59S 
F. H. EDGEWORTE. 
internal pterygoid, tensor palati and tensor tympani — and of 
tlie mylohyoid nerve are more complicated. In each case the 
persisting afferent nerve-fibres in the motor root, accompanied 
by (degenerated) motor fibres, pass into those branches by 
two routes. The ramus medialis (figs. 5, 6, 7) is formed 
partly by fibres which pass downwards and inwai-ds, from the 
motor root, into the ramus, partly by fibres which leave the 
lateral part of the motor root (fig. 6) and sweep round the back 
of the ramus posterior from without inwards and so enter the 
ramus. The relative numbers of the (degenerated) motor 
fibres following these two paths — internal and external — 
could not be determined, but it was possible to do so in the 
case of the persisting afferent fibres. In animal “A’’ the 
internal path contains 50 medullated fibres, whilst the ramus 
medialis, when fully formed, contains 219, i. e. about one 
quarter followed the internal path and three quarters the 
external one, round the ramus posterior. The ramus medialis 
passes through the otic ganglion, giving off, just as it enters, 
the branch for the tensor tympani (fig. 7), and subsequently 
dividing into branches for the internal pterygoid and tensor 
palati. The branch to the tensor tympani receives a fine 
filiiment from the otic ganglion containing (in animal ‘‘A^’) 
eight medullated fibres ; above that point it contains twenty- 
eight medullated fibres. The branch to the internal pterygoid 
and tensor palati receives three fine filaments from the otic 
ganglion containing twenty-nine medullated fibres. The 
medullated fibres entering these branches from the otic 
ganglion are all small — under 4 fx in diameter. 
The mylohyoid nerve is formed partly from internal fibres 
(degenerated and intact) which pass from the inner part of 
the motor root (fig. 5), a little higher up than the direct 
fibres of the ramus medialis, round the back of the ramus 
posterior from within outwards, and thus come to lie between 
the ramus lateralis and the ramus posterior (figs. 6 and 7) ; 
they are joined by external fibres (degenerated and intact) 
from the deeper, more posterior part of the ramus lateralis, 
and pass inwards on the anterior aspect of the ramus posterior 
