What is going on with this egg?

I have been watching this spot on one of my 3 eggs. I don't know what the spot means, if anything. Any thoughts? The eggs are on day 18, and all have nice red veins. First picture is of the egg and the spot. And second picture is of all 3 eggs. How do they look as a whole? Thanks everyone:)

http://i108.photobucket.com/albums/n...4/IMG_5669.jpg
http://i108.photobucket.com/albums/n...4/IMG_5670.jpg

It looks like what some on here call a window. Basically the calcification isn't correct there so the egg will be almost see through at that spot. It usually doesn't effect anything. It just looks like that. The eggs look good to me. What was the pairing? Good Luck

A possible Het Pied female to a Poss. Het Pied male and a Spider male:)

They look fine from what I can tell :gj:

Thanks:D This is my very first clutch ever and I am so excited! I can't wait to see what they are. Now I just need to get onto building another rack so I have a place to put them once they hatch. But another rack means more space and maybe I can get a couple of double gene males or something too:snake: So exciting!