[Action of theor-gene on pigmentation inPlatynereis dumerilii (Polychaeta) : I. Time-course and sites of pigment deposition].

1. In theor-mutant ofPlatynereis dumerilii pigmentation is deficient in the iridophores and retinal supporting cells. The course of pigment deposition was examined in wildtype larvae (Figs. 2-5) in order to obtain a standard for further observations. The first detectable eye pigments are orange-colored pigment granules in the visual cells in 54-hour larvae (Fig. 2). The juvenile eye is complete in 60-hour larvae when a brown pigment cup consisting of retinal supporting cell pigment becomes visible (Fig. 3). White iridophore pigment is seen in most 72-hour larvae (Fig. 4). 2. The pterin pigments causing pigmentation of supporting cells are deposited in pterinosomes characterized by internal lamellae (Fig. 9). In mutant supporting cells, which are almost devoid of pigments, granules are also present, but internal lamellae are defective (Fig. 10). 3. The supporting cell pigments are not inherited but are synthesized actively during eye differentiation in wildtype larvae, as shown by thin layer chromatography (Figs. 6, 7), 4. In mutant larvae, no pigmentation or at most a faint brownish hue is visible in supporting cells (Fig. 8a).