PROC. BIOL. SOC. WASH. 103(3), 1990, pp. 731-745 CORRECTION OF IJIMA'S (1927) LIST OF RECENT HEXACTINELLID SPONGES (PORIFERA) Henry M. Reiswig Abstract. —Errors in the final species list of Ijima's posthumously pubhshed Siboga Monograph on the Hexactinellida (Porifera) have been the cause of misallocations of species in later publications and disorder of museum collec-tions. The text of the entire monograph has been reviewed in detail in an attempt to provide a faithful reflection of Ijima's opinions and a corrected list of species as understood by him at the time of his death. A total of 42 1 forms are recognized, consisting of 381 species and 40 additional subspecies. The taxonomic actions attributable to Ijima in this monograph are summarized in an action list. Isao Ijima's (1927) monograph, "The Hexactinellida of the Siboga Expedition," is still regarded by specialists as the most important authority for present taxonomic arrangement of this class of Porifera. It does, however, contain significant, unrecognized hazards for both casual and serious research users. Its prominence is attributable both to its major reorganization of higher taxa, which has served as the basis for later re-views (de Laubenfels 1936) and modifica-tions (e.g., Reid 1957, 1963), and to its in-clusion of a revised list of all extant hexactinellids— the last such attempt. The monograph's appended "List of Recogniz-ably Known Recent Hexactinellids Ar-ranged Systematically," pp. 364-377 (here-after referred to as the "Final List" or "FL"), has served as reference for subsequent hex-actinellid collection reports (e.g.. Burton 1954) and as the basic guide for systematic arrangement of specimen collections of most major museums throughout the world. Un-fortunately, the Final List is extensively flawed at lower taxonomic levels due to ed-itorial actions in the preparation of the final publication. As noted in Kaburaki's preface and the introduction to the monograph, Ijima in-herited responsibility for the Siboga hex-actinellid collection in 1907 after ill health incapacitated F. E. Schulze. Ijima spent the final ten years of his life preparing the re-port, but died in 1921 before completing his revision of the second half of the material— basically the Lyssacinosa. Responsibility for final preparation fell upon Y. Okada, Iji-ma's assistant, and Max Weber, the editor of the Siboga Series. While the main text is accepted here as a faithful reflection of Iji-ma's taxonomic opinions, the Final List, presumably assembled by Okada and/or Weber, contradicts Ijima's text conclusions on many points. The Final List, with its unappreciated errors, continues to be the most widely used portion of the monograph due to omission of an index of scientific names in this work. Even Burton ( 1 928), in his careful taxonom-ic review for the Zoological Record, failed to detect several new genera erected by Iji-ma. These errors continue to be perpetuated in modem literature (e.g., Hartman 1982, Koltun 1967, Reiswig 1979, Tuzet 1973), hence correction of the list is urgently need-ed. Ijima, a major figure in hexactinellid systematics, ranking second only to F. E. Schulze in terms of total contributions to the field, deserves better recognition for his last major accomplishment than appearing
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