Outer cell. Outer cells 



Polar bodies 



Inner cells 



Inner cells. 



Outer cells. 



Inner cells 



Inner cells. 



Outer cells. 



Oute 

 cells 



Fig. 532. — 1, 2, 3. Diagrams Illustrating the Segmentation of the Mammalian 

 Ovum (Allen Thomson, after van Beneden). 4. Diagram Illustrating the Rela- 

 tion OF THE Primary Layers of the Bi^astoderm, the Segmentation-cavity of this 

 Sta(}e Corresponding with the Archenteron of Amphioxus (Bonnet). 



