Erratum.
In the report "Size of the chloroplast genome in Codium fragile" by M. F. Hedberg et al. (24 July, p. 445), measurements in the legend to Fig. Ia are mistakenly reported. The correct value of the contour length of the chloroplast DNA is 26.1 micrometers (54 x 10(6) daltons) and that of the scale is 5 microm.