128 
behind the second root and much ventral to it. Its 
nucleus lies in the floor of the fourth ventricle very near 
the middle line, and the root below joins the ventral 
lateral line root proximal to its ganglion as in Menidza. 
After leaving the brain the motor root, which consists of 
deeply staining heavily myelinated fibres, becomes so 
confused with the anterior part of the auditory root that 
their separation is difficult even with the microscope. The 
auditory nerve, however, passes dorsally into the tuber- 
culum acusticum, whilst the motor vii. enters the brain 
below and immediately in front of it. The motor vii. 
passes into the Truncus hyomandibularis. 
Of the four ganglia of the complex (g. v.-vii.) only 
one remains distinct macroscopically. ‘This is the 
ganglion of the dorsal lateral line root, which in front is 
situated just dorsal to the Gasserian ganglion, and behind 
overlaps externally the root of the trigeminus. It is 
entirely intracranial and is partly shown in the chart as 
the cells at the base of the R. buccalis vii. The other 
three ganglia are crowded between the brain and the skull 
wall and apparently form one mass also entirely intra- 
cranial except for the narrowed anterior extremity of the 
Gasserian ganglion which extends outside the skull along 
the R. ophthalmicus superficialis v. as far forward as sec- 
tion 472 (cp. chart). When these three ganglia are 
examined in serial sections it is seen that the most 
anterior is the Gasserian ganglion. This overlaps exter- 
nally the geniculate ganghon situated behind it, which in 
its turn overlaps externally the ventral lateral line 
ganglion—the most posterior of the three. Although the 
three ganglia form a single very compact mass, it is not 
difficult to define their boundaries, even where, as in the 
case of the first two, the character of their cells is much 
the same. In the ventral lateral line ganglion, the cells, 
