in the direction indicated by the arrow. The movement of these contraction waves tends to move the organism towards the dotted figure (from Lowndes, 1941). In all cases Lowndes found that the flagellum is moved by waves of bending that pass from the base of the flagellum to the tip, there being sometimes one and sometimes several waves in the length of the flagellum, depending on the length of the flagellum and on the rate of propagation of the bending wave. The flagellum is bent back to lie roughly parallel to the body, and waves of bending propagated along the flagellum were found by Lowndes to cause a rotation of the flagellar tip, because the long distal part of the flagellum was not easily moved in the water, and the most stable position was that in which the. 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 Sleigh, Michael A. Oxford, New York, Per
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