CONTENTS. 



INTRODUCTION, - - xi 



CHAPTER I. 

 The Microscope and its Parts, - i 



CHAPTER II. 



Common Aquatic Plants useful to the Micros- 

 copisT, - 45 



CHAPTER III. 



Desmids, Diatoms, and Fresh-Water Alg^, 6i 



CHAPTER IV. 

 Rhizopods, - - no 



CHAPTER V. 



Infusoria, - - - 132 



CHAPTER VI. 

 Hydras, - - - 165 



