SPONGE, in natural history; a genus of animals belonging to the class of vermes, and order of zoophyta. It is fixed, flexible, and very torpid, growing in a variety of forms, composed either of reticulated fibres, or masses of small spines interwoven together, and clothed with a living gelatinous flesh, full of small mouths or holes on its surface, by which it sucks in and throws out the water. Fifty species have already been discovered, of which 10 belong to the British coasts.
1. Oculata, or branched sponge, is delicately soft and very much branched; the branches are a little compressed, grow erect, and often united together. They have rows of cells on each margin, that project a little. This species is of a pale yellow colour, from five to ten inches high. The fibres are reticulated, and the flesh or gelatinous part is so tender, that when it is taken out of the water it soon dries away. It is very common round the sea-coast of Britain and Ireland. This description will be better understood by Plate ccccLXXV. fig. 1. At b, b, along the edges and on the surface of the branches, are rows of small papillary holes, through which the animal receives its nourishment.
2. Cristata, or cock's comb sponge, is flat, erect, and soft, growing in the shape of cock's combs, with rows of little holes along the tops, which project a little. It abounds on the rocks to the eastward of Hastings in Sussex, where it may be seen at low-water. It is commonly about three inches long, and two inches high, and of a pale yellowish colour. When put into a glass vessel of sea-water, it has been observed to suck in and squirt out the water through little mouths along the tops, giving evident signs of life.
3. Stupa, tow-sponge, or downy branched sponge, is soft like tow, with round branches, and covered with fine pointed hairs. It is of a pale yellow colour, and about three inches high. It is frequently thrown on the shore at Hastings in Sussex. Fig. 2. represents this sponge; but it is so closely covered with a fine down, that the numerous small holes in its surface are not discernible.
4. Dichotoma, dichotomous or forked sponge, is stiff, branched, with round, upright, elastic branches, covered with minute hairs. It is found on the coast of Norway, and also, according to Berkenhiout, on the Cornish and Yorkshire coasts. It is of a pale yellow colour, and full of very minute pores, guarded by minute spines. Fig. 3. 5. *Urenis* or *tomentosa*, stinging sponge, or crumb of bread sponge, is of many forms, full of pores, very brittle and soft, and interwoven with very minute spines. It is full of small protuberances, with a hole in each, by which it sucks in and throws out the water. It is very common on the British coast, and is frequently seen surrounding fucuses. It is found also on the shores of North America, Africa, and in the East Indies. When newly taken out of the sea, it is of a bright orange colour, and full of gelatinous flesh; but when dry, it becomes whitish, and when broken has the appearance of crumb of bread. If rubbed on the hand, it will raise blisters; and if dried in an oven, its power of stinging is much increased, especially that variety of it which is found on the sea-coast of North America.
6. *Palmata*, palmated sponge, is like a hand with fingers a little divided at the top. The mouths are a little prominent, and irregularly disposed on the surface. It is found on the beach at Brighthelmstone. It is of a reddish colour, inclining to yellow, and of the same soft woolly texture with the *Spongia oculata*, fig. 4.
7. *Coronata*, coronet sponge, is very small, consisting of a single tube surrounded at top by a crown of little spines. The tube is open at the top. The rays that compose the little crown are of a bright, shining pearl colour; the body is of a pale yellow. It has been found in the harbour of Emsworth, between Sussex and Hampshire.
8. *Botryoides*, grape sponge, is very tender and branched, as if in bunches; the bunches are hollow, and are made up of oblong oval figures having the appearance of grapes; and each bunch is open at top. This species is of a bright, shining colour. The openings at the top are evidently the mouths by which the animal imbibes and discharges moisture. When the surface is very much magnified, it appears covered with little masses of triple, equidistant, shining spines.
9. *Lacustris*, creeping sponge, has erect, cylindrical, and obtuse branches. It is found in lakes in Sweden and England.
10. *Fluvialitis*, river sponge, is green, erect, brittle, and irregularly disposed in numerous branches. It abounds in many parts of Europe, in the fresh rivers of Russia and England, but particularly in the River Thames. It scarcely exhibits any symptoms of life, is of a filthy smell; its pores or mouths are sometimes filled with green gelatinous globules. It differs very little from the lacustris.
So early as the days of Aristotle sponges were supposed to possess animal life; the persons employed in collecting them having observed them shrink when torn from the rocks, thus exhibiting symptoms of incitation. The same opinion prevailed in the time of Pliny: But no attention was paid to this subject till Count Marigliani examined them, and declared them vegetables. Dr Peyronell, in a paper which he sent to the Royal Society in the year 1752, and in a second in 1757, affirmed they were not vegetables, but the production of animals; and has accordingly described the animals, and the processes which they performed in making the sponges. Mr Ellis, in the year 1762, was at great pains to discover these animals. For this purpose he dissected the sponge *Urenis*, and was surprised to find a great number of small worms of the genus of nereis or sea-scolopendra, which had pierced their way through the soft substance of the sponge in quest of a safe retreat. That this was really the case, he was fully assured of, by inspecting a number of specimens of the same sort of sponge, just fresh from the sea. He put them into a glass filled with sea-water; and then, instead of seeing any of the little animals which Dr Peyronell described, he observed the papillae or small holes with which the papillae are surrounded contract and dilate themselves. He examined another variety of the same species of sponges, and plainly perceived the small tubes inspire and expire the water. He therefore concluded, that the sponge is an animal, and that the ends or openings of the branched tubes are the mouths by which it receives its nourishment, and discharges its excrements.