MECHANISMS OF LOCOMOTION IN FLAGELLATES. I. CERATIUM.

Abstract

SYNOPSIS. Observation of the longitudinal flagellum of Ceratium tripos and C. furca with stroboscopic light revealed that this flagellum beats with a planar wave very close in form to a sine wave. The transverse flagellum, however, was seen to beat with a circular or elliptical helical wave, the amplitude of which was such that about half the wave was out of the girdle. With dark‐field illumination, suspensions of polystyrene spheres (1.18 μ in diameter) made possible the observation and photography of currents set up by the organism's flagella. This technique revealed an unsuspected component of the force generated by the transverse flagellum, which drives the organism forward.A wire helix, rotating under water, was found to generate a current in one direction along the axis of the helix. When a “girdle” formed from modeling clay was placed around the helix, thus simulating the transverse flagellum, the current was found to flow across the axis of the helix. The girdle in both the model and the dinoflagellate is assumed to cancel those components of force generated by the portion of the helical wave within it which would tend to cause the water to rotate about the helix. The only effective components of this force are therefore those generated by that side of the helix not enclosed in the girdle, and their action is to drive water across the girdle.