Help identify and explain this part
 

Hello and please excuse me if this is a poor title.
I have the item in the attached picture that hangs under my '72 350SL right near where the return gas line enters the fuel tank. I received this car a few years ago and it wasn't running so I decided to clean the fuel tank and lines prior to attempting to start it. I'm re-installing the fuel tank now and would like to connect up this item also but it had no pipes/hoses attached to it when I got it and I'm not sure how it connects up. Can someone identify it and educate me on it's purpose and how it should be connected? Thanks

It is a fuel tank vent valve assembly, containing three valves:
1) Fresh air into tank
2) Tank overpressure relief
3) Fuel vapors to crankcase storage/carbon canister

The center connection goes to the tank, the side connection goes forward.

Not only are the bots here, they have cameras!