oe H. BERKELBACH VAN DER SPRENKEL 
gray next to the ventricle above the fibrae arcuatae internae. 
First running frontally, it then turns laterally over the spinal 
V tract, curves backward again and leaves the brain. Whether 
its gray substance is mixed with that of the VII, lies medial to it, 
or caudad, could not be stated with exactness. It seems probable 
that most of its fibers end in front of those of the VII. 
The motor IX root is small and enters the brain medially of 
the sensory IX at the same level. Shifting in a frontal direction 
along the sensory V tract, it then turns in a medial direction to 
the chief nucleus of the motor VII. It is very difficult to say 
whether the root leaves the nucleus again or whether its fibers 
split up in it. It seems possible that a part of the motor cells 
of the IX nucleus are joined with those of the motor VII nucleus, 
and that the rest are joined with the dorsal VIJ-IX—X column. 
A careful examination of my sections seems to show that IX 
fibers pierce through the VII nucleus and the fibrae arcuatae dor- 
sales and run backward (to the dorsal VIJ-IX—X cell column?). 
The sensory X roots are fairly strong bundles (fig. 19). The 
four sensory roots which I found enter the brain separated by 
short distances from each other. It is a striking fact that the 
sensory rootlets, before running to the ventricle, remain for some 
distance along the ventro-lateral border. Then they pass be- 
neath the spinal V tract (fig. 19) and run to their gray in a some- 
what frontal direction. This frontal deviation of the sensory 
X roots is, however, so trifling that the whole transverse course 
can be studied in a few sections. 
Since there is no question of an hypertrophy of the sensory IX 
and X roots, the condition of these roots also is not in favor of 
Sanders’ interpretation that the vagal apparatus is execssively 
developed. t 
As I mentioned before, the addition of somatic sensory fibers 
of the vagus to the spinal V tract is not so obvious as in Silurus, 
but I did not find evidence to doubt their presence in Mormyrus, 
since some of the vagus roots run so closely along the spinal V 
tract that a transfer of their fibers into the spinal V is very well 
possible, if not even probable. 
