CRANIAL NERVES OF SILURUS AND MORMYRUS 39 
medially and ventrally from the end-nucleus of the nervus lateralis 
anterior (fig. 15). In this region large faintly colored cells are 
found everywhere. 
The finer fibers of the vestibular nerve form the most lateral 
and caudal part of that nerve [fig. 20 (6)]. Part of them pass 
in a frontal direction after their entrance into the bulb, and 
shifting laterally along the coarse fibers (fig. 16) mentioned above 
they partly go to the medial unpaired nucleus of the nervus 
lateralis anterior (fig. 15), partly end in the ventro-lateral gray 
substance, in which also fibers of the posterior lateral nerve 
terminate (fig. 14). 
Apart from these frontal root fibers, a set of fibers [fig. 20 (7)| 
enters the bulb directly behind the frontal ones (not separated 
from them), which also first take a fronto-dorso-medial course 
but then seem to bifureate so that an ascending part of therm 
runs to the region of the lobus lateralis anterior, while the de- 
scending fibers (figs. 16, 17, 6.f.VIZI) run backward in a hori- 
zontal direction and then, passing through the fibrae arcuatae 
dorsales, also split up in the gray substance of the lobus lateralis 
anterior (fig. 18) caudally from the entrance of the root. I have 
been able to distinguish with great accuracy the two bundles 
here mentioned, and need not say that also at the level of en- 
trance itself vestibular fibers end in the gray matter of the nervus 
lateralis anterior (fig. 17). 
CONCLUSIONS 
After this exposé of the cranial nerves of Silurus and Mormyrus, 
I will briefly discuss the results. Comparing the diagram of 
the motor nuclei and roots of Silurus with those of Tinca (fig. 
21), we see that in both the motor V and motor VII nuclei have 
acquired a very ventral position. Both fishes are pronounced 
‘taste fishes’ and it is probable that this ventral position of the 
V and VII nuclei in both is due to the same cause. 
This cause is the considerable development of the anterior 
secondary gustatory tract and the shorter reflex gustatory paths 
that may accompany it. The anterior secondary gustatory tract 
