Comprehensive Revision of a Worldwide Collection 

 of Freshwater Sponges (Porifera-Spongillidae) 



Introduction 



In spite of the fact that serious scientific efforts in the taxonomic 

 study of freshwater sponges were begun in the mid-19th century, and 

 that a great niunber of subsequent investigators have contributed a 

 massive amount of additional descriptive information, the taxonomy 

 of this group has remained in a most chaotic state. Following 

 Bowerbank's (1863) initial revision of all species of Spongilla, Gray 

 (1867) was first to establish usefid criteria for their generic differen- 

 tiation and to erect six new genera in addition to Spongilla Lamarck. 

 Unfortunately, this system was criticized and its vahdity questioned 

 by Carter (1881a), who claimed that Gray estabhshed his new genera 

 without having seen Bowerbank's material upon which they were 

 erected. Although fully unjustified in doing so. Carter (1881a) alto- 

 gether ignored Gray's existing generic names and devised his own 

 system for the inclusion of Bowerbank's species and subsequently 

 collected material. Thus it happened that Gray's well-established 

 genera fell into complete obscurity for many decades, and Carter's 

 system became firmly established, without being seriously challenged 

 by any subsequent taxonomist. 



From the turn of this century, several attempts were made to 

 revise comprehensively the status of the ever increasing numbers of 

 species. After the publication of the first bibHography of all freshwater 

 sponges by Weltner (1893), it was chiefly Annandale (1906-1919) who 

 began to build the foundations to an improved and modernized 

 knowledge of spongillid taxonomy. Annandale reestablished some of 

 Gray's generic names, at least at a subgeneric level, and added a 

 number of well-defined new genera to the conglomerate systems of 

 Gray and Carter. Additional revisions were subsequently undertaken 

 by Gee (1926-1937), Schroder (1926-1942), and Arndt (1923-1938), 

 to name just the most important contributors. Generic revisions were 

 attempted by De Laubenfels (1936) and Jewell (1952). However, 

 in spite of the fact that all these investigations have certainly helped 

 to overcome a number of taxonomic difficulties, they seemed to have 

 little effect on the stability of taxonomic nomenclature. 



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