Fig. 3. Immunohistochemical localization of lamprey parapinopsin and lamprey rhodopsin in the pineal organ by confocal imaging. (A) Lamprey parapinopsin immunoreactivity (green) is localized in the dorsal and peripheral regions. (B) Lamprey rhodopsin immunoreactivity (magenta) is localized in the ventral and peripheral regions. (C) In the peripheral region, the photoreceptor cells contain either lamprey parapinopsin or lamprey rhodopsin (arrowheads). (D) Panel C at higher magnification. l, lumen; p, pineal organ; pp, parapineal organ. Scale bars, 100 µm.