Pineal Gland, a small cone-shaped body of yellowish matter in the brain, the size of a pea, and situated in the front of the cerebellum, notable as considered by Descartes to be the seat of the soul, but is now surmised to be a rudimentary remnant of some organ, of vision it would seem, now extinct.
Definition taken from The Nuttall Encyclopædia, edited by the Reverend James Wood (1907)
Pindus, Mount * Pinel, Philippe