PLATE 2 
EXPLANATION OF FIGURES 
Figures 7 and 8 are flat reconstructions of the neural crest and mesoderm made 
by projecting the camera figures on coordinate paper. The plates give an accu- 
rate picture of the extent of the neural crest (diagonal lines) and mesoderm (stip- 
ple). The neural canal, notochord, alimentary canal, and sense organs are repre- 
sented by lines. Both figures are from larvae 3 mm. in length, but the larva 
from which figure 8 is taken is six hours older than the larva from which figure 
7 is taken. 
