Jag tror att du tänker på Sterling E. Lanier s serie Brigadier Ffellowes berättelser. De samlades in i två volymer, Brigadier Ffellowes särpräglade exploateringar (1971) och The Curious Quests of Brigadier Ffellowes (1986) och i italiensk översättning som Le fantastorie del brigadiere (1981). Det här är verkligen sagor berättade i en klubb av en pensionär brittisk militär man.
Den speciella historien du beskriver är noveletten "Och sköldpaddans röst ...". , som ursprungligen publicerades i The Magazine of Fantasy och Science Fiction , Oktober 1972 (tillgängligt på Internetarkiv ) och reprinted i The Curious Quests of Brigadier Ffellowes ; även på italiensk översättning som "L'isola della tartaruga" på Urania # 658 och Le fantastorie del brigadiere . Historien är inställd på Holländska Östindien (idag Indonesien) år 1940:
And it was there, from a most charming man, a self-exiled Norwegian who had settled as a trader years before, that I heard first of Pulau Tuntong, the Island of the Turtle, and also, incidentally, of Dr. and Mrs. Strudwick.
[. . . .]
" 'That's a funny place, Mr. Ffellowes. Only a few natives and they are not liked much either, sort of pariahs, like they have up in India. They seem to have always lived there, and the other peoples in these parts never go there, and they themselves, they never leave, neither. But I can't say they ever give trouble, no killings or nothing. The Dutch Controleur here, he don't never go there, and no ships call, no Chink traders even, and they go anywhere they can for a profit, with them old, beat-up junks. I never been there, but they say there ain't no harm in the place. Anyone can go there, if you see what I mean, but no one does. Except for the American and his wife. They are there right now, been there six months about. I forward their mail in my own boat once a month. They're some kind of scientists, studying turtles, they said. It's supposed to be a great place for turtles. Guess that's how it got its name. But the whole thing, by Joe, even looks like a turtle. One maybe three miles long, that is half in the water, with only the point of the head sticking out, which is another little island, maybe a quarter mile from shore, from the big one.
" 'How far? Maybe thirty miles southeast, as the crow is flying from here. Lots of bad reefs and no good anchorage. I wouldn't like to be there in a storm, I tell you. The place is always foggy, too. All kinds of mineral sinks and steams and smokes, so it takes a good wind to give you a view of the whole thing. Must be a capped volcano or something. Lots of these islands are, but I never heard that this one blew or nothing. Just the steams and smokes all the time, like Yellowstone Park in the U. S., or some of our warm springs back in Norway. But it is a kind of place that makes you—well—discomfortable. My boys don't like to go there, never go ashore, and they leave plenty quick, too.'
[. . . .]
"But at the back of the crowd there were figures which made my flesh crawl. Whatever disease affected these people, the ones in the last stages, or at least I surmised, were not good to look upon. I could see long swaying necks, covered with leathery skin, and high, arched humped backs which looked rounded and hard. The terminal stages of the peculiar island blight ought not to have been viewed at all, not by normal people. All of the folk, though, were swaying the same way, their bodies still, but their necks weaving, as if in some ghastly parody of those little girls who do the formal Thai and Javanese dances. And all were watching Strudwick and his wife.
[. . . .]
"To this day, I have trouble convincing myself I saw what I think I saw. As the head rose higher on a monstrous, rugose neck, I half noticed the beginning of a great rounded dome of a back, glistening and rigid in the unearthly moon glow. But it was on the head which I concentrated, because it was moving, the whole incredible thing was moving, slowly with hardly a ripple, directly toward where Dr. Sylvanus Strudwick, Ph.D., author of more learned papers than I can remember hearing, stood holding his wife. And I knew what it had come for, as if I somehow had known all along. This was the Father and Ethel Strudwick was what it wanted.