76 U.S. NATIONAL MUSEUM BULLETIN 2 72 



Description. — Sponge, according to previous descriptions, forming 

 flat crusts of small dimensions; surface and skeletal structure in- 

 sufficiently known. Consistency recorded as fragile. 



Megascleres distinctly fusiform, sharply pointed, and slightly 

 curved amphioxea, covered with minute and inconspicuous spines 

 except at their extremities; length range 230-275 n, width range 

 8-10 M. 



Microscleres absent. 



Gemmoscleres slightly curved, somewhat abruptly pointed am- 

 phioxea, armed with rather coarse spines throughout their length, 

 spines in terminal region of sclere somewhat aggregated, without much 

 increasing in length; length range 47-62 n, width range 3-4 /x. 



Gemmules spherical, ranging in diameter 310-330 ju; pneumatic 

 layer well developed, consisting of clearly visible subspherical air 

 spaces, or granular without discernible air spaces; gemmoscleres 

 embedded in this coat strictly radially, forming a single layer, their 

 extremities penetrating outer gemmular membrane, so that surface of 

 gemmules appears distinctly hispid ; foramen distinctly tubular, porus 

 tube slender and straight, shghtly surpassing in length outer gemmular 

 membrane, and without a smTounding conical depression. 



Distribution. — Known only from the vicinity of Bombay (S. 

 cinerea) and the Himalayas {S. perviridis). Weber's (1890) record 

 from Indonesia based on wrong identification. 



Color in life. — Ash gray to bright green. 



Discussion. — The generic position of this insufficiently known 

 species must still be considered as highly dubious. As mentioned in 

 the discussion of Stratospongilla gravelyi, the slides of the syntype of 

 Spongilla cinerea contain some gemmules which, in addition to the 

 radially arranged gemmoscleres of this species, also possess a very few 

 stratospongiUid tangential amphistrongyla. While in these few cases 

 the pneumatic coat, although of the same thickness, does not display 

 any discernible air spaces, those of the remaiiung more numerous 

 gemmules are small and subspherical, a typical feature in all Radio- 

 spongilla species. In spite of the striking sunilarity of the acerate 

 radially arranged gemmoscleres in both types of gemmules, it is 

 possible that gemmules of two different spongillids are present in the 

 type material examined. However, it is equally possible that the sponge 

 known as S. cinerea represents a distinct growth form of a Strato- 

 spongilla species, as suggested by Annandale (1912d, p. 386). This 

 would also account for the most apparent paucity of material of S. 

 cinerea collected. Its inclusion in the genus Radio spongilla must 

 therefore be considered a tentative solution of this unsolved taxonomic 

 problem, and additional studies are highly desirable. 



