ZOOLOUICA.

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Original-Abhandlungen

aus

dem Gesamtgebiete der Zoologie.

Herausgegeben
von
Professor Dr. Carl Chun in Leipzig.
Heft 57.
— Zweiundzwanzigster Band. ——

Vierte Lieferung.

Inhalt:

Edwärd Phelps Allis, jr, The Cranial Anatomy of the Mail-cheeked Fishes. Lfg. 2.

Mit 3 Tafeln.

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STUTTGART.
E. Schweizerbart’sche Verlagsbuchhandlung, Nägele & Dr. Sproesser.
1909.

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the lachrymal bone by the single large aperture on the dorso-anterior edge of that bone. The canal
then traverses the lachrymal, giving off two primary tubes in its course, these tubes opening on the
outer surface by small groups of pores which lie one between the anterior and next posterior spine
of the bone, and the other between this latter spine and the next posterior one. The fourth tube of
the line leaves the canal as it passes from the lachrymal into the first suborbital, and the fifth tube
as it passes from that bone into the second suborbital, these tubes both opening on the outer surface
by small groups of pores that lie ventral to the canal.

In the second suborbital (third infraorbital) the canal runs backward nearly to the hind edge
of the bone, where it issues from the bone on its external surface and ends, having given off one
primary tube in its course. This latter tube is the 6th. tube of the line, the canal ending in a terminal
tube which represents one half of the 7th. tube of the line, as will be further explained below. These
two tubes lie rather close together, near the hind edge of the bone, the 6th. tube directed postero-
ventrally and the 7th. one postero-dorsally. Both tubes open on the outer surface by a group of
pores, and certain pores of the 7th. group had secondarily fused, in all the several specimens examined,
with certain pores of the penultimate dendritic system of the preopercular canal, a dermal communi-
cation between the hind end of the suborbital section of the main infraorbital canal and the preoper-
cular canal thus here being established. This communication is large and important, and one not
thoroughly conversant with this subject might naturally be led to say, as Garman (’99) has said of
Ectreposebastes imus, that the postorbital portion of the main infraorbital canal and the dorsal
portion of the preopercular canal were here ‚‚reduced to a single canal“. This however would cert-
ainly be, if said of Scorpaena, and must also be of Ectreposebastes, a most misleading statement
of the case, for the two main canals themselves do not in any sense here run into each other, a cert-
ain pore or pores of a dendritic system of one of them simply anastomosing, secondarily, with a
certain pore or pores of a dendritic system of the other.

Beyond the 7th. primary tube, the main infraorbital canal is interrupted, the next posterior
section of the canal being enclosed in the little postorbital ossicle, and not having any direct connection
with the suborbital portion of the line. The 7th. tube of the line is thus the terminal tube of an
anterior, suborbital portion of the line, and is the anterior half, only, of what would be the 7th.
primary tube of a continuous canal. The other half of this primary tube lies directly behind the eye,
at the ventral edge of the little postorbital ossiele, and forms the anterior tube of the postorbital
section of the eanal. In some specimens the dendritic system formed by the repeated subdivisions
of this posterior half of the 7th. primary tube seemed to be in secondary communication with the
penultimate system of the preopercular canal, but, in the one wholly satisfactory preparation
made, this connection did not exist. The dissection necessary to establish this is a difficult and
delicate one, and the use of injecting fluids is usually misleading, for the delicate walls of the tubes
are easily broken down and artificial connections thus established.

Starting from the posterior half tube of the 7th. primary system of the line, the canal runs
upward through the postorbital ossicle and then traverses the relatively wide interval between this
ossicle and the postfrontal bone, there lying immediately beneath the thin dermis. From this part
of the canal the 8th. primary system of the line arises, this system being a large and complicated
one, and having much more the appearance of two half systems that have secondarily anastomosed
than of two half tubes that have completely fused to form a single tube and system. The branches

of this system extend backward across the cheek, and one of them anastomosed, in all of the spec-
Zoologiea. Heft 57. 10

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imens examined, with the double dendritic system formed where the terminal tube of the preoper-
cular canal anastomoses with the main infraorbital; a second, or third secondary connection thus
here being established between these two canals.

Beyond the 8th. dendritic system the canal enters and traverses the postfrontal, at the hind
end of which bone it anastomoses with the penultimate tube of the supraorbital canal, a small double
system here arising from the canal. The canal then turns backward and traverses the pterotic, at
the hind end of which bone it anastomoses with the dorsal end of the preopercular canal, giving rise
to a double system, 10 inf.-12 pnd. This double system had, in the one satisfactory dissection
made, separated into two parts, one lying dorsal and the other ventral to the main infraorbital canal.
The dorsal one of these two portions was small, and opened on the outer surface in a small group
of pores, the ventral one being large and undergoing anastomosis not only with the Sth. infraorbital
system, as above described, but also with the Ilth. system of that same line. This last anastomosis
gives rise to a large and complicated system which spreads backward in the dermis that covers the
levator operculi muscle, extending even beyond that muscle onto the dorsal portion of the outer
surface of the opercular.

Posterior to the 10th. tube of the line, the main infraorbital canal traverses the lateral extra-
scapular and then the suprascapular and supraclavicular, the 11th. tube of the line being given oft
between the first two bones, the 12th. tube between the last two, and the 13th. tube at the hind
end of the supraclavicular. The 11th. tube gives rise, as just above stated, to a large dendritie system
which anastomoses with the ventral half of the double system 10 inf.-12 pmd. The 12th. and
13th. systems are small.

In the full length of the main infraorbital canal there are twelve sense organs, one organ thus
being found between each two consecutive primary tubes. Three of these organs lie in the lachrymal,
one in the first suborbital, two in the second suborbital, one in the postorbital ossicle, and one each
in the postirontal, pterotic, lateral extrascapular, suprascapular and supraclavicular. The first six
organs of the line are each innervated by consecutive and independent branches of the ramus buccalis
facialis. The eighth (postfrontal) and ninth (pterotic) organs are innervated by branches of the ramus
oticus facialis. The innervation of the 7th., or postorbital organ could not be determined either
in the sections or the dissecetions, but it is quite unquestionably innervated by a nerve that corres-
ponds to that somewhat independant branch of the buccalis that innervates, in Amia, the posterior
group of buccal organs of that fish. If this be so, the postorbital break in the main infraorbital canal
oceurs between two groups of organs of the line, and is strietly similar to the break found in this
same line in Batrachus tau (Clapp, ’98) and Chimaera monstrosa (Cole, ’96), and to which I have
made full reference in several of my works.

The 10th. (extrascapular) and 11th. (suprascapular) organs are innervated by branches of
the supratemporal branch of the nervus lineae lateralis vagi; the 12th. (supraclavicular) organ being
innervated by the first single branch of the latter nerve.

The supratemporal canal arises from the main infraorbital canal as that canal traverses the
lateral extrascapular. Running mesially it traverses the lateral extrascapular and then the parieto-
extrascapular, and then unites, in the mid-dorsal line, with its fellow of the opposite side, thus
forming a complete cross-commissure. As the canal passes from the lateral extrascapular into the
parieto-extrascapular it gives offa primary tube which separates into two parts one directed anteriorly
and the other posteriorly and both giving rise to relatively important dendritie systems. A similar

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system arises where the canals of opposite sides anastomose in the mid-dorsal line. The canal con-
tains two sense organs, one lying in the lateral extrascapular and the other in the parieto-extra-
scapular; both organs being innervated by branches of the supratemporal branch of the nervus lineae
lateralis vagi.

The supraorbital canal begins at the anterior end of the nasal, traverses that bone, and then
runs backward in the frontal nearly to its hind edge. The anterior dendritic system of the line lies
at the anterior end of the nasal and is represented by a small and somewhat scattered group of pores.
The 2nd. system of the line arises from the canal as it passes Irom the nasal into the frontal. It is
larger than the first system and sends a long branch laterally and downward in the dermal bridge
between the two nasal apertures. This branch opens on the outer surface by several pores, and in
one specimen, as already stated, one of these pores seemed to have anastomosed with a pore or pores
of the anterior dendritic system of the main infraorbital line, thus here establishing a connection
between these two lines. The 3rd., 4th. and 6th. systems all arise from that part of the canal that
lies in the frontal, the canal then ending while still in that bone, in the 7th. or terminal system of
the line. The 5th. system, which should normally be formed between the 4th. and 5th. organs
of the line, is wholly wanting even in the young specimens examined in sections. The trunk of the
3rd. system is directed forward, and branching gives rise to an elongated group of from twelve to
eighteen pores. The trunk of the4th. system is directed postero-mesially and traverses the frontal to its
mesial edge, where it anastomoses with its fellow of the opposite side to form the frontal (supraorbital)
cross-commissure,. The single median pore here first formed by the fusion of the single primary
pores of opposite sides has, by subsequent division, given rise to a small median group of pores.
The trunk of the 6th. system runs postero-laterally in the frontal, to its lateral edge, where it
anastomesed with the 9th. trunk of the main infraorbital to form a double system. Having given
off this trunk, the canal turns posteriorly and issues from the frontal beneath the frontal spine,
the 7th. or terminal system of the line being represented by a circular group of some ten to
fifteen pores.

The supraorbital canal contains six sense organs, this being one more than is warranted by
the number of dendritie systems actually found in the fish. One of these organs lies in the nasal, and
five in the frontal. The organ in the nasal is normal in its relations to the trunks of the dendritic
systems, as are also the first two organs in the frontal; one of these latter organs Iying between the
trunks of the 2nd. and 3rd. systems of the line and the other between the trunks of the 3rd. and
4th. systems. The fourth organ lies partly opposite and partly posterior to the trunk of the 4th.
system, the fifth organ being similarly related to the trunk of the 7th. or terminal system. The
sixth organ is a small one lying in the trunk of the 7th. or terminal system of the line. Between the
fourth and fifth organs there is no primary tube in Scorpaena, but both in Cottus scorpius and
Cottus oetodecimospinosus there is here a small tube. As, otherwise, the organs and tubes are exactly
similar in the three fishes, a tube has certainly either aborted or never been developed, in
Seorpaena, between the fourth and fifth organs of the line. These two organs lie quite close together
and are innervated by branches of-a single branch of the ophthalmicus lateralis, the other organs
of the line all being innervated by independent branches of the same nerve. The nerve that inner-
vates organs 4 and 5 perforates the frontal, at the base of its ventral flange, to reach the organs it
supplies, sometimes separating into its two parts external to the frontal and sometimes while tra-
versing that bone. In one young specimen examined in serial sections the branch to organ 5 separated

Tan a

from the branch to organ 4 after the main branch had entered the main infraorbital canal itself,
and then continued its course inside that canal. This all certainly indicates that organs 4 and 5 lie
so elose together at the time that they become enclosed in the canal that no primary tube can be
developed between them, this tube thus never being formed. In Menidia also these two organs lie
close together (Herrick, ’99, p. 198), but there is a primary tube between them as there is in Cottus.
In Gadus (Cole ’98) there is, as in Scorpaena, no primary tube between the 4th. and 5th. organs
of the supraorbital canal, but Gadus differs from Scorpaena in that there is no 6th. supraorbital
organ and related primary tube.

Organ 6 of Scorpaena differs from the other organs of the line in being much smaller than
any of them. It is innervated by the first branch of the ophthalmicus lateralis, this branch perforating
the alisphenoid from its lateral surface and then running upward inside the ceranial cavity to per-
forate the frontal immediately beneath the organ it supplies.

The preopereulo-mandibular canal begins near the symphysis of the mandible, and, running
posteriorly, traverses the dentary, artieular and preopercular, and then anastomoses with the main
infraorbital canal at the hind end of the squamosal. The canal lodges eleven sense organs, four |ying
in the dentary, one in the articular and six in the preopercular, all of them innervated by branches
of the ramus mandibularis externus facialis. A primary tube arises from the canal between each
two consecutive organs, this making, with the two terminal tubes, twelve tubes in all. The eleventh
tube anastomoses secondarily, as already stated, with the seventh tube of the main infraorbital canal,
the twelfth tube anastomosing primarily with the tenth infraorbital tube and secondarily with the
eighth and eleventh tubes of the same line.

6. NERVES.

The investigation of the nervous system of the several fishes of the group has been mainly
limited to the adult of Scorpaena scrofa, and to serial sections of small specimens of that fish and of
Lepidotrigla aspera; but certain features of the innervation in the adults of Cottus octodecimospinosus
and Trigla hirundo, in small specimens of Dactylopterus volitans, and in embryos of Cottus scorpius
have been also somewhat carefully examined. The intention at first was to simply determine the
relations of the roots, ganglia and proximal portions of the cranial nerves to the skeletal elements,
the study of the skeleton being the prineipal object of the research; but as certain of the series of
sections examined permitted the tracing, with comparative accuracy, of the components of the
several nerves, these results, so far as obtained, are given. There was however no attempt whatever
to make these results complete. So far as given they are intended to be correct.

In recent English and American works on the cranial nerves of the lower vertebrates there
is a marked tendency to consider the central origin of a given cranial nerve of much more import-
ance for the determination of its segmental position than the course of the nerve and its general
relations to the skeletal elements. Underlying this manner of considering the subject, is the implied
acceptance of the neurone theory of the nervous system, according to which theory all nerve fibers
grow either centrifugally or centripetally between two primarily disconnected points, choosing always
the path of least resistance. Directly opposed to this manner of considering the subject is the earlier
conception of the nervous system, recently re-presented by Gaskel (05), according to which the peri-
pheral and central cells are from the very beginning, and as soon as they begin their separate exis-

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tence, always connected by nervous tissue. While my own work has never yet ied me to investigate,
or even to seriously consider, the manner in which the cranial nerves develop, it has led me to con-
clude, as I have already had occasion to state, that; (I) the relations of the nerves to the skeletal
elements are so remarkably constant that if the nerve itself does not exist from the very beginning,
some tissue or condition of tissue, defining its path, or some markediy strong inherited tendeney
must certainly so exist; and (2), that whenever a nerve is deflected from its accustomed and apparently
predetermined path, careful examination and consideration will almost always show that it has
simply been pushed or pulled one way or the other, surrounded to a different extent or in a different
manner by the encroaching and enveloping growth of adjacent tissues, or even actually displaced
relative to certain tissues or structures by a variation in the relative time, or in the relative degree
of development of the nerve and those other tissues. That there are certain apparently inexplicable
exceptions to this rule, I know full well.

According to the latter of these two conceptions of the nervous system, the general course
of a nerve and its relations to the skeletal and other elements, properly determined, definitely define
the segmental position of the nerve, and its centers of origin must be in accord with those determ-
inations.

According to the other conception, carried to its legitimate extreme, the course of nerve fibers
is not necessarily segmental, and, the terminal distribution of sensory fibers also not being necess-
arily segmental, the only positive criterion of the segment or segments to which the component
fibers of a certain nerve belong is their points of origin in the central nervous system. Furthermore,
the cranial segment to which it is assumed that certain fibers must necessarily belong having been
determined by their central origin, the elements of accident, individual experience, or even a sort
of elective selection are introduced as natural and constant occurrences to explain the apparently
unsegmental peripheral course of certain of those fibers; and where certain sensory fibers are assumed,
in the wording of the descriptions, to grow centripetally from certain sense organs to the braın,
the same elements of accident, experience or elective selection may determine their peripheral
course in one segment and their central origin in another. It is needless to refer to the many
expressions and statements that seem to lead legitimately to these conelusions, and while these
statements definitely impress the reader it is possible that they may not always give correctly
the definite opinions of the authors making them.

These tworadically different conceptions of the origin and development of the peripheral nervous
system lead, frequently,to totallydifferent interpretations of the facts of distribution, this being especially
marked in relation to the branches of thetrigemino-facialis complex. Stannius, apparently an advocate
of the earlier conception of the nervous system, assigned the fibers of this complex to the trigeminus
or facialis nerves according as they issued from the skull by one set of foramina or another, or had a
distribution to what he considered as trigeminus or facialis regions; and he accordingly considered the
roots of the complex as partly trigeminus, partly facialis, and partly mixed. Later authors first assigned
all the lateralis fibers of the complex to the facialis, irrespeetive of their course and distribution, and
now, still later, recent advocates of the component theory assign all the communis fibers also to that
same nerve. I, myself, have accepted and advocated the assigning of the lateralis fibers of the complex
to the facialis, but as I am not prepared to accept the assigning of the communis fibers to that nerve,
I begin to doubt the justice of so assigning the lateralis ones. This will be further discussed when
describing certain of the branches of the complex. To avoid confusion I still adhere to the nomen-

clature heretofore adopted in my works, excepting only as it relates to the lateralis nerves. In refer-
ring to these nerves I shall replace facialis by lateralis, and refer to the so-called dorsal and ventral
lateralis roots of the trigemino-facialis complex as the lateralis trigemini and lateralis facialis res-
pectively. The brain is not described, as no special examination of it was made.

NERVUS OLFACTORIUS.

The nervus olfactorius arises in Scorpaena from the anterior end of a lobus olfactorius which,
as Stannius (’49) has said for Cottusand Trigla, lies beneath the anterior end of the cerebral hemisphere.
The nerve is long and relatively slender, and the two nerves run forward, close together, a certain
distance in the cranial cavity, there Iying immediately dorsal or dorso-mesial to the nervi optici.
The two nerves then enter a small median recess in the membrane that closes the orbital opening
of the brain case. From this recess a membranous tube leads forward on either side of the posterior,
membranous portion of the interorbital septum, each tube conducting the corresponding nervus
olfactorius into the orbit. There the nerve continues forward along the lateral surface of the cartilag-
inous portion of the interorbital septum, passes dorsal to both of the oblique muscles, close to their
origins, and traversing the olfactory canal in the antorbital process reaches the nasal pit.

In Menidia the olfactorius is said by Herrick (’99, p. 239) to be „‚crowded under the m. obliquus
superior near its origin‘‘, which if it means that the nerve passes ventral to the muscle, must be ex-
ceptional for fishes (Stannius, ’49, p. 7).

No indication of Loey’s (’05) nervus terminalis could be found in any of the fishes of the group.

NERVUS -OPTTEUNS.

The nervi optiei are large and much pleated in all of the fishes of the group, as Stannius has
already stated for Cottusand Trigla. In Scorpaena, as well as in Cottus, Sebastes and Trigla (Stannius),
the chiasma is a simple crossing of the nerves, the left nerve lying dorsal to the right one in all the
specimens examined, excepting in one specimen of Scorpaena. In that one specimen the right nerve
was the dorsal one.

Beyond the chiasma the nerve of either side, in Scorpaena, runs almost directly forward in
thecranialcavity until it reaches the anterior edge of the basisphenoid, where it turns antero-laterally,
pierces the membrane that closes the orbital opening of the brain case and, entering the orbit, courses
onward to the eyeball.

NERVUS OCULOMOTORIUS.

The nucleus of the nervus oculomotorius lies near the median line, mostly ventral to the fas-
cieulus longitudinalis dorsalis, but, as in Menidia, partly dorsal to it. The fibers from the dorsal
portion run downward mesial to the fasciculus and, joining the other fibers, turn ventro-laterally
and issue from the base of the brain dorsal to the hind end of the lobus inferior. From there the nerve
runs forward along the lateral surface of the dorsal portion of the lobus inferior, Iying at first ventro-
mesial to the nervus trochlearis and then in similar relation to the profundus ganglion and truncus
ciliaris profundi. In one instance the nerve was, in part of its course, closely applied to the mesial
surface of the 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 the proötic, usually alone, but in one 55 mm specimen, and on one side of the adult
specimen used for figure No. 28 accompanied by the truncus ciliaris profundi.

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Issuing from its foramen the nerve lies antero-dorsal to the rectus externus and postero-ventral
to the rectus superior, to which latter muscle the superior division of the nerve immediately passes.
The inferior division of the nerve then comes into close contact with the 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 the branch 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 that
goes to the recti internus and inferior and is connected with it by fibers which represent the radıx
brevis. The branch to the obliquus inferior turns downward and forward anterior to the rectus
externus but postero-ventral to the other three recti muscles, and so reaches its muscle.

The branches of the oculomotorius and their relations to the recti muscles and the nervus
opticus, are thus exactly as in Scomber.

In Lepidotrigla and Cottus the same arrangement is found; and Dactylopterus differs only
in that the oculomotorius separates into three parts 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 the cranial cavity,
pierces the membrane that closes the orbital opening of the brain case, instead of there being enclosed
in bone.

NERVUS TROCHLEARIS.

The trochlearis has a central origin and intracerebral course similar to that 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 the 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.

NERVUS ABDUCENS.

The abducens issues from the ventral surface of the medulla oblongata slightly posterior to
the lobus inferior, and between or slightly anterior to the anterior roots of the nervi acustici of op-
posite sides. In all the young specimens of Scorpaena examined, it arose by a single root, but in the
adult 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
and Cottus. The one or two rootlets have their origin in a nucleus which lies, as in Menidia, at some
distance from the median line and at about one third the distance from the ventral surface of the
medulla to the floor of the overlying ventriele. A strong tract of fibers erosses transversely between
the nuclei of opposite sides, but my sections did not give any indication either of the tract or the
bundle of fibers, described by Herrick in Menidia, that 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

BUNT ae

edge of the cartilaginous proötic bridge and then runs backward beneath that bridge to enter and
supply the rectus externus. In the adults both of Scorpaena and Trigla, the nerve perforates the
bony proötic bridge to reach its muscle. In Cottus octodecimospinosus it runs over the anterior edge
of the bony bridge. In small specimens of Dactylopterus it enters the trigemino-facialis chamber
through the facialis foramen, and traversing that chamber ventral to all the other nervous struc-
tures issues by the trigeminus opening of the chamber and then immediately enters its muscle.

TRIGEMINO-FACIALIS COMPLEX.

This complex has, in Scorpaena, five apparent roots, as Stannius has stated that it has in
Trigla, but two of these roots, the lateralis roots, may issue as a single root from the medulla and
then immediately separate. These two lateralis roots and the motor facialis root are so closely applied,
at their origin, that they appear almost as a single root, and are so shown in figure 28. In that figure,
furthermore, the communis root appears crowded down between the trigeminus and the lateralis
and motor facialis roots, this not being its position in sections of young specimens.

My sections did not permit of more than a very general determination of the central origin
and peripheral distribution of the fibers of the several roots, but comparison with Menidia will show
that these determinations are probably correct.

a. Roots and Ganglia of the Complex.

The anterior one of the five roots of the complex is the so-called root of the trigeminus, and
it contains both motor and general cutaneous fibers. The motor fibers lie on the dorso-mesial aspect
of the root as it emerges from the medulla. The fibers of the deep sensory root lie lateral to these
motor fibres, the two bundles of fibers extending dorso-mesially into the medulla, Iying close together,
and certainly having their prineipal origins in groups of cells that represent respectively the chief
sensory and motor nuclei of the trigeminus. The remaining, ventral fibers of the root enter the
spinal V tract. The motor fibers, having issued from the medulla, soon cross, as in Menidia, to the
ventral surface of the root, and so continue during their intracranial course. The entire root, running
forward and laterally, lies at first, in sections, mesial to the other roots of the complex and then be-
tween the lateralis trigemini and lateralis facialis roots, ventral to the former and dorsal to the latter.
While still in the cranial cavity it gives off the profundus root. It then traverses the trigeminus
foramen, enters the trigemino-facialis chamber, and there immediately swells into the large trigem-
inus ganglion, which, in my young specimens, seems wholly distinet and separate from any other
portion of the ganglionie complex excepting only the large related sympathetie ganglion. The gang-
lion lies almost wholly in the trigemino-facialis chamber, a small collection, only, of cells being found
on the ventral surface of the root just before it issues through its foramen; these cells being connected
with the main ganglion by a small ganglionie strand which traverses the foramen. The ganglion
thus lies almost entirely in the cranial wall and not in the cranial cavity, all the other ganglia of the
complex, excepting only the related sympathetie ganglion, lying in the cranial cavity itself.

The profundus root arises from the sensory portion of the trigeminus root, on its antero-mesial
aspect, and running antero-laterally enters the intracranial profundus ganglion which lies slightly
antero-mesial to the large stalk formed by the other roots of the complex.

The next posterior root of the complex is the motor root of the facialis. This root emerges
from the medulla close to the anterior root of the nervus acusticus, almost as a part of that root,

N

and directly anterior to the low swelling of the acusticus part of the tuberculum acusticum; the
anterior root of the acusticus spreading, and entering the medulla both dorsal and ventral to the level
of the point of exit of the motor root of the facialis. After the root emerges from the medulla it lies
dorso-anterior to the anterior root of the acusticus, between it and the overlying lateralis facialis
root, but it soon passes up along the lateral surface of the latter root and reaches its dorsal surface.
There it continues forward closely applied to the lateralis facialis and issues, with that nerve, through
the facialis foramen. As the two nerves pass through the foramen, of shortly before, they receive a
large bundle of fibers from the communis ganglion, the three components together forming the
truncus facialis. This truncus does not traverse the trigeminus ganglion, passing postero-ventral
to that ganglion. As in Menidia, it contains no general cutaneous component.

The next posterior root is the communis root. This root leaves the medulla almost directly
dorsal to the motor facialis root, its point of origin lying immediately dorsal to the low, acusticus
swelling of the tuberculum acusticum, and immediately anterior to the low, lateralis swelling of
the same structure. Immediately after issuing from the medulla it lies wedged in between the
lateralis trigemini and lateralis facialis roots, and, anterior to that point, lies lateral and then ventral
to the trigeminus root as that root passes between the two lateralis roots. It then swells into a large
pear-shaped intracranial ganglion, the large end of the pear directed antero-laterally, and the ganglion
occupying the ventral or ventro-mesial portion of the large root-stalk of the complex. From the
anterior portion of this ganglion, three bundles, or groups of sub-bundles of fibers arise, their arrange-
ment being somewhat different on the two sides of the one specimen in which they were traced. One
of these bundles is the ramus palatinus facialis which runs downward in the cranial cavity and, per-
forating the base of the proötie bridge, enters the myodome. A second one of the three bundles is
a group of sub-bundles which traverses the trigeminus foramen; containing two separate sub-bundles
on one side of the specimen and three on the other. One of these sub-bundles enters and traverses
the trigeminus ganglion, going mainly if not entirely to the ramus oticus; the other one or two sub-
bundles traversing the ganglion to enter the truncus maxillo-mandibularis trigemini. The third
bundle that arises from the main ganglion traverses the facialis foramen and it was single on one side
of my specimen but double on the other. On the single side the entire bundle entered the truneus
facialis, a small branch being immediately sent to Jacobson’s anastomosis. On the double side, one
of the two sub-bundles went to the truncus facialis and Jacobson’s anastomosis, the other sub-bundle
running upward in the trigemino-facialis chamber and entering the truncus maxillo-mandibularis.
This latter arrangement was also found on one side of the adult specimen used for figure 28, and
hence is probably not unusual.

- The communis root of Scorpaena thus differs from that of Menidia only in that two separate
bundles of fibers, instead of a single one, go to the truncus maxillo-mandibularis.. Whether both
bundles go to the ramus maxillaris, or one to that ranıus and the other to the ramus mandibularis,
I could not determine. Scorpaena further differs from Menidia in the absence of any intracranial
recurrent communis nerves, and Trigla, Lepidotrigla and Dactylopterus all agree with Scorpaena
in this respect. In Cottus, on the contrary, there is an important intracranial recurrent branch.

