Fig. 101. 



68 



Pleurosiggna dellcatulum , (10), cells 60-100u long, 10-15u 

 wide. 



valve view 

 X495 



Notes 



valve view 

 XL 300 



31a Frustules with septae - MAST0GL0IA 



Fig. 102. Mastogloia Braunii, (5), cells 35-95U long, l4-27u wide, 

 X 1000. 



valve view 

 Notes : 



girdle view 



31b Frustules without septae 



32a Raphe enclosed in a siliceous rib - DIPLONEIS 



32 



