The sponge is definitely not a plant, as some naturalists still believe, but an animal of the lowest order, a polypary inferior even to coral. Its animal nature isn't in doubt, and we can't accept even the views of the ancients, who regarded it as halfway between plant and animal.
Ma már kétségtelen, hogy a szivacs: állat, bár a természettudósok eltérő nézeteket vallanak arról, hogy milyen a szivacs szervezete.