1. Illuminated and dark-adapted parietal eyes of 44 Western Fence Lizards, Sceloporus occidentalis, were studied cytochemically. Additionally, the eyes of 46 non-experimental animals were variously fixed and stained, many of them with 1% osmium tetroxide for electron microscopy. 2. Glycogen, demonstrated by the periodic acid Schiff (PAS) reaction, was more abundant in dark-adapted eyes and occurred particularly in the basal (luminal) half of the lens, the humor of the eye, “paraboloid” and perinuclear regions of photoreceptors, and “vesicles” in the nervous layer. Illuminated eyes showed a decrease in PAS-positive material, especially in lens and lumen. It is concluded that the lens secretes glycogen and perhaps other polysaccharides into the cavity of the eye and that possibly these substances may be used by the photoreceptoral processes. 3. Oil red O and oil blue N revealed pyridine-soluble lipids in the chromatophores of the capsule of the eye. These chromatophores appear to have characteristics of both lipophores and guanophores. 4. Staining with methyl green-pyronin showed desoxyribonucleic acid in nuclei and ribonucleic acid (RNA) in the following: basal (luminal) part of lens cytoplasm, the luminal humor, “paraboloid” and perinuclear regions of photoreceptors, and perikarya of ganglion cells. The RNA in ganglion cells is identified with Nissl substance. There was no apparent difference in RNA content of light and dark-adapted eyes. 5. Metachromasia to azure B and toluidine blue was observed in the RNA-positive regions of lens, lumen, and retina. 6. Osmium tetroxide was bound especially by the basal (luminal) ends of lens cells and by some of the cytoplasmic granules in capsular chromatophores. 7. Melanin pigment in the retinal melanocytes was observed to shift lumenward in a 48-hour illumination of the eye and to retreat basally during darkadaptation. 8. It is suggested that the luminal melanin-bearing cells may be macrophages.