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.