REVISION OF FRESHWATER SPONGES OF SPONGILLIDAE 33 



Discussion. — The fact that E. geminus has been found only once 

 renders its comparison with other allied species highly unreHable. 

 Furthermore, the paucity of material for this study does not permit 

 any assessment of its intrageneric relationships. The species discussed, 

 however, seems to possess features similar to those displayed by E. 

 fragilis, and it is not unlikely that when additional specimens are 

 available it will have to be relegated to a mere synonym of that truly 

 cosmopolitan species. On the other hand, future material may also 

 prove its identity mth some of the lesser known congeners, and it is 

 thought advisable to retain provisionally its separate specific status. 



Ennnpins coniferus (Annandale, 1916) 



Spongilla conifera Annandale, 1916, p. 51; liJlSa, p. 203. — Gee and Wu, 1927, 

 p. 258.— Gee, 1931e, p. 36; 1932c, p. 37; 1932d, p. 54.— Penney, 1960, p. 15. 



Material. — Fraction of syntype, and several slides of syntype 

 obtained by N. Gist Gee; material and slides from China (N. Gist 

 Gee). 



Description. — Sponge forming thin crust of moderate dimensions; 

 surface smooth, oscula small and inconspicuous. Skeleton consisting 

 of a close and regular network of slender spicule fibers, running 

 obliquely through the sponge, and held together by very little 

 spougin. Consistency of dry sponge very brittle. 



Megascleres small and slender fusiform amphioxea, entirely smooth, 

 straight or only slightly curved; length range 157-210 n, width range 

 4-9 /x. 



Microscleres absent. 



Gemmoscleres extremely minute, feebly curved amphioxea, covered 

 with microspines in an irregular manner; length range 19-32 n, width 

 range 2-3 n. 



Gemmules not very abundant in mature sponge, scattered freely 

 throughout skeletal meshwork; they have a conical outline and a 

 flattened base, and rarely measure more than 155 /x at their greatest 

 diameter; pneiunatic layer well but unevenly developed; base and 

 sides of gemmule covered with a single layer of large polygonal air 

 spaces, the upper surface mth several to many tiers of such air spaces; 

 the few gemmoscleres embedded in this layer only in the thicker upper 

 part, more or less tangentially; foramen distinctly tubular, porus tube 

 long and slender, traversing the thick polygonal pneumatic layer. 



Distribution. — Apparently restricted to China. 



Color in life. — Light brown (Annandale) . 



Discussion. — The unique structure, form, and armature of the 

 gemmules of E. coniferus, as well as its considerably smaller spicular 

 components, make this species readily distinguishable from any other 



