REVISION OF FRESHWATER SPONGES OF SPONGILLIDAE 117 



Distribution. — Apparently restricted to the eastern half of the 

 North American Continent, ranging from Florida to Canada. 



Color in life. — Recorded as gray. 



Discussion. — A. argyrosperma can be easily separated from other 

 congeners by its only slightly pronounced difference in the shape of 

 both classes of gemmoscleres. However, as in all other species of this 

 genus, the spicular components are often malformed due to varying 

 chemical properties of the environment, and the retention of a separate 

 status for Potts' "variety" A. a. tenuis seems fully unwarranted. 



Anheteromeyenia ryderi (Potts, 1882) 



Plate 10, figures 1-4 



Meter omeyenia ryderi Potts, 1882a, p. 13; 1884b, p. 216; 1887, p. 242.— Mills, 

 1884, p. 146.— MacKay, 1885, p. 233; 1889, p. 87.— KeUicott, 1891, p. 103.— 

 Hanitsch, 1895b, p. 511.— Weltner, 1895, p. 114.— Stephens, 1912, p. 9; 

 1920, p. 237.— Smith, 1921, p. 17.— Arndt, 1926, p. 344; 192Sb, p. 156.— 

 Gee, 1931e, p. 48; 1932c, p. 34; 1937, p. 285.— Old, 1932b, p. 450; 1936b, 

 p. 11.— Jewell, 1939, p. 20.— Eshleman, 1950, p. 41.— Penney, 1954, p. 156; 

 1956, p. 38; 1960, p. 44. 



Heteromeyenia {Anheteromeyenia) ryderi Schroder, 1927b, p. 108. 



Heteromeycnia ryderi var. baleni Potts, 1887, p. 247. — Stephens, 1920, p. 242. — 

 Smith, 1921, p. 17.— Arndt, 1926, p. 344; 1928b, p. 164.— Gee, 1931e, p. 33; 

 1931c, p. 34.— Penney, 1931, p. 242; 1956, p. 36; 1960, p. 44. 



Heteromeyenia ryderi var. walshii Potts, 1887, p. 246. — Schroder, 1927b, p. 108. — 

 Gee, 193 le, p. 52; 1932c, p. 34.— Penney, 1960, p. 45. 



Heteromeyenia macouni MacKay, 1900, p. 319. — Gee, 1931e, p. 42. 



? Heteromeyenia conigera Old, 1931, p. 298. — Gee, 1932c, p. 33. — Penney, 1960, 

 p. 43. 



Material. — Numerous specimens from the United States (Louisi- 

 ana to Maine) and Canada. 



Description. — Sponge, according to original descriptions, forming 

 massive, often hemispherical cushions on solid objects; surface 

 irregular to lobose, oscula conspicuous and numerous. Skeleton form- 

 ing an irregular network joined together by a small amount of spongin. 

 Consistency of live sponge comparatively soft, texture loose. 



Megascleres variable in shape and armature, as a rule somewhat 

 short and fusiform amphioxea, covered with broadly conical spines 

 except at the extremities; length range 190-220 n, width range 13-19 fi. 



Microscleres absent. 



Gemmoscleres birotulates of two distinct classes, both in regard to 

 length and shape; the longer class with rather robust and irregularly 

 cylindrical shafts, bearing a number of recurved spines, and terminally 

 with a smaller number of rather short and strongly recurved hooks; 

 the smaller class considerably shorter, their cylindrical shafts with 

 one or few spines, and terminally with flat to slightly umbonate rotules 



