CONTENTS 



PAGE 



Preface to the First Edition vh 



Preface to the Second Edition xi 



List of Illustrations xxui 



Introduction 1 



Phylogeny and Relationships— The Zoospore— Occur- 

 rence— Hydrobiological Aspects— Geographic Distribu- 

 tion—Isolation and Culture— Preservation— Key to the 

 Orders 



Uniflagellatae 42 



Chytridiales 42 



Development and Morphology: The Thallus— Repro- 

 duction — Cytology — Parasitism 



Systematic Account 119 



Inoperculatae 121 



Olpidiaceae 121 



Olpidiomorpha 122 



Nucleophaga 123 



Sphaerita 125 



Olpidium 128 



Pringsheimiella 157 



Pleotrachelus 158 



Plasmophagus 164 



Rozella !65 



?Blastulidium 181 



?Chytridhaema 182 



ACHLYOGETONACEAE 182 



Achlyogeton 183 



Septolpidium 187 



Bicricium 188 



xv 



