110 JOHN BEARD. 
takes no part in its formation. Above the cleft the main nerve 
fuses with the skin, and there as in other cases ganglion and 
primitive branchial sense organ are formed. In this case too 
—and fig. 34 shows it fairly well—the sensory thickening must 
be considered as taking part in the formation of the ganglion. 
Later, the ganglion separates from the skin, and, along with 
this separation, the sensory thickening grows forwards and 
takes also a dorsal direction, a supra-branchial nerve splits off, 
and the sense organs formed are part of the supra-temporal 
branchial sense organs (fig. 51, st. v.). Here as in the glosso- 
pharyngeal, the supra-branchial branch has a dorso-anterior 
direction. 
Vagus 1 also fits into the schema very well. It is formed 
just in the way described in the schema, has the same relation 
to a cleft, develops a primitive branchial sense organ and 
associated ganglion, &c. In fact, its development might have 
been taken in giving the schema. 
For the rest of the vagus there is only one ganglionic mass, 
and one long, broadish thickening with which the ganglionic 
mass is associated. 
When the common nerve rudiment grows from the neural 
ridge and fuses with the epiblast, at the point of fusion the 
ganglionic mass is proliferated, probably entirely from the skin. 
From the ganglionic mass branches are sent off along the 
posterior sides of each of the three last clefts to the muscula- 
ture of the clefts. They are the post-branchial branches, 
and are not developed from the skin. The last of the three 
is the so-called intestinal branch of the vagus. Along with 
the separation of the ganglion from the skin, the sensory 
thickening begins to grow backwards along the lateral surface 
of the trunk (fig. 39). This thickening is the rudiment of 
the so-called lateral line. The description of its development 
to be given here is in the main identical with that given by 
Van Wijhe.! It agrees with Gotte’s? and Semper’s® researches 
1 Op. cit., pp. 34, 35. 
2 Goette, ‘ Entwickelungsgesch. d. Unke.,’ p. 672. 
3 Op. cit., p. 256. 
EE 
