In 1960, Alpern, Falls, and Lee reviewed the extensive literature on congenital monochromatism and then described the visual characteristics of five patients with typical total monochromacy.1 At the time these data were presented, one of us (H.F.F.) made a plea for eyes of this kind which might become available for histological examination. One such case has now been described, but the eyes were only obtained 40 hours after death, at which time considerable autolysis of the photoreceptor layer had already occurred.2 In the case to be presented, the eye was fixed immediately after surgical enucleation. While we had no psychophysical measurements on this observer at that time, we have since obtained good measurements of the color vision and dark adaptation characteristics of her remaining eye. The present paper will describe the results of both the histological examination and the psychophysical measurements. Report of Case A 69-year-old white woman,