clature heretofore adopted in my works, excepting only as it relates to the lateralis nerves. In referring
to these nerves I shall replace facialis by lateralis, and refer to th e so-called dorsal and ventral
lateralis roots of the trigemino-facialis complex as the lateralis trigemini and lateralis iacialis respectively.
The brain is not described, as no special examination of it was made.
N E R V U S O L F A C T O R I U S .
The nervus olfactorius arises in Scorpaena from th e anterior end of a lobus olfactorius which,
as Stannius (’49) has said for Cottus and Trigla, lies b eneath the anterior end of th e cerebral hemisphere.
The nerve is long and relatively slender, and the two nerves ru n forward, close together, a certain
distance in the cranial cavity, there lying immediately dorsal or dorso-mesial to th e nervi optici.
The two nerves th en enter a small median recess in the membrane th a t closes th e orbital opening
of th e brain case. From this recess a membranous tube leads forward on either side of th e posterior,
membranous portion of th e interorbital septum, each tube conducting the corresponding nervus
olfactorius into the orbit. There th e nerve continues forward along th e lateral surface of th e cartilaginous
portion of th e interorbital septum, passes dorsal to both of th e oblique muscles, close to their
origins, and traversing th e olfactory canal in th e antorbital process reaches th e nasal pit.
In Menidia th e olfactorius is said b y Herrick (’99, p. 239) to be „crowded under th e m. obliquus
superior near its origin“ , which if it means th a t the nerve passes ventral to th e muscle, must be exceptional
for fishes (Stannius, ’49, p. 7).
No indication of Locy’s (’05) nervus terminalis could be found in any of th e fishes of th e group.
N E R V U S O P T I C U S .
The nervi optici are large and much pleated in all of th e fishes of the group, as Stannius has
already s tated for Cottus and Trigla. In Scorpaena, as well as in Cottus, Sebastes and Trigla (Stannius),
th e chiasma is a simple crossing of th e nerves, th e left nerve lying dorsal to th e right one in all the
specimens examined, excepting in one specimen of Scorpaena. In th a t one specimen th e right nerve
was th e dorsal one.
Beyond the chiasma th e nerve of either side, in Scorpaena, runs almost directly forward in
the cranial cavity until it reaches th e anterior edge of the basisphenoid, where i t turns antero-laterally,
pierces th e membrane th a t closes the orbital opening of the brain case and, entering the orbit, courses
onward to the eyeball.
N E R V U S O C U L O M O T O R I U S .
The nucleus of th e nervus oculomotorius lies near the median line, mostly ventral to the fasciculus
longitudinalis dorsalis, b u t, as in Menidia, p a rtly dorsal to it. The fibers from the dorsal
portion run downward mesial to th e fasciculus and, joining th e other fibers, tu rn ventro-laterally
and issue from th e base of the brain dorsal to th e h ind end of th e lobus inferior. From there the nerve
runs forward along the lateral surface of the dorsal portion of th e lobus inferior, lying a t first v entro-
mesial to the nervus trochlearis and then in similar relation to th e profundus ganglion and truncus
ciliaris profundi. In one instance th e nerve was, in p a rt of its course, closely applied to the mesial
surface of th e communis ganglion of the trigemino-facialis complex. While still in the cranial cavity
it separates into its superior and inferior divisions, both of which issue through the oculomotorius
foramen in th e prootic, usually alone, b u t in one 55 mm specimen, and on one side of the ad u lt
specimen used for figure No. 28 accompanied by th e truncus ciliaris profundi.
Issuing from its foramen th e nerve lies antero-dorsal to th e rectus externus and postero-ventral
to the rectus superior,- to which la tte r muscle th e superior division of the nerve immediately passes.
The inferior division of the nerve then comes into close contact with th e ciliary ganglion, and there
immediately, separates into two portions, the larger one of which is the branch for the recti inferior
and internus and the smaller one th e b ranch for the obliquus inferior. The larger branch immediately
separates into its two parts, both of which run forward postero-ventral to the rectus superior, the
branch to the rectus inferior immediately entering its muscle, while the branch to the rectus internus
passes dorsal to the rectus inferior to reach its muscle. The ciliary ganglion lies upon the branch th a t
goes to the recti internus and inferior and is connected with it by fibers which represent the radix
brevis. The branch to th e obliquus inferior turns downward and forward anterior to the rectus
externus b u t postero-ventral to th e other three recti muscles, and so reaches its muscle.
The branches of th e oculomotorius and their relations to the recti muscles and the nervus
opticus, are thus exactly as in Scomber.
In Lepidotrigla and Cottus th e same arrangement is found; and Dactylopterus differs only
in th a t the oculomotorius separates into three pa rts while still inside the cranial cavity, one branch
destined to the rectus superior, one to the obliquus inferior, and the other to the recti inferior and
internus. In Cottus, there being no basisphenoid, the nerve, as it issues from th e cranial cavity,
pierces the membrane th a t closes th e orbital opening of the brain case, instead of there being enclosed
in bone.
N E R V U S T R O C H L E A R I S .
The trochlearis has a central origin and intracerebral course similar to th a t given by Herrick
for this nerve in Menidia, and it issues from the brain along the ventral margin of the lobus opticus.
Running forward in th e cranial cavity it does not come into close relations with any of the roots of
the trigeminus, or with nerves arising from those roots, differing, in this, from the nerve in Menidia.
This is also true of Lepidotrigla, Cottus and Dactylopterus.
The nerve issues from the cranial cavity either along or through the edge of the alisphenoid,
and running dorsal to all the muscles of the eyeball enters and supplies the obliquus superior.
N E R V U S A B D U C E N S .
The abducens issues from the ventral surface of the medulla oblongata slightly posterior to
th e lobus inferior, and between or slightly anterior to the anterior roots of the nervi acustici of opposite
sides. In all the young specimens of Scorpaena examined, it arose by a single root, b u t in the
ad u lt specimen used for figure 28 it arose by two roots. In all of the specimens of Lepidotrigla
examined it arose by two roots, one slightly posterior-to the other, as Stannius has said for Trigla
an d Cottus. The one or two rootlets have their origin in a nucleus which lies, as in Menidia, a t some
distance from the median line and a t about one third the distance from the ventral surface of the
medulla to the floor of the overlying ventricle. A strong tra c t of fibers crosses transversely between
th e nuclei of opposite sides, b u t my sections did not give any indication either of the tra c t or the
bundle of fibers, described by Herrick in Menidia, th a t runs from the nucleus or root of the nerve
of either side dorsally into the fasciculus longitudinalis dorsalis.
The abducens, having issued from the medulla oblongata, runs forward beneath the hypo-
arium and, in the sections both of Scorpaena and Lepidotrigla, turns downward over the anterior