TABLE OF CONTENTS 



PAGE 

 PREFACE iii 



I. HISTORICAL REVIEW i 



II. ORGANIZATION OF THE EGG 4 



III. CLEAVAGE 16 



IV. FORMATION AND COMPLETION OF THE BLASTODERM. . . 27 

 V. THE GERM LAYERS 43 



1. Formation of the Mesoderm 43 



2. Formation of the Rudiments of the Mid-intestine 56 

 VI. THE AMNION AND THE CEPHALO-DORSAL BODY 82 



1 . The Amnion 82 



2. The Cephalo-dorsal Body 88 



VII. GENERAL ACCOUNT OF THE DEVELOPMENT OF THE 



EMBRYO, WITH ESPECIAL REFERENCE TO THE EX- 

 TERNAL FORM 95 



1. Changes in the Form of the Egg up to Stage 



VIII 95 



2. The Development of the Embryo 97 



3. Segmentation 105 



VIII. THE NERVOUS SYSTEM 113 



1. Newly-hatched Larva 113 



2. Development 124 



A. The Ventral Cord 127 



