John Carter of Mars: (#11) (Martian Tales of Edgar Rice Burroughs)

Menace from Space
No sooner had John Carter fought off the seemingly invincible giant warrior attacking the mighty city of Helium than he was faced with a more terrifying challenge from the gulfs of space. Skeleton creatures from Jupiter were plotting the conquest of Mars—and their first act was to kidnap the red planet's warlord!\nIncludes:
John Carter and the Giant of Mars
Skeleton Men of Jupiter