Fig. 6. Dorsal midline curvature (K) and lateral displacement (D) calculated at five axial positions (0.4, 0.5, 0.6, 0.7 and 0.8L: positions shown in A) for multiple consecutive complete tailbeat cycles. To illustrate the degree of lateral motion along the body during steady swimming, the dorsal midline through one tailbeat cycle is shown in B. Colors for each data trace in C–F correspond to the axial positions indicated in A. Scale bar, 8 cm. One tailbeat cycle is magnified to show the difference in the rates of propagation of the waves of curvature (E) and lateral displacement (F) along the body.