CONTENTS. 



INTRODUCTION ..... 



Limited Condition of our Knowledge of Diatoms 



The Biology of Diatoms 



The Geographical Distribution of Diatoms . 



The Bathymetrical Limit of Diatoms 



Hypothesis on the Formation of Banks and Deposits of Diatoms 



1 

 1 

 3 



9 

 11 

 14 



DESCRIPTIONS OF GENERA AND SPECIES 

 Raphidie^e .... 



PsEUDORAPHIDIE/E 



CryptoraphidiezE 



17 

 17 

 41 

 69 



INDEX 



EXPLANATION OF THE PLATES 



171 



