xvi TABLE OF CONTENTS 



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B. Physiological Relations of Nucleus and Cytoplasm 341 



1. Experiments on Unicellular Organisms ....... 342 



2. Position and Movements of the Nucleus ....... 346 



3. The Nucleus in Mitosis 351 



4. The Nucleus in Fertilization 352 



5. The Nucleus in Maturation 353 



C. The Centrosome 354 



D. Summary and Conclusion 358 



Literature, VII 359 



CHAPTER VIII 

 CELL-DIVISION AND DEVELOPMENT 



A. Geometrical Relations of Cleavage-forms 362 



B.* Promorphological Relations of Cleavage 378 



1. Promorphology of the Ovum 378 



(a) Polarity and the Egg-axis 378 



() Axial Relations of the Primary Cleavage-planes .... 379 



(c~) Other Promorphological Characters of the Ovum .... 382 



2. Meaning of the Promorphology of the Ovum 384 



C. Cell-division and Growth 388 



Literature, VIII 394 



CHAPTER IX 

 THEORIES OF INHERITANCE AND DEVELOPMENT 



A. The Theory of Germinal Localization 397 



B. The Idioplasm Theory 401 



C. Union of the Two Theories 403 



D. The Roux-Weismann Theory of Development 404 



E. Critique of the Roux-Weismann Theory 407 



F. On the Nature and Causes of Differentiation 413 



G. The Nucleus in Later Development 425 



H. The External Conditions of Development 428 



I. Development, Inheritance, and Metabolism 430 



J. Preformation and Epigenesis. The Unknown Factor in Development . . 431 



Literature, IX 434 



GLOSSARY 437 



GENERAL LITERATURE-LIST 449 



INDEX OF AUTHORS . 471 



INDEX OF SUBJECTS 477 



