viii CONTENTS. 



INVERTEBRATES. 

 CHAPTER VII. 



PAGE 



Protozoa . ■ * 



CHAPTER VIII. 

 Sponges. . . n 3 



CHAPTER IX. 



CCELENTERA . . • I2 5 



CHAPTER X. 

 Unsegmented "Worms" ... '55 



CHAPTER XI. 



Segmented Worms or Annelids . i8h 



CHAPTER XII. 



ECHINODERMS . . 223 



CHAPTER XIII. 



Crustaceans . . 247 



CHAPTER XIV. 



Perifatus, Myriopods, and Insects . . 281 



CHAPTER XV. 

 Arachnoidea and Pal«<eostraca . 322 



CHAPTER XVI. 

 Molluscs 337 



