As regards Spongilla decipiens*, Weber, from the Malay Archipelago, see p. 97.
II.
History of the Study of Freshwater Sponges.
The bath-sponge was known to the Greeks at an early date, and Homer refers to it as being used for cleansing furniture, for expunging writing, and for ablutionary purposes. He also mentions its peculiar structure, "with many holes." "Many things besides," wrote the English naturalist Ray in his 'Historia Plantarum' (1686), "regarding the powers and uses of sponges have the Ancients: to them refer." Ray himself describes at least one freshwater species, which had been found in an English river, and refers to what may be another as having been brought from America. In the eighteenth century Linné, Pallas and other authors described the commoner European Spongillidæ in general terms, sometimes as plants and sometimes as animals, more usually as zoophytes or "plant-animals" partaking of the nature of both kingdoms. The gemmules were noted and referred to as seeds. The early naturalists of the Linnæan Epoch, however, added little to the general knowledge of the Spongillidæ, being occupied with theory in which theological disputes were involved rather than actual observation, and, notwithstanding the fact that the animal nature of sponges was clearly demonstrated by Ellis[[U]] in 1765, it was not until the nineteenth century was well advanced that zoologists could regard sponges in anything like an impartial manner.
One of the pioneers in the scientific study of the freshwater forms was the late Dr. H. J. Carter, who commenced his investigations, and carried out a great part of them, in Bombay with little of the apparatus now considered necessary, and with a microscope that must have been grossly defective according to modern ideas. His long series of papers (1848-1887) published in the 'Annals and Magazine of Natural History' is an enduring monument to Indian zoology, and forms the best possible introduction to the study of the Spongillidæ. Even his earlier mistakes are instructive, for they are due not so much to actual errors in observation as to a faithful transcription of what was observed with faulty apparatus.
Contemporary with Carter were two authors whose monographs on the freshwater sponges did much to advance the study of the group, namely, J. S. Bowerbank, whose account of the species known at the time was published in the 'Proceedings of the Zoological Society of London' in 1882, and the veteran American naturalist Mr. Edward Potts, whose study of the freshwater sponges culminated in his monograph published in the 'Proceedings of the Academy of Natural Sciences of Philadelphia' in 1887. Carter's own revision of the group was published in the 'Annals and Magazine of Natural History' in 1881. The names of Vejdovsky, who prefaced Potts's monograph with an account of the European species, and of Dybowsky, who published several important papers on classification, should also be mentioned, while Weltner's catalogue of the known species (1895) is of the greatest possible value to students of the group.
Many authors have dealt with the physiology, reproduction and development of the Spongillidæ, especially in recent years; Dr. R. Evans's description of the larva of Spongilla lacustris (1899), and his account of the development of the gemmule in Ephydatia blembingia (1901), Zykoff's account of the development of the gemmule and of the sponge from the gemmule (1892), and Weltner's observations on colour and other points (1893, 1907), may be mentioned in particular. Laurent's observations on development (1844), which were published in the 'Voyage de la Bonite,' and especially the exquisite plates which accompany them, have not received the notice they deserve, probably on account of their method of publication.
Literature.
The fullest account of the literature on the Spongillidæ as yet published will be found in the first of Weltner's 'Spongillidenstudien' (Archiv für Naturgeschichte, lix (i), p. 209, 1893). Unfortunately it contains no references of later date than 1892. The following list is not a complete bibliography, but merely a list of books and papers that should prove of use to students of the Oriental Spongillidæ.