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distally into the central part of the ganglion, where they gradually 
give way to the finer, less heavily medullated, and less deeply stamed 
neurites of the neryvus ciliaris crassus (main short ciliary nerve). To 
this portion of the ganglion, related thus to the oculomotor nerve, we 
may for convenience apply the name of oculomotor region (reg. 0 c’- 
mot.). It comprises approximately three-fourths of the whole structure. 
Turning our attention now to the radix longa (rad. long.) we 
find that the fibers from the communicating ramus of the trigeminus 
enter the remaining fourth of the ganglion at its distal end. These 
very fine and only shghtly medullated fibers give the portion of the 
ganglion they supply (reg. trig.) a lighter and more finely fibrillar 
appearance than that presented by the oculomotor region. Darkly 
stained, heavily medullated fibers, such as those of the oculomotor nerve, 
are completely absent. This area will hereafter be referred to as the 
trigeminal region. From it emerges a bundle of neurites (n. cil. brev.), 
which accompanies the nervus ciliaris crassus cephalad, at first closely 
applied to it, but farther on separating from it to form a small inde- 
pendent ciliary nerve. The fibers of this bundle are smaller and less 
well medullated than those of the large ciliary nerve they accom- 
pany. 
The limits of the two regions just described are not, it is true, 
sharply defined. One area merges gradually into the other with some 
intermixture of the elements characteristic of each. In their central 
portions, however, they are distinctly unlike. As will shortly be seen 
they can be further differentiated by the peculiar types of nerve endings 
found in connection with their ganglon cells. 
The Ciliary Ganglion Cells. The cells of the hen’s cthary 
ganglion are apparently all unipolar, as first definitely determined by 
v. Lenhossék (:10, :11). With that author’s full description of their 
characters my observations agree. The single process springs from one 
pole of the somewhat elliptical cell (Fig. 5 and 10), and soon acquiring 
more or less medullation, passes without branching into a ciliary nerve. 
A T-shaped division of the process, such as is characteristic of the 
neurones of spinal ganglia, has never been observed. The ganglion cells 
are inclosed in capsules rather abundantly supplied with amphicyte or 
satellite nuclei. A conspicuous accumulation of amphicyte nuclei is 
frequently found near that pole of the cell from which the neurite takes 
its origin. Dendrites appear to be completely absent. 
Nerve Endings in the Oculomotor Region. The neurites 
of the oculomotor nerve show, in their terminations about the cells of 
the ciliary ganglion, at least three different types of end structures. 
These are connected, however, by intermediate forms. In the classifica- 
