Function
The lizard-like reptile tuatara has a "well-developed parietal eye, with small lens and retina". Parietal eyes are also found in lizards, frogs and lampreys, as well as some species of fish, such as tuna and pelagic sharks, where it is visible as a light-sensitive spot on top of their head. A poorly developed version, often called the parapineal gland, occurs in salamanders and in fish such as zebrafish. In birds and mammals the parietal organ (but not the pineal gland) is absent.
Read more about this topic: Parietal Eye
Famous quotes containing the word function:
“Our father has an even more important function than modeling manhood for us. He is also the authority to let us relax the requirements of the masculine model: if our father accepts us, then that declares us masculine enough to join the company of men. We, in effect, have our diploma in masculinity and can go on to develop other skills.”
—Frank Pittman (20th century)
“To make us feel small in the right way is a function of art; men can only make us feel small in the wrong way.”
—E.M. (Edward Morgan)
“Philosophical questions are not by their nature insoluble. They are, indeed, radically different from scientific questions, because they concern the implications and other interrelations of ideas, not the order of physical events; their answers are interpretations instead of factual reports, and their function is to increase not our knowledge of nature, but our understanding of what we know.”
—Susanne K. Langer (1895–1985)