THE AMERICAN NATURALIST. [VoL. XXXIV. 
938 
upwards into the dorsal zone to form there the tractus solita- 
rius (7.5.). Its motor or lateral root (L.AR.) is below the 
ganglion and nearer the median line. As it enters the brain 
it curves and as a still distinct bundle runs towards the 
median plane. Its similarity to the motor root of the facial is 
P very striking, but so far 
as I am aware has not 
been recorded hitherto 
(compare Figs. 9, 10). 
Inside of the trigeminal 
ganglion lies the jugu- 
mes. 
Ep. 
D.Z. lar vein. 
The next figure (Fig. 
Giver ^"- 19) through the acus- 
Du tico-facial ganglion, 
Jug. - T shows the thickened 
Gan -—— ventral wall of the hind- 
brain (Z.e., the anlage of 
N.xii. Ph. the medulla oblongata) 
pug PU n baladi, D Z 
CD.: 
dulla oblongata; Æc., ectoderm; Zj., 
roof of the fourth ventricle; /., median fissure of the 
medulla oblongata; Fac., sensory root of the facial 
erve ; 
ranc n 
in x. hypoglossal: nerve; Ph. ; £.71., motor 
x 
no longer spread out 
nearly horizontally, but 
rising obliquely from the 
median line. The right 
and left sides of the 
medulla oblongata are 
dividedfrom one another 
by a deep median fissure 
(f). Inthe median line 
just below appears the 
basilar artery (a77.), and 
still lower the wide, slit-like pharynx (24.), the outer portion of 
which ascends obliquely towards the jugular vein. The ascend- 
ing part isa portion of the first gill-pouch (future Eustachian tube) 
and is quite clearly marked off from the pharynx proper. Of the 
acustico-facial complex the section shows four parts: the gan- 
glion vestibuli (G.vesz.) ; the geniculate ganglion (G.gez.) ; the 
sensory root (Fac.) of the facial nerve arising from the genicu- 
late ganglion and entering the brain to form there a distinct 
