a2 F. L. LANDACRE 
13) that lateral line primordia arise from discontinuous areas 
rather than from a continuous area on the ectoderm. After 
supplying three twigs to the lateral line primordium mentioned 
above, the ramus continues beyond this point and disappears 
near the anterior border of the spiracular gill cleft. The nature 
of this terminal twig could not be determined. This nerve is 
identified provisionally as the r. oticus VII. 
11. THE ACUSTICO-FACIALIS GANGLIONIC COMPLEX 
These ganglia are rather closely fused, especially at their 
proximal ends, in the specimen plotted, but with the aid of a 
20 mm. embryo the relations seem to be intelligible. The genic- 
ulate (fig. 1, G.Gen.) and ventral lateralis VII (fig. 1, G.L.VII 
V) form the ventral portion of a V-shaped mass, of which the 
auditory ganglion (fig. 1, G.Aw.) forms the dorsal arm. The 
apex of the V projects cephalad and is formed by the point of 
union of these two masses near their roots. The apex of the V 
is In contact with the dorsal lateralis VII ganglion on its posterior 
surface. The ventral arm of the V extends caudad and slightly 
ventral, while the dorsal arm formed by the auditory is approxi- 
mately horizontal. The most anterior member of the group is 
the geniculate, which lies on the ventral and anterior border 
of the ventral arm of the V. The ventral lateralis VII les 
slightly dorsal and lateral to the geniculate partly concealing the 
geniculate from a lateral view. The VIII ganglion is partly 
concealed by the auditory vesicle. 
The root of this complex enters the brain along with that of 
the dorsal lateralis VII ganglion and occupies a position posterior 
and mesial to the root of that gariglion. Reading from posterior 
to anterior the first root encountered, that of the auditory (fig. 
1, Rt.Aud.), lies lateral to the two succeeding roots and enters 
in conjunction with that of dorsal lateralis VII. The next root 
(fig. 1, Rt.Gen.) encountered is that of the geniculate accom- 
panied by the motor fibers of the r. hyomandibularis. The third 
root (fig. 1, Rt..VII V) encountered is that of the ventral 
lateralis VII. These last two roots mentioned leave the proxi- 
mal end of the combined ventral lateralis VII and geniculate 
