Saturday, May 23, 2009
nictitating membrane noun: a thin translucent sheet or layer beneath the eyelids present in some animals that can be drawn across the eye to protect and/or moisten it while retaining visibility
Apparently humans possess vestigial remnants of nictitating membranes. Check in the mirror if you don’t believe me. (You can reference this chart so you know what to look for; the bit in question is called the the plica semilunaris.) I just checked myself, and sure enough there it was! Who knew?