SO DISSECTION OF THE BRAIN, 
9, THE Pons Varo ii is the large band of trans- 
verse fibres lying back of the crura cerebri. It con- 
sists of transverse commissural fibres connecting the 
two sides of the cerebellum. Followed up toward 
the dorsal side it will be seen to pass into the cere- 
bellum on each side, forming the mzddle peduncles of 
the cerebellum. 
h. Coreus TRAPEZOIDEUM, a band of similar trans- 
verse fibres lying posterior to the pons, and inter- 
rupted in the mid-line by the axderzor pyramids. 
i, LHe ANTERIOR PyrRamips, the two bands of 
longitudinal fibres lying on the ventral surface of the 
medulla and ending (apparently) anteriorly in the 
pons. The anterior median fissure also ends at the 
pons. 
3. The Roots of the Twelve Cranial Nerves. 
a. THE OLractory or I. cranial nerves arise from 
the under side of the olfactory lobes; most probably 
they were torn off in removing the brain. 
b. Tue Optic or II. cranial nerves arise from the 
anterior border of the optic chiasma. 
c. THe OcuLo-morTor or III. cranial nerves arise in 
the space between the two crura cerebri. 
d. Tue Patueticus or IV. cranial nerve is very 
small, and on the ventral surface appears in the space 
between the cerebral hemisphere and the crus cerebi 
on each side. The real origin is from the valve of 
Vieussens on the dorsal’side of the brain. It may be 
followed back easily to this point. 
e. THE TRIGEMINAL or V. cranial nerve is very 
large, and arises from the sides of the pons by two 
roots. The smaller, inner one is the motor root; the 
larger, outer one the sensory root. 
f. THe AxBpucENS or VI. cranial nerve is small, and 
