No. 1.] AMPHIBIAN BRAIN STUDIES. ey 
arises from two closely applied roots, V.-VII. # and /, which may 
be described as the upper and lower roots. The upper root 
apparently passes directly forwards as the reinforcing branch of 
the Trigeminus. I may anticipate by saying that this is proba- 
bly to be regarded as a detached sensory root of the 5th, and 
not as properly a part of the 7th. But it is, thus far, somewhat 
uncertain whether some of the fibres of the lower root do not 
also join the 5th. The lower root passes directly outwards, 
and either wholly or for the most part unites with the 8th. For 
a short distance these roots form a single trunk, and it is at this 
point that the chief uncertainty arises as to their distribution. 
A short distance outwards the 8th turns back into the auditory 
capsule, and the 7th extends and divides into two branches, 
R. mentalis and R. alveolaris, then into four (Fischer, op. cit., 
p- 135)." 
VIII. The 8th springs from four roots. _The most anterior 
root, VIII. 1, is small, and is given off immediately below and 
behind the lower root of the 7th. Behind this is the large root 
of the 8th, VIII. 2, and this is reinforced by another small root, 
arising somewhat internal and posterior to it, VIII. 3 and 4, by 
two small branches. This root may possibly join the lower 
division of the 7th, this uncertainty being expressed in Fig. 21 
by its double designation, VII.-VIII. 
IX., X. The Glossopharyngeus arises by three roots, 
IX. 1, 2, 3, which unite to form a single branch, passing back 
into the ganglion of the Vagus. Behind these, two more roots, 
X. a and 4, unite to form a single branch, also passing back to 
the ganglion. Somewhat internal to these two roots, and ex- 
tending at about equal intervals backwards, arise five small 
roots, which unite to form the third main branch of the Vagus, 
system, X. 1-5. Some distance behind these is given off the 
12th pair, on either side of the anterior fissure, much nearer the 
median line than any of the preceding nerves. 
The above description of the exit of the 5th to 1oth pairs, 
applies especially to Cryptobranchus, but so far as the main 
branches are concerned holds good of the other genera as well. 
lieved is formed from the fibres coming from the 7th. 2, Ramus nasalis. 3. Ramus 
maxil. superior. And 4. Ramus max. inferior. I have observed but three main 
branches from the ganglion. See Appendix, Note 2. 
1 See Appendix, Note 2, 
