These are "The Outer Space Men" from 1968. They are bendable figures similar to the then popular Major Matt Mason.
They were designed by toy inventor Mel Birnkrant who maintains an archive site here, and it's the source for several of the images in my post. The Outer Space Men are the citizens of the other planets of our Solar System.
My brothers and I had three of these. "Men" from Venus, Mars and Neptune. Always interested in space travel, and science fiction, these guys made an indelible impression on me. I clearly remember playing with them, but at some point they were lost to me, never to be found again...
... until the advent of ebay. I suppose it was about 1998 when I reacquired the lost aliens, as well as those I never had the first time around. It was a bit of magic recaptured to hold an Astro-Nautilus again.
Looking through Mel's archive site, I was a bit surprised, and really impressed that he shared the various inspirations and reference images for his designs. This was the clipping from the back of Famous Monsters Magazine that inspired the Man From Neptune. I have no idea what film it was from, but it's wonderful to see source material like this.
Eventually, I'll take my own alien menagerie on a tour of our Solar System. I can hardly wait to get started on it, but I've some other pieces to finish first.
The Outer Space Men are back today, and being released by the Four Horsemen. The first figures are here. They are releasing the original figures and a second set that were designed, prototyped but never mass produced. Best yet, Mel Birnkrant remains involved in the series.