Values of E are obtained by taking the ratio of the diameters parallel and perpendicular to the plastic tube that compresses the agar. Measured values of the elasticotaxis coefficient are plotted for various motility mutants of M. xanthus. ○, wt (A+S+); ●, A−S+ mutants; □, A+S− mutants; ▵, frz−; ▴, A−frz−; ⋄, S−frz−; ■, mgl−; ♦, A−S−. Error bars indicate one SD on either side of the mean.