Thanks Dirk,
Your are correct. There is a round tube that brings warmed air from the defrost duct to the round tube on the chrome molding.
There is also the plastic housing in my photo and I couldn't figure out where the other end goes - or what attaches to it. I took another look and that end goes to an opening in the bulkhead that most likely brings in fresh air if the main fresh air flap (outside, under the windshield is open). So the other duct that I was looking for is actually part of the steel bulkhead. I took another look on the right side of the dash which is easier to see. This picture (taken through the opening for the glove box) shows the round port on the defrost duct and the squarish opening that must be fresh air.
Nothing like answering your own question. The trick was looking at the right side where there was less wiring etc obstruction the view.
Thanks again Dirk! Lee