Tarzan and the Jewels of Opar was first published by A.C. McClurg & Co in 1918. The image to the left shows the dust jacket from that book.
Metropolitan Newspaper Feature Service, Inc., a subdivision of Metropolitan Books, published an illustrated condensed newspaper comic-strip version of the story. It doesn't seem to have run simultaneously in all the newspapers carrying the series. The Worcester Evening Post carried it from about September 1930 to January 1931. This newspaper series was illustrated by Rex Maxon.
These comic strips were collected by Roland N. Anderson (1916-1982) while working as a paperboy. He delivered both the Worcester Evening Post and the Worcester Evening Gazette, both newspapers published in Worcester, Massachusetts. The strips appeared in the paper six days a week, from Monday to Saturday.
When Ballantine Books republished this book in paperback in 1963, it summarized it on the back cover as follows: "In the forgotten city of Opar, the bloodied sacrificial altar of the Flaming God stood above vaults piled high with the gold destined for fabled, lost Atlantis. There La, the beautiful high priestess, still dreamed of Tarzan, who had escaped her knife before. Around her, the hideous priests vowed that he should never escape again. For now Tarzan was returning, and they were waiting for him. Tarzan planned to avoid La and the priests. But he could not avoid the earthquake that struck him down in the vaults and left him without memory of his wife or home - only with what memory he had had as a child among the savage apes who reared him."
Inasmuch as the Tarzan series was more a series of illustrated short novels than a typical comic strip, the amount of text in each strip far exceeded the amount of text in other comic strips, and consequently of rather small size, about 10 points. In order to make the material more readable, the strips are presented here in halves at about 50% magnification.
This adventure begins at this link. On the left side of each comic strip, next to the title, there is a number which indicates that particular strip's position in the series. Some browsers will display this number in the lower left hand corner of the window frame. If someone quits reading some segment of Tarzan and the Jewels of Opar before having read it all and then at some later date wishes to return to where he left off, this can be done by entering the number of that particular comic strip here.