In 1940, science-fiction art pionneer Frank R. Paul did pieces showing what life could be on other planets. In his own words:
The inhabitant of Uranus lives on a rigorous planet indeed. He is confronted with tremendous gravity, dense atmosphere, poison gases, and great storms.
While he only shows them in exosuits, Paul describes the Uranians as Seal Men, living in amazing underground metal and glass cities such as Metalis. While nothing let us believe that they have developed a space technology, the Seal Men nevertheless appear to have developed an advanced tehcnological civilisation, making cybernetics part of their everyday life.