CentralNotice From Wikipedia, the free encyclopedia Jump to: navigation , search The parietal eye (very small grey oval between the regular eyes) of a juvenile bullfrog ( Rana catesbeiana ) Adult Carolina anole ( Anolis carolinensis ) clearly showing the parietal eye (small grey/clear oval) at the top of its head. Parietal eye of the Merrem's Madagascar swift ( Oplurus cyclurus ) is surrounded by a big black-and-white spot on the skin, giving it the "three-eyed" appearance A parietal eye , also known as a third eye or pineal eye , is a part of the epithalamus present in some animal species. The eye is photoreceptive and is associated with the pineal gland , regulating circadian rhythmicity and hormone production for thermoregulation . [1] 1 Presence in various animals 2 Anatomy 3 Comparative anatomy 4 Analogs in other species 5 See also 6 Re...