35 



Fig. 



39* Diatoma vulgare , (5), cells 30-60u long, 10-13|i wide; 



internal costae narrow, 6-8 in IOji; striae very delicate, 

 about 18 in lOu. Widely distributed. 



Girdle view of 

 part of colony 



X 500 



valve view 

 X 1000 



valve view, 

 var. brevis , 

 X 1000 



Notes : 



Notes on other species of DIATOMA. 



