14 U.S. NATIONAL MUSEUM BULLETIN 2 72 



Color in life. — Not yet observed. 



Discussion. — The status of this species cannot possibly be fully 

 elucidated until fui'ther material will become available. S. helvetica 

 shows close affinities to the S. lacustris complex, and will probably be 

 found synonymous with the latter. In view of the paucity of material 

 examined, however, it seems advisable to retain the separate status 

 of aS. helvetica in order not to obscure possible taxonomic evidence. 



Annandale (1909a) did not mention the presence of true gem- 

 moscleres, a fact which immediately separates S. helvetica from both 

 S. inarmata Annandale and S. aspinosa Potts. The cages of mega- 

 scleres around the gemmules in S. helvetica, as recorded by Annandale, 

 could not be observed in the material available for this study. 



Spongilla aspinosa Potts, 1880 



Spongilla aspinosa Potts, 1880b, p. 357; 1887, p. 184.— Kellicott, 1891, p. 102.— 

 Weltner, 1895, p. 114.— Smith, 1921, p. 17.— Gee, 1931e, p. 32; 1932c, p. 36.— 

 Old, 1932a, p. 131; 1932b, p. 468.— Eshleman, 1950, p. 38.— Penney, 1960, 

 p. 13. — (Not Spojigilla aspinosa Annandale and Kawamura, 1916, p. 6= 

 Spongilla inarmata Annandale). 



Material. — Sponge fragments and slides: Deep Creek Basin, 

 Vu-ginia; N. Gist Gee, no number. New Jersey. 



Description.— Sponge, accordmg to Potts (1880), encrusting, thin, 

 producing long and waving branches from an irregular base; oscula 

 small and inconspicuous. Skeleton consisting of slender spicule fibers 

 encased in spongin, and transverse spicule tracts. Consistency of live 

 sponge soft. 



Megascleres slender and fusiform amphioxea, completely smooth; 

 free megascleres of somewhat smaller dimensions often in dermal 

 membrane and symplasm, sometimes also forming loose layer around 

 gemmules; length range 155-215 n, width range 3-8 ju- 



Microscleres not restricted to either dermal membrane or symplasm, 

 but apparently very rare; they are small and slender amphioxea, 

 invariably completely smooth; length range 30-42 n, width range 

 1-1.5 M. 



Gemmoscleres not yet recorded. 



Gemmules rather large and spherical, ranging 450-700 ix; pneumatic 

 layer extremely thin and granular, but much firmer than in the "un- 

 armed" type of gemmules of S. lacustris; smaller megascleres often 

 embedded in this layer, occasionally also freely curving around the 

 gemmules; foramen singular, slightly elevated, bearing a shallow 

 peripheral collar. 



Distribution. — At present known only from the United States. 



Color in life. — Bright green, due to the presence of zoochlorellae. 



Discussion. — The absence of gemmoscleres, and the somewhat 

 mutilated condition of the material examined during the present 



