OUTLINES OF 

 CHORD ATE DEVELOPMENT 



CHAPTER I 

 THE DEVELOPMENT OF AMPHIOXUS 



PAGE 

 2 



INTRODUCTION 



I. THE GERM CELLS AND THEIR PRODUCTION ...... 4 



II. THE EMBRYONIC PERIOD ....... . ......... 9 



A. FROM FERTILIZATION TO THE TIME OF HATCHING 



1. Fertilization ............. 



2. Cleavage . 



3. Gastrulation .................. 



4. The Formation of the Central Nervous System .... 20 



5. The Formation of the Notochord .......... 23 



6. The Formation of the Mesoderm and Enterocoels ... 24 

 B. FROM HATCHING TO THE FORMATION OF THE 



1. The Central Nervous System ...... 



2. The Notochord . . .......... 



3. The Mesodermal Somites and Ccelom . . . 



4. The Enteron and Its Appendages ..... 



III. THE LARVAL PERIOD 



1. The Central Nervous System 



2. The Gill Slits 



3. The Club-shaped Gland 



4. The Endostyle 



5. The Mouth and Associated Structures ........ 



6. The Preoral Pit and Its Derivatives ........ 



7. The Blood-vessels ................ 



8. The Atrium ......... ........ 



9. Larval Asymmetry ................ 



10. The Mesodermal Somites . . . . . ......... 



11. TheNephridia ......... ......... ^3 



12. The Larva at the Critical Stage ........... 



IV. THE ADOLESCENT PERIOD .............. 55 



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