The next two roots of the complex, in Scorpaena, the two that have the most posterior apparent
origin from the medulla, are the roots of the lateralis trigemini and lateralis facialis nerves. These
two roots arise as a single root from the tubereulum acusticum immediately posterior to the communis

root and immediately dorso-posterior to the anterior root of the acusticus, between that root and
Zoologica. Heft 57. 11

br OR gen

the posterior root of the same nerve. Running forward, and soon separating, each root swells slightly
into an elongated intracranial ganglion, from which the lateralis trigemini and lateralis facialis nerves
respectively arise.

In the other fishes of the group the roots and ganglia of the complex conform closely to those
in Scorpaena, excepting only in the number and arrangement of the bundles of fibers that arise from
the communis ganglion. In the one specimen of Lepidotrigla that was examined, all of these latter
fibers arose from the ganglion as a single bundle which immediately separated into two parts, both
of which traversed the facialis foramen and entered the trigemino-facialis chamber. One of these
two parts is the palatinus facialis which turns forward in the trigemino-facjalis chamber and issues
through the trigeminus opening of that chamber. The other part separates into two bundles as soon
as it enters the chamber, one of these bundles joining the trigeminus nerves and containing all the
communis fibers destined to those nerves, while the other bundle contains the fibers destined to
Jacobson’s anastomosis and the truncus hyoideo-mandibularis facialis. In Dactylopterus one bundle
of fibers traverses the trigeminus foramen, and another the facialis foramen, the latter bundle sepa-
rating into three parts, the facialis branch to Jacobson’s anastomosis, the ramus palatinus and the
communis component of the truncus hyoideo-mandibularis facialis.

The fact that all of the communis fibers destined to the nervus trigeminus issue from the cran-
ial cavity, in Lepidotrigla, by the facialis foramen might be considered as evidence in favor of the
assumption that the communis fibers of the V—VII complex of that fish all belong to the nervus
facialis; but it must not be overlooked that the fibers destined to the trigeminus all issue from the
trigemino-facialis chamber by the trigeminus opening of that chamber, the fibers that issue through
the facialis opening of the chamber all going to the nervus facialis. It is also to be noted that on one
side of the 55 mm Scorpaena, and also on one side of the adult Scorpaena used for figure 28, a con-
dition is found that is intermediate to that found on the other side of those two specimens and to that
found in Lepidotrigla. These differences in the course of these fibers would all be explained by the
assumption that the entire trigemino-facialis ganglionic complex was, in the immediate ancestor or
ancestors of all teleosts, enclosed in a trigemino-facialis chamber in the cranial wall, as it actually
is in Amia, and that the perforations of the inner wall of this chamber are not necessarily of seg-
mental importance. But while there is much in favor of these assumptions it is to be noted: that
in the Plagiostomata, according to Stannius, (’49, p. 32), the ganglion of his third root of the trigemino-
facialis complex is always extracranial, while the ganglion of his first root, is intracranial; and that
in Petromyzon, according to Johnston (’05 b), the ganglion of the facialis has its general cutaneous
and communis components intracapsular, but its lateralis components extracapsular in position;
and that the descriptions lead one to conclude, although it is not definitely so stated, that the ganglion
of the trigeminus is extracapsular.

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The truncus ciliaris profundi is the only nerve that arises from the profundus ganglion. Running
forward in the cranial cavity it usually issues, in Scorpaena, through a special foramen in the proötic,
but in two instances it was found traversing the oculomotorius foramen with the oculomotorius.
In Cottus, Trigla and Lepidotrigla, in all the specimens examined, it issued through a foramen that
lies close to the trigeminus and facialis foramina, these two latter foramina lying, the former
dorso-anterior to the latter and the profundus lying between and immediately anterior to them.

Be re

In small specimens of Dactylopterus the ciliaris profundi issues through the large trigeminus
foramen.

According to Stannius (°49, p. 38), the ciliaris profundi of teleosts perforates the ‚„Keilbein-
flügel“{alisphenoid), but this certainly is not true of any of the mail-cheeked fishes I have examined,
nor of Scomber, in all of which fishes it perforates the proötie.

In Cottus, Trigla and Lepidotrigla, as in Ophiodon (Allen, ’05), the truncus ciliaris profundi
is accompanied, in its passage through its foramen, by the encephalie branch of the jugular vein.
In Dactylopterus and Scorpaena, that vein traverses the trigeminus foramen, associated with the
truncus profundi in Dactylopterus, but not in Scorpaena.

In Scorpaena, the ciliaris profundi receives, immediately after issuing from the skull, a branch
from the large sympathetic ganglion associated with the trigeminus, and then separates into its two
parts, the ciliaris longus and the radıx longa. The ciliaris longus is much the thicker nerve of the
two, and running upward and forward, dorsal to the rectus externus and posterior and somewhat
parallel to the rectus superior, pierces the eyeball between that muscle and the rectus externus. The
radix longa continues onward near the nervus oculomotorius and soon enters the ciliary ganglion;
this latter ganglion also receiving, on both sides of the adult specimen used for figure 28, an inde-
pendent sympathetic strand coming from the trigeminus sympathetie ganglion. This latter strand
was not evident in the sections. The ciliary ganglion is connected with the oculomotorius by the
radix brevis, and from it a single nerve arises, the ciliaris brevis, which joins and accompanies the
nervus opticus and pierces the eyeball not far from that nerve.

In Lepidotrigla the ciliaris profundi, after issuing from its foramen with the encephalie vein,
turns downward and forward close against the outer surface of the cranial wall, closely accompanying
the internal jugular vein and lying, with that vein, immediately beneath the anterior portion of
the trigeminus sympathetic ganglion. From the latter ganglion it receives a strand, and then, joining
and accompanying the nervus oculomotorius, separates into its two portions shortly before it reaches
the ciliary ganglion. In both Cottus scorpius and Cottus octodecimospinosus, and also in Dactylopterus,
strietly similar conditions are found.

The profundus ganglion and its root, and the ciliaris longus and radıx longa, are all described
by Stannius in Trigla gurnardus and Trigla hirundo, these two teleosts being the only ones in which
that author found an independent profundus ganglion. Of Cottus (species not given) Stannius says
(’49, p. 38), that the ramus ciliaris arises from the trigeminus ganglion, close to the ramus ophthal-
micus trigemini; a statement certainly not true of either of the two species of Cottus that I have
examined.

In Menidia, the radix ciliaris longa of Herrick’s descriptions is simply the sympathetie strand
sent from the trigeminus sympathetic ganglion to join the true radix longa, this latter radix being
his ramus ophthalmicus profundus.

In Petromyzon, the root of the profundus is said by Johnston (’05 b, p. 186) to contain some
lateralis fibers.

c. Nervus Trigeminus.

The several motor and general cutaneous branches of this nerve all have, in all the fishes of
the group, their apparent origin from the trigeminus ganglion, that ganglion lying in the trigemino-
facialis chamber.

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The lateralis fibers destined to the 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 that go to the ramus ophthalmicus lateralis do not traverse the ganglion,
lying, in sections, either wholly separate and immediately dorsal to the ganglion or partly embedded
in its dorsal surface. This ophthalmicus bundle of lateralis fibers always traverses the skull either
through a partly separate part of the trigeminus foramen or through a wholly separate but closely
adjacent foramen.

From the trigeminus ganglion, in Scorpaena, the ramus ophthalmieus 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
by its trigeminus opening excepting only the ramus communicans ad nervus facialis, which latter
nerve issues through the facialis opening of the chamber. Two or three bundles of communis fibers
traverse the ganglionie mass, one or two bundles going to the truncus maxillo-mandibularis and the
other one going toward the ramus ophthalmicus, but, so far as could be determined in my quite un-
satisfactory sections, going wholly to a branch that accompanies the ramus oticus lateralis.

The ramus ophthalmicus trigemini arises from the anterior end of the trigeminus ganglion
by two strands in all the sections of Scorpaena, Cottus and Lepidotrigla, one of these strands running
forward dorsal and the other ventral to the 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 the lateralis branch that goes to the small sixth organ of
the supraorbital canal, the two nerves being accompanied by a branch of the external carotid and
also by a branch of the vessel x. The general cutaneous component of this small nerve
would seem to be the homologue of one or both of the two meningeal nerves said by Herrick (’99,
p-205) to have an extracranial origin in Menidia; and it may be added that no intracranial meningeal
nerves were evident in Scorpaena. Of these two nerves in Menidia, Herrick says, ‚‚I regard them as
primarily general eutaneous nerves‘‘ but „doubtless accompanied by sympathetic or other visceral
fibers.“ They are said to be ‚„‚destined chiefly at least, for the skin of the top of the head“, which
would seem to exelude them largely from the meningeal category. In embryos of Cottus this small
reöntrant branch of Scorpaena and Lepidotrigla was not traced.

After giving off this small reöntrant branch, the two ophthalmie nerves of Scorpaena and
Lepidotrigla, accompanied by the ophthalmicus lateralis, run forward dorsal to all the nerves and
muscles of the orbit, give off several branches while in the orbit, and then pass through the canal
between the frontal, mesethmoid and ectethmoid to reach the dorsal surface of the snout; their further
course not being investigated. In Ameiurus, Herrick (°01) says that the ramus ophthalmicus, his
supraorbital trunk, contains communis as well as general cutaneous fibers, which seems certainly
not true of the mail-cheeked fishes. According to Sagemehl (°84b, p. 71) the ramus ophthalmicus,
in the Characinidae, perforates the ectethmoid by a special canal; which is also not true 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 erioss,
the former being accompanied by the buccalis lateralis. A small branch is given off before the 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 ofgeneral cutaneous fibers, and running postero-laterally through the facialis opening
of the trigemino-facialis chamber joins the truncus facialis immediately beyond the motor branches
to the adductor arcus palatini and adductor hyomandibularis. In Cottus a corresponding branch is
found, and it is doubtless a general cutaneous one though this could not be determined in my sections.

The two independent branches that arise from the trigeminus ganglion in Scorpaena, arise
from its anterior end. One runs upward and laterally across the anterior edge of the levator arcus
palatini, and is distributed to the skin along the hind margin of the orbit. The other branch apparently
contains both general cutaneous and communis fibers, and as it joins and accompanies the oticus
lateralis it will be described with that nerve. In Lepidotrigla the first one of these two branches is
found, but there is apparently no branch joining the oticus lateralis.

In Dactylopterus two general cutaneous branches arise from the anterior end of the trigeminus
ganglion. One of these branches joins and accompanies the ophthalmieus lateralis and is the ramus
ophthalmicus trigemini. The other separates into two parts, one of which joins the oticus lateralis,
the other traversing the alisphenoid by an independent foramen, accompanied by a blood vessel
which is apparently the anterior cerebral vein of my descriptions, but not accompanied by lateralis
fibers; the lateralis branch to the posterior supraorbital organ not perforating the alisphenoid in this
fish and not having a partly intracranial course, as in the other fishes of the group. Dactylopterus
differs also from the other three fishes examined in this connection, in that there are two instead
of one communicating branches from the trigeminus ganglion to the nervus facialis, both of them
containing general cutaneous fibers only. One of these branches arises from the posterior end of the
ganglion, and passing backward through the facialis opening of the trigemino-facialis chamber joins
the nervus facialis internal to the hyomandibular. The other branch arises further forward from
the ganglion, passes outward through the trigeminus opening of the chamber and then runs postero-
ventrally, external to the hyomandibular, to join the truncus mandibularis facialis after it issues
from the facial canal in the hyomandibular. This condition in Dactylopterus is somewhat similar
to that described by Herrick in Menidia, where there are also two communicating branches, one quite
undoubtedly issuing through the facialis and the 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. But the two branches in Menidia differ from those in Dactylopterus in that they
unite to form a single nerve which passes internal to the hyomandibular to join the truncus hyoideo-
mandibularis, no portion of either of them joining the nerve external to that bone. Stannius says
(°49, p. 47) that this communicating branch from the trigeminus to the facialis is found in nearly
all teleosts, and that it issues from the skull with the truncus maxillaris trigemini; the latter part of
the statement being an evident error as regards certain teleosts.

d. Nervus Facialis.

This nerve includes, according to.-the component theory, all the fibers that are contained in the
lateralisand communisroots of the trigemino-facialis complex, as well as those ofthe motor facialis root.

The dorsal one of the two lateralis roots, which I have called the 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

use

of and does not traverse the trigeminus ganglion. Immediately after issuing from the skull it gives
off a small branch which turns upward and inward and, perforating the alisphenoid, enters the cranial
cavity. There it runs upward along the inner surface of the skull, Iying in the membranous tissue
that lines that surface, and, piereing the frontal, reaches the small sixth organ of the supraorbital
canal, which it innervates. It is accompanied by a delicate branch of the trigeminus, apparently
of general cutaneous origin, as already stated, but this branch could not be separately traced in the
cranial cavity. In Lepidotrigla the same mixed nerve is found. In Cottus scorpius a similar nerve
is also found; but in the sections of this fish the nerve is lost beneath the terminal tube of the supra-
orbital canal, and no organ is evident in that tube. In the adult Cottus octodecimospinosus the
nerve is found innervating the terminal organ of the supraorbital canal, as in Scorpaena and Lepi-
dotrigla. Slightly posterior to this nerve, in Cottus, and having a closely parallel course, there is
a communis nerve which has an intracranial origin from the communis ganglion, and from there
runs upward and then backward along the side wall and roof of the cranial cavity. Whether or not
this nerve anastomoses with an intracranial branch of the vagus could not be determined in Cottus
scorpius, but in Cottus octodecimospinosus it does anastomose with such a branch and then issues
near the hind end of the skull; this seeming to indicate that it must form the anastomosis in Cottus
scorpius also. The nerve is accordingly the ramus lateralis trigemini of Stannius’s descriptions, called
by Herrick, in his descriptions of Menidia, the facialis root of the ramus lateralis accessorius. It is
said by Stannius not to be found in Trigla, which I confirm. It is also not found in Scorpaena or
Dactylopterus.

In the Cod, the facialis root of the lateralis accessorius is said by Herrick (00) to be present
and to be accompanied by a few coarse fibers from the lateral line ganglion, which fibers would accor-
dingly seem to correspond to the branch to organ 6 supraorbital in Scorpaena. Whether or not this
latter branch of Scorpaena is represented in Pleuronectes by any part of Cole & Johnstone’s (°01,
p. 128) ramus lateralis accessorius facialis, I can not decide. In Ameiurus it is represented in Herrick’s
(01) branch N. 5, which has a wholly intracranial course until it pierces the frontal to reach its organ;
a branch of the nerve going to the anterior head line of pit organs.

The ophthalmiecus lateralis, in Scorpaena, having given off the branch to organ 6 supraorbital,
runs forward between the two strands of the ophthalmicus trigemini and soon gives off a branch
which, running upward, separates into two parts and supplies the fourth and fifth organs of the supra-
orbital canal. This branch, in the several specimens of Scorpaena examined, and as already stated,
sometimes separated into its two parts before it pierced the frontal, sometimes so separated while in
its canal in the frontal, and, in one specimen, entered the supraorbital canal as a single nerve which
then, lying in the canal, supplied, first, organ No. 4 and then organ No. 5. After giving off this branch
the ophthalmieus lateralis continues forward, sends branches in succession to the third and second
supraorbital organs, and then supplies and terminates in the first organ of that line.

The ramus oticus, in Scorpaena, separates from the buccalis while that nerve is traversing
the trigeminus ganglion, and issues from the ganglion as an independent lateralis branch but accom-
panied by two bundles of fibers one of which is of general eutaneous and the other of communis origin.
This latter bundle issues from the cranial cavity through the trigeminus foramen, and, so far as my
quite unsatisfactory sections show, contains all the communis fibers that go to the trigeminus excep-
ting those that accompany the truncus maxillo-mandibularis. These three bundles of fibers, united
to form a single nerve, run upward and laterally along the hind wall of the orbit and, traversing the

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oticus canal in the sphenotic, issue on the dorsal surface of the skull beneath the frontal bone. A
lateralis branch is then sent to the infraorbital organ in the postfrontal, and a second branch to the
organ in the pterotic, these two branches apparently containing all the lateralis fibers of the nerve.
The remainder of the nerve then runs backward beneath the dermal bones of the top of the skull,
enters the temporal fossa and there runs into and anastomoses with the supratemporal branch of the
vagus, branches being sent backward, from the united nerves, along the dorsal surface of the trunk.
As the main nerve passes dorso-mesial to the dilatator groove, it lies very close to that groove, and
may even be exposed in the bottom of it. A venous vessel, a branch of the external jugular, here
perforates the bottom of the groove and joins the nerve, accompanying it in its further course toward
the hind end of the skull.

In Lepidotrigla the ramus oticus is a purely lateralis nerve, and is not continued posteriorly
beyond the second organ in the pterotic, the pterotie in this fish lodging two organs innervated
by the oticus, without an intervening primary tube. This condition of these two organs in this fish
would seem to represent a stage in the reduction of the two organs here found normally developed
in Amija and certain other fishes to the one organ found in Scorpaena and still other fishes; a reduction
strietly similar to that that is taking place in the 4 th. and 5 th. supraorbital organs both of Lepido-
trigla and of Scorpaena. In Lepidotrigla, the general cutaneous and communis fibers that accom-
pany the oticus in Scorpaena are represented (or replaced) by fibers that do not traverse the oticus
canal; and this is also the condition in Amia, in which fish the ramus oticus is also a purely lateralis
nerve while the ophthalmicus lateralis branch that supplies the anterior head line of pit organs is
accompanied by fibers the character of which was not determined in my work on that fish, but which
have an apparent origin and distribution similar to that of the fibers that accompany the oticus in
Scorpaena.

In Dactylopterus the oticus lateralis is accompanied by a bundle of general cutaneous fibers,
and apparently by those fibers only.

In Ameiurus, the ramus oticus is said by Herrick (’01) to contain lateralis, general cutaneous,
and communis fibers, to have an intracranial origin, and, running upward, to pierce the roof of the
skull; which would seem to mean that it does not first issue in the hind end of the orbit before
entering and traversing the oticus canal. In Menidia the ramus oticus is said by Herrick (’99) to
contain lateralis and general cutaneous fibers, and to correspond to the ramus oticus plus the external
buccal of Cole’s descriptions of Gadus: that is, its lateralis fibers innervate not only the latero-sensory
organs in the postfrontal and pterotic sections of the main infraorbital canal but also the organ
in the dorsal postorbital bone. The ramus oticus of Menidia, minus the external buccal portion, is said
to traverse a canal in the sphenotic and, as just above stated, it contains both lateralis and general
cutaneous fibers. This intimate association, in this nerve, of fibers that are considered by the author to
have a central origin in the facialis and trigeminus segments, respectively, leads Herrick to conclude
that the oticus „was probably originally the dorsal ramus of the facial nerve to which lateralis ele-
ments have been secondarily added and whose general cutaneous portion has, like that of the pro-
fundus nerve, been cenogenetically fused with the-Gasserian ganglion“. That is, it is assumed, in
this statement, that general eutaneous fibers that originally issued from the brain by three distinctly
different apparent roots, and that belonged to three distinetly different but adjacent metameric
segments, have come, in Menidia, to issue by a single apparent root and from a single, unsegmented
cerebral center; this being the result of a central condensation so complete that all traces of the ori-

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ginal subdivisions of the root and center have been lost. The equally evident assumption that all
the lateralis fibers associated with trigeminus nerves are trigeminus ones cenogenetically fused with
the lateralis fibers of the facialis segment, is not made; and yet this assumption has apparently much
more evidence in fact, for the lateralis trigemini and lateralis facialis fibers here, and in many other
fishes also, arise by separate apparent roots and each have an independent ganglion. Johnston, in
a recent work (°05 a, p. 222), does make what is practically the equivalent of this assumption, for
he there says that it seems probable to him that the supraorbital, infraorbital and hyomandibular
latero-sensory lines belong respectively to the profundus, trigeminus and facialis segments. He does
not, however, say that the nerves innervating the three lines must also belong to those same seg-
ments, and such may not be his meaning.

One other point relating to this same subject can here be mentioned. In many teleosts, as
already stated, a strand of general cutaneous fibers, arising from the Gasserian ganglion, joins the
truneus hyoideo-mandibularis facialis.. These fibers join that nerve extracranially in Scorpaena,
Menidia and many other fishes, but intracranially in Pleuronectes (Cole & Johnstone, ’01, p. 124).
Here then is another instance in which the cenogenetic fusion of fibers belonging originally to the
trigeminus and facialis segments might be suggested, but neither Herrick nor Johnston (°05a) even in-
timate it; and yet, in Amia, Kingsbury (°97), before the publication of Herrick’s work, had stated that
general cutaneous fibers issue from the brain in the root of the facialis in all the specimens of that
fish that he had examined, and Johnston (05 b), since the publication of Herrick’s work, says that
they also issue in that root in Petromyzon.

And if the assumption of cenogenetic fusions can be made either for the general cutaneous
or lateralis fibers of the complex, why can it not also be made for the communis fibers? Those fibers
then would, in large part at least, normally belong to the nerves with which they are associated,
certain juxtapositions perhaps being possible where there are no skeletal elements to prevent them;
and the varying quantity of communis fibers in the several trigeminus and facialis nerves would
be due to a corresponding variation in the development ofthe terminal organs innervated by either nerve.

Returning now to the descriptions, the buccalis facialis traverses, in all the fishes examined,
the trigeminus ganglion, and, accompanying the ramus maxillaris trigemini, supplies the organs of
the post- and sub-orbital portions of the main infraorbital canal.

The truncus facialis, in Scorpaena, Lepidotrigla and Dactylopterus contains motor, lateralis
and communis fibers, the latter fibers, in all these fishes, traversing the facialis foramen and joining
the other fibers of the truncus either as they are traversing, or after they have traversed the same
foramen.

The ramus palatinus contains communis fibers only, and in Scorpaena it usually has an inde-
pendent origin from the communis ganglion. In the 55 mm Scorpaena, it had such an origin on one
side of the head, while on the other side it arose from the base of the bundle of communis fibers sent
to the trigeminus ganglion. Turning downward in the cranial cavity, the nerve traverses the palatine
canal in the proötie, enters the myodome, and, turning forward, enters the orbit along its floor; its
further course not being traced. In Cottus, the palatinus has a course similar to that in Scorpaena,
but in Trigla, Lepidotrigla and Dactylopterus it does not separate from the other communis fibers
until after those fibers have traversed the facialis foramen. There it turns forward and downward
along the floor of the trigemino-facialis chamber, issues through the trigeminus opening of that
chamber, and, traversing the myodome of the fish, enters the orbit.

The next branch of the truncus facialis, in the 55 mm Scorpaena, is given off as the truncus
traverses its foramen, and contains communis fibers only. Turning downward and backward it issues
through the facialis opening of the trigemino-facialis chamber and then almost immediately joins
and anastomoses completely with the ramus anterior of the nervus glossopharyngeus. The nerve
so formed is Jacobson’s nerve. It runs antero-ventrally along the dorso-anterior aspect of that part
of the hyoid cleft that lodges the opercular hemibranch, and is distributed to that hemibranch and
to the adjacent tissues on the anterior surface of the cleft, delicate branches of the nerve accompanying
both the efferent and afferent arteries of the hemibranch. In both Cottus and Lepidotrigla this nerve
is found in almost identical conditions, and it doubtless also is in Dactylopterus, but in this latter
fish it was not traced beyond the point of its anastomosis with the glossopharyngeus. The fibers
of the glossopharyngeus all run distally with the facialis fibers, none of them turning proximally
along the facialis nerve, as I was led to suppose might be the case in Scomber.

Immediately before or after the facialis branch to Jacobson’s nerve arises from the truncus
facialis, that truncus receives, in both Scorpaena and Lepidotrigla, a communicating branch or
branches from the facialis sympathetie ganglion, this connection doubtless existing also in the other
fishes of the group but not there being traced.

After giving off the nerve to Jacobson’s anastomosis, the facialis, in Scorpaena and Lepido-
trigla, sends a motor branch to the adductor arcus palatini, and then a branch to the adductor hyo-
mandibularis; this latter branch also innervating the adductor and levator opereuli. These two nerves
together form the ramus opercularis profundus of Herrick’s nomenclature. The branch that goes
to the adductor hyomandibularis is joined posteriorly by and anastomoses with a branch of the supra-
temporal branch of the nervus vagus, certain of the fibers of the vagus running proximally along
the fibers of the opercularis profundus and the two nerves thus appearing as a complete and uninter-
rupted circuit. In Cottus and Dactylopterus the opercularis profundus is also found, but its ana-
stomosis with a branch of the vagus was not traced.

The truncus facialis, in Scorpaena and Lepidotrigla, is then joined by the communicating
branch from the trigeminus ganglion and becomes the truncus hyoideo-mandibularis of Stannius’
nomenclature. This nerve continues laterally and slightly downward and enters the facialis canal in
thehyomandibular, lying, in its course, postero-dorsal to the adductor arcus palatini and anterior to the
adduetor hyomandibularis and to all of thelevator muscles of the branchial arches. As it entersitscanal
in the hyomandibular, a branch is sent backward in the small branch canal in the hyomandibular, and,
separating into two parts, innervates the two dorsal latero-sensory organs in the preopereular canal.
This small branch is the ramus opercularis superficialis of Herrick’s nomenelature, and it was traced
in the dissections and not in the sections of Scorpaena; the sections here being quite imperfect. In
the dissections no branch could be found distributed to the outer surface of the operculum, such as
Herrick describes in Menidia, but in Lepidotrigla this branch was found, though the character of its
fibers could not be determined. In Menidia these fibers of the nerve are said by Herrick to be partly
general cutaneous and partly lateralis. These latter fibers are said to supply certain naked cutaneous
sense organs lying on the outer surface of the operculum, these organs being of that intermediate
type between pit-organs and terminal buds which are always puzzling to every observer. Herrick
concludes that these organs must, because of their innervation, belong to the lateral line rather than
the communis system, a conclusion I am not prepared, from the facts so far presented, to accept.
In the Cod the corresponding fibers of this nerve are said by Herrick (’00) to probably be wholly

Zoologica. Heft 57. : 12

u, 9)

lateralis ones, and they are said to have been definitely traced to certain opercular pit organs. In
Pleuronectes, Cole and Johnstone (’01, p. 132) also find the nerve a purely lateralis one, its terminal
branches supplying an opercular line of pit organs.

