— 739 — 
staining and the silver impregnation of Cajal. Sections stained with 
Weigert’s haematoxylin, acid fuchsin, and methylene blue (for Niss1- 
bodies) have also been studied, as well as teased preparations. Care has 
been taken to examine a number of serial sections, including not only 
the whole ganglion, but also surrounding structures lying in the orbit. 
In this way all connections of the ganglion with adjacent nerves have 
been determined. 
The observations have been confined to three representatives of 
the group of birds: the hen, duck, and pigeon. The largest number of 
preparations, and the most successful ones, were made from material 
obtained from the hen, and the following account is based almost 
exclusively on that form. I have no reason’to believe that the histo- 
logical conditions in. the ciliary ganglia of the duck and pigeon differ 
essentially from those described below. 
While the present investigation was in progress, v. Lenhossék’s 
interesting article on the same subject appeared in the Archiv fur 
mikroscopische Anatomie for February, 1911. Frequent references 
to this paper will be found in the following pages, and as the account 
proceeds, it will become apparent to what extent my observations and 
interpretations agree or disagree with those of v. Lenhossék. 
I wish to express my thanks to the directors of the Anatomo- 
Biological Institute in Berlin and the Zoological Institute in Munich for 
privileges enjoyed in their laboratories, and to Professor Rudolf 
Krause and Professor Ludwig Neumayer for friendly interest taken 
in the preparation of this paper. 
Connection of the Ciliary ganglion with the Oculomo- 
tor Nerve. An ordinary dissection of the orbital nerves of the hen 
reveals in the vicinity of the ciliary ganglion the conditions shown in 
Figure 1. The abducent nerve passes through this region, but has been 
omitted in the drawings, since it is in no way connected with the gang- 
lion in question. The oculomotor nerve (n. oc’mot.) gives off behind 
the eyeball a small branch (rm. mu. rt. d.) to the dorsal rectus muscle, 
and then turns ventral to run along the floor of the orbit to its ter- 
mination in the ventral oblique muscle. As it bends downward the nerve 
sends a small ramus (rm. mu. rt. v.) to the ventral rectus muscle. 
Between these branches to dorsal and ventral eye muscles lies the 
spindle-shaped ciliary ganglion (gn. cil.) approximately 2 mm. in length, 
with its proximal (caudal) end in direct contact with the trunk of the 
third nerve. In my dissections a radix brevis has never been observed, 
and this lack of a special bundle of fibers between the nerve stem and 
the ganglion has been verified in eleven series of sections, which 
show (Fig. 2) that the most proximal ganglion cells are in contact with 
