6 
Die H. W. NORRIS 
tract passes antero-medially through the acusticum, first as a 
rather loose tract or separate bundles, but near the base of the 
cerebellum collected into a compact bundle. Here it divides 
into a lateral and a medial portion. The lateral becomes closely 
associated with the fiber tract of the cerebellum, and gives off to 
it fibers, that possibly have been derived from the tractus tecto- 
bulbaris et spinalis. But the most of the lateral fibers are dis- 
tributed to the posterior part of the tectum. The medial portion 
of the radix passes to the more anterior part of the tectum. 
A definite connection of the radix mesencephalica trigemini 
of Siren with a nucleus in the tectum was not established. Hence 
this paper adds little if anything to the information that recently 
has been summed up by van Valkenburg (’11) regarding such a 
nucleus. 
2. The Gasserian ganglion 
From its external origin the trigeminal nerve extends anteriorly 
into the Gasserian ganglion in the characteristic manner. The 
ganglion is wholly intra-cranial and occupies a hollow along the 
medial border of the anterior part of the ear capsule and the an- 
terior cartilaginous extension of the latter, the postorbital pro- 
cess (fig. 12, gg.). The ganglion is at first somewhat triangular 
in cross-section with the nerve root passing along its medial border 
and soon penetrating it. Not far from its posterior end the Gas- 
serian ganglion is joined on its ventro-lateral border by the genicu- 
late ganglion of the communis component of the facialis nerve 
(figs. 12, 36, gen.), the two sometimes becoming indistinguishably 
fused, but in some cases remaining clearly distinct from each other. 
Dorsally the Gasserian ganglion soon comes into contact with the 
dorsal lateral line ganglion of the seventh nerve (glld.) and fuses 
with it, the two forming in cross-section a somewhat half-lens 
shaped mass (fig. 12). The sensory fibers spread diffusely through 
the ganglion in the process of becoming ganglionated, and the 
main divisions of the trigeminal nerve are soon outlined. The 
motor component (md.) preservesitsintegrity through the ganglion 
to the ramus mandibularis, joined by sensory fibers; ventrally 
in the ganglion fibers become aggregated to form the ramus oph- 
