PLATE 3 



EXPLANATION OF FIGURES 



20, 21 and 22 Transverse sections through embryo of figure 13, n., notochord; 

 s.c, spinal cord; d.s.c, dissociated and partly 'degenerated' spinal cord; s.c.i, 

 s.c.t and s.e. 3 , dissociated, multiple spinal cord, cavities lined with endothelium. 

 X 105. 



440 



