xiv Illustrations 



FIGURE PAGE 



31. Transverse Section through the Body of a 



Tadpole at the Time of Hatching. (After 

 Marshall) 84 



32. The Skull of a i2-mm. Tadpole: A seen from 



the Right Side; B seen from Dorsal Side; 

 C seen from the Ventral Surface. (After 

 Marshall) 86 



THE DEVELOPMENT OF THE CHICK 



33. Semi-Diagrammatic View of the Egg of the 



Fowl, at the Time of Laying. (After Parker 

 and Haswell, slightly altered from Mar- 

 shall) 92 



34. A Yolk with the Blastoderm in the Centre, 



the Latter Showing the First Two Cleavage 

 Planes. B The Blastoderm on a Larger 

 Scale and at a Later Stage of Segmentation. 

 (After Duval) 96 



35. Surface View of the Blastoderm at a Later 



Stage of Segmentation than that Shown in 

 Fig. 34, B. (After Duval) ... 98 



36. Longitudinal Section of the Blastoderm after 



the Completion of Segmentation. (After 

 Duval) . . . . . . .104 



37. Series of Diagrams to Illustrate the Formation 



of the Chick Embryo, Especially the Rela- 

 tions of the Embryo, Yolk- Sac, Amnion, 

 and Allantois. (After Foster and Balfour), 



I06, 109, IT2 



