Fauna von Süd-Afrika. 561- 



sharply pointed, irreg-ularly spined in the middle but smooth at 

 the ends. 



Transverse diameter of gemmule 0.36 mm (averag-e). 



Skeleton spicules (megascleres) 0.2(364 >< 0,012 mm (averag-e). 



Gemmule spicules ( microscleres) 0,12 >< 0,008 mm (average). 



Free spicules (microscleres) 0,08 X 0,006-0,06 >< 0.008 mm. 



Habit at. Eiver Umhloti. near Yerulam, Natal, S. Africa; on 

 stones. M. Webee, leg., Nov., 1904. 



This sponge exhibits close affinities, especiall}^ in the structure 

 of its gemmules, to the group represented by S. carteri Bowerbank, 

 and S. nitens Carter, and by several otlier African species. Apart 

 from ditterences in the spicules and skeleton, however, it ditters from 

 all the species of this group in that its gemmules are adherent and 

 grouped. in this character agreeing with the species of the subgenus 

 Spongilla, of wliich »S. fragüis Leidy, is the type. I am therefore 

 inclined to think that this subgenus should be regarded as including 

 all the species of Spongilla (sensu lato) the gemmules of which bear 

 a coat of relatively large, polygonal air-chambers, and should not 

 be confined to those in which the gemmules are grouped. In S. 

 fragüis, S. crassissima mihi, and other allied species the gemmules 

 exist both. as free groups and as a pavement layer; but in S. amUgua 

 the sponge forms too thin a film to contain free groups of gemmules, 

 and the gemmules are therefore adherent, being formed at the base 

 of the sponge in contact with its support. 



Subgenus Str(itospon<jiUa n, subg. 



Gemmules covered with one layer or two or more layers of 

 microscleres lying parallel or nearly parallel to the chitinous coat 

 and embedded in a dense chitinoid substance. No air-chambers; 

 granulär layer absent or imperfectly developed. Free spicules, when 

 present, amphioxous or amphistrongylous. 



Type Spongilla bomhaycnsis Carter. 



Spoiigilla homhayensis Carter. 



Carter in describing this species had in his possession only a 

 few gemmules witli the spicules that adhered to them. His 



