Fig. 3. Kinematic analysis of swimming. (A) Undulatory frequency is the only significant (P<0.05) predictor of swimming speed, U_L, in a multivariate regression with individual hagfish treated as a random effect (see Table 2). Also, is significantly correlated, as determined by univariate regression (see Table 3), with tailbeat amplitude y0,30 (B) and phase lag between heave and curvature at body point 11, _y- (C). (D) The amplitude of the midline curvature at point 11 (0.37 L), ₀, is not a significant predictor of U_L. It is, however, a significant predictor of pitch angle ₀ (E) and phase lag, curvature _y- (F). Lines are significant regressions (see Tables 2, 3). Symbols in A and D indicate eight different individuals (total N=23).