And now we arrive at the last of the valuable fisheries in which divers are concerned—that of the sponge. The ancients recognised the fact that the sponge exhibited vitality, but were rather undecided as to whether it should be counted animal or vegetable. Rondelet—the friend of the celebrated Rabelais, whom the merry curate of Meudon designated under the name of _Rondibilis_—himself a physician and naturalist of Montpellier, long promulgated the idea that these productions belonged to the vegetable kingdom. Linnæus late in life withdrew the sponges from among the vegetables, for he had satisfied himself, in short, that they fairly belonged to the animal kingdom. Sponges live at the bottom of the sea in from 500 to 1,250 fathoms of water, among the clefts and crevices of the rocks, always adhering and attaching themselves, not only to inorganic bodies, but even growing on algæ and animals, spreading, erect, or pendent, according to the body which supports them and their natural habit. Figuier tells us that all naturalists are now satisfied of the animal nature of sponges, although they once were thought to represent the lowest and most obscure grade of animal existence, and that so close to the confines of the vegetable world that it was considered difficult to some species to determine whether they were on the one side or the other. “Several of them, however,” says Mr. Gosse, “if viewed with a lens under water while in a living state, display vigorous currents constantly pouring forth from certain orifices, and we necessarily infer that the water thus ejected must be constantly taken in through some other channel. On tearing the mass open, we see that the whole substance is perforated in all directions by irregular canals leading into each other, of which some are slender, and communicate with the surface by minute but numerous pores, and others are wide, and open by ample orifices; through the former the water is admitted, through the latter it is ejected.” [Illustration: SPONGE FISHING OFF THE COAST OF GREECE.]