Tarzan and the Tarzan Twins

Tarzan and the Tarzan Twins is a collection of two Tarzan novellas by American writer Edgar Rice Burroughs, for younger readers. It was originally published as two children's books, "The Tarzan Twins" by Voland in October 1927, and "Tarzan and the Tarzan Twins, with Jad-bal-ja, the Golden Lion", by Whitman in March 1936. These were brought together in November 1963 under the title of "Tarzan and the Tarzan Twins" in the first complete edition.
Despite the gap in when they were written and first published, the events of the two stories occur in the same time-frame. The opening passage of "Tarzan and the Tarzan Twins, with Jad-bal-ja, the Golden Lion" specifies that its events occur immediately after those of "The Tarzan Twins." In relation to other Tarzan stories, the two parts of the Tarzan Twins tale presumably fall between "Tarzan and the Ant Men" and "Tarzan, Lord of the Jungle" chronologically, as the initial part was published between these two novels. The second part confirms their placement in approximately this period, as it introduces a family that figures prominently in "Tarzan and the Lost Empire", the next book after "Tarzan, Lord of the Jungle"; specifically, it features Tarzan's first meeting with Doctor Karl von Harben, with whom he is already acquainted in "Empire". Because "Twins" is a children's book, however, it is customarily omitted from listings of the main Tarzan series. Thus "Tarzan, Lord of the Jungle" is generally considered the eleventh Tarzan book rather than "Twins".
Plot.
Two schoolboys, Dick and Doc, are cousins who resemble each other because their mothers are twins. As Dick is also related to Tarzan through his father, they become known as the Tarzan Twins. Invited to visit Tarzan's African estate, they become lost in the jungle and are imprisoned by cannibals, from whom they escape. They are then reunited with their host, who introduces them to his pet lion, Jad-bal-ja. Subsequently, they become involved in an adventure involving exiles from the lost city of Opar, who have kidnapped Gretchen von Harben, the daughter of a missionary.
Comic adaptations.
The book has been adapted into comic form by Gold Key Comics in "Tarzan" no. 196, dated April 1971, with a script by Gaylord DuBois and art by Mike Royer.