REVISION OF FRESHWATER SPONGES OF SPONGILLIDAE 47 



shallow encrustations of considerable dimensions; surface smooth, 

 oscula inconspicuous. Skeleton rather loosely defined, consisting of 

 slender spicule fibers, about six scleres thick, mth little amounts of 

 spongin. Consistency of live sponge apparently not yet recorded. 



IMegascleres usually sUghtly curved and entirely smooth amphioxea, 

 often vnih subtornote tips; length range 210-260 /x, width range 

 12-19 fji. 



Microscleres such as known in other congeners apparently absent. 



Gemmoscleres variable in size and shape; as a rule stout and slightly 

 curved amphistrongyla, covered with short and blunt spines that are 

 more numerous at the extremities of the scleres than in their center; 

 length range 63-71 n, width range 12-16 n. 



Gemmules spherical, ranging 380-420 n in diameter; pneumatic coat 

 comparatively thick but irregular and apparently without air spaces; 

 gemmoscleres embedded in this coat tangentially in one or more 

 layers ; when only one layer is produced, the mosaic-like arrangement 

 of the gemmoscleres can be readily observed; foramen or foramina 

 provided with a porus tube of varying shape and thickness, rising up 

 to 18 )u above the outer gemmular membrane. 



Distribution. — Apparently restricted to tropical Africa. 



Color in life. — Recorded as dirty white. 



Discussion. — This species differs clearly from all other congeners 

 mentioned earher by its rather stout and entirely smooth amphioxous 

 megascleres, and by the absence of free microscleres in the symplasm. 

 Its specific separation from other members of the genus is therefore 

 justified. The material studied by the present authors did not reveal 

 any additional criteria for discussion. 



Stratospongilla schubotzi Weltner, 1913 



Spongilla (Stratospongilla) schubotzi Weltner, 1913, p. 481. — Annandale, 1914, 

 p. 245.— Stephens, 1919, p. 95.— Gee, 1931e, p. 48; 1932c, p. 41.— Arndt, 

 1936, p. 15.— Penney, 1960, p. 28. 



Material. — Slides of type obtained from ZMB by N. Gist Gee. 



Description. — Sponge, according to Weltner (1913), forming 

 shallow encrustations on shells of Aetheria elliptica; additional data on 

 external features lacking. Skeleton apparently well defined and mod- 

 erately firm, consisting of slender spicule fibers, 1-6 scleres thick, with 

 little amounts of spongin. Consistency of live sponge recorded as hard. 



Megascleres extremely variable in shape and length; the majority 

 are stout and cylindiical amphioxea with more or less abruptly pointed 

 tips, occasionally with a few true amphistrongyla intermixed; however, 

 all possible types of scleres are present, ranging from oxea over styles 

 or tornotes to strongyla; the surface of all these skeletal components 

 is entirely smooth; length range of typical amphioxea 120-170 n, 