Having given off this small branch the main truncus, in Scorpaena and Lepidotrigla, traverses
the facialis canal in the hyomandibular and issues on the external surface of the shank of that bone.
There it separates into its two parts, theramushyoideus and truncus mandibularis, the latter of which
soon separates into the rami mandibularis externus and internus. The ramus hyoideus runs downward
and backward through the opening between the hyomandibular and the preopercular and so reaches
the hyoid arch, its further course not being traced. The rami mandibularis externus and internus
run downward and forward across the hyomandibulo-symplectie interspace of cartilage, and then
pass, respectively, through the openings on the posterior and anterior side of the sympleetic, as
already fully described, and so reach the inner surface of the palato-quadrate apparatus and then
the mandible. The externus sends branches, as usual, to the latero-sensory organs of the preoper-
culo-mandibular line, and certain branches also to the general tissues, the nerve thus not being a
simple latero-sensory nerve. The internus goes to the inner surface of the mandible, its special distri-
bution and relations to the other nerves not being investigated. Whether it contains communis fibers,
and those fibers only, as in Menidia, could not be determined, but, whatever its composition may
be, it is a true ramus mandibularis internus as that nerve is defined by Stannius. Herrick (’99, p. 171)
takes the position, and it may be correct, that a nerve can not be a mandibularis internus unless
it contains communis fibers; and the inference is that it must contain those fibers alone, for he says
that the nerve is absent in Gadus notwithstanding that both Stannius and Cole deseribe a nerve in
that fish that is said to have the topographical position of an internus. Neither Stannius’ nor Cole’s
descriptions of the course of the nerve being very definite, I have had the nerve looked for in dis-
sections of Gadus merlangus, but it could not be found; which would seem to confirm Herrick’s con-
clusion that the nerve, when present, contains communis fibers only.

In Dactylopterus the truncus hyoideo-mandibularis facialis does not traverse a single canal
in the hyomandibular and issue on the external surface of that bone, as it does in Scorpaena, Cottus,
Trigla and Lepidotrigla. When it reaches the internal surface of the hyomandibular the nerve, in
Dactylopterus, separates into its two portions, the ramus hyoideus and the truncus mandibularis,
the latter of which alone traverses the facialis canal through the bone and issues on its external sur-
face. The ramus hyoideus simply passes beneath a bridge of bone on the internal surface of the
hyomandibular and reappears on the internal surface of that bone. This will be further discussed
when describing the bones in this fish. From the truncus mandibularis, as it enters its canal in the
hyomandibular, a lateralis branch, accompanied by what are apparently wholly general eutaneous
fibers, passes backward through a small branch canal in the bone, this nerve supplying the two dorsal
organs of the preopercular canal and the tissues on the outer surface of the opereular. The truncus
mandibularis contains communis fibers and is joined, after it reaches the outer surface of the hyo-
mandibular, and as already stated, by the communicating general cutaneous branch that issues
through the trigeminus opening of the trigemino-facialis chamber. After being joined by this com-
municating branch, the entire truncus mandibularis passes to the internal surface of the palato-
quadrate through an opening that lies posterior to the symplectic, no evident branch passing in-
ward anterior to that bone. There is thus no evident ramus mandibularis internus in this fish. The
mandibularis externus, after it reaches the internal surface of the palato-quadrate, certainly con-

ae

tains fibers other than lateralis ones, but whether they are all general cutaneous ones, or partly com-
munis, could not be determined. Ifthey are all general cutaneous ones, Dactylopterus would resemble
Ameiurus (Herrick, ’01) in this respect, the communis fibers that form part of the ramus mandibularis
facialis in that fish all being distributed to regions external to the palato-quadrate.

NERVUS ACUSTICUS.

The nervus acusticus has, in sections of Scorpaena and Lepidotrigla, two roots, which enter
the tubereulum acusticum close together, the slight swelling at their point of entrance Iying im-
mediately ventral to the swelling for the lateralis nerves. The anterior root belongs to the anterior
division of the nervus, the posterior root to its posterior division.

The anterior division, or ramus vestibularis, running forward sends, in my 55 mm Scorpaena,
two branches to the macula acustica sacculi. In the 63 mm Lepidotrigla, one of the two branches
that go to this organ has a separate origin from the medulla, between the anterior and posterior roots
of the nervus, the second branch arising from the posterior root. In both fishes, the ramus vestibularis
then sends a branch to the macula acustica utriculi, another branch to the crista acustica in the
ampulla of the external canal, and then ends in the crista acustica of the ampulla of the anterior
canal. All of these several branches separate distally into two parts, the two parts of the two
nerves that go to the ampullae supplying two separate and distinet organs in each of the ampullae,
but the nerve that goes to the utriculus supplying different parts, only, of the large and continuous
utricular macula.

The posterior division of the nervus, or ramus cochlearis, runs backward and separates into
two parts one of which passes dorsal to the root of the glossopharyngeus and the other ventral to that
root. The dorsal branch supplies the two organs of the crista acustica in the ampulla of the posterior
canal, the ventral one supplying the two organs of the macula neglecta and also the papilla acustica
lagenae. The lagena is partially differentiated as a diverticulum arising from the dorsal surface ot
the hind end of the sacculus.

The papilla lagenae and the maculae sacculi and utrieuli each have related otoliths.

There was no indication of a ductus endolymphaticus in the dissections of Scorpaena, but in
sections, both of embryos and of the adult, a small remnant of the ductus is evident. In Trigla hirundo
the ductus is two or three times as large as in Scorpaena, being evident even in dissections. Retzius
(’81) shows the ductus in Trigla gurnardus.

NERVUS GLOSSOPHARYNGEUS.

The nervus glossopharyngeus of Scorpaena arises by a single apparent root, composed, as in
Menidia, of two bundles of fibers, a motor and a communis one.

After issuing from the medulla the root runs at first posteriorly, then turns outward between
the dorsal and ventral branches of the ramus cochlearis acustici, and then forward and laterally to
its foramen, passing between the sacculus and the sinus utriculi posterior. At the bend in the root
there is an important collection of ganglion cells lying on the posterior aspect of the nerve, and from
this ganglion, in the adult, an intracranial communicating branch was found, going to the root of the
vagus. In the 55 mm specimen this branch could not be satisfactorily traced. In the 63 mm Lepi-
dotrigla two branches arise from the ganglion, one of which joins the root of the vagus, the other one
entering the intracranial vagus ganglion. The dorsal one of the two branches receives, on one side of

= 9 =

the specimen, but not on the other, a relatively important branch from the dorsal branch of the ramus
cochlearis acustici.

Having traversed its foramen the nerve turns forward along the outer surface of the skull and
swells into an elongated ganglion, which has a sympathetie ganglion associated with it. From this
ganglion two nerves arise. One of these nerves is the ramus anterior of the nervus, which, running
forward, anastomoses with the communis branch from the facialis to form Jacobson’s nerve, as al-
ready described. The other branch is the ramus posterior of the nervus and was not further traced.

NERVUS VAGUS.

a. Nervus lineae lateralis vagi.

The root of the nervus lineae lateralis vagi issues from the tuberculum acusticum directly dorsal
and slightly posterior to the root of the glossopharyngeus. In the 63 mm Lepidotrigla it arises by two
roots, a small anterior and a large posterior one. It runs posteriorly in the cranial cavity and issues
through the vagus foramen, there lying directly upon the dorsal surface of the root of the vagus.
A supratemporal branch is immediately given off, and running upward innervates the latero-sensory
organs of the supratemporal commissure and also those of the extrascapular and suprascapular sec-
tions of the main infraorbital canal; this branch having a separate extracranial ganglion. The main
nerve then enters its own ganglion, and was not further traced. No ganglion cells are found in the
main nerve before it issues from the cranial cavity, and there is no branch of the nerve accompanying
the nervus glossopharyngeus.

b. Nervus. Vargus:

The roots of this nerve could only be properly traced in the 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 the main root of the nervus. These rootlets, in Lepidotrigla, arise one anterior
to the other, in the line of the main root, at intervals of about 80 ı. They pierce what is apparently
a two layered cranial membrane, richly supplied with blood vessels, the anterior rootlet then joining
the main vagus root, while the other two traverse the intracranial vagus ganglion, as will be later
described. The anterior rootlet seems to be a purely motor one, the other two apparently containing
communis fibers only; but of these determinations I am not at all certain.

The main root of the nervus contains motor, communis and general cutaneous fibers, most of
these latter fibers arising from the spinal V tract 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 the three anterior rootlets, and also by one of
the two communicating branches from the intracranial ganglion at the bend in the root of the glosso-
pharyngeus. On or in connection with the general cutaneous portion of the root, an important intra-
eranial ganglion is formed, and this ganglion is joined by one of the branches from the glossopharyn-
geus and is traversed by two of the anterior rootlets of the vagus itself. From the ganglion a stout
intracranial branch is sent upward in the cranial cavity and issues on the 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 the sections of Lepidotrigla it could not be determined whether or not this nerve anastomosed
with the recurrent component that accompanies that branch of the lateralis facialis that innervates

Een

organ 6 supraorbital; but in dissections of Trigla hirundo, where this intracranial branch is also found,
the anastomosis of the nerve with the branch of the facialis was readily established. Stannius (’49,
p- 85) says that this anastomosis is not found in Trigla gurnardus, and he also says that, in that fish,
the nerve arises partly from the root of the nervus lineae lateralis. This last statement is certainly
an eTTor.

In Scorpaena no intracranial branch of the vagus could be found either in the sections or in
the adult.

The main root, in Lepidotrigla, traverses the vagus foramen, there being distinctly separable
into two bundles, one of which contains the motor and communis fibers, and perhaps also certain
of the general cutaneous fibers, while the other arises directly from the intracranial ganglion and must
be largely, if not entirely, composed of general cutaneous fibers. This latter bundle immediately turns
upward, accompanying the supratemporal branch of the nervus lineae lateralis; but it soon leaves
that nerve, and turning laterally and forward passes onto the external surface of the levator and
adductor opereuli muscles and is there in large part distributed to the inner and outer surfaces of the
operculum, one branch of it, however, joining and anastomosing with the terminal fibers of the ramus
opercularis profundus facialis. Whether any fibers of this nerve accompany the supratemporalis
lateralis, or not, could not be positively determined, but none of them seemed to.

The remaining fibers of the root of the vagus soon swell into the large ganglionie mass of that
nerve and were not further investigated.

OCCIPITAL NERVES.

The oceipital nerves were not carefully traced, none of the 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 trunk which issues through the foramen in the exoceipital.

NERVUS SYMPATHETICUS.

A large sympathetic ganglion, the anterior cerebral sympathetie 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, but posteriorly it is separated from that ganglion by the
jugular vein, the two ganglia being connected by several bundles of fibers.. From the anterior end of
the ganglion a branch is always sent to join the radix longa of the ciliary ganglion, and, in the one
adult specimen of Scorpaena that was examined, a second branch is sent direct to the ciliary ganglion,
as already fully described.

A second sympathetic ganglion lies ventral to the truncus facialis and is conneeted with that
truncus by one or two strands; this ganglion sometimes being an independent ganglion and sometimes
simply an enlargement of a posterior prolongation of the anterior ganglion. From the hind end of
this second ganglion, the sympathetiec trunk 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 sympathetie ganglia both being connected by fibers with the related ganglia of the
cranial nerves.

— N

Il. Sebastes dactylopterus.

The skull of Sebastes dactylopterus is relatively taller and shorter than that of Scorpaena
serofa; the orbits being relatively larger, the interorbital region narrower, the antorbital region shorter,
and the mid-dorsal line considerably more convex than in the latter fish. The space between the eyes
is concave.

The ventral surface of the skull, starting immediately posterior to the dentigerous ridge on the
ventral surface of the anterior end of the vomer, is slightly convex, the summit of the convexity
lying beneath the foot of the basisphenoid.

The internasal ridge is similar to that in Scorpaena, but the mesethmoid processes are smaller
and project almost directly forward instead of forward and upward. The bases of these processes
are connected by a curved transverse ridge, concave anteriorly, against the anterior surface of which
the hind end of the internasal ridge abuts and ends. Against the wide and slightly concave lateral
surface of each process the corresponding nasal rests, that bone being firmly bound to the process and
bearing, on the dorsal surface of its hind end, the nasal spine.

Immediately lateral to the base of the mesethmoid process, there is a large aperture which
lies between the ectethmoid below and the anterior end of the frontal above. This aperture is the
anterior opening of that section of the supraorbital latero-sensory canal that lies in the frontal, com-
bined with the anterior opening of a small canal, between the ectethmoid and the frontal, that
transmits the rami ophthalmicus lateralis and ophthalmicus trigemini. Starting from this aperture,
a large rounded ridge runs backward between the orbits, curving at first slightly toward the middle
line and then diverging slightly from it, and marking the course of the supraorbital latero-sensory
canal. Beginning slightly posterior to its anterior end, the ridge bears on its dorsal surface a narrow
ridge that runs posteriorly, concentric with the dorsal edge of the orbit, and, gradually increasing in
height, terminates in a spine. This spine lies posterior to the transverse commissure formed by the
fusion, in the middle line, of the fourth primary tubes of the supraorbital canals of opposite sides,
and overhangs the seventh or terminal tube of the supraorbital canal. It is accordingly the frontal
spine of the fish, and the narrow ridge that terminates in it is the frontal spinous ridge. The third
primary tube of the supraorbital canal opens on the dorsal surface of the frontal, lateral to this frontal
ridge, at about the middle point of the orbit.

The hind border of the supraorbital commissure is marked by a slight ledge, that part of the
dorsal surface of the skull that lies posterior to the ledge lying at a slightly deeper level than the
part that lies anterior to it. The frontal spinous ridge, curving postero-laterally, crosses the lateral
end of the transverse ledge, and at this point, or from the mesial surface of the frontal ridge slightly
posterior to it, the parietal spinous ridge begins. Running backward and slightly laterally from there,
the parietal ridge terminates in the parietal spine, that spine Iying directly above the supratemporal
cross-commissural canal. The anterior end of the parietal ridge lies on the hind edge of the frontal,
the remaining and larger part of it lying on the parieto-extrascapular. Immediately posterior to the
parietal spine, a short ridge begins on the dorsal surface of the extrascapular part of the parieto-extra-
scapular, and, continuing the line of the parietal ridge, terminates, at the hind end of the skull, in the
nuchal spine.

The nasal, frontal, parietal and nuchal spines of Sebastes thus form a row of spines on the dorsal
surface of the skull that is strietliy comparable to the middle row of spines in Scorpaena, but, as will

ee

be explained below, the frontal spine has been displaced laterally to such an extent that it might
be mistaken for one of the lateral row of spines.

The parietal spinous ridge and the transverse commissural ledge bound laterally and anteriorly
a flat smooth median portion of the dorsal surface of the brain case, this surface lying at a slightly
lower level than the anterior part of the dorsal surface of the skull. This flat and slightly depressed
surface thus certainly represents a slightly developed subquadrangular groove on the vertex of the
skull of the fish, notwithstanding that Günther (’60, vol. 2, p. 95) says that all members of this family
are without that groove. Posteriorly, this slightly developed groove is bounded by a slight transverse
ridge which lies on the dorsal surface of the parieto-extrascapular of either side, near its hind edge.
This ridge extends to the mesial edge of either parieto-extrascapular, but as these bones do not meet
in the middle line, the ridge does not extend entirely across the hind edge of the skull. The ridge
marks the course of a portion of the supratemporal commissure, the median portion of that commissure
lying in the dermal tissues, between the ridges of opposite sides, in a slight groove on the flat dorsal
surface of the supraoceipital. The slishtly depressed surface that represents the subquadrangular
groove is thus not bounded posteriorly by a complete ridge, as in Scorpaena, simply because the
median portion of the supratemporal commissure is not here enclosed in bone.

The lateral row of spines is represented by five spines. The anterior spine of the row is the
preoeular spine, Iying on that edge of the ectethmoid that forms the anterior portion of the roof of
the orbit. The next two spines of the row are the supraocular and postocular ones, both of which lie
close together, one directly behind the other, on the dorsal surface of the roof of the orbit, near ıts
lateral edge, and immediately anterior to the frontal spine. In the speeimen used for illustration the
postocular spine is bifid on one side of the head, and, anterior to the supraocular spine, there is a small
additional spine. The supraocular and postocular spines, as normally found, together with the frontal
spine form a short line of three spines lying close together and equidistant one from the other, and
they eorrespond in position to the supraocular, postocular and tympanic spines of Jordan & Gilbert’s
diagram of the spines in Sebastodes. The frontal spine however belongs, as just above described,
to the middle row of spines and not to the lateral one. The remaining two spines of the lateral row
are small ones that hardly rise above the outer surface of the body, one of them lying on the hind
edge of the suprascapular and the other on the hind edge of the supraclavieular. On the pterotic
there is a ridge, but it does not end in a spine.

The intermediate row of spines is represented by a small spine on the hind edge of the epiotie
process of the suprascapular, this spine lying slightly mesial to the suprascapular spine of the lateral row.

The bones of the snout of Sebastes differ in no important respect from those of Scorpaena
scrofa. The mesethmoid processes, as already stated, are shorter than in Scorpaena, and are directed
forward instead of upward and forward. The nasals are traversed by the supraorbital latero-sensory
canal, and are relatively larger than in Scorpaena. The lateral arm of the ectethmoid is not dit-
ferentiated from the wing of the bone, as it is in Scorpaena, the ventral edge of the wing being simply
thickened and giving articulation, by two articular surfaces, to the lachrymal and palatine. The
vomer has, on either side, an ascending process, which gives articulation, as in Scorpaena, by the
intermediation of a disk of semi-cartilaginous tissue, to the ascending process of the maxillary. The
maxillary has a right-angled ascending process and a ligamentary process, the former artieulating
both with the premaxillary and the vomer, and the latter giving support to the lachrymal and pala-
tine, as in Scorpaena. The rostral is more deeply grooved on its ventral surface than in Scorpaena.

By

There are naso-maxillary, ethmo-maxillary, intermaxillary, rostro-palatine, rostro-nasal, rostro-
maxillary, vomero-palatine, lachrymo-palatine and maxillo-mandibular ligaments, as in Scorpaena.
And, in addition to these ligaments, there were, in the large specimen of Sebastes that was particu-
larly examined, other well-developed ligamentous or fibrous bands that were not evident in the fibrous
and connective tissue that, in the smaller specimens of Scorpaena that were examined, connected
the several bones. One of these fibrous bands extended from the dorso-anterior edge of the ascending
process of the maxillary to the mesial surface of the maxillary process of the palatine; and, lyıng
on the dorsal surface of this wide band, a flat ligament extended from the same point to the anterior
edge of the lachrymal. Another ligament extended from the proximal end of the shank of the
maxillary into the angle between the ascending and maxillary processes of the premaxillary, binding
these two bones together in the region of their articular surfaces. The naso-maxillary ligament, in
this fish, spreads at its anterior end, and is there inserted partly on the anterior edge of the lachrymal
as well as on the ligamentary process of the maxillary.

The frontal has a ventral flange as in Scorpaena.

The alisphenoid has slight ridges on its outer surface which represent those two little processes
of the bone of Scorpaena that form, in that fish, ossified portions of the parasphenoid leg of the bone.
The bone is traversed by a canal which transmits the nerve that innervates the terminal or sixth
organ of the supraorbital canal, this canal beginning on the outer surface of the skull in the sutural
line between the alisphenoid and proötie, and from there running upward in the alisphenoid to about
the middle point of the bone, where it opens into the cranial cavity.

The trigemino-facialis chamber and related nerves are as in Scorpaena. On the outer surface
of the proötic, immediately ventral to the trigemino-facialis chamber, the dorsal end of the first
infrapharyngobranchial is strongly attached by fibrous tissues. The pedicle of the basisphenoid is
straight, instead of being strongly curved. The myodome has proötic and basioceipital portions,
and opens posteriorly onto the ventral surface of the basiocecipital. The sphenotie is perforated,
from its orbital face, by the oticus canal, this canal crossing the mesial end of the dilatator fossa
and transmitting the oticus lateralis accompanied by a more slender nerve which runs backward
into the temporal fossa. The dilatator fossa is relatively larger than in Scorpaena, but has no apprec-
iable roof excepting along its anterior edge where it is roofed by the small postfrontal bone.

The dorsal surface of the pterotic is deeply excavated by the main infraorbital canal, the
section of canal that is related to it being roofed only by a single narrow and delicate bridge of bone.
Anterior to this bridge, and lying partly on the sphenotic and partly on the frontal, there is a large
groove which lodges those portions of the main infraorbital and supraorbital canals that adjoin their
point of anastomosis. Posterior to the pterotic bridge, between it and the anterior edge of the lateral
extrascapular, there is a smaller, but still relatively large opening which is the latero-sensory opening
between the pterotie and lateral extrascapular. The narrow pterotice bridge, and the narrow pterotic
edges of the large groove that lodges the main infraorbital canal represent all there is of the outer,
dorsal surface of the dermo-pterotic.

The lateral extrascapular is a delicate bone that covers a part only of the temporal fossa.
It is traversed by the main infraorbital and supratemporal canals, both of which canals are large.
The main infraorbital canal lies mainly in a deep groove on the lateral edge of the bone, the canal
being wholly enclosed, at one point only, by a narrow bridge of bone. The anterior corner of the
bone rests on the dorsal surface of the pterotic, and its posterior corner on the dorsal surface of the

one

suprascapular. Elsewhere the bone is entirely suspended in dermal tissues. Between its anterior
edge and the adjoining edges of the pterotic and parieto-extrascapular, there is a large eircular opening
which leads directly into the anterior end of the temporal fossa.

The suprascapular has opisthotic and epiotie processes, the former process resting on and
being bound by tissues to an eminence on the hind end of the opisthotie. The epiotic process rests
on the dorsal surface of the suprascapular process of the epiotie, its anterior end apparently coming
into contact with, but not being completely overlapped dorsally by the hind end of the parieto-
extrascapular. The lateral edge of the bone is traversed by the main infraorbital canal, and gives
artieulaticn, on its ventral surface, to the dorso-anterior corner of the supraclavicular; there
here being, as in Scorpaena, two articular surfaces, an articular head, and a closely adjacent
articular facet.

The supraclavicular resembles the bone of Scorpaena. Its dorsal edge is traversed by the main
infraorbital canal. Near its anterior edge, at or about its ventral third, it gives insertion to the occip-
ito-supraclavieular ligament.

The parieto-extrascapular, in the two specimens examined, did not meet, in the mid-dorsal
line, its fellow of the opposite side. In one of these two specimens the two bones were widely separated:
in the other, a much smaller specimen, they approached each other closely at their antero-mesial
corners. A considerable, but varying portion of the dorsal surface of the supraoceipital thus here
comes to the dorsal surface of the skull, and on its hind edge the median portion of the supratemporal
commissure lies, enclosed in dermal tissues only. The hind edge of the parieto-extrascapular overhangs
but slightly the posterior surface of the skull, giving rise to a shallow supratemporal pocket.

The supraoceipital has a spina oceipitalis similar to that of Scorpaena, its ventral end being
held, as in Scorpaena, but to a less extent than in that fish, between thickened process-like portions
of the exoccipitals. The posterior surface of the bone is crossed, as in Scorpaena, by what I there
described as the hind edge of the primary skull, this edge being represented in its lateral portion
by a strong ledge, but in its median portion by a low and rounded ridge.

The temporal fossa is large, and similar to that in Scorpaena; but a large eircular opening
between the pterotie, lateral extrascapular and parieto-extrascapular leads from it onto the dorsal
surface of the skull.

The epiotie, opisthotie, exoccipital, and basioceipital are similar to those bones in Scorpaena.
The exoccipital has a mesial process on its cerebral surface, as in Scorpaena. The proötie, in the
specimen used for illustration, was perforated, on one side, by two small foramina lying immediately
beneath the trigemino-facialis chamber, due doubtless to wear or to defects in the bone.

The bulla acustica is large, and in the angle that marks its dorsal boundary there are separate
glossopharyngeus and vagus foramina, the glossopharyngeus foramen lying in the exoceipital on
one side of the specimen examined in this connection, but in the sutural line between that bone and
the proötie on the other side of the specimen. Posterior to the vagus foramen, the exoceipital is
pierced by a foramen for the oceipital nerves, as in Scorpaena.

The infraorbital chain of bones includes a lachrymal, two suborbitals and two postorbitals.
The lachrymal and two suborbitals correspond to the sames bones of Scorpaena, but they are much
narrower and more delicate than in that fish. The two postorbitals are delicate semieylindrical bones
that extend from the dorsal edge of the second suborbital to the ventral edge of the postfrontal and

bound the hind edge of the orbit. They transmit the main infraorbital canal from the second sub-
Zoologica. Heft 57. 13

ge

orbital to the postirontal, the canal here forming a continuous suborbital ring, instead of being
interrupted as in Scorpaena. The orbital edges of the lachrymal and two suborbitals are broadened
to form a flat, curved and delicate suborbital shelf.

The lachrymal articulates, by its dorsal edge, with the ectethmoid. Its ventro-anterior corner
rests upon, and is firmly bound to the ligamentary process of the maxillary, the dorso-mesial portion
of its anterior edge resting upon the dorsal surface of the maxillary process of the palatine. At the
hind end of this surface of contact with the palatine a short stout ligament connects the two bones.
Posterior to the point of attachment of this ligament, between it and the articular surface for the
ectethmoid, the large anterior primary tube of the main infraorbital canal opens on the external
surface of the bone. The second and third tubes of the main infraorbital canal issue from that canal
as it traverses the lachrymal, the fourth tube issuing between the lachrymal and first suborbital,
as in Scorpaena. The anterior edges of the second and third tubes, one or both, are produced in
short sharp spines, these being the only spines on the infraorbital chain of bones. The fifth tube
opens on the lateral surface of the second suborbital bone, and the prolonged hind end of the dorsal
edge of this tube reaches and is bound to the preopercular. The sixth tube lies between the dorsal
edge of the second suborbital and the ventral end of the first postorbital, the seventh tube Iying
between the two postorbitals, and the eighth tube between the second postorbital and the postfrontal.

The hyomandibulo-palato-quadrate apparatus does not differ in any important respect from
that of Scorpaena. The operceular process of the hyomandibular is not so long as in Scorpaena. The
preopercular has five spines on its hind edge; but the second spine from the dorsal edge of the bone,
instead of the first one, is the longest, and there is no supplementary spine either at the base of this
spine or at the base of the dorsal spine, as there is in Scorpaena. The quadrate has a posterior process,
the posterior surface of which is applied against and firmly bound to the ventral end of the preoper-
cular. On the inner surface of the quadrate there is a symplectie groove which lodges the ventral
portion of the symplectic. The metapterygoid has lateral and mesial flanges on its hind edge, both
of which are connected with the anterior edge of the hyomandibular, as in Scorpaena: but these
flanges of Sebastes do not meet to form a dorsal prolongation of the hind edge of the bone, and there
is no continuation of the flanges along the dorso-anterior edge of the bone, as in Scorpaena. The
ectopterygoid and entopterygoid differ but little from those of Scorpaena. The palatine is relatively
shorter than in Scorpaena, and its ventral process is not so tall as in that fish. The opercular, sub-
opercular and interopercular are as in Scorpaena.

The mandible has artieular, angular and dentary elements, closely resembling those of Scorpaena.

II. Cottus octodecimospinosus.

The skeleton of the head of Cottus octodecimospinosus differs considerably, in several important
respects, from that of Scorpaena and Sebastes.

