pineal eye

American  

noun

1. an eyelike structure that develops from the pineal apparatus in certain cold-blooded vertebrates.

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pineal eye British  

noun

1. an outgrowth of the pineal gland that forms an eyelike structure on the top of the head in certain cold-blooded vertebrates

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pineal eye Scientific  

/ pĭn′ē-əl,pī′nē-əl /

1. A sensory structure capable of light reception, appearing as a spot on the top of the head in lampreys, hagfish, amphibians, and some reptiles, especially the tuatara. Pineal eyes can contain a rudimentary cornea, lens, cone cells, and retina, and are thought to be sensitive to light and dark but not to be able to form images.

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Etymology

Origin of pineal eye

First recorded in 1885–90

Example Sentences

In humans, who may be descended, like the lizards and snakes, from something very like a tuatara, this third "pineal" eye has become the pineal gland deep inside the head.

From Time Magazine Archive

The pineal eye, as it is now named, once useful, long useless, has persisted as a fossil structure through a far extended line of development.

From Man And His Ancestor A Study In Evolution by Morris, Charles

There it is, to be reckoned with, like the coccyx, the pineal eye, and the vermiform appendix.

From A Modern Utopia by Wells, H. G. (Herbert George)

Albert was mercifully unconscious as it bent over him to inspect his prone body with a purple-lidded pineal eye that was blue with concern.

From Insidekick by Bone, Jesse F. (Jesse Franklin)

In the Lacertilia the pineal eye, if it be an eye, is better developed than in any existing vertebrate, though even in them there is no evidence of its being used for sight.

From Encyclopaedia Britannica, 11th Edition, Volume 4, Slice 4 "Bradford, William" to "Brequigny, Louis" by Various