REVISION OF FRESHWATER SPONGES OF SPONGILLIDAE HI 



Heteromeyenia latitenta (Potts, 1881) 



Carterella latitenta Potts, 1881b, p. 176; 1882a, p. 12.— Carter, 1882, p. 370. 

 Carterius latitentus Petr, 1886, p. 92. — Wurtz, 1950, p. 7. — Penney, 1960, p. 33. 

 Carterius latitenta Mills, 1887, p. 162. — Potts, 1887, p. 246. — Kellicott, 1891, p. 



104.— Weltner, 1985, p. 114.— Kirsch, 1909, p. 38.— Smith, 1921, p. 17.— 



Schroder, 1927b, p. 101. 

 Heteromeyenia latitenta Schroder, 1927b, p. 107. — Gee, 193 le, p. 41; 1932c, p. 33. 



Material. — Slides of specimen from Pennsylvania (N. Gist Gee) . 



Description. — Sponge, according to original descriptions, forming 

 shallow cushions on rocks in rapidly running water; surface even but 

 distinctly hispid, oscula inconspicuous. Skeleton forming an irregular 

 network of spicule fibers, joined together by a small amount of spon- 

 gin. Consistency of live sponge, soft, texture loose. 



Megascleres smooth to sparsely microspined fusifrom amphioxea, 

 slender and sharply pointed; length range 265-285 n, width range 

 8-11 fi. 



Microscleres slender amphioxea, entirely spined, spines only 

 slightly larger in central portion of sclere; length range 85-100 /i, 

 width range 2-3 n. 



Gemmoscleres birotulates of two length groups, usually possessing 

 identical ro tides, rarely displaying marked differences in the shape of 

 the rotules in the two groups; shafts of both stout, armed with numer- 

 ous long and pointed spines; rotules of equal diameter, slightly but 

 distinctly umbonate, at their lateral margins deeply cleft into a num- 

 ber of recurved teeth; length range of longer class 60-78 m, of shorter 

 50-55 n] diameter of rotides in both about 16-18 ju. 



Gemmules numerous in mature sponge, ranging in diameter 410- 

 480 fj,, spherical; pneumatic layer well developed and granular, con- 

 sisting of minute subspherical an- spaces; shorter gemmoscleres con- 

 tained within this layer, the few longer projecting beyond outer 

 gemmular membrane; foramen distinctly tubular, porus tube slender 

 and long, bearing one to two very long cirrous projections, arising 

 from a flat disk, flat and ribbon-like at their base and cylindrical in 

 distal parts. 



Distribution. — Found only in northeastern parts of the United 

 States. 



Color in life. — Recorded as green. 



Discussion. — In view of the only slightly differing lengths of the 

 two classes of birotulate gemmoscleres, Annandale (1909d) suggested 

 the inclusion of this species in the genus Ephydatia, together with 

 H. tentasperma. However, subsequent studies have clearly revealed 

 the heterogenous character of the gemmoscleres in both these species, 

 which together with the presence of typical microscleres make their 

 retention within the genus Heteromeyenia necessary. Even omitting the 