1.2SKÜELE:
The skull as a whole is relatively low and flat, and the brain case is relatively long, occupying
nearly one half the length of the skull. The bones of the skull are all much thinner and more delicate
than those of Scorpaena and Sebastes, the brain case being little more than a thin shell of bone.

a Egg =

The postorbital process of the skull is a short broad pyramidal process which lies at the anterior
two-fifths, approximately, of the length of the brain case, and in the dorsal two-fifths only
of the lateral surface of the skull. The process, as always, separates the orbital and lateral surfaces
of the brain case, but these two surfaces here lie in nearly the same plane, the postorbital process
forming simply a large ridge and not a marked angle between them, as it does in Scorpaena. Because
of the position of the orbital surface of the brain case, so slightly inclined to its lateral surface, and
because, also, of the absence of a basisphenoid, the orbital opening of the brain case is very large.
The postorbital corner of the frontal lies in the transverse plane of the lateral bounding edges of the
orbital opening of the brain case, considerably anterior to the postorbital process of the skull.

The postorbital process is formed, as usual, by portions of the proötic and sphenotic bones,
and it bears a large circular facet for the anterior head of the hyomandibular. Starting from the
base of the process, an angular edge runs antero-laterally toward the antero-ventral corner of the
brain case, another but much more rounded edge running postero-ventrally toward the hind end of
the brain case. Between these two edges and the base of the skull there is a flat smooth and raised
portion of the lateral surface of the brain case, the flat bulla acustica forming the rounded dorso-
posterior edge of the surface.

Anterior to this flat surface and to the postorbital process, there is a depressed region which
forms the orbital surface of the brain case. Dorso-posterior to the flat surface there is, on the lateral
surface of the brain case, a large triangular subtemporal depression, similar to but more extensive
than the one in Scorpaena, the depression here reaching almost to the dorsal edge of the lateral sur-
face of the skull. Anterior to this subtemporal depression, between it and the postorbital process,
there is a shallow groove, which apparently represents the fossa there found in Scorpaena. In the
postero-ventral corner of the subtemporal depression is the vagus foramen, the glossopharyngeus
foramen lying slightly anterior to it at the ventral edge of the depression; both foramina perforating
the exoccipital. The anterior corner of the subtemporal depression is shut off from the orbital surface
of the brain case by the base of the postorbital process, and does not, as in Scorpaena, connect, by
a groove, with the facialis opening of a trigemino-facialis chamber. Dorsal, or dorso-anterior to the
dorsal corner of the subtemporal depression is the small oval facet for the posterior articular head
of the hyomandibular, this facet lying wholly on the pterotie.

The DILATATOR FOSSA is small, lies directly anterior to the posterior articular facet
for the hyomandibular, and almost directly dorsal to the anterior articular facet for that bone.
The fossa lies partly in the sphenotic and partly in the pterotie, and is roofed by the pterotic alone,
the postfrontal here lying wholly anterior to it.

The TEMPORAL FOSSA is small, and five of the six fossae in my three specimens open
mainly on the lateral surface of the skull, between the opisthotie leg of the suprascapular and
the posterior process of the pterotic. The usual opening, on the posterior surface of the skull, be-
tween the opisthotie leg of thesuprascapular and the epiotic, is, in four of these five instances, reduced
to a small opening, and in one instance almost entirely closed.

This reduction of this opening is due to the encroaching ingrowth of both the epiotie and
the opisthotic leg of the suprascapular, but mainly to the marked broadening of the latter leg. When
the suprascapular is removed the hind end of the fossa is found to be fairly large, and to lie at the
extreme dorso-lateral corner of the hind end of the skull. The fossa, thus exposed, seems short when

— 100 —

viewed from above, but this is largely due to the marked elongation of the brain case; for the fossa
extends from the hind end of the skull about halfway to the postorbital process, which is about its
normal length. At about the middle of its length the fossa is bridged by the narrow and tubular,
mesial one of the two lateral extrascapular ossieles found in this fish. Posterior to this bridge, the
central portion of the fossa is without roof, its mesial edge being slightly overhung by the lateral
edge of the epiotie, and its lateral edge being roofed by the lateral one of the two lateral extrascapular
ossieles. Anterior to the bridge, the fossa is wholly without roof. The posterior opening of the fossa
is roofed, as usual, by the suprascapular and the suprascapular process of the epiotic. The fossa
thus opens on the dorsal surface of the skull by two large openings. In the mesial wall of the posterior
portion of the fossa there is a pronounced preöpiotic recess.

The SUPRATEMPORAL FOSSA is as in Scorpaena, but much smaller.

There are, as is well known, three SPINES on either side of the dorsal surface of the skull,
and one on the supraclavicular. The three spines on the dorsal surface of the skull form a row that
corresponds to the mesial row of spines of Scorpaena, the supraclavicular spine being the only one
of a lateral row.

Of the three spines that form the mesial row, the anterior one lies on the dorsal surface of
the hind end of the nasal, and, projecting backward, overhangs the opening of the second primary
tube of the supraorbital latero-sensory canal. The next posterior spine of the row lies on the dorsal
surface of the frontal, and its relations to the supraorbital canal show that it is a frontal spine. It
lies, however, near the postorbital corner of the frontal, considerably anterior to its hind edge, this
position thus differing considerably from that of the frontal spine in either Scorpaena or Sebastes.

The base of the spine, in Cottus, overlies that part of the supraorbital canal that lies
between the fifth and sixth tubes of that line, and projects backward toward the seventh tube or
between that tube and the fifth tube. The sixth tube anastomoses with the main infraorbital canal,
and it was double in each of the two specimens examined, the fifth tube being also double in one
specimen. There is no spinous interorbital ridge related to the frontal spine.

From the base of the frontal spine a strong ridge begins, the oceipital ridge of Jordan and
Evermann’s (’98) descriptions, and running backward in a curved course across the posterior portion
of the frontal and then across the parieto-extrascapular, ends, at the hind end of the latter bone,
in a stout spine. This spine lies partly above but mostly posterior to the supratemporal canal, its
position thus not definitely indicating whether it is a parietal or a nuchal spine. It is however, in all
probability, a spine developed in relation to the parietal bone, and hence a parietal spine, the ridge
that terminates in it then being a parietal ridge.

The parietal ridges of opposite sides lie relatively widely apart, and that part of the dorsal
surface of the skull that lies between them is flat, and corresponds to the subquadrangular groove
on the vertex of Scorpaena; but here, in Cottus, there is, aside from the presence of parietal spinous
ridges, no indication whatever of a groove; for the region is not depressed and there are no anterior
and posterior bounding ridges whatever.

The supraclavieular spine projects posteriorly from the dorso-posterior corner of the supra-
elavieular, ventral to the section of latero-sensory canal that traverses the bone.

The MESETHMOID is, in all my specimens, a relatively delicate bone that extends but slightly
into the underlying cartilage. It has, on either side, a short stout mesethmoid process which is direeted

— 11 —

antero-laterally and gives attachment, on its outer end, to the ethmo-maxillary ligament. The latero-
posterior, or ventro-latero-posterior, surface of the process gives support to a process on the hind end
of the nasal bone, the latter bone being strongly bound to the mesethmoid process by fibrous tissues.

The ECTETHMOID has a body of delicate perichondrial bone, and a stout lateral process
which corresponds to the wing and arm together of the bone in Scorpaena. On the ventral edge of
this lateral process there is a single large condylar eminence, which gives articulation to the lachrymal
alone, the palatine not anywhere coming into articular relations with the ectethmoid. Lateral to this
articular eminence, the ventro-lateral corner of the lateral process is free. On the antero-dorsal
surface of the bone there is a short but relatively large process which projects antero-mesially and gives
support, on its summit, to the lateral end of a lateral process on the hind end of the nasal, this process
of the nasal being strongly bound to the ectethmoid process by fibrous tissues. Between this ecteth-
moid process and the mesethmoid process, the lateral process of the nasal bridges the hind end of
the olfactory depression, Iying between the two nasal apertures. In Scorpaena scrofa, as already
stated, this nasal process of the ectethmoid of Cottus is apparently represented by an eminence, or
short spine, sometimes but not always found on the ectethmoid of that fish.

The VOMER has a’short dorsal limb formed of thin bone, of perichondrial appearance, which
comes into contact posteriorly with the perichondrial portions of the three ethmoid bones. A raised
portion on the ventral surface of the anterior end of the bone bears a band of villiform teeth which
extends, uninterruptedly, from one side to the other.

The PREMAXILLARY has large ascending and articular processes, the former resting on the
dorsal surface of the rostral, and the latter articulating with the maxillary, as in Scorpaena. The body
of the bone is shorter than in Scorpaena, extending but half the length of the maxillary and ending
practically at the hind edge of its own postmaxillary process; the posterior half of the body of the
bone of Scorpaena being represented, in Cottus, by tough gristly tissue. The oral surface of the bone
of Cottus is furnished nearly its full length with small villiform teeth.

The MAXILLARY has a stout, right-angled ascending process which artieulates with the
premaxillary and, through the intermediation of a pad of semi-cartilaginous tissue, with the dorsal
limb of the vomer. The antero-mesial (proximal) end of the ligamentary process is well-developed
and gives insertion to the ethmo-maxillary ligament. The postero-lateral (distal) end of the process
is represented by a slight eminence which gives insertion to the maxillo-mandibular ligament, this
ligament having a course, and an insertion on the artieular, similar to that in Scorpaena. Between
these two ends the ligamentary process is but slightly if at all developed, but the dorsal surface of
the shank of the bone here gives articulation to the enlarged anterior end of the maxillary process
of the palatine. The ventral edge of the anterior end of the lachrymal here also comes into slight
contact with the maxillary, but the lachrymal is here bound to the palatine alone, and is not supported
by, and bound to the maxillary, as in Scorpaena.

The NASAL has, as already stated, a lateral process on its hind end, this process giving to the
hind end of the bone an expanded appearance. This expanded hind end of the bone is bound mesially
to the mesethmoid process, and laterally to the nasal process on the dorso-anterior surface of the
ectethmoid, thus bridging a part of the nasal pit. The bone is traversed by the supraorbital latero-
sensory canal and lodges one organ of that line. No part of the canal traverses the process that
bridges the nasal sac.

— 12 —

The FRONTAL has a well developed ventral flange which comes into contact with the ali-
sphenoid and sphenotic, and possibly also, in some specimens, with the dorsal end of the ascending
process of the parasphenoid; but the exact relations of the bones here could not be determined, for
their outlines were not distinct in either of my three skulls, and I could not disarticulate the bones
in the one skull that I could spare for the purpose. Posterior to this ventral flange, there is a smaller
flange on the ventral surface of the frontal, the two flanges embracing the dorsal edge of the alisphenoid,
and the small posterior flange forming the dorsal portion of a partition between the fore and mid-
brain recesses of the cranial cavity. The ventral flanges of the frontals of opposite sides are relatively
widely separated from each other and form the lateral boundaries of the dorsal portion of the wide
orbital opening of the brain case.

The frontal is bounded posteriorly by the parieto-extrascapular and supraoccipital. Anterior
to the latter bone it rests directly upon the postepiphysial cartilage, this part of the bone, and also
the part that lies immediately anterior to it, being so thin as to be almost transparent. The hind
end of the lateral edge of the bone is bounded by the pterotic, and anterior to that bone is in contact
with a corner of the postfrontal.

The bone is traversed by the supraorbital canal and lodges five organs of that line, a primary
tube leaving the canal between each adjoining two of the five organs. There is thus one tube more in
this fish than in Scorpaena, this seeming to confirm the conclusion that a tube has disappeared in the
latter fish, as already explained. The fifth frontal organ of Cottus, the sixth one of the line, lies in the
small terminal tube of the canal, is well developed, and is innervated by a branch of the ophthal-
micus lateralis that pierces the skull from the outside and has an intracranial course, as in Scorpaena.
The penultimate, or sixth tube of the line anastomoses with that tube of the main infraorbital canal
that lies between the postfrontal and pterotic.

The POSTFRONTAL has a postorbital position, and is, in appearance, the dorsal one of
two postorbital bones. This bone, however, lodges the anterior one of the two infraorbital sense
organs that are innervated by the ramus oticus, this definitely identifying it as a postirontal. The
hind end of the dorsal edge of the bone lies on the dorsal surface of the sphenotic, the anterior and
larger part of this edge of the bone abutting against the lateral edge of the postorbital part of the
frontal.

The PARIETO-EXTRASCAPULAR is traversed, near its hind edge, by the mesial section
of the supratemporal latero-sensory canal, and bears at its hind edge the parietal spine. It lodges
one organ of the supratemporal commissure.

The LATERAL EXTRASCAPULAR is usually represented by two ossicles, one traversed
by the main infraorbital latero-sensory canal, and the other by the lateral section of the supra-
temporalcanal, but in one of thetwo fishesexamined, the two ossicles were fused to form a single bone.
The ossiele that lodges the lateral section of the supratemporal canal bridges the temporal fossa,
the other ossicle roofing the lateral portion of the postcommissural portion of the same fossa; the
commissural ossicle lying at the anterior end of the infraorbital ossiele. Each ossicle lodges a single
organ of the related latero-sensory line.

The SUPRASCAPULAR has a stout, pointed epiotic process which rests upon the dorsal

surface of the suprascapular process of the epiotic; and a short, stout and broad opisthotie process.
The latter process is directed downward and forward, its flat surface lying in a somewhat transverse

— 13 —

position, and, on one side of one of my three specimens, it almost entirely closed not only the
posterior but also the lateral opening of the temporal fossa, leaving only small openings on either
side of it. On the other side of that one specimen, and on both sides of the two other specimens, the
opening lateral tothe process was the larger of the two, the opening mesial to the process being practic-
ally closed in one of the two specimens. Mesial to the base of the opisthotic process there is, on the
under surface of the bone, an articular facet, and directly posterior to the base of the process there
is an articular eminence; the two surfaces giving articulation to the supraclavieular. The body of
the bone is traversed by the main infraorbital canal and lodges one organ of that canal, inner-
vated by a branch of the supratemporal branch of the nervus lineae lateralis. The bone is
without spine.

The SUPRACLAVICULAR has, on the anterior corner of its dorsal edge, a facet which gives
articulation to the articular eminence on the under surface of the suprascapular. From the mesial
surface of this part of the bone a process arises, directed antero-mesially, and on its anterior end
it has an articular eminence which articulates with the articular facet on the suprascapular. The
dorsal edge of the bone is traversed by a short section of the main infraorbital latero-sensory canal
and lodges one organ of that line. The posterior corner of the bone is prolonged into the stout supra-
clavicular spine.

The PARASPHENOID has, on either side, a tall and broad ascending process with two dorsal
ends. These two dorsal ends are pointed and separated by a large V-shaped incisure in my small
specimens, but bifid and separated by a shallow depression in the large specimen used for illustration.
The posterior and shorter end, or point is directed toward, and nearly reaches the trigeminus foramen,
and is in contact with and firmly bound to the proötic. The anterior and longer point is in contact
with and firmly bound to the alisphenoid, and almost, if not quite reaches in certain specimens the
ventral edge of the ventral flange of the frontal. These two ends, or points, belong respectively to
posterior and anterior portions of the ascending process, and between the two portions the outer
surface of the process is quite concave, its inner surface being correspondingly convex. Between
the posterior portion of the process and the body of the parasphenoid there is a normal internal
carotid foramen.

On the dorsal surface of the parasphenoid, between the bases of the ascending processes, there
is a raised median portion on the dorsal surface of which there is a relatively large median pit, the
point of the pit directed downward and backward. The pit gives insertion to the recti interni muscles.
Immediately posterior to it there is a depressed region on the dorsal surface of the bone, and then a
raised median rib, this rib lying between the ventral edges of the proöties of opposite sides and
forming the median portion of the floor of the myodome.

The ALISPHENOID is bounded posteriorly by the sphenotic and proötic, with both of which
bones it is in synchondrosis. Antero-dorsally it is overlapped externally by the ventral flange of the
frontal, and ventrally it is in contact with the anterior portion of the ascending process of the para-
sphenoid. It has short but broad basisphenoid and parasphenoid legs, these two legs enclosing a
V-shaped groove which begins at nothing, at the anterior end of the ventral edge of the bone, and
deepens gradually toward its hind end. The external bounding plate of this V-shaped groove is the
parasphenoid leg of the bone and is the part of the bone that is in contact with the ascending process

of the parasphenoid. The internal bounding plate of the groove is the basisphenoid leg of the bone,

— 14 —

and it projects ventro-mesially into the cranial cavity of the prepared skull and terminates with
a free edge.

The hind edges of the two legs of the alisphenoid are in contact with the anterior edges of
corresponding plates of bone on the ventral edge of the orbital portion of the proötie; and these two
plates of this part of the proötic may for convenience be called the parasphenoid and basisphenoid
legs of the orbital part of that bone. The basisphenoid leg corresponds to that part of the external
surface of the proötie of Scorpaena that forms the mesial wall of the jugular groove on the orbital
surface of the bone; the parasphenoid leg corresponding to the membrane that spans that groove
and was referred to, when describing Scorpaena, as a membranous anterior extension of the lateral
wall of the trigemino-facjalis chamber. This membrane having ossified, in Cottus, as part of the
proötie, the jugular groove of Scorpaena becomes, in Cottus, a canal which opens anteriorly into the
cranial cavity, while posteriorly it opens by a foramen-like opening onto the external surface of the
proötic. The anterior end of the canal is much larger than its posterior end, and the canal is con-
tinuous anteriorly with the V-shaped space between the two legs of the alisphenoid, the two spaces
together forming a recess in the cranial cavity which may be called the internal jugular recess. The
internal jugular vein and the truncus ciliaris profundi enter this recess at its anterior end, and, running
posteriorly, issue through the foramen-like opening at its hind end. This latter foramen is accordingly
an internal jugular foramen, but it is not the striet homologue of the foramen that I have described
as the internal jugular foramen in one specimen of Scorpaena; for the foramen in Cottus is bounded
by the proötic and the parasphenoid alone, while in Scorpaena it is bounded by the alisphenoid,
the proötic and the parasphenoid. The foramina in the two fishes result, however, from the
bridging of one and the same canal by a bridge of bone that is narrow in one fish and wide in
the other.

On the internal surface of the alisphenoid of Cottus, there is, as in Scorpaena, a brace-like
flange, which lies between the fore-brain and mid-brain recesses of the cranial cavity. In Cottus
this flange is thin and tall and forms, with a corresponding flange on the ventral surface of the frontal,
a somewhat important partition between the dorsal corners of the two recesses.

The alisphenoid is perforated, in its antero-ventral portion, by a foramen which varies consi-
derably in position in my specimens. It transmits the lateralis nerve destined to innervate the 6th.
or terminal organ of the supraorbital canal, the nerve always being accompanied by a blood vessel.
Whether other than lateralis fibers form part of the nerve was not investigated. The nervus troch-
learis passes across the free edge of the alisphenoid without perforating it.

The SPHENOTIC is normal in position and forms, as usual, the dorsal portion of the facet
for the anterior artieular head of the hyomandibular and the anterior portion of the dilatator fossa.
The oticus canal enters the bone on its orbital surface, and traversing the bone opens into the bottom
of the dilatator fossa. A flange on the cerebral surface of the bone forms part of the anterior bounding
wall of the labyrinth recess. The dorsal surface of the bone is almost entirely covered by the frontal
and pterotic, comes nowhere to the level of the dorsal surface of the skull, and gives support to a
part only of the dorsal edge of the postfirontal.

The PROÖTIC differs in certain important respects from the bone in Scorpaena and Sebastes. _
One of these differences is the enclosing of the internal jugular groove, and has just above been de-
seribed. The other relates to the trigemino-facialis chamber, and is described below. The bone is

— 15 —

bounded as usual by the sphenotic, pterotie, exoccipital and basioceipital, and its ventral portion
is overlapped externally by the parasphenoid. From the opisthotie it is separated by a considerable
interval.

Immediately anterior to the base of the postorbital process, the proötie is perforated by two
or three foramina, which transmit the profundus, trigeminus and facialis nerves; the profundus
issuing alone through one of the foramina, where there are three, but issuing with the trigeminus
where there are but two. The profundus foramen, when present, is a small canal which, running
inward, either opens into the trigeminus foramen, or close to that foramen on the inner surface of
the skull. The trigeminus foramen is the largest of the two or three and lies antero-dorsal to the
facialis foramen, both foramina opening into a trigemino-facialis recess on the internal surface of
the proötie, similar to the recess described in Scorpaena. This recess in Cottus is, however, relatively
larger than in Scorpaena, and its floor as well as its roof is formed by a thin shelf-like flange of bone.
The recess lodges, as in Scorpaena, the profundus ganglion and the ganglia formed on the communis
and lateralis roots of the trigemino-facialis complex. The communis ganglion is a large, pear-shaped
ganglion, and from it, two intracranial nerves arise. One of these nerves is the ramus palatinus faci-
alis, which runs downward forward and mesially, perforates the horizontal ledge that forms the floor
of the trigemino-facialis recess and then the prepituitary portion of the mesial process of the proötic,
and so enters the myodome at its extreme dorso-lateral corner. The other nerve runs upward and
backward, perforates the thin shelf of bone that forms the roof of the trigemino-facialis recess, and
then continues upward and backward along the edge of the bony anterior wall of the labyrinth recess,
until it reaches the roof of the cranial cavity. There it turns backward and mesially along the internal
surfaces of the frontal and parieto-extrascapular, passes between those bones and the supraoccipital,
and issues on the dorsal surface of the skull close to its hind edge and close to the median line. On
one side of the one specimen examined, the thin roof of the trigemino-facialis recess was perforated
by two foramina, the communis nerve just above described there doubtless arising from its
ganglion by two strands. This nerve, in its general course, closely resembles the so-called lateralis
accessorius of Gadus and Silurus, and, like the palatine, must consist largely, if not entirely of
communis fibers.

In addition to these two intracranial nerves, two large nerve trunks and the smaller truncus
ciliaris profundi arise from the complex and issue by the two or three foramina in the proötic.
One of the two trunks is the root of the trigeminus accompanied by lateralis and communis
fibers, and this root is closely accompanied by the truncus ciliaris profundi. The other trunk is the
root of the facialis accompanied by lateralis and communis fibers. The truncus ciliaris profundi separ-
ates from the root of the trigeminus while still inside the cranial cavity and either issues through
the trigeminus foramen, or through a separate and independent profundus foramen. It then enters
the internal jugular canal through its posterior opening, and traversing that canal enters and traverses
the anterior end of the myodome, and so issues in the orbit. The root of the trigeminus swells into
a ganglion either as it traverses its foramen or wholly but immediately beyond that foramen, the
trigeminus ganglion thus being largely or wholly extracranial in position. The facialis passes close
to the hind end of this extracranial ganglion, and, as in Scorpaena, receives from its hind end a large
communicating branch. Associated with the trigeminus ganglion and lying immediately ventral
to it, there is, as in Scorpaena, a large sympathetie ganglion, but this ganglion here lies on the external

surface of the proötic. The jugular vein and external carotid artery both come into the same rela-
Zoologica. Heft 57. 14

— 16 —

tions with these two ganglia that they do in Scorpaena, but they here both lie along the external
surface of the proötie.

There is thus, in Cottus, no bony trigemino-facialis chamber, the outer wall of that chamber
being represented by membrane only, as it is in the 44 mm and 55 mm specimens of Scorpaena. But
singularly enough, the outer wall of the internal jugular canal, which canal is simply an anterior
prolongation of the trigemino-facialis chamber, has been ossified in Cottus, while in Scorpaena it
is almost wholly membranous. In the specimen of Cottus used for the figure, two little eminences
on the outer surface of the proötic indicate a partial ossification of the outer wall of the trigemino-
facialis chamber. In the other two of my three specimens these eminences did not exist, the bone
there being simply slightly hollowed where the trigemino-facialis foramina perforated it.

The proötic of Cottus has a perfectly normal mesial process, connected, by intervening car-
tilage, with its fellow of the opposite side. The prepituitary portion of the process is short, not reaching
the middle line. The pituitary opening is thus not closed anteriorly by bone, and so forms an apparent
part of the large orbital opening of the brain case. The membrane that closes the latter opening
is greatly thickened in the optic and basisphenoid regions, and there becomes a thick, tough, fibrous
structure the lateral edges of which are attached to both edges of the internal jugular recess. The
nervus oculomotorius pierces this membrane, on either side, near its lateral edge and enters the myo-
dome, lying, in this part of its course, between the ascending process of the parasphenoid and the
basisphenoid membrane, and hence morphologically between the two legs of the alisphenoid; its
normal position. A median, encephalic artery, formed by the union of the internal carotids of opposite
sides, pierces the membrane near the anterior edge of the membranous pituitary fossa, and enters
the cranial cavity.

The MYODOME is well developed; and it would seem as if the skull of this fish must have
been unknown to Cope when he placed the Cottidae among those fishes in which the canal is wanting.
The hind end of the canal is continued a short distance in the basioccipital, but it does not open
posteriorly on the outer surface of the skull.

The PTEROTIC presents no features differing especially from those of the bone in Scorpaena,
excepting that it lodges two sense organs of the main infraorbital line, one innervated by the ramus
oticus and the other by the supratemporal branch of the nervus lineae lateralis vagi; the preoperc-
ular canal joining the main infraorbital between these two organs. The bone accordingly contains
a post-preopercular latero-sensory ossicle, this ossicle not being found in either Scorpaena or
Sebastes.

The BASIOCCIPITAL is much less deeply and extensively grooved by the posterior portion
of the myodome than in Scorpaena, and the cavum sinus imparis is simply a shallow depression.
The bone forms part of the boundary of the foramen magnum, as in Scorpaena, and otherwise
resembles the bone in that fish.

The EXOCCIPITAL is perforated by three foramina, as in Scorpaena, but the oceipital
foramen is very small and represents a part only of the foramen of Scorpaena; a deep ineisure in
the hind end of the exoccipital, immediately dorsal to the base of its condylar process, transmitting
the larger part of the nerves that traverse the occipital foramen in Scorpaena. The bone, as in Scor-
paena, has a mesial process, which rests on the dorsal surface of the basioccipital and roofs the hind
end of the saccular groove.

— 17 —

The EPIOTIC has on its posterior surface, an epiotic ridge, which projects postero-laterally
to an unusual extent and nearly meets the opisthotic process of the suprascapular; thus nearly or
even quite closing the posterior opening of the temporal fossa.

The SUPRAOCCIPITAL has dorsal and ventral limbs, the former of which is largely
exposed, on the dorsal surface of the skull, between the frontals and parieto-extrascapulars. The
hind edge of the dorsal limb projects backward, forming a short horizontal plate-like process
which slightly overhangs the ventral limb and rests upon, and is fused with, the dorsal
edge of the spina occipitalıs.

2. INFRAORBITAL BONES.

The infraorbital bones are, as in Scorpaena, four in number; a lachrymal, two suborbitals,
and a postorbital.

