24. F, L. LANDACRE 
3. THE PROFUNDUS GANGLION 
The profundus or mesocephalic ganglion (figs. 1 and 2, G.Pro.) 
lies Just posterior to the mid-dorsal border of the eye. It is 
slightly crescent-shaped with the convexity on the dorsal sur- 
face. The root of the ganglion extends dorsally and slightly 
caudad until it comes into contact with the anterior surface of 
the Gasserian ganglion. The root from the ganglion to the 
point of contact with the Gasserian contains a rather large 
amount of cells and the relations of the fiber bundles are not 
easy to determine definitely. There seems to be little doubt, 
however, that the fibers from the profundus ganglion run on 
the anterior surface of the Gasserian ganglion, curve forward 
and upward and enter the brain wall through the most anterior 
of the three roots shown in figure 1 (Rt.Pro.). The point of 
entrance is just opposite the dorsal border of the spinal V 
column, which they enter. 
The relations of the remaining two divisions of the portio 
minor are not so clear. The second division does not enter the 
descending V tract but enters slightly mesial to that tract 
and as a well isolated bundle of fibers passes to a more mesial 
position. This root in the specimen plotted is evidently a 
visceral motor root and presumably comes from the motor com- 
ponent of the ramus mandibularis V after running through the 
Gasserian ganglion. The third root in the portio minor is sen- . 
sory and enters the spinal V tract. An examination of a number 
of other specimens ranging from 18 mm. to 23 mm. shows that 
there are in the older specimens several more small roots in the 
portio minor, all of which seem to be sensory, since they enter 
the spinal V tract. In all of the specimens there are two roots 
constantly present, the most anterior (the one identified as the 
root of the profundus), and the second of the three plotted in 
figure 1, which is identified as the visceral motor root of V. In 
the younger specimens these two roots are the only ones pres- 
ent, so that the remaining roots of the older specimens and the 
third root of my plot are in all probability accessory sensory 
roots of either the profundis or of the Gasserian, but from which 
ganglion they come I am unable to determine. 
