south of Canary Islands, Atlantic Ocean, Challenger Expedition Sta. 3 (25°45'N, 20°14'W; 25.75°, -20.23°); 1525 fathoms (= about 2789 m), hard ground, adhering to the sponge Poliopogon amadou Thomson, 1877, growing on the calcareous axis of a dead Corallium, coated with peroxide of manganese