204 JOURNAL OF COMPARATIVE NEUROLOGY. 
passing out through its foramen, which is long and traverses 
obliquely the supra-occipital bone. Just before entering this 
foramen a small twig is given off for terminal buds scattered 
over the supra-occipital region and several others follow while 
the nerve is within the foramen. Beyond the foramen the 
nerve continues to run caudad near the median line in the usual 
position between the dorsal and interspinous muscles. 
At the level of the first spinal nerve a small branch runs 
down from the r. lateralis accessorius along the lateral face of 
the occipital bone to join the ventral ramus of the first spinal 
nerve (Fig. 1, sp. z). A few sections farther caudad it is fol- 
lowed by a much larger branch which joins the ventral ramus 
of the second spinal nerve (Fig. 1, sf. 2). The sections leave 
no doubt that these are communis fibers from the accessory 
lateral nerve for the spinals and not spinal nerves for the acces- 
sory lateralis. This is plain at their origin dorsally from the 
accessory lateralis and also ventrally at the union with the 
spinals. In the case of the first nerve the anastomosing twig 
enters the ventral ramus some distance distally of the spinal 
ganglion and the communis fibers run out with that ramus and 
do not turn back into the spinal ganglion. In the case of the 
second nerve the communis fibers pass into the spinal ganglion, 
but can clearly be traced through the ganglion, without enter- 
ing into relation with its cells, into the ventral ramus. 
The r. lateralis accessorius during its course through the 
trunk sends filaments at more or less irregular intervals dorsally 
toward the skin. It also, behind the second spinal nerve, effects 
the typical anastomosis with the spinal ganglia via the r. com- 
municans. In the typical cases the r. communicans passes from 
the spinal ganglion dorsad and slightly caudad and enters the 
r. accessorius bodily. It doubtlesss carries some general cuta- 
neous fibers from the ganglion which later leave the r. lateralis 
with some of its twigs for the dorsal body surface. But these 
fibers can form buta small proportion of the anastomosing 
branch ; for the sections clearly show fibers from the r. lateralis 
accessorius entering this nerve and passing directly through the 
spinal ganglion to enter the corresponding ventral ramus. These 
