Fig. 4. Visco-elastic properties of the body axis (at 0.37 L) of hagfish during dynamic bending. The diameter of the plotted circle is proportional to the experimental angular frequency at , 2, 4, 6 rad s^-1. Statistically significant (P<0.05) overall differences for each property are listed in the far right-hand column (see Table 4); differences between treatments TRT (planned contrasts) are indicated by the labeled double-headed arrows between graphs (see Table 5). As indicated by the label for fish number, the notochord properties (penultimate right-hand column) were measured on different individuals, a condition necessitated by the isolation procedure and that accounted for use of a nested design (indicated as [TRT], or `curvature nested within treatment', when significance is indicated). Values of circles are means; error bars are ± one standard error from pooling of individuals (N=4).