In elementary school I read a juvie SF series. Might have been The Adventures of Digby Allen. That was the lead character at least.
In the first adventure the young heroes rescue little humanoids native to Mercury, then thought to be face-locked. They had long fingers, possibly with suckers, for keeping a grip on things given the eternal winds between light and dark side.
At least, I am remembering things that way. It has been at least 40 years since I read the story.
