Fig. 4. Comparison of the localization of lamprey parapinopsin-containing cells with that of lamprey rhodopsin-containing cells in the pineal organ. (A) Schematic drawing of the top view of the pineal organ. The horizontal lines show the position of the sections of B and C. (B) In the cross-section around the peripheral portion (about 200 µm rostrally from the centre), there are more lamprey parapinopsin-containing cells (green) than lamprey rhodopsin-containing cells (red). (C) In the cross-section around the central portion, there are fewer lamprey parapinopsin-containing cells (green) than lamprey rhodopsin-containing cells (red). There are more lamprey parapinopsin-containing cells in the peripheral portion than in the central portion. l, lumen; p, pineal organ; ps, pineal stalk. Scale bars, 100 µm.