PLATE 4 
EXPLANATION OF FIGURES 
10 Taken from section 569, is at the level of the origin of the r. post- 
trematicus X». It also passes through the middle of the ganglion laterale X; 
and through the extreme anterior end of the ganglion viscerale X3. 
11 Taken from section 596, is at the level of the origin of the r. pretre- 
maticus X3; from the ganglion viscerale X;. This is just posterior to the point 
of fusion of this ganglion with its epibranchial placode. This section passes 
through the posterior end of the ganglion laterale X3. 
12 Taken from section 628, passes through the fusion of ganglion viscer- 
ale X, with the ectoderm which is contributing cells to the ganglion at this 
point. 
This section also passes through the anterior end of the ganglion viscerale 
X;. The division between ganglia visceralia X, and X; is shown better in this 
section than in the reconstruction in figure 1. 
13 Taken from section 647, passes through the posterior end of the ganglion 
viscerale X; but anterior to its attachment to its epibranchial placode. 
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