The lateralis fibers destined to th e rami buccalis and oticus enter the trigeminus ganglion
as a single bundle, and while traversing the ganglion separate into two bundles, one destined to each
of the two nerves. The fibers th a t go to th e ramus ophthalmicus lateralis do not traverse th e ganglion,
lying, in sections, either wholly separate and immediately dorsal to th e ganglion or p a rtly embedded
in its dorsal surface. This ophthalmicus bundle of lateralis fibers always traverses the skull either
through a p a rtly separate p a rt of the trigeminus foramen or through a wholly separate b u t closely
adjacent foramen.
From th e trigeminus ganglion, in Scorpaena, th e ramus ophthalmicus trigemini, the truncus
maxillo-mandibularis trigemini, the ramus communicans ad truncus hyoideo-mandibularis facialis,
and two independent branches arise; all of these branches issuing from the trigemino-facialis chamber
b y its trigeminus opening excepting only th e ramus communicans ad nervus facialis, which la tte r
nerve issues through th e facialis opening of the chamber. Two or three bundles of communis fibers
traverse th e ganglionic mass, one or two bundles going to th e truncus maxillo-mandibularis and the
other one going toward th e ramus ophthalmicus, b ut, so far as could be determined in my quite un satisfactory
sections, going wholly to a branch th a t accompanies the ramus oticus lateralis.
The ramus ophthalmicus trigemini arises from th e anterior end of th e trigeminus ganglion
b y two strands in all th e sections of Scorpaena, Cottus and Lepidotrigla, one of these strands running
forward dorsal and th e other ventral to th e ophthalmicus lateralis. From the dorsal one of the two
strands, in Scorpaena and Lepidotrigla, a small branch, apparently, a purely general cutaneous one,
is soon sent through the alisphenoid with th e lateralis branch th a t goes to th e small sixth organ of
th e supraorbital canal, th e two nerves being accompanied by a branch of th e external carotid and
also by a branch of the vessel x. The general cutaneous component of this small nerve
would seem to be th e homologue of one or both of th e two meningeal nerves said b y Herrick (’99,
p. 205) to have an extracranial origin in M enidia; and it may be added th a t no intracranial meningeal
nerves were evident in Scorpaena. Of these two nerves in Menidia, Herrick says, „1 regard them as
primarily general cutaneous nerves“ b u t „doubtless accompanied by sympathetic or other viscerhl
fibers.“ They are said to be „destined chiefly a t least, for the skin of the top of the head“ , which
would seem to exclude them largely from the meningeal category. In embryos of Cottus this small
reentrant branch of Scorpaena and Lepidotrigla was n o t traced.
After giving off this small reentrant branch, th e two ophthalmic nerves of Scorpaena and
Lepidotrigla, accompanied b y th e ophthalmicus lateralis, run forward dorsal to all th e nerves and
muscles of th e orbit, give off several branches while in th e orbit, and then pass through th e canal
between th e frontal, mesethmoid and ectethmoid to reach th e dorsal surface of the snout; their further
course n o t being investigated. In Ameiurus, Herrick (’01) says th a t th e ramus ophthalmicus, his
supraorbital trunk, contains communis as well as general cutaneous fibers, which seems certainly
n o t tru e of th e mail-cheeked fishes. According to Sagemehl (’84b, p. 71) the ramus ophthalmicus,
in the Characinidae, perforates the ectethmoid b y a special canal; which is also n o t tru e of any of the
mail-cheeked fishes I have examined, nor of Scomber either.
The truncus maxillo-mandibularis separates, as usual, into maxillary and mandibular portions,
th e former being accompanied by the buccalis lateralis. A small branch is given off before th e truncus
separates into its two parts, and running upward and backward innervates first the levator arcus
palatini and then the dilatator operculi. The further course and distribution of the nerve was not
investigated.
The ramus communicans ad truncus hyoideo-mandibularis facialis, in Scorpaena and Lepido-
trigla, is entirely of general cutaneous fibers, and running postero-laterally through the facialis opening
of th e trigemino-facialis chamber joins th e truncus facialis immediately beyond th e motor branches
to th e adductor arcus palatini and adductor hyomandibularis. In Cottus a corresponding branch is
found, and i t is doubtless a general cutaneous one though this could n ot be determined in m y sections.
The two independent branches th a t arise from the trigeminus ganglion in Scorpaena, arise
from its anterior end. One runs upward and laterally across th e anterior edge of the levator arcus
palatini, and is d istributed to the skin along th e hind margin of the orbit. The other branch apparently
contains both general cutaneous and communis fibers, and as it joins and accompanies th e oticus
lateralis it will be described with th a t nerve. In Lepidotrigla th e first one of these two branches is
found, b u t there is apparently no branch joining the oticus lateralis.
In Dactylopterus two general cutaneous branches arise from th e anterior end of the trigeminus
ganglion. One of these branches joins and accompanies th e ophthalmicus lateralis and is the ramus
ophthalmicus trigemini. The other separates into two parts, one of which joins th e oticus lateralis,
th e other traversing the alisphenoid by an independent foramen, accompanied by a blood vessel
which is apparently th e anterior cerebral vein of my descriptions, b u t n o t accompanied by lateralis
fibers; th e lateralis branch to the posterior supraorbital organ not perforating the alisphenoid in this
fish and not having a p a rtly intracranial course, as in the other fishes of th e group. Dactylopterus
differs also from th e other three fishes examined in this connection, in th a t there are two instead
of one communicating branches from the trigeminus ganglion to th e nervus facialis, both of them
containing general cutaneous fibers only. One of these branches arises from th e posterior end of the
ganglion, and passing backward through th e facialis opening of th e trigemino-facialis chamber joins
th e nervus facialis internal to the hyomandibular. The other branch arises further forward from
th e ganglion, passes outward through the trigeminus opening of th e chamber and then runs postero-
ventrally, external to the hyomandibular, to join th e truncus mandibularis facialis after it issues
from th e facial canal in th e hyomandibular. This condition in Dactylopterus is somewhat similar
to th a t described by Herrick in Menidia, where there are also two communicating branches, one quite
undoubtedly issuing through th e facialis and th e other through the trigeminus opening of a trigemino-
facialis chamber, although this chamber is not described and the references to the related foramina
are perplexing. B ut th e two branches in Menidia differ from those in Dactylopterus in th a t they
u nite to form a single nerve which passes internal to the hyomandibular to join the truncus hyoideo-
mandibularis, no portion of either of them joining th e nerve external to th a t bone. Stannius says
(’49, p. 47) th a t this communicating branch from th e trigeminus to the facialis is found in nearly
a ll teleosts, and th a t it issues from the skull with the truncus maxillaris trigemini; the la tte r p a rt of
th e statement being an evident error as regards certain teleosts.
d. N e r v u s F a c i a l i s .
This nerve includes, according to th e component theory, all th e fibers th a t are contained in the
lateralis and communis roots of the trigemino-facialis complex, as well as those of th e motor facialis root.
The dorsal one of the two lateralis roots, which I have called th e lateralis trigemini, separates,
while still in the cranial cavity, into ophthalmicus and buccalis portions.
The ophthalmicus lateralis almost always, in the adult of Scorpaena, traverses a separate
foramen which lies directly above the trigeminus foramen, and the nerve lies upon the dorsal surface