The lachrymal is concave on its outer and convex on its inner surface. It has a short anterior
edge, the ventral half of which lies upon the lateral edge of the broad anterior end of the maxillary
process of the palatine, and is very firmly bound to it by tissue. The dorso-anterior corner of the
bone bears, on its dorsal edge, a large concave articular facet which articulates with the articular
head on the ventral edge of the lateral process of the ectethmoid. The mesial edge of this facet is
greatly thickened and forms a stout process projecting mesially, the outer end of which is deeply
grooved. The ventro-anterior surface of this process is rounded, and fits against and is firmly bound
to the bottom of a unshaped depression on the external surface of the palatine; some slight motion
being possible between the two pieces. The groove on the outer edge of the process is presented
posteriorly, is free, and simply gives attachment to tissues of the region. T'he bone lodges two sense
organs of the main infraorbital line, instead of three as in Scorpaena, the third and fourth organs
of the line here both Iying in the first suborbital.

The first suborbital is a short and irregular bone, and lodges two sense organs, instead of a
single one, as in Scorpaena.

The second suborbital is long and extends backward to the anterior edge of the preopercular,
either touching, or almost touching that bone, and being bound to it by tissue. A broad, low and
rounded ridge extends the full length of its outer surface. The main infraorbital canal traverses the
anterior two-fifths of the bone in a nearly horizontal position and then turns abruptly upward to
enter the postorbital bone, giving off at the bend a short tube directed ventro-posteriorly, this tube
being double in the specimen used for illustration. The bone lodges two sense organs, one lying
anterior and the other posterior (here dorsal) to this tube. The posterior three-fifths of the bone,
and the ridge on its outer surface, are thus not developed in any apparent relation to any of the tubes
of the latero-sensory canal.

The postorbital bone is bound to the dorsal edge of the second suborbital at about the anterior
two-fifths of its length, and it and the postfrontal form a slightly curved line which is convex anteriorly
and directed upward and backward to join the dorso-lateral edge of the skull at the sutural line between
the frontal and pterotic. The two bones lie slightly posterior to the orbit, the hind edge of the orbit
being formed by a stiff membrane that is attached to the anterior edges of the two bones. The post-
orbital lodges a single latero-sensory organ.

— 18 —

3. SUSPENSORIAL APPARATUS AND MANDIBLE.

The PREOPERCULAR is a stout bone with dorsal and ventral limbs lying at somewhat more
than a right angle to each other. In their natural positions the dorsal limb is directed dorso-anteriorly
and the ventral limb ventro-anteriorly. The dorsal portion of the dorsal limb rests against and is
firmly bound by tissue to the grooved hind edge of the hyomandibular, its dorsal end not extending
beyond the opercular process of that bone. The ventral portion of the ventral limb rests against
and is firmly bound to the grooved postero-ventral surface of the posterior process of the quadrate.
Between these two portions of the preopercular a large and thin web of bone extends across the angle
between the two limbs and supports, on its internal surface near its ventral end, that part of the
hyomandibulo-symplectie interspace of cartilage on which lies the artieular facet for the interhyal.
Dorsal to that facet, the web of bone is thickened to form a process-like portion, and the edge of this
portion is bound by tissue to the hind edge of the ventral portion of the hyomandibular. At the dorsal
end of the web there is an incisure, through which, between the preopercular and the hind edge of the
hyomandibular, the ramus hyoideus facialis passes from the outer to the inner surface of the apparatus.

The large and well known preopereular spine of the fish extends posteriorly in the direction of
the ventral limb of the bone, and almost as a posterior continuation of that limb. A second one of
the three preopercular spines lies directly ventral to this large one, either parallel with it, or directed
ventro-posteriorly at an angle to it. The third preopercular spine arises from the ventral edge of the
ventral limb of the bone, close to its anterior end. The bone is traversed its full length by the pre-
opercular latero-sensory canal and lodges five sense organs of that canal.

The HYOMANDIBULAR has anterior and posterior heads for articulation with the cranium,
and a very stout head for articulation with the opercular. The shank of the bone is relatively broad
and thin, and the longitudinal ridge on its outer surface is short, but stout. The bone is traversed
by a facialis canal, which opens on the outer surface of the shank anterior to the longitudinal ridge,
and also by a short branch canal which opens on the outer surface of the bone posterior to the ridge.
A large web of bone fills the angle between the anterior articular head and the shank of the bone,
and is in contact with and is firmly bound by tissue to the hind edge of the metapterygoid.

The SYMPLECTIC has a broad flat dorsal end, and from there tapers rapidly into a long
rod-like ventral portion which lies in the symplectice groove on the inner surface of the quadrate.
There is a canal along its anterior edge, between it and the anterior edge of the symplectic groove
on the quadrate, which transmits the ramus mandibularis internus facialis.

The QUADRATE has a stout and long posterior process which is separated from the body
of the bone by a shallow incisure. Anterior to the dorsal portion of the process, between it and the
symplectic, there is a long oval opening which transmits the ramus mandibularis externus facialis
and the arteria hyoidea. The posterior process of the quadrate is so long that it almost completely
shuts the preopercular off from bounding partieipation in this opening. Along the anterior edge of
the base of the process there is, on the inner surface of the body of the quadrate, a symplectic groove.
From the inner surface of the anterior edge of the bone a stout ligament arises and running forward
joins the tendon A,A,-A,.

The METAPTERYGOID is large and flat, and without evident flanges on its hind edge. This
edge of the bone is however in contact with the anterior edge of the flange on the anterior edge of

— 109. —

the hyomandibular, this contact being a characteristie of the flanges of the metapterygoids of Scor-
paena and Sebastes, and not of the bodies of those bones. The bone is perforated, in Cottus, in its
dorso-posterior portion, by a foramen which transmits the external carotid artery from the external
to the internal surface of the palato-quadrate apparatus. Immediately internal to the foramen,
the carotid falls into the arteria hyoidea at a sharp bend in that artery, the arteria hyoidea there
turning almost directly backward to enter the opercular hemibranch. The arteria hyoidea, ventral
to this bend, lies at first along the internal surface of the metapterygoid, but comes to the outer sur-
face of the apparatus through a large fenestra between the metapterygoid, hyomandibular and sym-
plectie. It then crosses the external surface of the symplectic and passes to the internal surface of the
apparatus through the opening between the symplectic and preopercular, the mandibular artery
being here given off, as in Scorpaena. The relations of these two arteries to the metapterygoid would
thus be the same as those in Scorpaena, if those parts of the hind edge of the bone of Cottus that
lie dorsal and ventral to the foramen for the external carotid represented respectively the internal
and external flanges on the hind edge of the bone of Scorpaena; and this is certainly the case, the
ventral edge of the internal flange abutting against and fusing with the dorsal edge of the external
flange, and the foramen for the carotid, in Cottus, representing the greatly reduced V-shaped space
between the two flanges in Scorpaena. The relatively large fenestra that transmits the arteria hyoidea
is then the homologue of the small opening that transmits that artery in Scorpaena.
The efferent pseudobranchial artery is as in Scorpaena.

The ECTOPTERYGOID and ENTOPTERYGOID are in normal position, the latter bone
being relatively long.

The PALATINE has a short body and a long but low ventral flange, this flange being wholly
without teeth and its hind end being prolonged posteriorly in a tapering point which lies against
the ventral surface of the dorsal limb of the ectopterygoid. On the lateral surface of the body of
the palatine, anterior to the base of the process-like posterior extension of its ventral flange, there
is a deep U-shaped depression, the legs of the U being directed posteriorly. In the posteriorly directed
hollow of this U, the process on the mesial edge of the articular head of the lachrymal is received,
and is firmly bound to it by tissues, some slight motion between the parts being possible. The body
of the palatine is in synchondrosis posteriorly with a well formed rod of cartilage which lies along
the dorsal surface of the dorsal limb of the ectopterygoid and connects the body of the palatine with
that portion of the palato-quadrate cartilage that lies between the quadrate and metapterygoid.

The maxillary process of the palatine is stout and its distal end is expanded into a broad flat
portion which rests upon and is firmly bound to the dorsal surface of the maxillary. At the base
of the process there is a small process directed dorso-mesially. This process is strongly bound by
tissue to the lateral edge of the ethmoid cartilage, but does not have articular contact with that
cartilage. In Scorpaenichthys this process is large, and articulates with a large articular surface
on the lateral edge of the ethmoid cartilage. In Cottus, the lateral surface of the little process gives
insertion to the rostro-palatine ligament. The vomero-palatine ligament is relatively long, arises
from the hind edge of the raised, toothed portion of the vomer, and running postero-laterally is in-
serted on the internal surface of the body of the palatine.

The anterior and posterior ethmo-palatine artieulations are thus both wanting in Cottus, the
posterior artieulation being replaced by the articular connection of the palatine with the lachrymal.

— 10 —

In Hydrocyon also, both articulations are wanting, according to Sagemehl (’84 b, p. 95), and in the
Cyprinidae, according to the same author (°91, p. 582), the posterior articulation is replaced by an
articulation of the entopterygoid with the ectethmoid.

OPERCULAR BONES.

The opereular is so firmly bound by articular ligaments to the stout opercular articular head
of the hyomandibular that it is capable of but little movement. From its articular head a stout raised
portion runs posteriorly or postero-ventrally across the outer surface of the bone and terminates
in the stout opercular spine; the point of that spine extending slightly beyond the point of the large
preopereular spine and Iying slightly dorsal to it.

The subopercular is an angular bone that embraces the ventral corner of the opercular. It
bears a short, small spine at its ventral corner.

The interopereular is long and tapering. Its broad hind end is bound by tissue to the ventral
. portion of the anterior edge of the subopercular, but it is separated from that edge by a considerable
interval, bridged by a connecting sheet of tissue. Its pointed anterior end is bound by ligament to
the lateral surface of the hind end of the mandible.

MANDIBLE.

The mandible is long and rather slender, and has angular, articular and dentary elements
that offer no special peculiarities. The dentary lodges three latero-sensory organs, and the articular
one organ. The summit of the coronoid process of the articular is separated by a considerable interval
from the hind end of the dorsal limb of the dentary, the intervening space being filled by a tough
pad of fibrous tissue. In the mandibular labial fold there is a gristly core, as in Scorpaena, but it is
smaller than in that fish.

4. MUSCLES.

The adductor mandibulae of Cottus resembles closely that of Scorpaena. The superficial
division, A,, of the muscle arises from the anterior portion of the external surface of the
preopercular and runs almost directly forward, lying external to the levator arcus palatini and to
the deeper division, A,A,, of the adductor. It terminates anteriorly in a tendinous band which ex-
tends the full length of its anterior edge and is inserted dorsally on the maxillary, while ventrally
it joins and becomes part of the tendon A,A,. The deeper division of the muscle, A,A,, is incom-
pletely separated into superficial and deeper portions, the superficial portion, A,, lying superficial
and ventral to the levator arcus palatini and the deeper portion lying internal to that muscle. The
two muscles have their origins, as in Scorpaena, from the anterior portion of the external surface
of the preopercular, ventral to the muscle A,, and from the external surface of the palato-quadrate
apparatus. Running almost directly forward, certain fibers of the muscle pass directly into the
mandible and are continuous with the fibers of A,,, others are inserted on the ventral end of the
tendinous band that edges the anterior end of the muscle A,, while the larger portion have their
insertion on a tendinous structure that forms on the inner surface of the muscle and runs forward
and downward into the mandible. In the mandible this tendon separates into four portions, two
of which give origin to the fibers of A,, the other two lying one external to the other and having
their insertions on the internal surface of the articular near the hind end of Meckel’s cartilage. From

— 11 —

this tendon, A,A,-A,,, a ligamentous band runs backward and is inserted on the internal surface
of the quadrate.

The levator arcus palatinı runs downward internal to A, and then internal to A,, Iying always
external to A, and also always external to the palato-quadrate. The course of the muscle is thus
in accord with the conclusion, already stated, that the dorsal portion of the hind edge of metapterygoid
of Cottus represents the inner one of the two flanges on the hind edge of the metapterygoid of
Scorpaena.

The dilatator operculi arises partly in the dilatator fossa, but mainly on the external surface
of the dorsal end of the hyomandibular and on adjacent portions of the preopercular, and is inserted
on the opercular as in Scorpaena.

The adductor hyomandibularis, and adductor and levator operculi are as in Scorpaena, but
the latter muscle is represented by several separate bundles of muscle fibers all of which extend from
the dorso-lateral edge of the skull to the dorsal edge of the opercular or subopercular; the posterior
bundles being delicate bands Iying in the membrane that closes the dorsal end of the opercular
opening.

5. LATERO-SENSORY CANALS.

The main infraorbital canal of Cottus traverses the four infraorbital bones without inter-
ruption, and then enters and traverses the postirontal, at the dorsal end of which it anastomoses
with the penultimate tube of the supraorbital canal. It then turns sharply backward and traverses
in succession the pterotic, lateral extrascapular, suprascapular and supraclavicular. The lachrymal
lodges two sense organs of the line; the first suborbital bone lodges two regular organs and, in the
one specimen examined, what was apparently a much smaller and additional organ between the
two regular organs; the second suborbital bone lodges two organs; and the postorbital bone one
organ: all of these organs being innervated by branches of the buccalis lateralis. The number of organs
in this part of the line, excepting the small and apparently supplemental organ in the first suborbital,
is thus exactly the same as in Scorpaena, but the third latero-sensory ossicle has, in Cottus, fused
with the fourth ossicle and so forms part of the first suborbital bone instead of fusing with the first
and second ossicles to form part of the lachrymal.

The postfrontal lodges one organ, innervated by a branch of the oticus lateralis; the pterotie
two organs, one innervated by the oticus lateralis and the other by a branch of the supratemporalis
lateralis vagi; the lateral extrascapular and suprascapular one organ each, innervated by branches
of the supratemporalis lateralis vagi; and the supraclavicular one organ, innervated by the first
branch of the lateralis vagi. This part of the line thus differs from that in Scorpaena only in that
the pterotic lodges an organ innervated by the lateralis vagi; the dermal component of that bone
thus being formed by the fusion of two latero-sensory ossicles.

The supratemporal commissure lodges two sense organs on either side, one lying in the lateral
extrascapular and the other in the parieto-extrascapular, both innervated by braüches of the supra-
temporalis lateralis vagi.

The supraorbital canal traverses the nasal and frontal bones, and anastomoses by its penulti-
mate primary tube with that infraorbital tube that lies between the postfrontal and pterotice bones.
The canal contains six sense organs, one lying in the nasal and five in the frontal, all innervated by
branches of the ophthalmicus lateralis. A primary tube leaves the canal between each two adjoining

— 112 —

organs, there thus being one more tube than in Scorpaena, that additional tube lying between the
fourth and fifth organs of the line. The fourth tube of the line anastomoses, in the middle line of the
head, with its fellow of the opposite side, thus forming a frontal commissure, as in Scorpaena.
The preoperculo-mandibular canal traverses the dentary, articular and preopercular bones,
but did not anastomose, at its dorsal end, in the one specimen examined, with the main infraorbital
canal: this specimen thus differing, in this, from the specimen examined in connection with one of
my earlier works (°04). It contains nine sense organs, three lying in the dentary, one in the articular
and five in the preopereular, all innervated by branches of the mandibularis externus facialis.
Most if not all of the primary tubes branch one to several times after they leave the bones
to which they are related and enter the cutis, but no interanastomoses of these tubes were found.

ll. CRANIOMI.

I. Trigla hirundo.
1. SKULL.

Of the Triglidae I have selected Trigla hirundo for detailed descriptions, a short separate
description being also given of Trigla Iyra. The other members of the family examined are referred
to only as they differ markedly from hirundo.

The dorsal surface of the skull of Trigla hirundo consists of two portions lying at slightly
different levels. The higher portion forms by far the larger part of the dorsal surface of the skull,
extending from the anterior ends of the nasals to the hind ends of the suprascapulars, and being
covered, in the recent state, by a thin cutis only. The deeper portion is small, forms the dorsal sur-
face of the anterior end of the snout, and is covered, in the recent state, by the rostral and the dermal
and connective tissues that surround that cartilage.

The bones that form the larger, higher portion of the dorsal surface are all firmly bound to-
gether, and present an even surface everywhere similarly marked with little granulations arranged
more or less distinetly in lines or ridges. At its anterior edge this part of the skull projects, eaves-
like, above the hind edge of the deeper, anterior portion, this giving to this higher part of the pre-
pared skull somewhat the appearance of a carapace, or, to use the expression employed by Gill in
his deseriptions of Dactylopterus, a „bony casque‘“. This casque-like dorsal portion of the skull
is somewhat rectangular in general outline, this being more marked in medium-sized than in large
specimens. Its anterior and posterior edges are deeply concave, and there are deep, sometimes almost
semi-cireular ineisures for the orbits. The mid-dorsal line is slightly convex, the amount and manner
of the convexity varying with the size of the specimen. In medium-sized specimens the mid-dorsal
line is nearly straight from its hind end to the middle of the orbits. Then it curves slightly downward
to the anterior end of the orbits, where it again becomes nearly straight, and so continues to its
anterior end. In the large specimen used for the drawings, the interorbital portion is, on the con-
trary, markedly flat and straight and is joined by slightly rounded angles to the straight anterior
and posterior portions of the surface.

The mid-ventral line of the skull is concave, and has, as the mid-dorsal line has, posterior
and anterior portions that are nearly straight and that are separated by an obtuse and rounded angle.
The whole skull thus appears bent downward in its anterior half.

On the anterior portion of the dorsal edge of the orbit there are, in all my medium-sized spec-

imens, two backwardly directed spines, but in my two large specimens there is but one spine, a
Zoologica. Heft 57. 15

— 114 —

large one, with one or two adjoining eminences rather than spines. Near the hind edge of the orbit
there is, in medium-sized specimens, a short and somewhat blunt spine, which is not evident in the
large specimens. The only other spines found on the head of the fish are two spines, or eminences,
on the hind edge of the preopercular, and two spines on the opercular; only one of these latter spines
showing on the outer surface of the fresh head.

Between the orbits, in medium-sized specimens, the dorsal surface of the skull is deeply con-
cave transversely, while in large specimens it is much less so; and in all specimens there is here no
longitudinal ridge, on either side, to mark, as in Scorpaena, the course of the supraorbital latero-
sensory canal. The crown of the head is flat, the subquadrangular groove on the occiput, so charac-
teristic of the Scorpaenidae, being slightly indicated in my medium-sized specimens by two little
tuberculated and longitudinal ridges, one on either side, on the dorsal surface of the parieto-extra-
scapular bone. These ridges are not evident in the large specimens. The preorbital portion of the
skull is relatively long, low and broad, the casque-like portion of its dorsal surface here being convex
transversely and having straight lateral edges which converge but slightly forward; the casque being
two-thirds or even three-fourths as wide at its deeply concave anterior end as it is at the anterior
edges. of the orbits.

The curved anterior ends of the lachrymals project forward and mesially, on either side, beyond
the anterior end of the skull, and, with the concave anterior end of the casque, nearly enclose a sub-
ceircular space in which the rostral lies. The anterior edge of the lachrymal is, in all my specimens,
serrate rather than being, as stated by Günther (’60), furnished with prominent spines.

The dorsal surface of the casque is formed by the nasals, mesethmoid, ectethmoids, frontals,
postfrontals, pterotics, parieto-extrascapulars, lateral extrascapulars and suprascapulars, and also
by a small portion of the sphenotie which comes to the level of the other bones and presents the same
granulated appearance. The supraoccipital and epioties are almost entirely, or even entirely covered
by the overlying frontals, parieto-extrascapulars and suprascapulars.

The mesethmoid and ectethmoids come, as just above stated, to the level of the dorsal surface
of the other bones that form the casque-like portion of the skull, and, having the same surface mark-
ings as those other bones, they form with them a uniform and continuous surface. They each contain
the two sornewhat different components, dermo-perichondrial and endosteal, referred to when des-
cribing these same bones in Scorpaena; but here, in Trigla, the dermal portion of the dermo-peri-
chondrial component is much more important.

The MESETHMOID, as seen on the dorsal surface of the skull, is sometimes, as Günther
(’60) says of the corresponding bone in Trigla gurnardus, a sexangular bone, once and a half as long
as broad; but the two posterior corners of the bone thus described, are usually replaced, in medium-
sized specimens, by a single point, the bone then being pentangular. The outer surface of the bone
is marked by granulated ridges that all converge toward the central point of the bone, and in the
substance of the bone, and converging toward this same point, there are tapering spaces. These
spaces lie in the dermal portion of the bone, between the dense outer surface of this portion of the
bone and the thin perichondrial layer, and the concave anterior edge of the bone is honeycombed by
the openings of the spaces. This anterior edge of the dermal portion of the bone is grooved, the dense
superficial layer of the bone projecting eaves-like above the deeper perichondrial layer. This latter
layer extends anteriorly slightly beyond the dermal layer, and is there bounded, in the middle line,

— 115 —

by the hind end of a narrow and low median ridge of cartilage which represents the relatively tall
internasal ridge of Scorpaena. On either side of this ridge the mesethmoid is bounded by the hind
edge of the corresponding ascending process of the vomer.

The mesethmoid is bounded, on either side, in its posterior half or two-thirds, by the ecteth-
moid, the hind end of the mesethmoid usually projeeting beyond the bounding portions of the ecteth-
moids and there suturating with or being overlapped externally by the frontals. The anterior half
or third of the bone gives support, on either side, to the nasal, the mesial half of the latter bone over-
lapping and lying upon a depressed lateral half of the dorsal surface of this part of the mesethmoid.
The antero-lateral corner of the dorsal surface of the mesethmoid projects forward as a sharp pro-
cess, and from this process and from the ventral surface of the overlying nasal, the ethmo-maxillary
ligament has its origin. This little corner or process of the mesethmoid, together with the adjacent
parts of the flat dorsal surface of the bone, thus replace functionally, in their relations to the nasal
bone and the ethmo-maxillary ligament, the pronounced mesethmoid process of the Scorpaenidae.

The lateral edge of the mesethmoid, beneath the nasal, is grooved and forms the median wall
and part of the floor of the shallow nasal pit. Posterior to the nasal, this same grooved edge of the
mesethmoid forms the mesial wall of the olfactory canal through the antorbital process. Dorsal to
this groove, between it and the thin dense external plate of the bone, there is another groove in the
lateral edge of the bone, this groove lying between the suturating edges of the mesethmoid and
ectethmoid. A canal is thus here formed between the two ethmoid bones, which, in large specimens,
may become entirely enclosed in the mesethmoid alone, continuing posteriorly to the hind edge of
that bone. It lodges that part of the supraorbital latero-sensory canal that lies between the frontal
and nasal bones, but contains no sensory organ, the sensory canal thus here being secondarily and
not primarily enclosed in the bone.

Under the central portion of the bone, primary ossification has begun, and, in large specimens,
extends entirely through the cartilage of the snout. In the central portion of this part of the bone,
in three specimens that were bisected, there was a large cavity filled with fatty tissue.

The ECTETHMOID has a convex dorsal surface, this convexity being so great in the posterior
portion of the bone that a transverse section here has the shape of a quadrant of a circle. The external
surface of the bone lies, as already stated, on a level with the corresponding surface of the other bones
of the dorsal surface of the skull, and is marked by radiating and granulated ridges. The hind edge
of the bone is thin and sharp, and projects posteriorly to form the anterior portion of the roof of
the orbit. It bears the two or three preocular spines, the postero-mesial one of these spines being
considerably longer than the others. The mesial edge of the bone suturates, in its posterior portion,
with the frontal, and, in its anterior portion, with the mesethmoid and the hind end of the nasal.
Along the mesial edge of the posterior portion of the bone, beneath the overlying frontal, there is
a small canal which transmits the ramus ophthalmicus superficialis, this canal leading from the orbit
into that larger canal, already described, that lies between the mesethmoid and ectethmoid and that
lodges the supraorbital latero-sensory canal.

The ventral surface of the ectethmoid is large and inclines downward and mesially at an angle
approximately of 30° with a horizontal plane. Along the lateral edge of this surface there is a stout
and irregular longitudinal ridge which projects downward and but slightly laterally. The anterior
half of this ridge has a somewhat rounded summit, and this part of the ridge gives articulation to

— 16 —

the united lachrymal and palatine bones in a manner that will be described when describing those
bones. It may however here be stated that the two articulating surfaces do not seem to come into
close contact, being separated by a line of tough fibrous tissue which not only binds the bones strongly
together but permits of a sort of swinging movement. The larger part of this articulation, such as
it is, is with the lachrymal, the articulation with the palatine being limited to the extreme anterior
end of the ridge, and the articulating surfaces there apparently coming into closer contact than else-
where. The posterior half of the ridge is double, having mesial and lateral portions which diverge
slightly. The mesial portion is a direct posterior prolongation of the anterior, articular portion of the
entire ridge, but it is low and narrow, and curving ventro-mesially vanishes near the hind edge of
the ventral surface of the bone. The other, lateral portion of the ridge is taller and more important
than the mesial one, and running posteriorly and slightly laterally, soon becomes continuous with
the posterior portion of the lateral edge of the bone. On the lateral surface of this portion of the
ridge the dorsal edge of the second infraorbital bone slides as the hyomandibulo-palato-quadrate
apparatus swings inward and outward.

The anterior end of the ventral surface of the ectethmoid projects forward beyond the rest
of the bone as a thin flat process, of perichondrial appearance, which lies upon the ventral surface
of that lateral portion of the ethmoid cartilage that forms the floor of the nasal pit; the lateral edge of
the process of the ectethmoid projecting slightly lateral to the lateral edge of the overlying cartilage
and so forming part of the floor of the nasal pit. The process extends forward onto the base of an
anterior palatine process of the ethmoid cartilage, its anterior end there being overlapped externally
(ventrally) by the small lateral process of the vomer.

The anterior palatine process of the ethmoid cartilage is a pronounced eminence on the lateral
edge of the snout, bounded antero-mesially by the ascending process of the vomer, postero-mesially
by the mesethmoid, and posteriorly by the process, just above described, of the ectethmoid. Ventrally
it lies upon the dorsal surface of the body of the vomer, but projects laterally considerably beyond
that bone. With the latero-ventral surface of the process the palatine artieulates. The summit of
the process always closely approaches, and is sometimes apparently in actual contact with, the ventral
surface of the lateral edge of the nasal, near its anterior end; this relation of the process to the nasal
varying considerably in different specimens. In most specimens a slight interval seems to separate
the two structures.

The posterior, orbital surface of the ectethmoid lies at an angle to its ventral surface, the two
surfaces being separated by a sharp ridge. This ridge, or angle, corresponds to the orbital rib of my
descriptions of Scomber, and to a slight ridge which, in Scorpaena, extends dorso-laterally from the
ventro-mesial corner of the orbital surface of the bone to the point of insertion of the posterior ethmo-
palatine ligament. This latter ligament is, in Trigla, double, the two ligaments found partly fused in
Scorpaena, here being wholly and quite widely separated. One of these ligaments is a flat band which
has its origin on the ventro-lateral surface of the orbital ridge above referred to, and, running down-
ward and forward, is inserted on the palatine cartilage in a manner to be later described. The other
is a slender and delicate ligament which has its origin on the ventral surface of the eetethmoid and,
running downward and forward, is also inserted on the palatine cartilage.

