CONTENTS 



Introduction page 153 



Method of working 159 



Acknowledgements 161 



List of stations 162 



Classification 199 



General notes 206 



The species as a polyphasic system 206 



Taxonomic notes 208 



Divisions of the flora 219 



Effect of environment on form 224 



Analytical key to the genera 228 



Systematic account 232 



Coscinodiscaceae 233 



Hemidiscaceae 264 



Actinodiscaceae 265 



Biddulphiaceae 273 



Anaulaceae 288 



Chaetoceraceae 289 



Bacteriastraceae 306 



Rhizosoleniaceae 309 



Leptocylindraceae 321 



Corethronaceae 325 



Fragilariaceae 330 



Achnanthaceae 340 



Naviculaceae 343 



Cymbellaceae 351 



Bacillariaceae 351 



References 353 



Index 359 



Plates VI-XIII following page 364 



