REVISION OF FRESHWATER SPONGES OF SPONGILLIDAE 21 



The spicular components of this species and the characteristics of 

 the gemmular pneumatic layer make S. wagneri a typical member 

 of the S. alba group of species that are all known to range into strongly 

 brackish water or to occur in distinctly alkaline habitats. Although 

 it is most likely that S. wagneri has been confused with S. lacustris 

 on many past occasions, it is distinctly different from the latter in 

 many important criteria. Its closest relative undoubtedly is S. cenota 

 from Yucatan with which it shares the typical lobose development of 

 the gemmular pneumatic layer, as well as a similar arrangement of 

 spines on its gemmoscleres. The only character differentiating S. 

 wagneri from both S. alba and -S'. cenota is its "loose and open" skeletal 

 network, according to Potts' description. However, it is possible that 

 additional collections of this sponge may yet show its skeletal structure 

 comparable with those of the remainder of the group, i.e., rather firm 

 and compact. 



Although S. wagneri is very closely related to S. cenota, the structure 

 and length of its gemmoscleres appear sufficiently different from 

 those of the latter species to warrant then' taxonomic separation. 

 After more detailed speciation studies in freshwater sponges, perhaps 

 it will be possible to decide whether the existing differences are of 

 specific or infraspecific importance. It will then also be possible to 

 demonstrate the pathway of expected structural changes from the 

 S. alba sensu stricto, now even recorded from South America, via the 

 form displayed by S. cenota from Yucatan, to the characteristics of 

 S. wagneri from the southeastern United States. Until such studies 

 can be carried out it is better to retain the specific status of both 

 S. wagneri and S. cenota in order not to obscure possible taxonomic 

 evidence. 



Genus Eunapius Gray, 1867, redefined 



Spongilla Leidj', 1851, p. 278.— Bowerbank, 1863, p. 445 (part) .—Carter, 1881a, 

 p. 86 (part).— MiUs, 1882, p. 57 (part).— Potts, 1884b, p. 216 (part); 1887, 

 p. 197 (part).— MacKay, 1885, p. 233 (part).— Wierzejski, 1885, p. 1.— 

 Vejdovsky in Potts, 1887, p. 167 (part) .— Kellicott, 1891, p. 102 (part).- 

 Weltner, 1895, p. 114 (part) .-Hani tsch, 1895a, p. 127 (part) .— Amiandale, 

 1909b, p. 106 (part); 1909d, p. 402 (part); 1911c, p. 95 (part) .— Annandale 

 and Kawamura, 1916, p. 11 (part) .—Stephens, 1912, p. 7; 1920, p. 207.— 

 Topsent, 1914, p. 538.— Smith, 1918, p. 239 (part); 1921, p. 17; 1930, p. 

 184.— Arndt, 1923, p. 74; 1936, p. 14.— Kozhofi, 1925, p. 54 (part).- Rezvoj, 

 1926b, p. 64; 1930, p. 175.— Schroder, 1926, p. 248; 1932b, p. Ill; 1935, p. 

 99; 1938b, p. 126.— Gee, 1926c, p. 110; 1927a, p. 1; 1927b, p. 63; 1928, p. 

 225; 1929b, p. 13; 1931e, p. 38; 1932a, p. 132; 1932b, p. 469; 1932c, p. 239.— 

 Sasaki, 1934, p. 226; 1940, p. 166.— Jewell, 1939, p. 16.— Eshleman, 1950, 

 p. 38.— Penney, 1954, p. 156; 1956, p. 37; 1960, p. 11 (part). 



Eunapius Gray, 1867, p. 552. 