The orbital surface of the ectethmoid of Trigla thus corresponds to one half only of the same
surface of the bones of Scorpaena and Scomber. The other half of this surface must then be looked
for in what is apparently, in Trigla, the ventral surface of the bone, and it seems probable that it is

— 1171 —

represented in that part of that surface that lies between the two diverging, posterior portions of the
articular ridge near its lateral edge. The ventro-lateral corner of the wing of the bone of Trigla, which
forms a sharp spine-like corner, is certainly the homologue of the rounded angle in the lateral edge of
the wing of Scorpaena, and the anterior end of the anterior, single portion of the articeular ridge of
Trigla must be the homologue of that process-like portion of the bone of Scorpaena that gives artic-
ulation to the palatine. The lachrymal articular process of the bone of Scorpaena must then be
represented in some part of the articular ridge of Trigla that lies between its anterior and posterior ends.

The small orbital surface of the ectethmoid of Trigla is strongly concave, converging forward
and inward to a large opening which leads into the hind end of a large median chamber in the ant-
orbital cartilage, the chamber perforating the extreme ventro-anterior portion of the interorbital
septum. This chamber is bounded laterally, on either side, by the primary portion of the corre-
sponding ectethmoid, and its floor is perforated by a cireular opening which is closed ventrally by
the underlying parasphenoid. From the chamber, on either side, a canal leads forward into the
nasal pit and transmits the olfactory nerve of its side, this canal lying between the mesethmoid and
ectethmoid bones and becoming, in my large specimens, a large vacuity in those two bones, filled
with loose fatty tissue. Anterior to this vacuity, there was, in the mesethmoid bone alone of the
three specimens examined in this connection, a separate median vacuity, already referred to, which
opened on the ventral surface of the bone. The oblique muscles of the eye extend into the median
chamber and have their origins there, the chamber thus being an anterior eye-muscle canal. Imme-
diately lateral to the epening that leads from the orbit into the anterior eye-muscle canal, there is,
in the ectethmoid, a small canal which transmits an artery coming from the orbit. Considerably
lateral to this canal there is another smaller canal, also in the ectethmoid, but no structure, either
nervous, arterial or venous could be found traversing it.

The NASAL is a somewhat quadrilateral bone that forms the antero-lateral corner of the
casque-like dorsal surface of the skull. The lateral portion of its hind end rests upon the dorsal
surface of the eetethmoid. Its mesial half overlaps externally and is quite firmly bound to the lateral
portion of the dorsal surface of the mesethmoid. Its anterior edge forms the lateral portion of the
concave anterior edge of the casque of the skull. Its antero-lateral corner projects beyond the under-
lying corner of the mesethmoid and also beyond the anterior palatine articular eminence of the ethmoid
cartilage, and is thickened by accretions to its ventral surface. This thickened portion rests partly
upon the dorso-lateral surface of the base of the maxillary process of the palatine, and partly upon
the external surface of a small flat process on the dorsal edge of the lachrymal. The lachrymal and
palatine are here immoveably bound together, and the extent of the contact of one or the other with
the nasal varies in different specimens. The nasal is strongly but somewhat loosely bound by dermal
or fibrous tissues to both the palatine and lachrymal, and gives sliding artieulation to them when
the palato-quadrate and cheek-plate swing inward and outward; the sliding contact being mainly
with the lachrymal. The ventral surface of this corner of the nasal closely approaches, and, as already
stated, may even rest upon the summit of the anterior palatine process of the ethmoid cartilage,
the palatine artieulating with the latter process by an articular surface at the base of its maxillary
process.

Between the summit of the anterior palatine process of the ethmoid cartilage and the projecting
antero-lateral corner of the mesethmoid, the nasal roofs a large passage which leads from the rostral
depression into the anterior end of the nasal pit. The nasal pit is a deep low fossa in the lateral edge

— 18 —

of this part of the skull, lying between the nasal above, the mesethmoid and the cartilage of the
snout mesially and below, the ectethmoid posteriorly and below, and the anterior palatine process
of the ethmoid cartilage anteriorly. The pit is not large enough to lodge the entire nasal sac, a part
of the sensory portion of the sac extending laterally, beyond the lateral edge of the skull, onto the
dorsal surface of the palatine, and there lying between the palatine and lachrymal bones. A mesial
diverticulum of the sac, corresponding to that in Scorpaena but somewhat differently disposed, runs
forward and mesially through the passage that leads from the nasal pit into the rostral depression,
and then turns mesially behind the rostral, between it and the anterior end of the mesethmoid, and
abuts against but is apparently not continuous with its fellow of the opposite side.

The nasal bone is traversed by the supraorbital latero-sensory canal, and lodges one organ
of that line, the anterior opening of the canal lying at the extreme antero-lateral corner of the bone.
De Sede de Lieoux (’84, p. 111) says that the cephalie portion of the latero-sensory canals is absent
„chez les Trigles‘‘, Trigla hirundo being the species particularly examined. This is far from being
true, as will appear in the course of my descriptions.

The VOMER has ascending processes which are in contact, posteriorly, with the anterior end
of the thin perichondrial layer of the mesethmoid. The ascending processes of opposite sides enclose
between them, as in Scorpaena, the anterior portion of an internasal ridge of cartilage, the bone and
cartilage here being, in medium-sized specimens, raised into a slight ridge, while in large specimens
they become a prominent knob with a flat summit. The cartilaginous rostral slides backward and
forward on this ridge or knob. The lateral corner of the ascending process of the vomer is slightly
raised and embraces the anterior edge of the base of the anterior palatine process of the ethmoid
cartilage; this raised or process-like portion of the vomer of Trigla corresponding strikingly, in position,
to the septomaxillaries of Sagemehl’s figures of the Cyprinidae. Antero-mesial to this little process
there is a rounded eminence, prominent in large specimens, near the anterior edge of the dorsal surface
of the bone. The lateral surface of this eminence, and the slight hollow between it and the palatine
process, give articulation to the ventral edge of the ascending process of the maxillary, a pad of tough
fibrous or semi-cartilaginous tissue lying between the two surfaces.

The ventral surface of the convex anterior edge of the vomer is slightly raised, and is furnished
with an uninterrupted band of small villiform teeth. Immediately posterior to the lateral end of this
band of teeth, there is a large depression which gives insertion to the very slightly developed vomero-
palatine ligament. A slightly developed lateral process projects postero-laterally, extending beyond
the anterior edge of the ventral plate of the ectethmoid and there lying upon the ventral surface of
that plate.

In Trigla lineata the anterior end of the vomer is bent abruptly, though but slightly, downward;
and although this is a natural formation, it has decidedly the appearance of having been produced by
a blow on the end of the snout of the fish.

The PREMAXILLARY has a broad oral surface, covered its full length with small villiform
teeth. At about the middle of the length of the bone, there is a thin flat postmaxillary process directed
backward and slightly upward. This process forms the hind end of a pronounced longitudinal ridge
on the internal surface of the bone, this ridge representing a thickened part of the bone, of membrane
origin, which lies slightly dorsal to its tooth-bearing portion. This membrane component of the bone
has a thin, flat and rounded hind (distal) end, which forms the postmaxillary process of the bone, and

— 119 —

a thickened anterior (proximal) end which, in my large specimens, forms a marked eminence on the
anterior end of the entire bone, the eminence being round in outline and having a flat summit. This
flat surface is presented toward a similar surface on its fellow of the opposite side, and is bound to that
fellow by a short strong ligament. The dorso-posterior corner of the eminence is in contact with the
ventro-anterior corner of the rostral. The bone has ascending and articular processes, more or less
fused to form a single large process which rises from the membrane component of the bone. The
ascending process is shorter and stouter than in Scorpaena, being but little if any longer than the
articular process. It lies upon and is firmly bound to the dorsal surface of the rostral, and between
it and its fellow of the opposite side there is a deep V-shaped groove, as in Scorpaena. The articular
process gives articulation to the maxillary in exactly the same manner that the corresponding pro-
cess does in Scorpaena, and here, as there, a pad of semi-cartilaginous tissue lies between the artic-
ulating surfaces.

The MAXILLARY has an anterior, articular end, strietly comparable to that of Scorpaena,
but the middle portion of the shelf-like ligamentary process of that fish is wanting here, as it is in
Cottus. This is doubtless due to the fact that, in both Trigla and Cottus, the anterior end of the lachrym-
al has not the strong attachment to the maxillary that it has in Scorpaena, the lachrymal, in
Trigla, projecting above and beyond the maxillary without coming into contact with it. The maxil-
lary process of the palatine articulates with the dorsal surface of the maxillary, as in Scorpaena, the
articulation taking place in a depression, which lies in the angle between the ascending process and
the shank of the bone. The extreme proximal end of the bone lies along and is bound by tissue to
the ventral surface of the rostral. The bone articulates by the dorso-posterior portion of its
ascending process, and through the intermediation of a pad of fibrous or semi-cartilaginous tissue,
with the lateral surface of the eminence, already described, on the dorsal surface of the ascending
process of the vomer. On the internal surface of the bone, beginning opposite its ascending process
and extending distally somewhat beyond it, there is a flat shelf-like ridge, the distal end of which
is enlarged and gives insertion to a large tendon of the superficial division, A, of the adductor
mandibulae muscle, that tendon having its insertion, in Scorpaena, in a slight depression in this
same part of the maxillary. The maxillo-mandibular ligament has its insertion, together with a
small tendon of the superficial division, A, of the adductor mandibulae, and also with a tendon of
the deeper division, A,A,, of that muscle, on a ridge-like eminence on the dorsal surface of the
maxillary, this eminence thus replacing the distal end of the ligamentary process of Scorpaena. The
ethmo-maxillary ligament is inserted on the base, or sometimes even near the summit of the ascend-
ing process.

The cartilaginous ROSTRAL is broader than in Scorpaena, and the median portion of its
posterior half, alone, has sliding contact with the dorsal surface of the snout. This surface of contact
is relatively wide and is usually slightly concave, but in some specimens it is flat or even slightly
convex, conforming in this to the much flattened dorsal surface of the snout of the fish. The dorsal
surface of the cartilage is conical, or pyramidal, sloping upward from all sides toward a central point.
The ascending processes of the premaxillaries rest upon the anterior half only of this surface, the
posterior portion being exposed. Immediately dorso-posterior to the ascending processes of the
premaxillaries, on the central point of the cartilage, there is a mass of tough fibrous tissue from which,
on either side, the rostro-palatine ligament has its origin. These ligaments do not form a continuous
band cerossing the middle line of the head, as in Scorpaena, and they are not, as in that fish, in contact

— 120 —

with the premaxillary. Each ligament is inserted, as in Scorpaena, on the base of the maxillary
process of the palatine. In one of four specimens examined, there was, in the middle line, between
the two ligaments, a small disk of bone on which the ligaments had their origins; and it would seem
as if this bone might be the rostral bone of Sagemehl’s descriptions, a bone which that author con-
sidered as an ossification of the rostral cartilage.

The FRONTAL has a ventral flange, but it is but slightly developed. The anterior end of
the bone overlaps externally the bounding edges of the mesethmoid and ectethmoid, those bones
separating the frontal, by a considerable interval, from the hind end of the nasal. Mesially the frontal
suturates, in the mid-dorsal line, with its fellow of the opposite side. Its hind edge is relatively straight,
forms a right angle with its mesial edge, and, extending from the middle line of the head to the mesial
edge of the pterotie, suturates its full length with the anterior edge of the parieto-extrascapular. The
posterior portion of the short postorbital portion of the lateral edge of the bone suturates with the
pterotic, its anterior portion touching a corner of the postfirontal and also abutting against a raised
portion of the sphenotic that comes to the level of the dorsal surface of the skull and has surface
markings similar to those of the dermal bones. This little raised portion of the sphenotie forms the
dorso-lateral corner of the postorbital process of the skull, and between its hind edge and the lateral
portion of the anterior edge of the pterotic there is a little notch which is occupied by the small post-
frontal bone. The postero-mesial corner of the raised portion of the sphenotic arches toward and,
in medium-sized specimens, touches, or almost touches, the anterior corner of the dermal portion
of the pterotic, a circular passage being left between the two bones, which transmits that primary
tube of the supraorbital latero-sensory canal that anastomoses with the main infraorbital canal as
that canal passes from the postfrontal into the pterotic. The frontal is traversed by the supraorbital
latero-sensory canal and lodges five sense organs of that line, the fourth and fifth organs of the line
lying relatively close together, without intervening primary tube, as in Scorpaena.

The PARIETO-EXTRASCAPULAR is a flat bone, and is traversed, near its hind edge, by
the supratemporal latero-sensory canal, that canal uniting with its fellow in the mid-dorsal line to
form a complete cross-commissure. The bone suturates, in the mid-dorsal line, with its fellow of the
opposite side, completely covering the supraoccipital excepting only a narrow hind edge of that
bone, and, slightly anterior to that edge, a small, variable and irregular median portion of the dorsal
limb of the bone. Anteriorly the bone suturates with the frontal. Laterally it suturates with the
pterotie, lateral extrascapular and suprascapular, not appreciably overlapping, in most of my spec-
imens, the epiotie process of the latter bone. On its dorsal surface, near the middle of the bone,
there is, in my medium-sized specimens, a slightly raised and granulated ridge, longitudinal in
position, which apparently corresponds to the ridge that forms the lateral boundary of the sub-
quadrangular groove on the vertex of Scorpaena. The section of the supratemporal latero-sensory
commissure that is enclosed in the bone lodges one sense organ of that canal.

The POSTFRONTAL is a small bone that lies in the angular interval between the pterotic
and the raised, dermal-like portion of the sphenotic. Its mesial corner approaches closely, or even
touches, between those two bones, the lateral edge of the frontal. It is traversed by the infraorbital
latero-sensory canal and lodges one organ of that line, innervated by a branch of the oticus lateralis.

The LATERAL EXTRASCAPULAR is a small subeircular bone that lies in the space between
the pterotic, parieto-extrascapular and suprascapular bones, with all of which bones it is firmly

— 121 —

united. It forms part of the roof of the temporal fossa, and is traversed by the main infraorbital
and supratemporal latero-sensory canals, lodging one organ of each of those lines.

The SUPRASCAPULAR is bounded anteriorly by, and firmly united with, the lateral extra-
scapular and the parieto-extrascapular, and forms part of the hind edge of the casque-like dorsal
surface of the skull. It has opisthotie and epiotie processes which are attached, respectively, and
in the usual manner, to processes of the opisthotic and epiotic bones. Immediately posterior to the
base of the opisthotic process there is a large articular facet, the lateral edge of which is slightly
differentiated as an articular eminence, this being more evident in small than in large specimens.
The two surfaces give articulation to articular surfaces on the dorsal end of the supraclavicular.
Immediately posterior to the articular eminence is the posterior opening of the section of latero-
sensory canal enclosed in the bone, this section of canal lodging one sense organ of the main infra-
orbital line. The bone extends some distance beyond the opening of the canal and terminates in
a stout point.

The SUPRACLAVICULAR has a small dorsal end, the anterior corner of which is entirely
occupied by a large condylar eminence. Immediately postero-lateral to this eminence, there is a
small flat or slightly concave articular surface. These two surfaces artieulate with the two articular
surfaces on the ventral surface of the suprascapular, the supraclavicular lying beneath the supra-
scapular and not extending back to the hind end of that bone. Immediately posterior to these artic-
ular surfaces the posterior half of the dorsal edge of the bone is traversed by the main latero-sensory
canal, the section of canal lodging one sense organ of the line. The ventral end of the bone is slightly
expanded, and has a large depression on its inner surface. The anterior and posterior edges of this
depression, and also the thin ventral edge of the bone, rest upon and are firmly bound by tissues
to the dorsal end of the clavicle, the supraclavicular fitting into a depression on the outer surface
of the latter bone. This depression in the clavicle surrounds a deep notch in the edge of that bone,
this noteh corresponding to the notch shown in my figures of the claviele of Scomber. The depressed
region on the inner surface of the supraclavieular overlies this notch in the claviele, and the oceipito-
supraclavicular ligament, passing through the notch, has its insertion in the depression on the supra-
clavicular. Nothing whatever in the arrangement of the parts is abnormal, as compared with Scor-
paena, nor is the supraclavicular (postero-temporal) at all crowded out of its normal place and
relation to the other bones, as stated by Gill (°88) and by Jordan and Evermann (’98). The bone
is simply inclined backward more than in Scorpaena, its dorsal end is smaller, and the prolonged
hind end of the suprascapular projects backward considerably beyond it.

The PARASPHENOID is large, with expanded anterior and posterior portions that are con-
nected by a short but relatively wide intervening portion. The ventral surface of the anterior portion
is deeply grooved to receive the vomer, the dorsal surface of this portion presenting a correspondingly
wide, low and rounded, median longitudinal ridge. On the dorsal surface of the posterior portion
of the bone there is a wide raised median portion, the deeply grooved lateral edge of which receives,
on either side, the cartilaginous ventral edge of the proötie; the raised portion thus not only closing
the hypophysial fenestra but also forming, on either side of that fenestra, a relatively considerable
part of the floor of the myodome. The ascending process of the bone, on either side, is represented
by a short, slender and sharply pointed dorsal extension of the thickened anterior edge of the ex-

panded posterior portion of the bone, and so unimportant is it that the process seems, at first sight,
Zoologica. Heft 57. 16

— 122 —

to be wholly wanting. A deep and narrow incisure, which separates the process from the almost
equally tall posterior portion of the bone, transmits the internal carotid artery. From this ineisure
a groove runs upward on the outer surface of the proötie, toward the facialis opening of the trigemino-
facialis chamber, and lodges the internal carotid artery. Ventral to the internal carotid foramen
this groove is continued on the outer surface of the parasphenoid, but there simply marks the
posterior limit of the surface of insertion of the adductor arcus palatini. The infrapharyngobranchial
of the first arch has its attachment to the skull anterior to the groove, in the immediate neighbour-
hood of the internal carotid foramen.

Between, or slightly anterior to the anterior edges of the ascending processes of the para-
sphenoid there is, in the middle line of the dorsal surface of the bone, a pronounced and sharply
pointed process, directed dorso-posteriorly. The anterior edge of this process is grooved, is presented
dorso-anteriorly, and lodges the ventral edge of the posterior portion of the cartilaginous interorbital
septum and, dorso-posterior to that cartilage, and continuous with it, the ventral end of the pediele
of the basisphenoid. On the ventral surface of the bone, slightly anterior to this little process, there
is, on either side, a slight process, or ledge directed laterally, which thus has approximately the pos-
ition of the well developed process of Osteoglossum.

The ORBITS are roofed by the ectethmoids and frontals, and are separated from each other
by an interorbital septum, the anterior portion of this septum being of cartilage, while its posterior
portion is of membrane. The extreme anterior end of the septum is perforated by an opening which
puts the orbits in communication with each other, this opening forming the median part ofthe anterior
eye-muscle canal. The hind wall of the orbit is formed by the alisphenoid, basisphenoid, proötie
and sphenotic, and is slishtly reöntrant in its lateral portion, this being due to the projecting anterior
edge of the lateral surface of the brain case. The ventral flange of the frontal being but slightly
developed, the orbital opening of the brain case is, in consequence, large and somewhat rectangular
in shape.

The MYODOME has proötic and basioccipital portions, the latter extending only about one
half the length of the basioceipital, and opening posteriorly on the ventral surface of that bone by
a small opening only. The orbital opening of the myodome is large and inclines strongly downward
and forward, while the roof of the proötie portion, or body of the myodome inclines strongly down-
ward and backward. This is due to a deepening of the orbits, posteriorly, and a correlated and marked
tilting upward of the mesial processes of the proöties, this giving to the myodome the appearance
of a large and deep recess at the hind end of the orbits.

There is no ORBITOSPHENOID.

The ALISPHENOID is bounded by the sphenotic, the frontal, and the prepituitary portion
of the mesial process of the proötic, the basisphenoid not coming into bounding contact with it. The
antero-mesial edge of the bone is slishtly concave, and bounds the orbital opening of the brain case.
This edge of the bone forms a continuous line with the anterior edge of the mesial process of the
proötie, and the adjoining edges of the two bones are cut away to form a rounded incisure which
transmits the nervus trochlearis. Dorsal to this incisure, in the anterior edge of the alisphenoid,
there is another incisure, often closed to form a small foramen, which transmits the cerebral branch
of the orbito-nasal vein. Near the center of the bone there is a larger foramen which transmits that
branch of the ophthalmicus lateralis that supplies the small latero-sensory organ in the terminal

tube of the supraorbital canal. This nerve, as in Scorpaena, perforates the alisphenoid, then runs
upward along the inner wall of the skull, traverses the lateral fontanelle, and, perforating the frontal,
reaches its organ. As in Scorpaena, the nerve is accompanied, as it traverses its foramen, by branches
of the external carotid artery and the vessel x.

On the external surface of the bone, near its ventral edge, there is a short and slight ridge which
is continued downward onto the external, ventro-anterior surface of the mesial process of the proötie.
Toward this ridge a small process projects dorsally from that part of the proötie that forms the anterior
edge of the lateral surface of the brain case, this process being of very variable length, and the process
and the ridge above it being connected by fibrous tissues. That part of the ridge that lies on the
alisphenoid represents a slight remnant of the parasphenoid leg of that bone, the part that lies on the
proötic here replacing a part of that process of the parasphenoid that, in Cottus, comes into contact
with the alisphenoid.

On the internal surface of the alisphenoid, at about its antero-dorsal quarter, there is a brace-
like thiekening of the bone, which is the greatly developed homologue of the small ridge described
on the internal surface of the alisphenoid of Scorpaena. The flat dorsal surface of the brace ıs cartı-
laginous in places, reaches the level of the dorsal edge of the bone, and abuts against the ventral
surface of the frontal; the hind edge of this surface of the brace almost reaching the anterior edge of
the supraoeeipital. The lateral edge of the dorsal surface of the brace forms the mesial boundary of
the anterior half of the lateral eranial fontanelle, its mesial edge being in synchondrosis with a large,
median postepiphysial interspace of cartilage which extends forward from the anterior edge of the
supraoceipital. The anterior edge of this postepiphysial interspace of cartilage is slightly concave, and
extends from the anterior edge of the alisphenoid of one side to that of the other side. From the
antero-lateral corner of the cartilage, a band of cartilage runs postero-laterally along the dorsal edge
of the plate-like body of the alisphenoid, the postero-lateral end of the band being continuous with a
band of cartilage that runs backward along the mesial edges of the sphenotie and pterotie and forms
the lateral boundary of the lateral cranial fontanelle. In Trigla gurnardus, a specimen of which was
used for the figure showing a dorsal view of the chondrocranium, there was a deep bay in the anterior
edge of the postepiphysial cartilage, much larger and deeper than that found in the specimens of
Trigla hirundo that were examined.

The BASISPHENOID has a long pediele which is direeted downward and forward at an angle
of from 30° to 45°, the two wings of the body of the bone being direeted laterallyand slightly upward.
The bone does not come into bounding contact with the alisphenoid. Along the dorsal surface of the
body of the bone, on either side, the optic nerve pierces the membrane that closes the orbital opening
of the brain case and enters the orbit. Slightly dorsal to the optie nerve, the nervus olfactorius pierces
the same membrane, and from there runs forward along the lateral surface of the interorbital septum,
lying wholly free in the orbit. In the hind edge of the body of the bone, in my largest specimen, there
is a median and imperfeetly closed foramen which unquestionably transmits the median encephalie
artery formed by the fusion of the internal carotid arteries of opposite sides of the head.

The LATERAL SURFACE OF THE BRAIN CASE is relatively flat and narrow, and its
anterior edge has a pronounced reöntrant angle, at about the middle of its height. That part of this
edge that lies ventral to the point of the angle inclines forward and downward and is formed by a thin
plate of bone which, in its dorsal portion, projects forward considerably beyond the adjomming portion

— 124 —

of the orbital surface of the brain case. The postero-ventral portion of the orbit is thus here bounded
laterally by bone, this part of the orbit leading into and being continuous with the myodome.

The PROÖTIC forms the middle three-fifths of the anterior edge of the brain case, the dorsal
fifth being formed by the sphenotic, and the ventral fifth by the short ascending process of the para-
sphenoid. At the middle of the entire edge there is a large foramen which perforates a thin plate-like
portion of the edge and leads directly into a small recess which lies on the orbital surface of the proötic
immediately dorso-lateral to the orbital opening of the myodome. This recess is the imperfectly
enclosed trigemino-facialis chamber, and the large foramen that opens from it onto the lateral surface
of the brain case is the facialis opening of that chamber. The lateral wall of the chamber is reduced
to the slender column of bone that forms the anterior boundary of the facialis opening. Anterior to
this column of bone there is, on the projecting plate-like edge of the proötic, a process of variable
length and shape, already referred to, which projects upward toward the slight ridge on the orbital
surface of the alisphenoid. This latter ridge, as already stated, represents the parasphenoid leg of
the alisphenoid, the process of the proötie being a proötie outgrowth which has invaded the alisphenoid
membrane, there replacing, in this fish, the parasphenoid outgrowth found in Cottus. Across the
dorsal surface of this process of the proötie, or between it and the column that bounds the anterior
edge of the facialis opening, this depending on the shape of the process, the truncus trigeminus has
its exit from the chamber.

The mesial wall of the trigemino-facialis chamber is perforated by three or four foramina;
two of them being large and the other one or two considerably smaller. Where there are four foramina,
one of the large ones transmits the root of the trigeminus together with the buccalis lateralis, the other
large one transmitting the motor root of the facialis together with the lateralis facialis and all of the
communis fibers of the trigemino-facialis complex; the two small foramina transmitting, one, the
ophthalmicus lateralis and the other the ciliaris profundi with the encephalic vein. Where there are
but three foramina, the ophthalmicus lateralis issues with the trigeminus and bucealis lateralis through
a partly separate portion of a single large foramen, the profundus and facialis always issuing through
independent foramina. The palatinus facialis issues through the facialis foramen, then turns mesially
along the floor of the trigemino-facialis chamber, and so enters the myodome. It is not here enclosed
in a separate canal. Directly mesial to the profundus foramen, the prepituitary portion of the mesial
process of the proötie is perforated by the oculomotorius, that nerve in 5 cm and 6 cm specimens of
Lepidotrigla, separating into its superior and inferior divisions before reaching its foramen. The
postpituitary portion of the mesial process is, in large specimens, either perforated or notched by a
foramen that transmits the abducens, that nerve passing directly from the cranial cavity into the
myodome.

In the ventral edge of the proötie, is the internal carotid ineisure. Posterior to that incisure
the ventral edge of the bone is capped its full length with cartilage and abuts against the parasphenoid
in the deep groove along the lateral surface of the median longitudinal ridge on the dorsal surface
of the bone.

On the internal surface of the proötic there is, as in Scorpaena, a trigemino-facialis recess, and
this recess lodges, as in Scorpaena, the communis, lateralis and profundus ganglia.

