PLATE 2 



EXPLANATION OF FIGUKES 



17, 18 and 19 More posterior sections through the embryo of figure 11. b., 

 brain; n., notochord; i., intestine; d.m., dissociated epithelium of mouth; m.o., 

 medulla oblongata of 'parasite'; s.c. spinal cord of 'autosite'; s.c. t , spinal cord of 

 'parasite'; y., yolk. X 105. 



438 



