CONTENTS OF VOLUME 2.


LIST OF ILLUSTRATIONS.


INDEX.


CHAPTER 2.16. STRUCTURE OF THE LANCELET AND THE SEA-SQUIRT.


CHAPTER 2.17. EMBRYOLOGY OF THE LANCELET AND THE SEA-SQUIRT.


CHAPTER 2.18. DURATION OF THE HISTORY OF OUR STEM.


CHAPTER 2.19. OUR PROTIST ANCESTORS.


CHAPTER 2.20. OUR WORM-LIKE ANCESTORS.


CHAPTER 2.21. OUR FISH-LIKE ANCESTORS.


CHAPTER 2.22. OUR FIVE-TOED ANCESTORS.