32o THE TANGANYIKA PROBLEM. 



AFFINITIES. 



This subject must be considered from two aspects. In 

 the first place, the character of the gemmulse must be taken 

 into consideration, since the grouping of the Spongillidae 

 into the three sub-families, Spongillinae, Meyeninae and Lubo- 

 mirskinae, and the division of the sub-families into genera, 

 usually adopted, depends on these characters. In the 

 second place, the spicules are of great importance, as pre- 

 senting a close resemblance to the spicules of Lttbomirskia 

 intermedia var. a (Dybowski, cf. pi. iv., fig. 3, b), which 

 belongs to the sub-family Lubomirskinae. 



(A) The Gemmule. — The gemmule of Spongilla tan- 

 ganyikcs lacks the amphidiscs which surround the gemmule 

 of the Meyeninae. It therefore appears that the species 

 cannot belong to that sub-family. But it equally lacks the 

 small spicules which are usually found in close relation with 

 the gemmule of the Spongillinse. Potts, however, places 

 Spongilla aspinosa among the Spongillinae, in spite of the 

 fact that its gemmules lack characteristic spicules. If this 

 arrangement be followed, the absence of such spicules from 

 Spongilla moorei and Spongilla tanganyikce should not be 

 considered as a barrier against including these species among 

 the Spongillinae. But the inclusion does away with the im- 

 portance of the presence of special gemmule spicules as a 

 sub-family character. 



The thin coat of the gemmule resembles that found in 

 Spongilla moorei, Spongilla aspinosa and others of the 

 spongillinae, and has no similarity to the thick coat of the 

 gemmule of the Meyeninae. The characters of the gemmule, 

 therefore, as far as they go, point to this new African species 

 as being one of the Spongillinae. 



