247 would be an arbitrary start to a run of any comic except Adventure; the significance lies in the Superboy story, of course, not with Aquaman or the other back-ups. A number of my attributions here were circulated through fandom in the Nineties by Rich Morrissey, but on this list I've filled in the gaps in the run.
Jack Miller typically uses the captions Just then..., Before long..., The answer comes the next instant..., and In the next [adjective] instant...; Robert Bernstein typically the caption Moments after... instead of Moments later.... But these are not hard and fast differences, of course; in "The Robinson Crusoe of the Sea" (252) there's a Moments after..., but more clues point to Miller. If so, he happened to use that style of caption once.
"A World without Water" (251), out of all the Aquaman stories, uses the exclamations "Owoofff" and "Eeaahh" (also used in only one Green Arrow story: "The Man Who Hated Arrows" in 249). These are seen throughout the Dale Evans and Sierra Smith stories by Joe Millard, at DC, as well as the myriad of stories he did at Quality. The "Y-i-i-i-i" in both turns up in 250's "The Guinea Pig of the Sea."
All Aquaman art in these Adventure issues is by Ramona Fradon except 284, which is by Jim Mooney.
"How Aquaman Got His Powers" in 260 is the new origin. "The Manhunt on Land" in 267 is the crossover with Green Arrow, the other back-up, also written by Robert Bernstein at the time; the two villains switch land and sea theatres of operation. "The Kid from Atlantis" in 269 introdues Aquaman's new partner, Aqualad.
Aquaman begins appearing in the forerunner to his own book, four Showcase appearances, in the same month as Adventure 280. With 281, the back-up space that held Aquaman and Congorilla stories is devoted to double-length stories of either one, alternating, so Aquaman doesn't appear in 281 or 283. After Adventure 284 his back-up slot moves to Detective and then to World's Finest.
The Superboy story in 280, by the way, "Superboy and the Mermaid from Atlantis" (written by Jerry Siegel), takes two panels to account for the difference between Aquaman's Atlanteans with legs and Lori Lemaris's fishtailed merfolk.
Aquaman in Adventure 247-284 Writers
|Apr/58||#247||Aquaman's Super Sea-Squad||Jack Miller|
|May/||#248||The Traitor of the Seven Seas||Miller|
|July/||#250||The Guinea Pig of the Sea||Joe Millard|
|Aug/||#251||A World without Water||Millard|
|Sept/||#252||The Robinson Crusoe of the Sea||Miller|
|Oct/||#253||The Ocean of 1,000,000 B.C.||Bernstein|
|Nov/||#254||The Menace of the Electric Man||Miller|
|Dec/||#255||Aquaman's Double Trouble||Bernstein|
|Jan/59||#256||The Ordeal of Aquaman||Bernstein|
|Feb/||#257||The Imitation Aquaman||Bernstein|
|Mar/||#258||The Incredible Fish of Doctor Danton||Miller|
|Apr/||#259||The Octopus Man||Miller|
|May/||#260||How Aquaman Got His Powers||Bernstein|
|June/||#261||Aquaman Duels the Animal-Master||Bernstein|
|July/||#262||The Undersea Hospital||Bernstein|
|Aug/||#263||The Great Ocean Election||Miller|
|Sept/||#264||Aquaman and His Sea Police||Bernstein|
|Oct/||#265||The Secret of the Super-Safe||Bernstein|
|Nov/||#266||Aquaman Meets Aquagirl||Bernstein|
|Dec/||#267||The Manhunt on Land||Bernstein|
|Jan/60||#268||The Adventures of Aquaboy||Bernstein|
|Feb/||#269||The Kid from Atlantis||Bernstein|
|Mar/||#270||The Menace of Aqualad||Bernstein|
|Apr/||#271||The Second Deluge||Bernstein|
|May/||#272||The Human Flying Fish||Bernstein|
|June/||#273||Around the World in 80 Hours||Bernstein|
|Aug/||#275||The Interplanetary Mission||Bernstein|
|Sept/||#276||The Aqua-Thief of the Seven Seas||Bernstein|
|Oct/||#277||The Underwater Olympics||Bernstein|
|Nov/||#278||Aqualad Goes to School||Bernstein|
|Dec/||#279||Silly Sailors of the Sea||Bernstein|
|Jan/61||#280||The Lost Ocean||Bernstein|
|Mar/||#282||One Hour to Doom||Bernstein|
|May/||#284||The Charge of Aquaman's Sea Soldiers||Miller|