The right eye of a goldfish, showing two dart-like vascular markings on the iris, one on each side of the pupil, and a remnant of the choroid fissure beneath it. The three marks are valuable external indicators of boundaries between different quadrants of the retina, from which optic axons take characteristically different routes to their central targets. For details, see papers by D. L. Becker and J. E. Cook (1988) Development 104, 317–320 and J. E. Cook and D. L. Becker (1988) Development 104, 321–329.

Please note that, from October 1988, correspondence and manuscripts for Chris Wylie should be sent to the Development Editorial Office (Department of Zoology, University of Cambridge, Downing Street, Cambridge CB2 3EJ).

We regret that Fig. 1, a colour tip-in, was omitted from the article by H. J. Clarke, S. Varmuza, V. R. Prideaux & J. Rossant in the September issue of Development.

Please attach the enclosed colour plate by the selfadhesive strip so that Fig. 1 faces its legend on page 178 of Volume 104 (1).

We apologize to the authors for this error.