As I was perusing through the web this morning, I came across this article that claims humans have a third eyelid. Well, had one...

Apparently (or transparently, as it would seem), our ancestors used to have a half-transparent nictitating membrane that would move sideways in order to spread moisture and clear debris, without losing site of their surroundings. You can see this in today's birds, reptiles, and fish - but it is rare among most mammals.

The theory is that once humans started living in communities, the need for an extra eyelid went the way of the dodo. Now, that little piece of pink flesh in the corner of your eye - known as a plica semilunaris - is pretty much useless. While some races of man may have a more pronounced version, the muscles that was used to control this cool feature is no longer hooked up. Basically, our bodies got lazy.

While I can't really think of any reason we would need this now-a-days - other than to make sure you never miss a play in the big game because of an annoying blink - it still makes me feel like we got hosed by evolution. Next thing you know, they'll try to tell us that we used to have tails...