CONTENTS. 



CHAPTER XTX. PAGS 



REPRODUCTION 191 



CHAPTER XX. 



DEVELOPMENT 197 



1. Metamorphosis 207 



2. Alternate Generation 211 



3. Growth and Repair 214 



4. Likeness and Variation 215 



5. Homology, Analogy, and Correlation 217 



6. Individuality 220 



7. Relations of Number, Size, Form, and Rank 221 



8. The Struggle for Life 226 



PART II. SYSTEMATIC ZOOLOGY. 



CHAPTER XXI. 



THE CLASSIFICATION OF ANIMALS 231 



Protozoa 238 



Porifera 244 



Ccelenterata 246 



Echinodermata 257 



Vermes 263 



Mollusca 269 



Arthropoda, 281 



Vertebrata 306 



CHAPTER XXII. 



SYSTEMATIC ARRANGEMENT OF REPRESENTATIVE FORMS 362 



CHAPTER XXin. 



THE DISTRIBUTION OF ANIMALS . 371 



NOTES 381 



THE NATURALIST'S LIBRARY 397 



INDEX.. . 399 



