​BATHYBIUS (βαθύς, deep, and βίος, life), a slimy substance at one time supposed to exist in great masses in the depths of the ocean and to consist of undifferentiated protoplasm. Regarding it as an organism which represented the simplest form of life, Huxley about 1868 named it Bathybius Haeckelii. But investigations carried out in connexion with the “Challenger” expedition indicated that it was an artificial product, composed of a flocculent precipitate of gypsum thrown down from sea-water by alcohol, and the hypothesis of its organic character was abandoned by most biologists, Huxley included.