X TABLE OF CONTENTS 



CHAPTER VIII 



PAGE 



HYDRA AND CCELENTERATES IN GENERAL . . . .116 

 Hydra, 116; Coelenterates in general, 139. 



CHAPTER IX 

 SPONGES, FIAT WORMS, AND ROUND WORMS .... 144 



Sponges Grantia Sponges in general, 144 ; Flat Worms 

 Planaria Flat Worms in general, 153 ; Round Worms 

 Ascaris Round Worms in general, 160. 



CHAPTER X 



THE EARTHWORM AND ANNELIDS IN GENERAL . . . 164 

 The -earthworm, 164; Annelids in general, 190. 



CHAPTER XI 



THE CRAYFISH AND ARTHROPODS IN GENERAL . . 193 

 The crayfish, 193; Arthropods in general, 225. 



CHAPTER XII 



THE HONEYBEE AND BEES IN GENERAL 233 



The honeybee, 233 ; Bees in general, 260. 



CHAPTER XIII 

 HISTORICAL ZOOLOGY ........ 267 



CHAPTER XIV 

 GENERAL CONSIDERATIONS OF ZOOLOGICAL FACTS AND THEORIES 275 



Heredity and evolution, 275 ; The social life of animals, 

 297 ; The animal mind, 305. 



BIBLIOGRAPHY 307 



GLOSSARY 323 



INDEX 337 



