PLATE XX. 



PAGE 



Rhabdodictyum delicatum, 0. Schmidt, . . .107 



Fig. 1. Macerated skeleton 'of a specimen of Rhabdodictyum delicatum, 0. 

 Schmidt ; natural size. 



Fig. 2. Two spicules connected by a synapticulum ; x 300. 



Fig. 3. Part of the framework of the connected principalia ; x 100. 



Fig. 4. Part of the framework of the connected principalia, with some ladder-like 

 structures ; x 25. 



