. The biology of cilia and flagella. Cilia and ciliary motion; Flagella (Microbiology). 142 MOVEMENT OF CILIA AND FLAGELLA The movements of the ciHa of Opalina, on the other hand, are more Uke those of flagella in many respects (Figs. 39 and 47, and PI. XVIIIb); in fact, it might be more satisfactory to regard them as flagella in agreement w^ith the findings of Grasse (1952) and Corliss (1955), who maintain that Opalina shows more affinity with flagellated than with ciliated protozoa. These cilia appear to be rather flexible organelles, and the long ones at the posterior end of the body trail
. The biology of cilia and flagella. Cilia and ciliary motion; Flagella (Microbiology). 142 MOVEMENT OF CILIA AND FLAGELLA The movements of the ciHa of Opalina, on the other hand, are more Uke those of flagella in many respects (Figs. 39 and 47, and PI. XVIIIb); in fact, it might be more satisfactory to regard them as flagella in agreement w^ith the findings of Grasse (1952) and Corliss (1955), who maintain that Opalina shows more affinity with flagellated than with ciliated protozoa. These cilia appear to be rather flexible organelles, and the long ones at the posterior end of the body trail in the w ater in a manner reminiscent of the flagella of Trichony^npha. It seems best to regard the " resting position " of these cilia as that in which they lie close to the body surface (Fig. 39, stage 1). A wave of bending passes. ^^y^^^^Ty/ ^ ^?//> ^// ^ ^ ^/ ^^ yy / ^^^ Fig. 39. The sequence of movements of a cilium of Opalina. Compare this with Fig. 47 and Plate XVIIIb, where these cilia form part of metachronal waves. up the cilium, straightening it out in a preparatory phase equivalent to the recovery phase of the Stentor ciliary beat. Before this wave of flexure has reached the tip of the cilium, a second bending wave on the other side of the cilium pulls the shaft back towards the body surface in the effective phase. The cycle of beat is completed when the second bending wave has been propagated to the end of the cilium. In the preparatory phase the cilia are lifted from the body surface in a smooth curve (see Fig. 47, p. 176) and in the effective phase ( that in the direction of the effective movement of water) they are brought back to the body surface. It seems likely that movements of the complete waves are responsible for the movement of the organism through the water, rather than movements of individual cilia; in this also the motion of Opalina resembles that of Trichonympha (see also. Please note that these images are extracted from scanned page
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