of very small caliber, and but weakly medullated. When the ramus is 
followed back to its origin from the ophthalmic division of the trigem- 
inus, it may be observed to run central for a short distance as a 
distinct bundle lying just under the perineurium of the ophthalmic 
nerve. Still farther central the bundle loses its identity, as its fibers 
gradually become mixed with those of the nerve trunk. Many of the 
latter fibers are as small in diameter as those of the ramus, 
A radix longa, i. e., a communicating nerve between the trigem- 
mus and the ciliary ganglion, was first described as present in the 
hen by Holtzmann (’96), who, however, influenced possibly by 
Schwalbe’s views as to the relation of the ganglion to the oculomo- 
torius, did not consider it of physiological importance. He looked upon 
it as a remnant of an embryological condition. That a communicating 
ramus passing directly to the ganglion occurs in chick embryos was 
pointed out by D’Erchia (95), and verified later by the present writer. 
v. Lenhossék, however, in his recent investigation, failed to find 
fibers representing a radix longa in the hen, and is of the opinion that 
the oculomotor nerve furnishes the only central connection of the ganglion. 
Zeglinski (85) and Jegorow (’86—87) have described for 
adult pigeons a direct nervous connection between the fifth nerve and 
the ciliary ganglion. Their observations on these birds I can corrob- 
orate. In my sections the communicating ramus runs to the cephalic 
end of the ganglion, and here divides. Part of its fibers enter the 
ganglion, and part turn forward to accompany the nervus ciliaris crassus 
to the eyeball. 
In agreement with v. Lenhossék and other investigators I have 
been unable to discover in the birds examined the slightest trace of 
a sympathetic root of the ciliary ganglion. The possibility exists, it is 
true, that the fibers which enter the ganghon from the communicating 
ramus are really sympathetic fibers which have joined the trigeminus 
somewhere along its course; but at least no independent nerve belong- 
ing to the cephalic extension of the sympathetic system enters the 
ciliary ganglion, as is the case in man and other mammals. The prob- 
able nature of the fibers of the radix longa will be discussed later. 
The Oculomotor and Trigeminal Regions ofthe Ciliary 
Ganglion. When a longitudinal section of the hen’s ciliary ganglion 
is examined under a lens of moderate power, two regions may be dis- 
tinguished. Figure 2 is a drawing of such a section, stained by the 
Cajal silver method, and cut in an especially favorable plane. It will 
be seen that the proximal end of the ganglion is invaded by the 
coarse, heavily medullated, darkly stained neurites of the oculomotor 
nerve. These fibers, winding in among the cells, may be followed 
