Parietal eye
The parietal eye of a juvenile bullfrog
A parietal eye, also known as a third eye or pineal eye, is an eye located at the top of the head. Reptiles, amphibians have this eye. The third eye is always smaller than the main paired eyes.[1] In living species, it is always covered by skin and is not visible externally. [1]
Parietal Eye Media
Adult green 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 black-and-white spot on the skin, giving it the "three-eyed" appearance
