th e specimen, b u t not on the other, a relatively important b ranch from the dorsal branch of the ramus
cochlearis acustici.
Having traversed its foramen the nerve tu rn s forward along th e outer surface of the skull and
swells into an elongated ganglion, which has a sympathetic ganglion associated with it. From this
ganglion two nerves arise. One of these nerves is the ramus anterior of th e nervus, which, running
forward, anastomoses with the communis branch from th e facialis to form Jacobson’s nerve, as already
described. The other branch is th e ramus posterior of th e nervus and was not further traced.
N E R V U S VAGU S,
a. N e r v u s l i n e a e l a t e r a l i s v a g i .
The root of th e nervus lineae lateralis vagi issues from th e tuberculum acusticum d irectly dorsal
and slightly posterior to the root of the glossopharyngeus. In th e 63 mm Lepidotrigla it arises by two
roots, a small anterior and a large posterior one. I t runs posteriorly in th e cranial cavity and issues
through th e vagus foramen, there lying directly upon the dorsal surface of th e root of th e vagus.
A supratemporal branch is immediately given off, and running upward innervates th e latero-sensory
organs of th e supratemporal commissure and also those of th e extrascapular and suprascapular sections
of th e main infraorbital canal; this branch having a separate extracranial ganglion. The main
nerve then enters its own ganglion, and was n o t further traced. No ganglion cells are found in the
main nerve before i t issues from th e cranial cavity, and there is no branch of the nerve accompanying
th e nervus glossopharyngeus.
b. N e r v u s V a g u s .
The roots of this nerve could only be properly traced in th e 63 mm Lepidotrigla. In this fish,
and also in the small specimens of Scorpaena and Dactylopterus, three small rootlets arise from the
medulla anterior to th e main root of the nervus. These rootlets, in Lepidotrigla, arise one anterior
to the other, in th e line of the main root, a t intervals of about 80 |*. They pierce what is apparently
a two layered cranial membrane, richly supplied with blood vessels, th e anterior rootlet then joining
th e main vagus root, while th e other two traverse th e intracranial vagus ganglion, as will be later
described. The anterior rootlet seems to be a purely motor one, th e other two apparently containing
communis fibers only; b u t of these determinations I am not a t all certain.
The main root of the nervus contains motor, communis and general cutaneous fibers, most of
these la tte r fibers arising from the spinal V tra c t while some seem to have a superficial origin, coming
down from above. The three bundles issue from the medulla, in Lepidotrigla, close together, as a
single large stalk which is joined by the anterior one of th e three anterior rootlets, and also by one of
the two communicating branches from th e intracranial ganglion a t th e bend in th e root of the glossopharyngeus.
On or in connection with th e general cutaneous portion of th e root, an important in tra cranial
ganglion is formed, and this ganglion is joined b y one of th e branches from th e glossopharyngeus
and is traversed by two of the anterior rootlets of th e vagus itself. From th e ganglion a s tout
intracranial branch is sent upward in the cranial cavity and issues on th e dorsal surface of the skull
near its hind end, this nerve apparently receiving all its fibers from the two anterior rootlets of the
vagus, and the nerve accordingly quite probably being largely if not entirely of communis origin.
In th e sections of Lepidotrigla it could not be determined whether or not this nerve anastomosed
with th e recurrent component th a t accompanies th a t branch of th e lateralis facialis th a t innervates
organ 6 supraorbital; b u t in dissections of Trigla hirundo, where this intracranial branch is also found,
th e anastomosis of the nerve with th e branch of the facialis was readily established. Stannius (’49,
p. 85) says th a t this anastomosis is not found in Trigla gurnardus, and he also says th a t, in th a t fish,
th e nerve arises p a rtly from th e root of the nervus lineae lateralis. This la st statement is certainly
a n error.
In Scorpaena no intracranial branch of the vagus could be found either in the sections or in
th e adult.
The main root, in Lepidotrigla, traverses the vagus foramen, there being distinctly separable
into two bundles, one of which contains th e motor and communis fibers, and perhaps also certain
of th e general cutaneous fibers, while the other arises directly from the intracranial ganglion and must
be largely, if n o t entirely, composed of general cutaneous fibers. This la tte r bundle immediately turns
upward, accompanying the supratemporal branch of the nervus lineae lateralis; b u t it soon leaves
th a t nerve, and turning laterally and forward passes onto the external surface of the levator and
adductor operculi muscles and is there in large p a rt distributed to the inner and outer surfaces of the
operculum, one branch of it, however, joining and anastomosing with th e terminal fibers of the ramus
opercularis profundus facialis. Whether any fibers of this nerve accompany the supra temporalis
lateralis, or not, could n o t be positively determined, b u t none of them seemed to.
The remaining fibers of the root of the vagus soon swell into the large ganglionic mass of th a t
nerve and were n o t further investigated.
O C C I P I T A L N E R V E S .
The occipital nerves were not carefully traced, none of th e series of sections prepared extending
far enough to permit it. They are shown in figure 28 as found in the adult Scorpaena. They unite
to form a single tru n k which issues through the foramen in the exoccipital.
N E R V U S S Y M P A T H E T I C US.
A large sympathetic ganglion, th e anterior cerebral sympathetic ganglion, lies in the trigemino-
facialis chamber. Anteriorly this ganglion lies immediately ventral to, and is in contact with, the
anterior portion of the trigeminus ganglion, b u t posteriorly it is separated from th a t ganglion by the
jugular vein, th e two ganglia being connected by several bundles of fibers. From the anterior end of
th e ganglion a branch is always sent to join the radix longa of the ciliary ganglion, and, in the one
ad u lt specimen of Scorpaena th a t was examined, a second b ranch is sent direct to the ciliary ganglion,
as already fully described.
A second sympathetic ganglion lies ventral to the truncus facialis and is connected with th a t
truncus by one or two strands ; this ganglion sometimes being an independent ganglion and sometimes
simply an enlargement of a posterior prolongation of th e anterior ganglion. From th e hind end of
this second ganglion, the sympathetic tru n k runs posteriorly along the side wall of the skull and swells
into a ganglion beneath the glossopharyngeus ganglion, and then into another beneath the vagus
ganglion; these sympathetic ganglia both being connected by fibers with the related ganglia of the
cranial nerves.