TWO NEW SPONGILL^ FROM LAKE TANGANYIKA. 479 



possesses more spongin than the Spongillidai are usually sup- 

 posed to have. As a matter of fact, it is difficult to make out 

 what structural reasons there are for retaining the family 

 Spongillidse. It is not at all improbable that when they are 

 more carefully studied they will be distributed among the 

 several genera of the Homorrhaphidae. But as our knowledge 

 has not yet attained a stage which will enable us to do this, it 

 is deemed advisable for the present to place this new species 

 among the Spongillid^, and to retain that assemblage of sponges 

 as a family, however artificial it may be. 



The characters of the gemmule of Spongilla moorei place 

 this species among the sub-family Spongillinse, and not among 

 the Meyininffi or the Lubomirskinse. They lack the amphidiscs 

 which surround the gemmule of the Meyenin^, while, on the 

 other hand, the Lubomirskinse is a sub-family which has been 

 created for the purpose of including certain fresh-water sponges 

 in which, up to the present, the gemmule has not been discovered. 



Spongilla moorei appears to be more closely related to 

 Spongilla aspinosa (Potts) than to any other species of 

 the Spongillinse. Both species agree in possessing spicules 

 which are smooth, straight or curved, and for the most part 

 rather abruptly pointed. Malformed spicules, as they are 

 described by Potts [9], are found in both, but they appear to be 

 more numerous and more complicated in Spongilla moorei 

 than in Spongilla aspinosa. Further, both species pro- 

 duce gemmules which are small in size, spherical in shape, and 

 supplied with a thin crust which is not protected by spicules 

 characteristic of the gemmule, but by the ordinary skeleton 

 spicules. Though the gemmules are few in Spongilla aspi- 

 nosa, they are more numerous than in Spongilla moorei, 

 a feature which may be explained either by the lesser import- 

 ance and consequent scarcity of the gemmule in the latter 

 species, or simply by the season at which the material was 

 collected. 



Spongilla aspinosa differs from Spongilla moorei in 

 that it possesses small flesh spicules, which lie on the dermal 

 membrane and among the smooth, slender skeleton spicules. 



