REVISION OF FRESHWATER SPONGES OF SPONGILLIDAE 43 



recorded as such by Weber (1890), are most likely deformed 

 gemmoscleres. 



Gemmoscleres are stout and short amphistrongyla, straight to 

 feebly curved, covered with rather uniform minute spines; length 

 range 32-43 n, width range 11-13 /x. 



Gemmules apparently not abundant in mature sponge, recorded as 

 free, never grouped together; diameter of gemmule 450-600 n; pneu- 

 matic layer irregularly developed, without noticeable air spaces; 

 outer gemmular membrane in continuity with a short and straight 

 porus tube; gemmoscleres closely crowded in this coat, embedded 

 strictly tangentially, and fomiing a mosaic layer. 



Distribution. — Ranging from Indonesia via India to Africa. 



Color in life. — Recorded as light gray. 



Discussion. — The great variability of scleres in the specimens 

 assigned to this species by a number of previous workers appears to 

 have marred earlier attempts to solve the true relationship of S. 

 sumatrana to other species of the genus. The species discussed has 

 never before been suspected of being extremely closely related to or 

 even identical with S. bombayensis, yet other and much more differing 

 specimens, such as S. indica and S. gravelyi, have been relegated to 

 mere "varieties" of S. sumatrana by Annandale after having been 

 considered separate species by him. As already stressed in the dis- 

 cussion of the foregoing species, S'. sumatrana and S. bombayensis 

 form a clearly defined group and are possibly even identical. On the 

 other hand, S. gravelyi differs from this group by the characteristics 

 of its microscleres, as well as by its apparently nonadhering gemmules; 

 S. indica with all its "varieties" differs by the amphistrongylous shape 

 of its megascleres. Should it be possible to consider these last two 

 species, including their races, conspecific with S. sumatrana it would 

 be just as possible to consider the entire range of characters from 

 S. bombayensis to S. indica a manifestation of ecomorphic changes in 

 distant populations, and aU these forms would have to become at the 

 most subspecies of S. bombayensis. Apart from the fact that such an 

 arrangement would certainly obscure possible taxonomic evidence, 

 the material hitherto collected does not allow such a decision. In this 

 paper, therefore, S. sumatrana with the varieties listed above is treated 

 as a separate species, and at the same time the specific status of 

 S. gravelyi and S. indica is restored. This appears to be a justified 

 preliminary arrangement before future studies, and particularly 

 additional material, will make a comprehensive revision of the entire 

 genus possible. 



Such a rearrangement, however, would make it necessary to review 

 the features displayed by the megascleres of the numerous "varieties" 

 in order to find reasonable means of allocating them between the two 



279-430—68 4 



