REVISION OF FRESHWATER SPONGES OF SPONGILLIDAE 27 



having been found in all continents and climates, as well as in caves 

 and at high altitudes. 



Color in life. — Usually light gray to whitish, occasionally green. 



Discussion. — The fact that the original description of E. jragilis 

 by Leidy (1851) has been overlooked by many authors of the 19th 

 centmy accounts for the extensive number of synonyms listed above. 

 In view of its successfid adaptation to waters of drastically different 

 chemical and physical properties, this species shows a large range 

 of morphological variations of its spicidar components as well as 

 gemmules that at first glance seem to justify at least racial discrim- 

 ination. However, the extensive study of all specimens from almost 

 to the Arctic Ckcle down to New Zealand reveals clearly that all 

 "forms" listed above as synonyms do not even represent geographic 

 races but must be considered as belonging to the one species, regard- 

 less of a possible later introduction of trinomial nomenclature for the 

 taxonomy of spongillids. The many names given to this species during 

 the previous century have akeady been corrected by previous 

 authors. Spongilla recticuba Kozhoff (1925), as well as the "varieties" 

 S.f. kendelana Schroder (1938a) and S.f. zempoalensis Rioja (1940b), 

 cannot be considered more than malformed or modified specimens of 

 E. Jragilis, the full morphological range of which has been observed 

 in Australian waters by Racek (MS.). Even the slight morphological 

 differences of S. decipiens Weber (1890), particularly the shorter 

 porus tube of its gemmides and the double arrangement of its gem- 

 moscleres, cannot possibly separate this species from E. jragilis with 

 which it is fully synonymous. Finally, S. ambigua Annandale (1909e) 

 has been shown by Arndt (1933c), who corrected a number of mis- 

 conceptions by Annandale, as synonymous with the species discussed ; 

 the present investigations fully support Arndt's view that the mega- 

 scleres are not microspined but invariably smooth, and that the few 

 observed microscleres are immature gemmoscleres. 



It is the opinion of the authors that E. Jragilis should be studied in 

 detail before final conclusions as to possible speciation trends in 

 distant populations can be made and subspecies be erected. Apart 

 from the clear synonyms, a number of species and "varieties" in the 

 literature are not present in the material studied. Most of them occur 

 in the Asian part of the U.S.S.R. and some in Lake Baikal, a 

 typically ancient lake. Until material from this part of the world 

 becomes available for a comprehensive study, it appears impossible 

 to draw any conclusions as to the relationship of these "forms" to 

 E. Jragilis, and they are here disregarded. 



In order not to obscure taxonomic evidence, some "variations" such 

 as S. J. calcuitana Annandale (1911c) are here treated as sej^arate 

 species, since they display morphological differences of importance. 



279-430—68 3 



