Fuel Tank Vent

[wbrian63]

'76 6.9, euro-spec.

The vent line that comes from the top of the tank attaches to a metal line that crosses over the rear subframe and ends at a tube under the passenger rear floor. Nothing attaches here?

What I found was a short length of rubber hose that had a plug in the end of it.

I suspect this is not how it should be.

Any ideas how this is supposed to work?