123 JOHN BEARD. 
The actual development is as follows: From the neural 
crest of the midbrain, just before the closure of the neural 
folds, cells grow outwards and downwards to a thickened patch 
of epiblast just above and behind the eye (fig. 7). 
This outgrowth has been seen and described by Marshall and 
Van Wijhe. But Marshall recognised in it the first rudiment 
of the motoroculi, and Van Wijhe that of the ophthalmicus pro- 
fundus. Neither observer saw the skin fusion or the develop- 
ment of the ganglion. When the outgrowth reaches the 
thickened patch of epiblast it fuses with it (fig. 6). Cells 
are then proliferated off from the skin to form the ganglion, 
and the outer portion of the thickening begins to form the 
primitive branchial sense organ (figs. 8 and 9). From 
the thickening cells are given otf for some time until a large 
ganglionic mass is formed, which still for some time remains 
fused with the skin. 
In fact, in the case of the ciliary ganglion the mode of 
development is well marked and very easy to study. The 
sensory thickening soon begins to grow forwards over the snout, 
and as it does so the ganglion begins to leave the skin. As this 
takes place a nerve is developed from the thickening, and con- 
nects the ganglion with its branchial sense organs. 
From its course, relations, &c., this nerve is seen to be the 
ophthalmicus profundus.! It is morphologically the 
supra-branchial nerve of the second segment. 
The distance between the ciliary and Gasserian ganglia, even 
in early stages, is very short. The outgrowth from the neural 
ridge which forms the main stem of the ciliary ganglion is 
practically continuous with the outgrowth which forms the 
main stem of the fifth. Van Wijhe has also drawn attention 
to this. 
Hence it can hardly be wondered at that the connection of 
the two ganglia with the brain soon becomes a common one, 
which distally divides into two portions, one of which is con- 
tinued on to the Gasserian ganglion, while the other goes 
1 Apparently also Van Wijhe’s indentification, but not very obvious from his 
description, 
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