On February 1st 1896, Professor Elstead on HMS Ptarmigan discovered an underwater civilisation in the South Atlantic off the coast of Brazil. Elstead described the underwater beings to the officers of the Ptarmigan as being "a strange vertebrated animal. Its dark purple head was dimly suggestive of a chameleon,but it had such a high forehead and such a braincase as no reptile ever displayed before; the vertical pitch of its face gave it a most extraordinary resemblance to a human beings. Two large and protruding eyes projected from sockets in chameleon fashion, and it had a broad reptilian mouth with horny lips beneath its little nostrils. In the position of the ears were two huge gill-covers, and out of these floated a branching tree of coralline filaments, almost like the tree-like gills that very young rays and sharks possess."
He added: "the face was not the most extraordinary thing about the creature. It was a biped; its almost globular body was poised on a tripod of two frog-like legs and a long thick tail, and its fore limbs, which grotesquely caricatured the human hand, much as a frog’s do, carried a long shaft of bone, tipped with copper. The colour of the creature was variegated; its head, hands, and legs were purple; but its skin, which hung loosely upon it, even as clothes might do, was a phosphorescent grey".
Before returning to the surface Elstead came across an underwater city on the submarine plane which he described as "a luminous arrangement of streets and houses grouped about a vast roofless erection that was grotesquely suggestive of a ruined abbey. The houses were all roofless enclosures of walls, and their substance being of phosphorescent bones".
Professor Elstead perished on his second descent at the hands of the Atlanteans (as they soon became to be known) and man found that he was not the only sentient race on Earth.