REVISION OF FRESHWATER SPONGES OF SPONGILLIDAE 85 



of polyspicular radiating fibers, coated together in well defined 

 sheaths of spongin ; and of a variable number of secondary transverse 

 fibers. Consistency of live sponge firm and moderately hard, skeleton 

 of dry sponge very brittle. Bubble cells abundant in inner symplasm. 



Megascleres very slightly curved, almost cylindrical amphioxea, 

 entirely smooth; length range 275-310 n, width range 11-15 n. 



Microscleres absent. 



Gemmoscleres birotulates of one class, with moderately stout 

 shafts, occasionally armed with 1-3 sharp spines, usually entirely 

 smooth; and termmally with rotules of equal diameter and more or 

 less flat shape, irregularly and deeply incised; malformations frequent 

 in adverse environments; length of shaft 28-33 n, diameter of rotules 

 ranging 25-29 m; marginal teeth on rotules 19-22. 



Gemmules abundant in mature sponge, scattered thi-oughout 

 skeletal mesh work, spherical, ranging in diameter 480-610 ju; pneu- 

 matic layer well developed but irregular, consisting of minute spherical 

 air spaces; gemmoscleres embedded in this coat in one or two layers, 

 the inner always strictly radially arranged, the outer layer often 

 irregularly inserted; while the inner layer is always fully contained 

 within the pneumatic coat, the distal rotules of the outer invariably 

 penetrate the outer gemmular membrane; foramen distinctly elevated 

 but simple, never attaining the shape of a tube. 



Distribution. — Known only from a few localities in India and 

 China. 



Color in life. — Light to dark brown. 



Discussion. — Ephydatia meyeni, although very closely related to 

 E. fluviatilis, displays a number of constant criteria that certainly 

 are not obvious within the normal morphometric range of the latter. 

 Unless a thorough study of the entire E. fluviatilis complex finally 

 can be contemplated that would result in a better understanding of 

 the various ecomorphic fluctuations in shape and measurements of 

 the spicular components, it seems advisable to retain the separate 

 specific status of the species discussed. Only the results of such 

 detailed future studies will be able to demonstrate whether E. meyeni 

 differs from E. fluviatilis by criteria of specific or subspecific 

 importance. 



Ephydatia niiilleri (Lieberkiihn, 1855) 



Plate 7, figures 6, 7 



Spongilla miilleri Lieberkiihn, 1856, p. 510. — Vejdovsky, 1877, p. 213. 

 Spongilla Jluviatilis var. parjitti Carter, 1868, p. 247; 1881, p. 93. 

 Spongilla parfitti Bowerbank, 1874, p. 295. 



Spongilla asperrima Dawson, 1878, p. 1. — Mills, 1882, p. 57. — Potts, 1887, p. 219. 

 Trachyspongilla miilleri Dybowsky, 1878, p. 53. — Vejdovsky, 1883, p. 26, 

 Spongilla astrosperma Potts, 1880b, p. 357. 



