BY R, VON LENDENFELD, PH.D. 511 



further developement in the dii'ection indicated has been attained 

 by Euspongia Matthevm, the representative of the following sub- 

 genus. The developement of this kind of ramification of connect- 

 ing fibre is ah^eady indicated in the variety tenuis of Euspongia 

 irregularis. 



It can be made clear by a perusal of the following table where- 

 in unchanged descendants of the true ancestors are enumerated in 

 a series which probably repi'esents the true ancestral descent very 

 olosely : — 



Subgenus Laxifibris Subgenus Ditela. 



Euspongia canaliculata dura. 

 Primaries straight. 



Euspongia canaliculata elastica. 

 Primaries slightly bent. 



Euspongia canaliculata mollissima. 

 Primaries much bent. 



Euspongia irregularis tenuis, indication of differentiation into 

 Primaries and Secundaries. 



This table also shows the mutual relationship of the different 

 varieties. 



Histology, 



The I'emarkable structure of this sponge led me to investigate 

 its histology more closely and I have arrived at some interesting 

 results differing to a great extent from the histology of other 

 sponges as described by F. E. Schulze, Vosmaer, Polejaeff, and 

 myself 