On the lateral surface of the dorsal portion of the proötic there is a fossa, and immediately
anterior to the fossa a brace-like process, the process and fossa giving insertion to the two internal

— 125 —

and first four external levators of the branchial arches, as in Scorpaena. Between the thick dorsal
end of this brace-like process and the adjoining portion of the sphenotic, there is a deep socket-like
articular facet for the anterior articular head of the hyomandibular. Slightly posterior to this facet,
on the lateral surface of the pterotic, is the oval and shallower facet for the posterior articular head
of the hyomandibular. Immediately dorsal to the line between these two articular facets, there is
a pit-like depression on the adjoining edges of the pterotic and sphenotic, the depression lying imme-
diately beneath the postfrontal. It is the dilatator fossa, the dilatator opereuli arising partly in this
fossa and partly on the external surface of the dorsal end of the hyomandibular, as in Scorpaena.
Immediately anterior to the dilatator fossa, and slightly dorsal to the anterior articular facet for the
hyomandibular, on the slightly concave dorso-lateral corner of the sphenotic, the levator arcus palatini
has its origin. A canal for the ramus oticus traverses the sphenotic, entering that bone on its
orbital surface.

At about the middle of the lateral surface of the brain case, and near the hind edge of the
proötic, there is a small foramen which transmits the root of the nervus glossopharyngeus. Dorsal
to the line between this foramen and the vagus foramen there is a triangular subtemporal depression
which, as in Scorpaena, gives origin to the adductor hyomandibularis and adductor opereuli, and also,
immediately posterior to the latter muscle, to the external levators of the fourth and fifth branchial
arches. The levator operculi has its origin along the dorsal edge of the lateral surface of the skull,
as in Scorpaena,

The PTEROTIC contains two latero-sensory organs innervated by the oticus lateralis, and
one post-preopercular organ innervated by the supratemporal branch of the lineae lateralis vagi.
The two organs innervated by the oticus were found in both of the two specimens examined, one being
an adult Trigla and the other a small Lepidotrigla. These two organs lie relatively elose together
and there is no indication whatever of a primary tube between them. They accordingly quite probably
represent the two independent otico-squamosal organs of Amia, here in process of concentration into.a
single organ, exactly as already set forth for the fourth and fifth supraorbital organs of this fish, of
Sebastes and of Scorpaena. Otherwise the pterotic of Trigla offers no apparent difference from the
bone in Scorpaena, excepting in that its posterior process is less extensive. The dorsal portion of the
hind edge of the lateral surface of the brain case projects latero-posteriorly as a tall, thin ridge of bone,
but this ridge is formed mainly by portions of the exoceipital and opisthotie, its dorsal edge only being
formed by the posterior process of the pterotie.

The OPISTHOTIC forms an actual part of the bounding wall of the posterior semicircular
canal, a part of that part of the pterotie region of the chondrocranium that, in Scorpaena, bounds
this canal having been suppressed in Trigla, and a large opening, leading directly into the canal, being
exposed when the opisthotie is removed. The opisthotie does not, however, seem to have anywhere
acquired primary relations to the skull, the underlying cartilage apparently having simply been
resorbed.

The EXOCCIPITAL is perforated by two foramina, one for the vagus and the other for the
occipital nerves, these two foramina being separated by the base of the condylar process that gives
articulation to the anterior artieular process of the first vertebra. In Scorpaena both of these foramina
lie antero-lateral to the base of the condylar process, separated by a slight ridge which is a ventral
prolongation of the postero-lateral angle of the skull. Dorsal to the foramen for the oceipital nerves

= 06

there is, in Trigla, a slight projecting ledge, this being much more marked in my small specimens
than in the large one used for the drawings. The hind edge of this ledge, in the small specimens,
projects posteriorly as a sharp angle, and beneath this part of the ledge the dorsal surface of the
condylar process of the exoceipital gives support to the lateral portion of the base of the first vertebral
arch. The mesial and larger portion of the base of the arch rests upon a portion of the dorsal surface
of the artieular process of the independent centrum of the first vertebra, this surface of contact Iying
postero-mesial to and contiguous with the supporting surface on the exoceipital. The arch does not
come into contact with the basioceipital.

The mesial process of the exoccipital, so well developed in Scorpaena, is but slightly developed
in Trigla. It is directed ventro-mesially, at about 45°, its ventral end, which is widely separated
from its fellow of the opposite side, resting upon a small process-like portion of the dorsal surface
of the basioceipital, this part of the basioccipital forming the mesial wall of the hind end of the
saccular groove.

The BASIOCCIPITAL is broad and relatively short. Its anterior end is deeply and widely
excavated by the hind end of the myodonıe, a narrow, longitudinal, and slit-like opening leading
from this groove onto the outer surface of the bone. That part of the basioceipital that forms the roof
of the myodome is flat and inclines downward and backward almost at an angle of 45°, the wide and
relatively shallow saccular groove of either side being, in consequence, pushed on to what appears
as a lateral portion of the cerebral surface of the bone, and being also tilted upward at a considerable
angle. The hind end of the saccular groove forms a recess in the basioccipital, and between the
recesses of opposite sides there is, on the dorsal surface of the bone, a large median pit which is the
cavum sinus imparis. Posterior to this pit, and at a considerably higher level, a short portion of the
dorsal surface of the bone forms the floor of the foramen magnum. The hind end of the bone is irregular,
the appearance being that of the ordinary vertebra-like hind end of this bone, with the dorso-lateral
corners deeply cut away. This leaves a depressed surface on either side of the dorsal portion of the
hind end of the bone, and this depression receives and gives support to the anterior articular process
of the first vertebra. On the lateral surface of the hind end of the bone there is a flattened surface
which gives origin to the occipito-supraclavicular ligament.

The centrum of the FIRST FREE VERTEBRA is an irregular disk of bone without attached
dorsal arch. The posterior surface of the disk has the usual concave vertebral depression, while on
its anterior surface there is simply a flat or slightly concave median portion. From the dorso-lateral
portion of the centrum, on either side, a stout process projects antero-laterally, rests upon the basi-
oceipital in the depressed region at the dorso-lateral corner of its hind end, and there articulates
with the condylar process of the exoccipital. The bases of these two anterior articular processes of
the first centrum are joined by a stout web of bone which forms a shelf projecting forward from the
dorsal edge of the centrum, thus making the dorsal surface of the centrum much wider, antero-
posteriorly, than its ventral surface. On either side of the dorsal surface of the centrum there is a
depression which receives the ventral surface of an anterior process of the second vertebra, this latter
process bearing and being fused with the base of the preforaminal portion of the arch of its vertebra.
This process of the second vertebra, in small specimens, but not in the large one used for the
figures, extends, in its lateral portion, almost to the anterior end of the corresponding process of the
first vertebra, the free arch of this latter vertebra thus appearing, in lateral views, to rest almost

ee

entirely upon the condylar process of the exoceipital. This appearance is however deceptive, for,
as stated when describing the exoccipital, the postero-mesial and larger portion of the base of the arch
of the first vertebra rests upon the mesial portion of the dorsal surface of the anterior process of its
own centrum. The dorsal arch of the first vertebra is represented by two bones, one on either side,
which touch in the mid-dorsal line above the spinal cord but are not there ankylosed with each
other. On the lateral surface of each half of the arch, there is a deep pit which gives insertion to the
most anterior rib. Ventral to this pit, the base of the arch is perforated by a foramen which transmits
the first spinal nerve. The base of the second arch is similarly pierced by a large foramen which
transmits the second spinal nerve; and dorsal to this foramen there is, on the lateral surface of the
arch, a large depression which gives insertion to the second rib. The two halves of this arch of the
second vertebra meet and ankylose in the mid-dorsal line above the spinal canal, but, like the arch
of the first vertebra, this arch does not extend dorsally beyond the point of ankylosis; these two
arches being much shorter than the next following ones.

The POSTERIOR SURFACE OF THE SKULL of Trigla differs somewhat from that of
Scorpaena. It slopes rapidly downward nearly to the level of the large foramen magnum, and then
curves rather abruptly backward to form the nearly straight and horizontal dorsal edge of that
foramen. Each half of the surface is separated into two portions by the nearly vertical epiotie ridge,
and across the dorsal portion of the mesial one of these two portions there is a large and rounded
transverse ridge. This ridge is formed entirely by the epiotic and supraoceipital, and apparently
corresponds to what I have described, in Scorpaena, as the hind edge of the primary skull; this
being more evident in Trigla gurnardus than in Trigla hirundo. Such being the case, the slightly
depressed region, on either side, between the transverse ridge and the hind edge of the secondary
skull would correspond to the supratemporal pocket of Scorpaena.

The TEMPORAL FOSSA is relatively small, as compared with Scorpaena. Its posterior
opening is bounded mesially and laterally, respectively, by the epiotice ridge and the opisthotie process
of the suprascapular, the latter process lying in a nearly vertical longitudinal plane, instead of, as
in Scorpaena, in the inclined plane of the lateral surface of the skull. Because of this position of the
opisthotie process of the suprascapular, there is a large opening leading into the fossa from the lateral
surface of the skull. In the mesial wall of the fossa there is a large but low preöpiotie fossa, this fossa
being simply a pocket-like diverticulum of the temporal fossa. The roof of the fossa is formed mainly
by the suprascapular and lateral extrascapular, but partly also by projeeting edges of the epiotic,
pterotic and parieto-extrascapular.

The SUPRAOCCIPITAL has a large postero-ventral limb which forms a large median portion
of the posterior surface of the skull. A small median ridge near the dorsal end of this limb of the
bone represents the much reduced spina oceipitalis. The dorsal limb of the bone is completely covered
by the overlying parieto-extrascapulars excepting only a narrow hind edge and a small and variable
portion of its dorsal surface which lies slightly anterior to that hind edge. The anterior edge of this
limb of the bone bounds and is continuous with the hind edge of the post-epiphysial cartilage, its
lateral edges bounding, on either side, the posterior portion of the lateral cranial fontanelle.

The EPIOTIC has a stout suprascapular process, this process and also the dorsal surface
of the bone itself, being entirely covered, dorsally, by overlying portions of the suprascapular and
parieto-extrascapular; the epiotie thus being wholly exeluded from the dorsal surface of the skull.

2.INFRAORBITAL BONES.

The infraorbital bones are all marked with granulated surface striae, and there were, in the
two large specimens, but three of these bones. In all of the several smaller specimens there were
four bones, the first and second bones of the series, found fused in the larger specimens, here being
separate and distinet. Trigla hirundo thus differs in the number of its infraorbital bones from any
of the combinations given by Günther in his descriptions of the fishes of the family, that author giving
five of these bones in Trigla pini, two in Trigla gurnardus and six in Trigla Iyra. But these numbers,
given by Günther, may not be correct for all ages of the fishes mentioned, for in two specimens of
T. gurnardus sent me by Dr. Allen, of Plymouth, England, there were five infraorbital bones instead
of two as stated by Günther.

The anterior bone of the series, in the smaller specimens of Trigla hirundo, is the lachrymal,
and is a large and somewhat triangular bone, the anterior end of which curves strongly mesially
and so gives to the bone a concave internal and convex external surface. The eurved anterior end of
the bone is considerably thickened, but its ventro-anterior edge is simply coarsely serrated and not
furnished with prominent spınes, as Günther states in his descriptions of this fish. In this the fish
resembles Günther’s deseriptions of Trigla gurnardus rather than T. hirundo, its colour and other
characteristics however identifying it as the latter. The thickening of this anterior end of the lach-
rymal is apparently due to aceretions to its inner surface, and this surface of this part of the bone
is partly covered with surface striae or granulations. From the hind end of this thickened portion,
two ridges run backward on the internal surface of the bone; one along the ventral edge of the bone,
and the other near and parallel to its dorso-anterior edge; both ridges being prolonged beyond the
body of the bone as relatively long and slender processes. The dorso-anterior edge of the bone, dorso-
anterior to the second one of the two ridges just above mentioned, is thin, and its anterior and posterior
thirds rest upon and are firmly bound to portions of the dorsal edge of the palatine. Between these
two regions of contact with the palatine, the lachrymal is cut away by a long oval ineisure which
is bridged by the underlying palatine. An opening is thus left between the lachrymal and the palatine,
this opening lying directly opposite the slit-like opening of the nasal pit and lodging the lateral half
of the nasal sac. That part of this edge of the lachrymal that lies anterior to this nasal incisure rests
upon the maxillary process of the palatine, and there has a flat, pointed, and more or less developed
process which, as stated when describing thenasal, gives sliding artieulation to the antero-lateral corner
of that bone. That part of the edge of the lachrymal that lies posterior to the nasal incisure inclines
mesially and rests upon those portions of the palatine bone and cartilage that form the posterior ethmoid
process. On the external surface of this part of this edge of the lachrymal there is a small groove,
parallel to the edge and extending posteriorly to the base of the slender and related dorso-posterior
process of the bone. At its anterior end this groove is bounded mesially by a part of the palatine,
and here, and throughout the larger part of its length, the groove is, in large specimens, filled with
a line of tough fibrous tissue which binds the bone to the summit of the articular ridge on the ventral
surface of the ectethmoid. There is thus artieulation here between these two structures, but there
are no regular articular surfaces. The articulation, such as it is, represents the combined ethmo-
lachrymal and posterior ethmo-palatine articulations. Posterior to this articular portion, the dorso-
posterior process of the lJachrymal projects backward as a free and slender process which lies against
and is closely attached to the larger one of the two ethmo-palatine ligaments already described. This

— 129 —

ligament, running forward from its point of origin on the ectethmoid, has its insertion on the palatine
cartilage, the process of the lachrymal thus being developed in supporting relation to it. The second
ethmo-palatine ligament is, as already stated, a slender and delicate one that arises from the ventral
surface of the ectethmoid. Running forward from there, parallel to but at a certain distance from
the larger ligament, it also is inserted on the hind end of the palatine cartilage.

The lachrymal is traversed by the infraorbital latero-sensory canal and lodges three organs
of that line.

The second infraorbital bone is a large and almost 'parallelogrammie bone. The striae on its
outer surface radiate mainly from a point that lies near the ventral quarter of the bone directly super-
ficial to the latero-sensory canal that traverses the bone, but partly also from a second point that
lies slightly antero-ventral to the first one, and also directly superficial to a portion of the latero-
sensory canal; these two points apparently representing the centers of ossification of two bones,
here fused but found separate in a 63 mm specimen of Lepidotrigla examined in serial sections. ')

In the hind edge of the bone, at about its ventral third, there is a more or less pronounced
angular incisure. Dorsal to this incisure the hind edge of the bone abuts against the anterior edge
of the preopereular, overlapping it but slightly at any place. Ventral to the incisure, the bone also
abuts against the anterior edge of the preopereular, but it there also rests upon the lateral edge of
the posterior process of the quadrate, the attachment to this latter bone being particularly strong,
inuch stronger than to the preopercular. The point of the incisure lies in the line, anteriorly produced,
of the dorsal and largest preopercular spine, and fits against a pointed portion of the anterior surface
of the outer edge of the preopercular. From the point of the incisure, and extending backward across
the outer surface of the preopercular to the base of its dorsal spine, there is a slight but distinetly
evident tuberculated ridge, this ridge being also continued forward across the second infraorbital
bone. Ventral to the ridge, both the preopercular and second infraorbital incline slightly downward
and inward, the ridge thus separating two somewhat inclined surfaces. In my large specimens this
ridge is but slightly indicated, while in the small ones it is quite pronounced.

The infraorbital latero-sensory canal enters the second infraorbital bone on its outer surface
near the middle point of its dorsal edge, this point Iying at the anterior edge of the orbit. Posterior
to this point there is a depressed region on the outer surface of the dorsal edge of the bone, the de-
pression lodging the ventral portions of the third and fourth infraorbital bones. From the point
where the canal enters the outer surface of the second infraorbital bone it runs downward and for-
ward in the line of the striae on the outer surface of the bone until it reaches the principal point from
which those striae radiate. There it sends a long primary tube backward nearly to the hind edge of
the bone, and itself turns gradually forward to leave the bone at its anterior end and enter the
lachryinal. The primary tubes that arise from the canal as it traverses the bone all open on its outer
surface ventral to the longitudinal striated ridge just above described. The bone lodges four organs
of the infraorbital line.

The third and fourth infraorbital bones are relatively small. The third bone has the shape
of an elongated rectangle, occupies the larger part of the depressed region along the dorsal edge of
the second infraorbital bone, and forms the ventral edge of the orbit. The fourth bone is somewhat

1) Since tke completion of the manuscript these two bones have also been found separate in a medium-sized specimen
of Trigla hirundo.
Zoologica. Heft 57. 17

— 130 —

triangular, with curved edges. Its ventral edge fits onto the outer surface of the second infraorbital,
its hind edge overlapping and resting upon the anterior edge of the preopercular, and extending
nearly to its dorsal end. Its concave anterior edge forms the posterior boundary of the orbit. Its
dorsal end does not quite reach the lateral edge of the postfrontal. These two bones are traversed
by the main infraorbital canal, and each lodges one organ of that line.

3, SUSPENSORIAL APPARATUS AND MANDIBLE.

The QUADRATE has the usual shape, with its ventral corner enlarged to form the articular
head for the mandible. Its antero-ventral edge is bevelled, and fits into the grooved hind edge of the
ventral limb of the ectopterygoid. Its ventro-posterior edge is greatly thickened, is prolonged dorso-
posteriorly in a short sharp posterior process, and between this process and the body of the bone,
on the internal surface of the element, there is a large symplectie groove. The ventro-posterior surface
of the posterior process is grooved and fits against and is firmly bound to the anterior edge of the ven-
tral end of the preopereular. The lateral surface of the process is raised in a large and tall ridge, the
outer surface of which is roughened and gives support to, and is firmly bound to, the ventro-posterior
corner of the second infraorbital bone. The dorso-posterior end of this raised portion fits into a small
notch in the anterior edge of the preopercular. Between this raised portion of the process and the
external surface of the body of the quadrate, there is a large depression which seems to have no special
morphological significance.

The METAPTERYGOID has its dorso-anterior edge bent slightly inward, and has lateral
and mesial flanges along its hind edge. The mesial flange is a small one excepting at its dorsal end
where it is prolonged into a process which meets, or almost meets a flat process that projects antero-
ventrally from the anterior edge of the thin web of bone that fills the space between the anterior
articular arm of the hyomandibular and the shank of that bone, and is bound to that process by
fibrous tissues. Ventral to this process-like portion, the hind edge of the mesial flange is connected
by & wide sheet of membrane with the shank of the hyomandibular. The lateräl flange projects
postero-laterally at a slight angle to the body of the bone, and reaches, or overlaps slightly, and is
attached to the outer surface of the ventral end of the shank of the hyomandibular. The ventral
corner of this lateral flange approaches, or may even reach and rest upon the outer surface of the
cartilaginous interspace between the hyomandibular and symplectic; and there is, in the corner
of the flange, an inceisure which, with the adjoining cartilage and the hyomandibular, forms a foramen
which transmits the arteria hyoidea.

The ECTOPTERYGOID has the usual two limbs lying at an obtuse angle to each other,
the dorso-anterior limb being a large plate the dorsal edge of which is grooved. This groove lodges
the ventral edge of the anterior end of the entopterygoid, and also that part of the palatine bone
and cartilage that forms the posterior ethmoid process of the apparatus, the lateral edge of the groove
being a tall plate which lines the lateral surface of the palatine cartilage and may even project dorso-
posteriorly slightly beyond the cartilage. The anterior edge of this part of the ectopterygoid is
somewhat jagged, and suturates with the hind edge of the ventral flange of the palatine. The ventro-
posterior limb of the bone is grooved on its posterior surface and fits against the antero-ventral edge
of the quadrate.

— Bl —

The ENTOPTERYGOID is small, and its ventral half lies closely against the inner surface
of a part of the cartilage of the apparatus that lies between the metapterygoid and the ectopterygoid,
along the dorsal edge of the quadrate. The dorsal half of the bone projects beyond the cartilage,
is concave on its outer and convex on its inner surface, and lies against the under surface of and gives
insertion to a portion of the adductor arcus palatini. The anterior end of the bone rests in the grooved
dorsal edge of the dorsal limb of the ectopterygoid, its posterior end not quite reaching, in small
specimens, the anterior end of the metapterygoid.

The PALATINE hasa body, a maxillary process, and a stout and large ventral flange of derm-
al origin. The hind edge of the ventral flange is jagged and suturates with the anterior edge of the
dorsal limb of the ectopterygoid. The hind end of the body of the bone is in synchondrosis with the
cartilage of the posterior ethmoid process of the apparatus. The maxillary process of the bone curves
slightly antero-mesially, is flattened on its dorso-lateral surface, and there rests against and is firmly
bound to the internal surface of the dorso-anterior edge of the lachrymal. A small eminence at the
base of the maxillary process gives insertion to the rostro-palatine ligament, and immediately posterior
to this process there is an obliquely transverse facet which articulates with the anterior palatine
process of the ethmoid cartilage. The vomero-palatine ligament is unimportant. The anterior end
of the maxillary process of the bone is capped with cartilage and articulates with the dorsal surface
of the maxillary, in the angle between the lateral surface of the ascending process and the shank
of that bone. The posterior portion of the body of the palatine, and the cartilage that forms the
posterior ethmoid process of the apparatus, are firmly bound to the lachrymal, in the manner already
described. Between this posterior part of the palatine and the base of its maxillary process, the dorso-
lateral surface of the body of the bone is slightly hollowed, this hollow lodging the lateral half of
the nasal sac.

The palato-quadrate, as a whole, forms a plate which is slightly concave on its ectal surface,
and the two anterior infraorbital bones together form a plate which is slightly concave on its ental
surface. These two plates are firmly bound to each other by their anterior edges, while by their
posterior edges they are firmly bound to the preopercular and hyomandibular. The two plates
together thus form a flat, hollow, trapezoidal structure, open both dorso-mesially and ventro-laterally
by large and relatively narrow openings. The space enclosed between the two plates is, in the recent
state, almost completely filled by the adductor mandibulae muscle.

The HYOMANDIBULAR is cross-shaped, the arm of the cross lying obliquely to the shank.
The summit of the longitudinal ridge on the outer surface of the shank projects forward, and so
gives to the anterior surface of the bone a grooved appearance. The dorsal portion of this forwardly
projecting ridge gives support, on its lateral surface, to the fourth bone of the infraorbital series.
The shank of the bone is traversed by a facialis canal, the ventral opening of that canal lying anterior
to the longitudinal ridge. From this canal a single branch canal arises, and running postero-ventrally
opens on the outer surface of the bone, near the ventral end of the thin web of bone that fills the
space between the opercular process and the ventral portion of the shank of the bone. It transmits
a nerve destined to innervate the two dorsal ones of the latero-sensory organs in the preopereular,
a single canal thus here replacing the two canals found in Scorpaena. A foramen leads directly
from the main canal for the facialis onto the anterior surface of the bone, but it only transmits
a blood vessel.

BE 12 ge

The rod-like SYMPLECTIG lies in the symplecti@ groove on the internal surface of the quad-
rate. Between it, and the preopercular and the posterior process of the quadrate there is a large
oval opening which transmits the mandibularis externus facialis and the arteria hyoidea. Anterior
to the symplectice, between it and the quadrate, there is a small canal which transmits the mandi-
bularis internus facıalıs.

The arteria hyoidea has a course exactly similar to that in the fishes already described.

The PREOPERCULAR has slightly indicated dorsal and ventral limbs, separated by a low
and granulated ridge on the outer surface of the bone. This granulated ridge is much more apparent
in small than in large specimens, and terminates posteriorly in a spine which, in small specimens, is
sharply pointed. Immediately ventral to this spine there is, in these small specimens, a smaller spine.
The dorsal limb of the bone is firmly bound to the hyomandibular, the ventral limb being similarly
bound to the posterior process of the quadrate. The anterior edge of the bone gives support and is
bound to the hind edge of the second bone of the infraorbital series. The bone is traversed its full
length by the preopereular latero-sensory canal, and lodges six organs of the line, the second organ
from the dorsal end of the bone being a double one in the one specimen examined.

The OPERCULAR has a large bluntly pointed process which rises from the dorsal edge of the bone
immediately dorsal to the articular facet for the hyomandibular, and, projecting dorsally or dorso-
anteriorly, nearly reaches the dorso-lateral edge of the skull in the suprascapular region. The inner
surface of the process is slightly concave and gives insertion to the adductor opereuli, that muscle
having a large surface of origin in the subtemporal depression on the lateral surface of the skull, the
surface of origin of this muscle lying immediately posterior to that of the adductor hyomandibularis.
Immediately posterior to the base of the process, on the inner surface of the dorsal edge of the oper-
eular, the levator operculi has its insertion; this muscle arising from the dorsal margin of the lateral
surface of the pterotie in a line beginning immediately posterior to the latero-sensory tube that
anastomoses with the dorsal end of the preopercular canal. The dilatator operculi arises partly in
the dilatator fossa and partly on the external surface of the dorsal end of the hyomandibular, and is
inserted on the anterior edge of the articular facet for the hyomandibular. On the hind edge of the
opercular there are two stout spines, the dorsal one curving upward so that its point is directed almost
dorsally.

TheSUBOPERCULAR is a long. thin and delicate bone. In one of my large specimens the ventral
half of this bone was wanting, and the dorsal half was almost completely ankylosed with the hind
edge of the operecular.

The INTEROPERCULAR is bound by strong ligamentous tissue, at about the middle of its
dorso-anterior edge, to the interhyal and ceratohyal. Its antero-ventral end is bound, by a short
strong ligament, to the hind end of the mandible.

The MANDIBLE is relatively longer and more slender than that of Scorpaena. The hind
edge of the dentary is V-shaped and receives, in the angle of the V, the long pointed anterior end of
the artieular, overlapping that bone externally. The dorsal arm of the V reaches the summit of the
coronold process of the articular, and is bound to its internal surface, slightly below the summit
of the process. Between this arm of the dentary and the adjoining parts of the artieular there is a
relatively small and narrow space. The dorsal edge of the dentary is broad and is covered with small
villiform teeth; and immediately ventral to this toothed surface there is a deep longitudinal groove

— 13 —

which lodges, as in Scorpaena, a gristly tapering rod-like structure which forms the core of the mandi-
bular labial fold of the fish. The pointed anterior limb of the articular is strongly convex externally
and concave internally, and lodges, in its concave internal surface, the rod-like Meckel’s cartilage.
Posterior to the hind end of Meckel’s cartilage the conformation of the rod is continued a short
distance by a rounded ridge of bone. There is a short, stout, sharply-pointed coronoid process. The
hind edge of the articular facet for the quadrate projects dorso-posteriorly as a stout process which
has a sliding articulation on the ventro-posterior surface of the posterior process of the quadrate,
as in Scorpaena. The angular is a small bit of bone that caps the hind end of th: articular and gives
insertion to the strong mandibulo-interopercular ligament. The articular and dentary are both
traversed by the mandibular latero-sensory canal, and lodge, respectively, one and four organs of
the line.

4. MUSCLES.

The adductor mandibulae muscle of Trigla has anterior and posterior divisions, instead of, as
in Scorpaena, superficial and deeper ones. The anterior division forms the anterior third or quarter
of the entire muscle and has its origin from a tendinous band that extends along its own dorsal edge
and then backward along the dorsal edge of the posterior division of the muscle, to have its origin
on the tendinous tissue that forms the anterior edge of the levator arcus palatini. This anterior
division of the adductor has its insertion wholly on a tendinous fascia that forms on its internal surface
and that terminates anteriorly in two tendons; a stout tendon inserted on the hind end of the liga-
mentary process of the maxillary, and a less important one inserted on the dorsal surface of the
same bone.

