GANGLIA. OF RANA 473 
that the ramus auricularis X takes its origin from the jugular 
ganglion farther posterior in a 10 mm. embryo than in the 8 mm. 
stage. A careful examination of twenty series lying between the 
8 mm. and the 10 mm. stages shows that in all but one of them the 
ramus auricularis arises as in the 8 mm. stage In the 10 mm. 
stage this nerve arises posterior to the fibrous bundle connecting 
the two ventral ganglia of X to the two dorsal ganglia. This 
fibrous bundle passes lateral to the jugular ganglion (figs. 6 and 
10) and it, is probable that it is the active factor in determining 
these relations, 1.e., it may form anterior or posterior to the point 
of exit of the ramus auricularis from the jugular ganglion. 
The differences between the fibers of different components is 
not sufficiently great to enable one, at this stage, to follow the 
general cutaneous fibers into all the nerve trunks figured by 
Strong. The size of the ganglion is entirely sufficient to furnish, 
in addition to the ramus auricularis, the rather large bundles 
running out in two of the branchial rami and the ramus commu- 
nicans IX ad VII. In describing this last ramus attention was 
called to the fact that, while it enters the anterior end of the glosso- 
pharyngeal ganglion, it runs past that ganglion and follows the 
root of the IX to enter apparently the jugular. Questions con- 
cerning the composition of mixed nerves are not easily settled on 
the material of the age used in this paper. Fortunately most 
nerves, even when mixed in the adult and in later embryonic 
stages, are likely to be pure and arise separately from a distinct 
ganglionic mass if the proper stage is studied. This is true of the 
ramus auricularis, but is not true of the other rami arising from 
the jugular ganglion, so that our findings as far as they go con- 
firm those of Strong with respect to the rami arising from this 
ganglion. 
THE SECOND V#SCERALIS X 
This ganglion (figs. 1, 2, 6, 10, G.V.X?) occupies the mesial 
portion of the distal division of the vagus complex. On its dorsal 
and proximal border it is in contact with the jugular and on its 
lateral, and later on its dorsal surface, it is in contact with the 
ventral lateralis. On its anterior border it is in contact withthe 
