Erratum.
Figure 1 in the report "Muscle fatigue and the role of transverse tubules" by C. P. Bianchi and S. Narayan (15 Jan., p. 296) was inadvertently transposed with figure 2 in the report "Sedimentation field flow fractionation of liposomes" by J. J. Kirkland et al. (p. 297). The figure legends are correct.