SPONGE (Fa. konge; GEB., Schwamm).
The term " sponge" is commercially applied to the elastic horny skeletons of certain marine animals helongiug to the class Poriferm, order Iferatosa, sub-order Sponynke, family Spongiadw. The commercial grades of sponge in Europe and America coincide very closely. The 3 principal European species are the bath-aponge (Spongia officinalis), the horse-sponge (S. eguina), and the zhnocca (S. agaricin4); in America, these are repreeented by the glove-sponge (S. officinalis, sub-sp. tubulifera); the wool-sponge (S. eguina, sub-sp. gossypina), and the yellow and hard-hcad (both S. agaricina, sub-sp. corlosia). The moat exhaustive account of everything bearing upon the growth and physiology of sponges i8 contained in Hyatt's very able paper published by the Boston Natural History Society, as quoted in the Bibliography (p. 1821). From it, much of the following information has been derived.
The whole group of Keratosa is confined to seas in which the differences between the winter and summer iaotherma are not exceasive. No American members are found N. of Cape Ilattenre and Bermuda; and doubtless a similar limit occurs S. of the equator. On the Paciflo shore, S. Culifornia aud Chili are the extreme points so far known. On the opposite coast of the Atlantic, they are recorded from England to the Cape of Good Hope, and also at the island of Teneriffe. In the Indian Ocean, they aro fouud all along the E. coast of Africa, at the Mauritiva, and on the shores of India. They have been described from the S. part of the Sea of Okhotz, on the Asiatic continent, aud specimens are not uncommon on the coasts of Australia and New Zealand. In the Pacific, they have been found at the Kingrnilla Islands and Hawaiian Islands. The extreme outlying form to the north, on hoth sides of the Atlantic, is the excessively coarae Dysidea fragilis, with ita fibres loaded with debris. Thoae from the Cape of Good Hope and S. Australia also belong to the coarser genera. It would seern, therefore, that the finer skeletona of the Keratosa, those of the genus Spongia, are only to be sought in the intermediate zone, where the waters are of equable and high temperature. And in examining the species of this genus with relation to each other, it becomes equally evident that they are finest and most numerous in archipelagoes, or off coasts which are bordered by larg,e numbers of islanda or long reefa, or in sheltered seas. The sponges near Nassau (Bahamas) lie on reefs very much exposed to the action of the waves, often 30 miles from land, and always in currents, sometimes running 3-4 knots' an hour. Such currents are usual where groups of islands confine the tide-water within certain definite channels, and they have also the effect of concentrating the floating food in the channels, or wherever tides meet. Both these conditions are esseutial to sueceasful sponge growth, viz. a continuous renewal of aerated water, and a plentiful supply of food, and are probably partly the cause of the abundance of sponges in such places. Constant reference to physical influence is also noticeable in the method of classification adopted by Von Eckhel.
The marketable qualitiea of sponge are deacrihed as " aorta," and the different sorts are designated by letters, " sort A." These sorts are most conveniently arranged accoiding to localities, and thus under some aorta all three speciea are repre,sented; all, however, are from the same place, and all have some local peculiarity which makes them either of superior or inferior quality. The slimy
character of the bottom is often given as a reason for inferiority or dark colour. On the American side of the Atlantic, this is also shown by the great difference in point of colour and fineness between the Nassau and Key West sponges. Again, the shallow-water sponges are coarser than the deep-water forms. Thia is probably due, in part, as in other species, to the quantity of sedi ment, which is of course less in deep than in shallow water, as, for example, at Key West in the winter time. No fine qualities of any sponges are found within the limits of the milky water, but all the finer qualities of the marketable kinds in the deepest water in which the species occur, except, perhaps, in the ease of tbe reef sponge. Glove, reef, and hard-he,sd are fished in shallow waters (greatest depth 2 fathoms), and the other aad generally finer niarketable varieties at 2-5 fathoms. This fact also explains in a measure, but not wholly, the greater coaneness of American sponges as compared with the European ; for though it may be assumed from the examination of the skeletons that Mediterranean sponges are much less exposed to turbid waters, and though it may be shown by the microscope that tbe primary fibres contain less debris, this does not wholly explain their greater fineness and elasticity. This may be attributed either wholly or partly to climatic conditions. Both the bathymetrica1 and geographical distributions of the Spongice seem to be limited by the minimum temperature of 13° (55° F.). Tbe N. shore of the Xt gean Sea and the E. shore of the Adriatic are populous with sponges, and yet the former throughout its whole extent, and the latter from Ragusa to Istria, have nearly the same average winter temperature as, and possess a colder climate ia winter than, the coast of S. Italy or Spain, where no Spongice exist. The sponges correspond in quality to this climatic change. The sort found at the head of the 2Egean is said to be S. officinalis alone, and to have a heavy, hard, close, very hairy skeleton, often containing slime. The same species exists also alone at corresponding localities along the shore of the Adriatic, and at the extreme locality, the island of Istria, upon the limit of its distribution, it is said to be very rare, the form to be ugly, the skeleton hard, the colour dark. Farther south, along the Dalmatian coast, it becomes abundant, finer in texture and of a lighter colour, but it is still inferior to the more southern or Levantine variety. In considering such classes of facts, it must also be borne in mind that the habitat of a certain sort or variety may largely determine the quality of the skeleton, even where the temperature may be very favourable. Thus, to the south of Quarnero, among the islands, a much better quality of S. officinalis occurs than in the milder sea about the Ionian Islands, which is probably attributable to the slimy character of the bottom. It would seem, from the absence of sponges where they rnight be expected to occur, that when the limits of temperature are neared, the lack of small islands, or very slight local peculiarities, may suffice to account for commercial sorts (to which our knowledge is confined) being wanting.