Oddities

Top 10 "Useless" Organs
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No. 10 - Plica semilunaris (third eyelid)

You may not know it, but you have a third eyelid. Pull open the two more noticeable eyelids and take a look - it's located right in the corner by the tear duct. The third eyelid is left over from what's known as a "nictitating membrane," which is still present in animals like chickens, lizards and sharks.

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