TABLE OF CONTENTS. 



PART I. THE HISTORY OF THE CHICK. 



CHAPTER I. 



THE STRUCTURE OF THE HEN'S EGG, AND THE CHANGES WHICH TAKE 



PLACE UP TO THE BEGINNING OF INCUBATION . pp. I 24. 



The shell and shell-membrane, i 3. The albumen, 3. The 

 vitelline membrane, 4. The yolk, 57. Area opaca, 7. Area 

 pellucida, 8. The structure of the blastoderm, 7 10. Eecapitu- 

 lation, 10. The ovarian ovum, n 15. The descent of the ovum 

 along the oviduct, 15 17. Impregnation, 17. Segmentation, 

 1824. 



CHAPTER II. 



BRIEF SUMMARY OF THE WHOLE HISTORY OF INCUBATION, 



PP- 2547- 



The embryo is formed in the area pellucida, 25. The germinal 

 layers, 25, 26. The extension of the blastoderm over the yolk, 26. 

 The vascular area, 27. The head-fold, 27 36. The tail-fold, 37. 

 The lateral folds, 37. The yolk-sac, 37. The alimentary canal, 39. 

 The neural tube, 39, 40. The body-cavity, 41. The somatopleure, 41. 

 The splanchnopleure, 42. The stalk of the yolk-sac, 42, 43. The 

 amnion, 43 46. The allantois, 46, 47. 



