Three little letters are making me fell dumb...PCV

[Moneypit]

I know all about what a PCV system is for and for the most part how it works, and until today I thought I knew how one was supposed to be hooked up. What has me stumped is when looking through the installation manual for my Edelbrock 1406 carb it shows the 3/8 inlet on the front of the carb as being for the PCV. I have never came across a PCV system that was hooked through the carb. All I've ever seen was a PCV valve on top of the valve cover and connected to the bottom side of the air cleaner. So can anyone tell me what the inlet on the front of the carb is for and how it is supposed to be hooked up.

In case anyone is wondering here is a link that shows the inlet on the carb (you have to scroll down a bit):
http://www.edelbrock.com/automotive_.../1000/1406.pdf