Dozens of artists/writers during the Golden-Age of comics went uncredited for their work in print form. Their names were completely left out of the issues they worked on. In a lot of cases they would actually sign the name of the artist they worked for/under and would have to mimic the style of another artist. A good example of this is Bob Kane. Dozens of artists worked as Bob Kane. Bob Kane got all the credit while the actual artist for the issue got none.
Some have referred to "Ghosting" as an assistant who works under another artist or writer and merely assists in writing stories/drawing panels etc. But many of these known artists and writers were doing 100% of the work while someone else took credit. This isn't to say that the person getting all the credit was bad or did it on purpose. This was just how things were in the Golden Age of comics. It was common practice.
Jerry Siegel and Joe Shuster even had many writers work as "Ghosts" penning scripts for Action Comics!
Inkers were not seen as a vital art form at the time. It took years before people noticed the true art form behind inking and inkers like Joe Sinnott (who was an excellent penciler in his own right) began getting their due credit!
A List of known "Ghost Artists"
Lew Sayre Schwartz
One result of so many people not getting their due credit in comics is the Bill Finger Award: which recognizes artists/writers who never got their due credit while working in the industry. (This award was started by Jerry Robinson: who never got his due credit for his Batman creations (but who recognized Bill Finger who never got his due credit as the co-creator of Batman))