First division in the polyp group, the class Spongiaria has been created by scientists precisely for this unusual exhibit whose usefulness is beyond dispute. 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. But I must say that naturalists are not in agreement on the structural mode of sponges. For some it’s a polypary, and for others, such as Professor Milne-Edwards, it’s a single, solitary individual.
The class Spongiaria contains about 300 species that are encountered in a large number of seas and even in certain streams, where they’ve been given the name freshwater sponges. But their waters of choice are the Red Sea and the Mediterranean near the Greek Islands or the coast of Syria. These waters witness the reproduction and growth of soft, delicate bath sponges whose prices run as high as 150 francs apiece: the yellow sponge from Syria, the horn sponge from Barbary, etc. But since I had no hope of studying these zoophytes in the seaports of the Levant, from which we were separated by the insuperable Isthmus of Suez, I had to be content with observing them in the waters of the Red Sea.
So I called Conseil to my side, while at an average depth of eight to nine meters, the Nautilus slowly skimmed every beautiful rock on the easterly coast.
There sponges grew in every shape, globular, stalklike, leaflike, fingerlike. With reasonable accuracy, they lived up to their nicknames of basket sponges, chalice sponges, distaff sponges, elkhorn sponges, lion’s paws, peacock’s tails, and Neptune’s gloves—designations bestowed on them by fishermen, more poetically inclined than scientists. A gelatinous, semifluid substance coated the fibrous tissue of these sponges, and from this tissue there escaped a steady trickle of water that, after carrying sustenance to each cell, was being expelled by a contracting movement. This jellylike substance disappears when the polyp dies, emitting ammonia as it rots. Finally nothing remains but the fibers, either gelatinous or made of horn, that constitute your household sponge, which takes on a russet hue and is used for various tasks depending on its degree of elasticity, permeability, or resistance to saturation.