The Beasts of Tarzan (Classic Ace SF, F-203)
It was later published as a novel in 1916.</p> <p>Tarzan’s old enemy, Nikolas Rokoff, escapes prison and plans his revenge by kidnapping the Tarzan’s son, the heir of Greystoke. He also captures Tarzan and Jane, and takes them all back to Africa, where he strands the Ape-man on an island before continuing on with his dastardly plan. On the island prison Tarzan befriends a troop of apes led by Akut and tames Sheeta the panther before escaping and setting off to rescue his wife and child.</p>