Classification of the Spongida. 133 



Family 3. Acervochalinida. 

 Massive clathrous, or compact and isodictyal. 



Family 4. Pseudochaljnida. 



Digitiferous, composed of fibre cored with proper spicules 

 and foreign objects. 



ECHINONEMATA. 

 Family 1. Ectyonida. 

 Echinated with proper spicules on the fibre. 



Family 2. Axinellida. 



Echinated with proper spicules projecting from the interior 

 of the fibre. 



HOLORHAPHIDOTA. 



Family 1. Renierida*. 



Spicules more or less arranged in a fibrous form. Structure 

 yielding to pressure like crumb of bread. 



Family 2. Suberitida. 



Tissue chiefly cork-like ; spicules matted felt-like ; cancel- 

 lous and crushable, or radiated compact and hard ; spicule 

 chiefly pin-like, with the sharp ends projecting from the surface 

 velvet-like. 



Family 3. Pachytragida. 



More or less corticate, with a cancellous, more or less 

 radiated structure internally well differentiated. 



Family 4. Pachastrellida. 



Without cortex ; densely spiculiferous, even to stony hard- 

 ness (Lithistina). Structure confused ; no fibre. 



Family 5. POTAMOSPONGIDA, Gray. 



Fragile sponges bearing seed-like bodies or statoblasts, and 

 inhabiting fresh water. 



* After Etienne-Andre Ilenieri, of 1793. 



