CONTENTS. 



PART II. 



Page 

 No. 12. — Maturation, Fecundation, and Segmentation of Limax campestris, 

 Binney. By E. L. Mark .... 173 



A. Observations 173 



I. Maturation 177 



II. Fecundation . . . . . . . . . . .215 



III. Segmentation .......... 222 



B. Bibliography 232 



I. Limax 232 



1. Egg Envelopes, etc 232 



2. The Yolk and its Changes 235 



II. Review of Maturation, Fecundation, and Cell-Division . . . 244 



1. Cell-Division 244 



a. Asters 245 



h. Quiescent Nuclei .... ... 253 



c. The Nucleus during Division . . . . .272 



Introductory 272 



a. Segmentation ....... 276 



j8. Tissues 341 



y. Plants 366 



2. Maturation 387 



3. Fecundation .......... 368 



C. Theoretical Considerations and General Conclusions . . 512 



Promorphology of the Ovum . . . . . . . .512 



Polar Phenomena . . . . . . . . . . 514 



Asters 519 



Spiral Asters ........... 533 



Nuclear Spindle 536 



Origin of Nuclei 539 



Germinative Vesicle .......... 545 



Polar Globules 547 



Appendix 558 



Alphabetic List of the Literature . . . . * . . . 591 



Index to Authors cited in the Text 615 



Explanation of the Figures 617 



