C. Porifera calcaria. 9 



Wierzejski describes some remarkable abnormalities of freshwater-sponges with 

 hints once more as to the uselessness of making new species on account of varia- 

 tions met with only in one or two specimens. 



Development of spicules in Spongilla, see Noll. 



B. Ceratina. 



Thomson found on the surface of a SpongeUa club-shaped knobs, of the size 

 of a small pin's head. They are covered with pavement epithelium and consist 

 inside of a compact mass of cells, exhibiting often great variability of shape. It 

 seems possible that they may secure the persistence of the organism in unfavou- 

 rable environment*. Thence T. feels inclined to call them regenerative capsules*. 

 Similar aggregations were observed in Reniera. 



C. Porifera calcaria. 

 See Bidder, supra, p 2, Sollas (S 2 ), supra, p 5, and Fiedler, supra, p 8. 



Zool. Jahresbericht. 188S. Porifera. 



