The Motion of Strigomonas Oncopelti

Abstract

1. The movement of the flagellum of Strigomonas oncopelti has been studied using high-speed cinephotography. Waves usually pass along the flagellum from tip to base but under certain conditions waves are propagated from base to tip, reversing the direction of movement of the organism. 2. Increasing the viscosity of the medium reduces the frequency of beat while the shape of the wave remains unaltered. The variations in the wave parameters with increasing viscosity are consistent with a mechanically propagated wave. 3. Calculated values for Young's modulus indicate that the membrane, the matrix, the nine peripheral fibrils or the central pair could act as the compressive elements needed to resist bending. The mechanism controlling the direction of wave propagation appears to lie in the membrane.