CONTENTS 



CHAPTER I 



PAGE 



Segmentation, Gastrulation, and the Formation op the Germ 



Layers 1 



CHAPTER II 



The Skin and its Derivatives . . . . .69 



CHAPTER III 



The Alimentary Canal ... . 144 



CHAPTER IV 



The Coelomic Organs . 197 



CHAPTER V 



The Skeleton . . 288 



CHAPTER VI 



Vascular System 360 



CHAPTER VII 



The External Features of the Body 429 



CHAPTER VIII 



Adaptation to Environmental Conditions during Early Stages 



of Development . • • .455 



