Deacon, I put a question mark after my Agassiz suggestion because one rarely can be sure of the actual maker of most Swiss watches, since there was so much rebranding and ebauche use. I don't collect Agassiz watches, so I am no expert on them. But whenever I see a high-end Swiss watch of this era that doesn't to have been made by anyone else, I always think of Agassiz as a possibility. That's what my question mark meant.
That said, I found a very similar movement attributed to Agassiz on the web at this
link.
While I don't collect Agassiz, I do collect Meylans and Patek Philippes. I have never seen a Meylan or Patek Philippe that looks like your watch. I don't collect Longines, but I don't recall seeing any Longines that look like your watch.
So put Agassiz down as a possibility. The maker's name might be stamped on the pillar plate below the dial. If you can, take a look there.