pineal eye

noun

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

pineal eye

noun

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

pineal eye

/ 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.

Word History and Origins

Origin of pineal eye¹

First recorded in 1885–90

Example Sentences

Let us turn now to the right pineal eye of Ammocœtes (Fig. 37) and see what its further structure is.

From Project Gutenberg

This pineal eye has been compared in structure to the eye of Ascidians.

From Project Gutenberg

Fig. 141 represents a section through the head near the pineal eye.

From Project Gutenberg

I described to her the brain, the pineal organ in Anguis, Sphenodon's pineal eye, etc.

From Project Gutenberg