Neurobiology. In the article “Zebrafish ultraviolet visual pigment: Absorption spectrum, sequence and localization” by Judith Robinson, Ellen A. Schmitt, Ferenc I. Harosi, Richard J. Reece, and John E. Dowling, which appeared in number 13, July 1, 1993, of Proc. Natl. Acad. Sci. USA (90, 6009–6012), the authors request the following correction. The proposed structure for the ultraviolet-sensitive visual pigment opsin (Fig. 3) is not correct. The proposed opsin structure was based on a DNA sequence, termed ZF02, that was identified as the ultraviolet-sensitive opsin gene based on messenger RNA in situ hybrid-ization studies that showed staining of the short-single cones, the ultraviolet-sensitive cones, in zebrafish. Subsequent in situ hybridization studies with the RNA probe generated from the ZF02 sequence have consistently shown staining of rods and no staining of the short-single cones in zebrafish [see Raymond, P. A., Barthel, L. K. & Stenkamp, D. L. (1996) Invest. Ophthal. Vis. Sci. 37 (5), 948–950 and Schmitt, E. A., Fadool, J. M. & Dowling, J. E. (1996) Invest. Ophthal. Vis. Sci. 37 (5), 695]. The original localization of the ZF02 riboprobe to the short-single cones may have resulted from diffusion. We have notified GenBank that the ZF02 sequence (accession no. L11014) is not that of an ultraviolet opsin gene, and their description of the sequence notes this fact. The other results reported in the paper, including the wavelength sensitivities of the various types of cones in zebrafish, the in situ absorption spectrum of the zebrafish ultraviolet visual pigment, and the structure of the zebrafish retinal mosaic are correct to the best of our knowledge.