In 1940 it was probably easier, and more logical to the reader, that in the future when people are zipping around the universe in rocket ships, that mail would be delivered the old fashioned way. In stamped envelopes, and delivered physically to other planets. Mars Mason is the Interplanetary Mailman, whose job it is to get mail to other planets, even when monsters attack.
I give artist Munson Paddock (here signing his name as Martin Nye) credit for some truly bizarre aliens. And I also give credit for their names, Sour Snouts.
The swirling creatures, the pulsating colors created by whomever the colorist for Fox Features was in those days, give the story something of a psychedelic effect.
In 1940 Munson Paddock was a real old-timer. He was born in 1886, and his art was being published shortly after the dawn of the twentieth century. I don’t want to get into too much conjecture, but I think of artists of his generation who went into comic books as artists who were not making a living in the art field. I think they found being a comic book artist in the earliest days of that industry better than going on relief, or starving in a garret. I consider Paddock one of the more interesting oddball artists of the period.
Paddock is also credited by the Grand Comics Database as being the writer of the story. From Speed Comics #11 (1940):













