CRANIAL NERVES OF SILURUS AND MORMYRUS 23 
At more caudal levels the more strong circular bundle (fig. 6, 
d.lat.ant.circ.) acquires more and more a lateral position (fig. 7, 
C.t.lat.ant.), lying at last next to the nervus lateralis posterior, 
and disappearing in the gray substance of the tuberculum acusti- 
cum. The fibers end in the gray substance lying beneath the 
crista and its fiber layer, the so-called dorsal nucleus of the 
acusticum, which contains a great quantity of medium sized cells. 
The coarse fibers of the nervus lateralis anterior [fig. 11 (7) 
and (8)], lying dorsally of the sensory VII, are remarkable on 
account of their enormous caliber, though their number is much 
smaller than that of the smaller fibers. : 
As soon as the sensory VII has entered the brain, they gather 
ventro-laterally from it, surrounding the VII at its peripheral 
end (fig. 6, c.f.lat.ant.). Then, continuing their course more 
and more in the medial direction, they can be traced caudad in 
the ventral region of the bulb, where they can be seen still in the 
region of the frontal vestibular root, disappearing successively 
in the environs of the nucleus tangentialis sive ventralis. I 
have not been able to decide whether they end in this nucleus, 
though it seems very probable (fig. 7, Lat.ant.c,f.). 
Apart from these fibers, coarse lateralis fibers occur which 
accompany fibers of the first vestibular root, running medially. 
Other components of the anterior lateral nerve join the bundles 
of the fibrae arcuatae internae running either dorsally or ventrally 
from the sensory VII, interrupted or not interrupted in the 
tangential nucleus [fig. 11 (7)]. 
The secondary ascending fibers of the nervus lateralis anterior 
form a strong richly myelinated bundle that can be easily dis- 
tinguished from the surrounding fiber tracts (figs. 6, 8, 10). 
Its most caudal fibers appear in the most dorsal part of the lobus 
lateralis between the gray matter and the crista. They run in a 
medial direction and cross the raphé (fig. 8) beneath the fasciculus 
longitudinalis posterior. As already stated above, the lobus 
lateralis medialis has its own fibers of this system. Together 
they form the lateral lemniscus, or fasciculus longitudinalis 
lateralis, which ends in the torus semicircularis of the midbrain 
which is the primitive homologue of the corpus quadrigeminum 
