84 U.S. NATIONAL MUSEUM BULLETIN 272 



membrane, with the other just reaching to outer membrane; foramen 

 only very sUghtly elevated, surrounded by a minute collar, never 

 tubular. 



Distribution. — Apparently cosmopolitan, widely dispersed in 

 both hemispheres, with preference to cold- to warm-temperate regions, 

 occasionally also occurring in subtropical climates. 



Color in life. — Usually drab yellow to brown, occasionally green 

 due to presence of zoochloreUae. 



Discussion. — As evident in all species with a truly cosmopolitan 

 distribution, E. jluviatilis displays great variabiUty in skeletal and 

 spicular structure and is subject to numerous ecomorphic malforma- 

 tions in adverse habitats. Our reexamination revealed that most of 

 the former "varieties" of this species certainly are nothing more 

 than malformed specimens of the nominal species. However, there 

 are some others, like E. f. syriaca and E. f. himalayensis, of which the 

 spicules seem to be transitory in shape and structure to those of the 

 E. ramsayi group of species, that are here temporarily listed as syn- 

 onymy of E. Jluviatilis until a future study of this complex will be 

 possible. 



This species has been adequately described in previous hterature 

 and the present studies have not revealed any additional criteria 

 of importance. Since a type specimen apparently has never been 

 designated, and most certainly does not exist today, a neotype of 

 Spongia Jluviatilis Linnaeus therefore had to be selected. This is a 

 specimen in the collection of the Rijksmuseum van Natuurlijke 

 Historie, Leiden, reg. no. 1166, coll. A. W. Lacourt, 12. ix. 1942, 

 Angstel E,., Abcoude, Holland, The mode of growth and spicular 

 components of this neotype correspond in all details with the majority 

 of descriptions of Ephydatia Jluviatilis Auct. available in previous 

 literature. 



Ephydatia meyeni (Carter, 1849)J 



Plate 7, figure 20 



Spongilla meyeni Carter, 1849, p. 84; 188 la, p. 93. — Bowerbank, 1863, p. 448. 

 Ephydatia meyeni Gray, 1867, p. 550. — Annandale, 1907a, p. 272; 1911c, p. 108; 



1912d, p. 384; 1918a, p. 204.— Gee, 1926c, p. 110; 1927a, p. 7; 1928, p. 225; 



1929d, p. 297; 1930b, p. 170. 

 Meyenia jluviatilis var. meyeni Potts, 1887, p. 221. — Penney, 1960, p. 50. 

 Ephydatia mulleri Weltner, 1895, p. 125 (part). 

 Ephydatia mulleri var. meyeni Annandale, 1908c, p. 306. 

 Ephydatia fluviatilis var. meyeni Gee, 1932c, p. 30; 1932e, p. 535; 1932f, p. 507. 



Material. — Slides of type (IM) and syntype (N. Gist Gee). 



Description. — Mature sponge forming massive growths of irregular 

 outline; surface uneven and distinctly corrugated; oscula rather 

 inconspicuous, dermal membrane well developed. Skeleton consisting 



