1881, ] Comparative Neurology. 105 
this tubercle (third system ganglion) forms the flocculus or pneu- 
mogastric lobule of the cerebellum. 
The Gasserian ganglion (unmistakably an intervertebral), where 
non-existent, must form a portion of the cerebellum. 
The cerebellum then appears to be he med from fused hyper- 
trophied intervertebral ganglia. 
Stilling regarded the law of isolated conduction as inapplicable 
to the cerebellar lobes, owing to the very great commissural 
(fused) union which occurs there. Thus a coordinating function 
between cranial nerves on the one hand (the cerebellum acting as 
connected intervertebral ganglia for many cranial nerve fibers), 
and the general spinal system on the other, must follow in such 
Vertebrata as are governed mainly by cerebellar supervision, 
while in higher forms it is brought directly into relation with the 
cerebrum itself. 
Above this the cephalic intervertebral ganglia developed in 
some animals, atrophic or rudimentary in others, appears to be 
the posterior and anterior tubercula bigemina, epiphisis cerebri, 
eminentia mammnillaria, olfactory lobes, cerebrum, which latter is 
itself composed of several lobes or ganglia, some of which, as 
the anterior, are undeveloped in most Vertebrata and even in 
many mammals. 
The posterior bigeminal lobe appears to be a third system 
ganglion related to special tactile sense (see Spitzka, N. Y. Medt- 
cal Record, March 13, 1880), while the optic lobes (anterior 
bigeminal) are third systems for the optic nerves. The primitive 
optic fibers were related to the gray matter above the chiasma, 
and even in man retain some primary thalamic connections. 
The epiphisis cerebri (pineal gland), bilobed in the foetus and 
_ devoid of sabulous matter in forms below man, attains quite a_ 
large size in some animals (Méleagris gallapavo, p: 260 “ Huxley’s 
Vertebrates ”). It may with the mammillary eminence indicate a 
sense between sight and olfaction. 
The mammillary eminences can be third systems, their posi- 
tions and cinereal envelope weighing nothing against the - 
for the Teliost cerebrum itself drops to a comparably d 
Structure and inferior position. 
These eminences are very large in monotremes, marsupials and 
the horse. They stand related to the fornix, which in turn is 
connected to the olfactory = 
VOL, KXY.~—NO. 11, 
