PLATE XXI. 



FIG. 155. 



FIG. 156. 



\ 



Various Ganglionic Nerve-cells. 



FIG. 157 



Nerve-fibres. 



Self-regulating System of Ganglia nerves, 

 arteries, and capillaries. 



Glandular Tissue. 



FIG. 160. 



Layers of Blastoderm. 



