4io 



CRYPTO-RAPHIDIE/E. 



SUB-FAMILY III. CRYPTO-RAPHIDIE^E. 



Frustules with 

 valve face gen- 

 erally circular, 

 subcircular, or 

 angular, more 

 rarely elliptic, 

 oval, or bacillar. 



frequently 



never 



much developed in girdle 

 view and filamentous ; or 



with processes, teeth, spines, 

 or awns ; or 



more or less hyaline ; or 



irregular ; or 



furnished with transverse 

 costae in girdle view. 



r 



i with a central linear blank 

 (hyaline) space or a true 

 1 raphe on the valves. 



All the crypto-raphidiese have a granular endochrome ; in 

 cylindrical forms the granules are scattered on the internal 



surface of the valves ; in discoid or analogous forms the 

 granules radiate round a central point. 



