CONTENTS. i x 



PART THIRD. 



THE MODE OF DEVELOPMENT OF ANIMALS CORRESPONDS 

 WITH THE TYPE OF THE GRAND DIVISION TO WHICH 

 EACH ONE SEVERALLY BELONGS. 



CHAPTER XVII. PAGE 



THE SEGMENTATION OF THE EGG. THE EMBRYOLOGY OF PROTOZOA, 



ZOOPHYTA, MOLLUSCA, ARTICULATA, AND VERTEBRATA .... 283 



INDEX 317 



