PLATE 1 
EXPLANATION OF FIGURES 
Figures 1,.2, 3, 4, 5 and 6 are transverse sections of Plethodon glutinosus at 
the level of the VII ganglion. The figures were drawn at a mangification of 275 
and reduced one-half in reproduction. Figures 1, 2, 3, 4 and 5 are from larvae 
between 2 and 3 mm. in length. Figure 6 is from larvae 3 mm. in length. 
1 Open neural canal stage. 
-2. Closed neural canal stage with the neural crest included in the neural tube. 
3 Shows the ‘eruption’ of the neural crest. The neural crest forms part of 
the neural tube, but is easily distinguished from the tube. 
4 The neural crest is largely outside the neural tube, but still forms a plug 
in its dorsal border. 
5 Shows the neural crest almost completely outside the neural tube. 
6 Shows the neural crest present in the form of typical cerebral ganglia. 
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