The large posterior division of the adductor is partly separated into two portions by the ramus
mandibularis trigemini, that nerve traversing the muscle from its inner surface and issuing on its
outer surface close to its ventral edge. That part of the muscle that lies anterior to the nerve has its
origin on the tendinous band that extends along the dorsal edge of the entire muscle, and that gives
origin also to the anterior division of the muscle. It is inserted in part on the tissues that extend
irom the palato-quadrate apparatus to the maxillary, partly on a tendon that joins the tendon A,A,,
described below, and partly on a tendon that runs forward and has its insertion on the dorsal surface
of the maxillary. This part of this division of the muscle, and the anterior division of the entire
muscle, thus together correspond approximately to the superficial portion, A,, of the muscle of Scor-
paena. That part of the muscle of Trigla that lies posterior to the mandibularis trigeminus then
corresponds to the muscle A, A, of Scorpaena, and, like that muscle, it arises from the hyomandibular,
the preopercular and the outer surface of the palato-quadrate arch, and has its insertion on a tendon
that may be called tendon A,A,. This tendon is double, having anterior and posterior portions.
The anterior portion separates into two parts one of which is continuous with a fascia that forms on
the inner surface of A,,, the other having its insertion on the internal surface of the articular ventral
to the hind end of Meckel’s cartilage. The posterior portion of the tendon A,A, runs downward
along the hind edge of A,, and has its insertion on the inner surface of the articular dorsal to the hind
end of Meckel’s cartilage. There is, in Trigla, no tendon running backward, as in Scorpaena, from
the tendon A, A, to the inner surface of the quadrate.

The maxillo-mandibular ligament is as in Scorpaena.

— 134 —

The levator arcus palatini is a strong muscle which arises from the small roughened surface
on the dorso-lateral corner of the sphenotice. Running almost directly downward it spreads forward
and backward, its deeper fibers being immediately inserted on the external surface of the dorso-anterior
portion of the hyomandibular. The more superficial fibers of the muscle are inserted in part on the
dorsal edge of the lateral flange on the hind edge of the metapterygoid, but in larger part they run
downward between that flange and the mesial one and have their insertions on the latter flange, in
the membrane that extends from that flange to the anterior edge of the hyomandibular, and also
partly on adjoining portions of the hyomandibular.

The adductor arcus palatini is a broad sheet of muscle that has an origin and insertion similar
to that of the muscle in Scorpaena. The surface of origin begins posteriorly on the external surface
of the narrow bridge of bone that forms the external wall of the trigemino-facialis chamber, runs
downward onto the ascending process of the parasphenoid and then, turning forward, extends along
the ventro-lateral surface of the parasphenoid nearly to the anterior end of that bone. Running
ventro-laterally the fibers of the muscle have their insertion in a long line that begins on the inner
surface of the anterior edge of the dorsal portion of the hyomandibular and extends forward along
the dorsal edge of the metapterygoid, and then onto the entopterygoid and the palatine cartilage and
bone, the line of insertion passing along the dorso-mesial edge of the metapterygoid instead of erossing
the internal surface of that bone, as it does in Scorpaena. The small entopterygoid lies upon the
internal surface of the ventral edge of the muscle and gives insertion to certain of its fibers.

The adduetor hyomandibularis, and the dilatator, adductor and levator operculi have already
been sufficiently referred to when describing the opercular bones.

5. LATERO-SENSORY CANALS.

The latero-sensory canals of Trigla differ in no essential particular from those of Scorpaena.
As in that fish, the primary tubes branch repeatedly after they leave the bones to which they are
related and enter the overlying dermal tissues, large and complex dendritic systems being formed.

The lachrymal lodges three sense organs of the main infraorbital line, the large second infra-
orbital bone, four organs, and the third and fourth bones one organ each. This makes nine organs
in all in this part of the line of Trigla, which is two more than is found in Scorpaena, and one more
than is found in Cottus even when counting the small supplemental organ in the second infraorbital
bone of that fish.

The postfrontal lodges one sense organ innervated by the oticus lateralis, and the pterotic
two organs innervated by the same nerve. The two organs in the pterotie are without intervening
primary tube, and are probably, as already explained, in process of condensation into a single organ.
The pterotie also lodges a post-preopercular sense organ, innervated by a branch of the supratem-
poralis lateralis vagi, this organ not being found in Scorpaena but being found in Cottus.

The lateral extrascapular, suprascapular and supraclavicular each lodge one organ of the main
line, the organs in the first two bones being innervated by branches of the supratemporalis lateralis
vagi,and theorgan in the supraclavicular by the next following and single branch of the nervus lineae
lateralis vagi.

The supratemporal canal forms a eross-commissure with its fellow of the opposite side, and
contains two organs, onelying in the lateral extrascapular and the other in the parieto-extrascapular,
both innervated by branches of the supratemporalis lateralis vagı.

— 135 —

The supraorbital canal contains six sense organs, one lying in the nasal and five in the frontal.
As in Scorpaena, the fourth primary tube anastomoses in the middle line with its fellow of the
opposite side to form a frontal commissure, the penultimate tube anastomoses with the main infra-
orbital canal between the frontal and pterotic bones, and the primary tube between the fourth and
fifth organs of the line has been suppressed.

The preoperculo-mandibular canal anastomoses at its dorsal end with the main infraorbital
canal between the pterotie organs that are innervated by the oticus lateralis and the supratemporalis
lateralis vagi. It contains eleven sense organs, four lying in the dentary, one in the articular and six
in the preopercular, as in Scorpaena, this being one more organ in the dentary and one more in the
preopercular than is found in Cottus. The next to the most dorsal organ in the preopercular was nearly
always a double organ.

Il. Triglia Iyra.

In Trigla Iyra the granulations on the dorsal surface of the skull are considerably smaller than
in T. hirundo, and the striae smaller and more numerous. This gives to the surface a sand-paper-like
feel and appearance. The preorbital part of the skull is bent downward somewhat more than in
T. hirundo and the skull is everywhere relatively taller than in that fish, excepting only in the anterior
half of the snout, where it has the same relative height. On the posterior half of the dorsal surface
of the snout there is a large, low, median swelling. The interorbital portion of the dorsal surface of
the skull is but slightly concave, and there is, on either side, but one, short and stubby, preorbital
spine. The postorbital portion of the dorsal surface of the skull is decidedly convex in transverse
section, and slightly convex in median longitudinal section; and there is no slightest indication of a
subquadrangular groove.

The rostral depression is relatively larger than in T. hirundo. The nasal rests definitely upon
the summit of the anterior palatine process of the ethmoid cartilage, the rounded antero-ventral
surface of the latter process articulating with a facet at the base of the maxillary process of the palatine.
The anterior edge of this facet on the palatine is raised to form an eminence which gives insertion
to the rostro-palatine ligament, and this eminence, lying in front of the palatine process of theethmoid
cartilage, fits. in between the nasal above and the ascending process of the vomer below in such a
manner that it seems to form part of the articular contact of the palatine with this part of the skull.
The lateral edge of the nasal has a sliding artieulation with the dorsal surface of the lachrymal, as in
T. hirundo.

The ectethmoids suturate with each other in the middle line behind the mesethmoid, as Günther
has stated. The orbital surface of the bone includes the orbital surface of the bone in T. hirundo
and also that little surface that lies between the two posterior portions of the ridge along the lateral
edge of the ventral surface of the bone in the same fish. This condition thus being intermediate
between that in T. hirundo and that in Scorpaena.

The median anterior eye-muscle canal, in the antorbital cartilage, so well developed in
T. hirundo, is here represented by what is little more than a perforation of the extreme anterior end of
the interorbital septum. From there a canal for the olfactory nerve runs forward on either side, this
canal being enlarged, as in T. hirundo, to form a deep and large recess in the hind end of the meseth-

— 136 —

moid, the recesses of opposite sides being separated by a thin wall of bone. The mesethmoid extends
entirely through the antorbital cartilage, and presents, on the ventral surface of that cartilage, a median
circular surface which lies directly upon the parasphenoid; the vacuity found in this part of the bone
of T. hirundo not here being present.

The parasphenoid has much the shape that it has in T. hirundo, but the ascending processes
are well differentiated, and there is no median process in the interorbital region.

The basisphenoid has a short pedicle which descends only about one half the depth of the
myodome, and there terminates with a free end. This free end gives attachment to the middle point
of the anterior edge of a stout membrane which extends backward and downward in the middle line,
and laterally and slightly downward on either side, and has its insertion on the floor and sides of the
myodome. This membrane separates the myodome into two parts, a larger dorso-posterior portion
and a smaller antero-ventral one. The dorsal portion lodges the rectus externus, the ventral portion
lodging the rectus internus. This membrane, judging from the serial sections of the several fishes
that I have examined, must be found in all teleosts, in a more or less developed condition. In Scomber
I have already described it (Allis, ’03, p. 92).

In other respects there are, in the eranium of T. lyra no important differences from that of
T. hirundo.

The hyomandibulo-palato-quadrate apparatus difiers somewhat in shape from that of
T.hirundo, but in all important respects it closely resembles theapparatus of thatfish. Thelachrymal
is somewhat differently shaped, and its anterior edge is furnished with a number of stout sharp spines.
Two bones replace the large second infraorbital bone found in medium-sized specimens of T. hirundo,
thus making five bones, in all, in the series.

According to Günther there are six bones in the series, but the specimens examined by hım
must have been young fish, for in all of my specimens, which are large ones, there are but five bones.
The ridge that extends horizontally across the outer surface of the preopercular is much more pro-
nounced than in T. hirundo, and extends forward to that point of the third infraorbital bone from
which the striae of the bone all radiate. The dorsal end of the preopercular is prolonged upward
and touches and is firmly bound to the outer surface of the hyomandibular, thus forming a closed
oval passage through which that part of the dilatator operculi that has its origin in the dilatator
fossa passes to reach its point of insertion on the opercular. The spine on the opereular, at about
the middle of its hind edge, is much longer and stouter than in T. hirundo.

Il. Peristedion cataphractum.

1. SKULL.

The orbital and postorbital portions, together, of the skull of Peristedion, oecupy the posterior
halfonly of the total length of theskull, and the posterior third only of thetotallength of the skeleton
ofthe head. The anterior half of the skull is formed by the long, broad, flat and thin preorbital portion,
or snout of the fish, which is straight and inclines slightly downward. The outer surfaces of all the
bones are finely granulated, the granulations being arranged, in certain places, but not everywhere,
in faintly indicated striae.

— 137 —

The flat anterior ends of the lachrymals form the so-called preorbital processes. These processes
are nearly as long as the snout of the fish, and their edges are finely serrated, each little tooth being
the end of a vein on the thin edge of the process, this vein appearing both on the dorsal and ventral
surfaces of the process as a slight and finely granulated ridge. At the base of the process two ridges
begin. The dorsal one is much the stronger and extends backward, across the cheek bones, as a longi-
tudinal, horizontally-projecting shelf, to the hind edge of the preopereular, where it terminates in
a tall, thin, obtuse and finely serrated hind end. The anterior half of the ridge bears two groups of
small point-like spines; a short anterior group, on the second bone of the infraorbital series, and a
long posterior one, on the third bone of the series. Dorsal to the ridge the outer surface of the cuirass
of the cheek inclines dorso-mesially, while, ventral to it, it inclines ventrally or ventro-mesially, the
ridge making a prominent angle on the outer surface of the cuirass. The ventral ridge is much less
important than the dorsal one, and lies near the ventral edge of the cheek bones. It, also, extends
to the hind edge of the preopercular, but it is always interrupted, as, or just before, it reaches the
anterior edge of that bone, and there usually breaks up into several slishtly diverging ridges, all of
which are finely serrated their full length.

On the anterior quarter line, approximately, of the dorsal surface of the snout, at about the
middle of the length of the nasal bone, there is, on either side, either one stout vertical spine, or two
or more smaller spines lying one directly behind the other. On the posterior quarter line of the snout,
or even still nearer its base, there is, near the lateral edge of its dorsal surface, on the ectethmoid
bone, a group of from one to three similar but smaller spines. Postero-lateral to these latter spines,
there are, also on the ectethmoid, two or three short diverging lines of small tooth-like spines. The
dorso-mesial one of these lines is continuous with the dorsal edge of the orbit, that edge being
serrated. Slightly anterior to the transverse line of the ectethmoid spines, there is, on the dorsal
surface of the mesethmoid, a single large median spine.

Starting from the group of ectethmoid spines, on either side, a ridge runs backward to the
hind edge of the dorsal surface of the skull, traversing the ectethmoid, frontal and parieto-extra-
scapular bones. The ridges of opposite sides converge slightly, at first, in a gentle curve, and then
run backward in slishtly curved and slightly diverging lines to the hind end of the interorbital region,
when they again converge slightly to the hind edge of the skull. As they pass between the orbits
each ridge lies slightly mesial to the dorsal edge of the corresponding orbit. Each ridge bears a variable
number of spines, the spines that lie on the ectethmoid part of the ridge being small and sharply
pointed, while the others, on the frontal and parieto-extrascapular portions, are usually serratures
that increase gradually in size toward the hind end of the ridge. The large posterior serrature lies
on the parieto-extrascapular, extending the full length of that bone and ending almost directly
dorsal to the summit of the epiotic. The next anterior serrature is slightly smaller than the posterior
one, rises from the hind edge of the frontal, and extends across that part of the frontal that lies
posterior to the frontal commissure of the latero-sensory canals. The next anterior serrature is still
smaller, is sometimes double, and lies opposite and slightly posterior to the lateral end of the frontal
commissure. Beneath the base of this last serrature the sixth tube of the supraorbital canal passes,
on its way to join and anastomose with the main infraorbital canal at the edge of the frontal. The
fifth tube of the supraorbital canal has been suppressed, as in Scorpaena, the seventh or terminal
tube opening on the outer surface of the frontal slightly mesial to the point of this same serrature.
This third serrature from the hind end of the line thus has the position, relative to the supraorbital

Zoologi?a. Heft 57. 18

— 133 —

canal, of the frontal spine of Scorpaena, but it does not lie at the hind end of the frontal, that
position being held by the penultimate serrature of the line. Whether this latter serrature
represents a part of the frontal spine or not, I can not determine, but it apparently does. The
spine on the parieto-extrascapular must then be a parietal spine, and there is no nuchal spine.
Starting from or slightly postero-lateral to the frontal spine, and running at first postero-laterally,
and then posteriorly, near the lateral edge of the dorsal surface of the skull, there is another
ridge, which corresponds in position to the lateral row of spines of Scorpaena. This ridge has
a wavy or bluntly serrated edge and sometimes terminates, at the hind end of the suprascapular,
in a small spine.

Emery (85) has given a figure of the skull of the adult Peristedion in which the spines that
I have just described are roughly shown, with the exception of themesethmoid and ectethmoid spines,
which are neither shown in the figure nor mentioned in the text. The spines are also shown by the
same author in two figures of larvae of Peristedion of different ages, the skull of the youngest larva
being said to so greatly resemble the skull of the adult Scorpaena that Emery calls that larva the
scorpaenoid stage of the fish. At these two stages of Peristedion the spines are all very large, and a
single spine on the nasal, and a single large spine on the frontal represent the several spines on those
bones of the adult. A spine is also shown on the pterotie of the youngest larva, this spine being wholly
wanting in the adult. Similarly, a spine is said by Emery to be found on the nasal of the young ot
Trigla hirundo, and to wholly disappear in the adult.

The dorsal surface of the skull of Peristedion, between the fronto-parietal serrated ridges,
and posterior to the frontal commissure, is perfectly flat, lies in a horizontal position, and corresponds
to the region of the subquadrangular groove on the vertex of Scorpaena. Lateral to the ridge that
bounds this surface, on either side, the dorsal surface of the skull is a flat surface that slopes rapidly
downward at an angle of approximately 30° to the vertical plane. Between the orbits the dorsal
surface is concave. A low rounded ridge, on either side, here marks the course of the supraorbital
latero-sensory canal, the two ridges converging forward, in nearly straight lines, toward the median
spine on the mesethmoid. In the preorbital region the lateral edge of the dorsal surface of the skull
lies, as it does in Trigla, in the level of the ventral surface of this part of the skull; and the line of
this edge, prolonged posteriorly, falls, in Peristedion, nearly into the line of the lateral edge of the
postorbital part of the dorsal surface of the skull.

The posterior surface of the skull resembles that of Trigla but is steeper, and hence shorter
than it is in that fish. The hind edge of the secondary skull is sharp and finely serrated, and slightly
ventral to this edge, and parallel with it, there is a slight but sharp ridge which projects posteriorly
and forms a little shelf which gives support to the anterior edges of the anterior row of the bony
plates of the body. The middle portion of the shelf is formed by the supraoccipital, its lateral
portion, on either side, being formed by the parieto-extrascapular and suprascapular. Beneath the
ridge, or shelf, there is a slicht median vertical ridge which represents the spina oceipitalis. This
little shelf in Peristedion is apparently simply the ventral edge of the somewhat thickened hind end
of the secondary skull of the fish. Ventral to it there is a low and rounded transverse ridge which
represents what I have described in Scorpaena and Trigla as the hind edge of the primary skull.
Between this ridge and the little shelf that represents the hind edge of the secondary skull, there is
a shallow groove which, althougsh it here lies definitely on the hind surface of the skull, evidently
represents the supratemporal fossa.

— 139 —

The ventro-posterior limb of the supraoceipital extends ventrally almost to the dorsal margin
of the foramen magnum, being separated from that margin by a median bit of cartilage. This exposed
bit of cartilage forms the hind end of a median band which separates the dorsal edges of the exocei-
pitals. The postero-lateral edge of the skull, the edge that separates its posterior and lateral surfaces,
is thin, and projects ventro-laterally as a tall ridge. The ventral portion of this edge is formed by
the exoccipital and lies in a nearly horizontal position; its dorsal portion, formed by the posterior
process of the pterotie, Iying in a nearly vertical position. Between these two portions there is a
large rounded corner formed by the opisthotie. This gives to the posterior surface of the skull a
flattened hexagonal appearance.

The temporal fossa is small and shallow, and on one side of one of the three specimens examined
was almost obliterated by the encroaching growth of the bounding bones. The anterior portion of
the fossa was especially affected by this contraction, but still remained as a small recess roofed by
the small lateral extrascapular.

The dorsal surface of the skull is formed, as in Trigla, by the nasals, mesethmoid, ectethmoids,
irontals, postfrontals, sphenotics, pterotics, parieto-extrascapulars, lateral extrascapulars and supra-
scapulars. All of these bones come to the level of the outer surface of the skull, the exposed portions
of all of them being similarly marked by surface granulations. Slightly grooved lines mark most of
their contours. Anterior to the nasals, and lying at a but slightly lower level, there is a small rostral
depression. The floor of this depression is formed in part by a narrow, thin and smooth projeeting
plate of the deeper layers of either nasal, in part by the ascending processes of the vomer, and in
part by a small intervening portion of the cartilage of the rostrum. The mesethmoid is entirely
shut off, by the nasals, from bounding relations to the depression.

The MESETHMOID has an exposed dorsal surface that is usually somewhat lentieular in
shape, and the stout, median, mesethmoid spine rises from it, slightly anterior to its middle point.
Beneath the superficial, dermo-perichondrial portion of the bone there is a primary portion, of less
extensive surface, which extends completely through the cartilage of the snout. In its deeper portion
this primary component expands, and becomes a circular plate formed around a point that lies directly
beneath the median mesethmoid spine. Between this circular basal plate of the bone and the dorsal
dermo-perichondrial plate, there is, on the lateral and posterior edges of the bone, a deep groove;
the grooves on the lateral surfaces of the bone being exposed laterally, but the one on the posterior
surface lying within the cartilage of the skull. The lateral edge of the dermo-perichondrial component
of the bone suturates with the mesial edge of the corresponding component of the ectethmoid, a canal,
large anteriorly but small posteriorly, being left between the two bones; the canal lying partly be-
tween the primary components and partly between the deeper layers of the dermo-perichondrial
components of the bones. The smaller, posterior portion of this canal transmits the supraorbital
latero-sensory canal and the ramus ophthalmieus superficialis; the larger anterior portion trans-
mitting that same canal and nerve, and also the nervus olfactorius. A varying number of openings,
between the ethmoid bones, lead from the canal to the outer surface of the skull, but they are all
closed externally by membrane. Anteriorly the mesethmoid suturates with the nasal bones, and
posteriorly with the frontals. Ventrally, its primary portion lies direetly upon the dorsal surface
of the parasphenoid, the two bones being so firmly attached to each other that they would seem
to be in process of ankylosis.

— 10 ° —

The ECTETHMOID has dermo-perichondrial and primary portions, and resembles, in general
shape, the corresponding bone in Trigla. Its posterior surface forms the anterior wall of the orbit.
Posteriorly, its superficial component suturates with the frontal, while mesially it suturates with
the mesethmoid and nasal, extending forward, along the lateral edge of the latter bone, almost and
sometimes quite to the hind edge of a small oval nasal incisure in the lateral edge of the skull. This
anterior end of the ectethmoid, when it reaches the nasal ineisure, forms only a point in the hind
wall of that ineisure, and the bone has no other bounding relations to the nasal pit. The mesial edge
of that part of the ectethmoid that bounds the nasal bone is grooved, and the lateral edge of the
related portion of the nasal bone, that edge of the nasal bone here being grooved on its dorsal sur-
face, fits into the groove on the ectethmoid; the nasal bone thus appearing, in dorsal views, to here
underlie the ectethmoid, while in reality it overlies it. Between the dorsal edge of this portion of the
ectethmoid and the dorsal surface of the body of the nasal, there is the long and wide groove above
referred to, which groove, although it appears to lie between the two bones, lies largely on the dorsal
surface of the nasal bone alone. This groove is roofed, in the recent state, by a thin and tightly
stretched drum-head-like membrane, which is pierced by several small holes, the groove lodging
he anteriorly-direeted second supraorbital primary tube, and the several small holes being the pores
by which that tube opens onto the outer surface. Similar drum-head-like membranes, perforated by
several small holes, are found associated with nearly all of the primary latero-sensory tubes on the
head of the fish, but none of them are so large as this second supraorbital one.

The ventro-lateral edge of the ectethmoid presents three regions, one of which forms the
anterior half of the edge, and the other two its posterior half. The edge of the bone in the posterior
one of these three regions is presented ventrally, in a line that extends posteriorly and slightly
laterally, and forms the ventral edge of the lateral portion of the orbital surface of the bone. On
the outer surface of this part of the bone there is a smooth surface which gives a sliding artieulation
to a corresponding surface on the inner surface of the dorsal edge of the third infraorbital bone. Imme-
diately anterior to this posterior portion of the ventro-lateral edge of the bone, there is a short portion
which is thickened and rounded to form an articular edge which articulates with a groove on the
dorsal edge of what I shall later describe as the dermo-ectopterygoid. Direetly mesial to this articular
edge, a groove begins on the ventral surface of the ectethmoid and continues forward along the
ventral surface of the lateral edge of the anterior half of the bone. The anterior portion of the lateral
edge of the bone, lateral to the groove, is rounded. When the cheek bones swing inward the groove
receives the dorsal edges of the palatine and dermo-ectopterygoid, and limits the swing of the bones.
When the cheek bones swing outward the rounded lateral edge of the ectethmoid enters a groove
on the dorsal edge of the lachrymal, between it and the palatine, and limits the swing of the bones
in that direction.

A small olfactory canal perforates the antorbital cartilage, mesial to the ectethmoid, Iying,
in its posterior portion, in the specimens examined, wholly in that cartilage.

The VOMER caps the end of the thin flat and broad cartilage of the snout, and is wholly
without teeth. It has a broad thin and delicate body, which lies partly on the ventral surface of the
cartilage of the snout and partly on the ventral surface of the parasphenoid, and two short wide
and somewhat stouter ascending processes which lie on the dorsal surface of the cartilage of the
snout and come into contact, posteriorly, with the anterior edges of the ventral plates of the nasals.

— 1411 —

There is a broad rounded incisure between the two ascending processes, the incisure embracing the
anterior end of a small median interspace of cartilage which lies between this incisure and a median
ineisure between the adjoining anterior edges of the ventral plates of the nasals. Directly anterior
to the incisure in the vomer, there is a very small median eminence on the anterior edge of the bone,
and midway between this eminence and the lateral edge of the bone there is a larger eminence, also
on the anterior edge of the bone. Running dorso-laterally from this latter eminence there is a slight
ridge which terminates in an eminence on the dorsal surface of the ascending process of the bone.
Lateral to this ridge and eminence there is a broad and shallow groove which gives artieulation, through
the intermediation of a pad of tough fibrous tissue, to the postero-mesial surface of the ascending
process of the maxillary. Lateral to this articular groove, the ascending process of the vomer bounds
and supports the anterior palatine process of the ethmoid cartilage.

The ROSTRAL is pyramidal in shape, as in Trigla, and gives support, on its anterior surface,
to the ascending processes of the premaxillaries. Its internal surface rests upon the little median
interspace of cartilage on the dorsal surface of the snout, and also on the adjoining portions of the
ascending processes of the vomer. This interspace of cartilage lies considerably anterior to the nasal
pits, as it does in Trigla, instead of being internasal in position, as it is in Scorpaena.

Whether there is in Peristedion, as in Trigla, a diverticulum of the nasal sac of either side
that extends into the rostral depression, was not investigated; but it would seem not, the space
beneath the anterior end of the nasal seeming too small to permit it.

The PREMAXILLARY is a slender untoothed bone, with a large flat and thin postmaxil-
lary process, and small ascending and articular processes. The proximal end of the shank of the
bone is bent so as to project postero-ventrally and slightly mesially, and from the base of this bent
portion the short ascending process arises; this process and the proximal end of the bone together
forming a straight edge, and together looking like the flattened and broadened proximal end of the
bone. This straight edge of the bone lies close to its fellow of the opposite side, the ascending process
being directed dorso-anteriorly instead of dorso-posteriorly. From the dorso-anterior end of the
process, or from the rostral immediately posterior to it, a ligament arises, and running ventro-postero-
laterally is inserted on the maxillary at the base of the ascending process of that bone. This ligament
is apparently the homologue of one half of the rostro-palatine ligament of Scorpaena and Trigla,
the other half of the ligament arising on the maxillary, close to the point of insertion of this one,
and extending from that bone to the palatine. The articular process of the premaxillary is small,
is directed dorso-posteriorly, and articulates with a large but low articular eminence on the anterior
surface of the proximal end of the maxillary.

The MAXILLARY has a slender shank, with its distal end abruptly expanded. On the anterior
surface of the proximal end of the bone there is a large oval eminence which gives articulation to
the premaxillary, the long axis of the eminence being directed dorso-distally across the anterior
surface of the bone. From the dorsal edge of the bone, in the line of the axis of the articular eminence,
the ascending process of the bone arises, the process lying transverse to the shank of the bone and
being directed dorso-postero-laterally. The postero-ventral edge of the process is thickened, and
has a sliding articulation with the dorsal surface of the ascending process of the vomer, in the groove
already described, the articulating surfaces being separated by a pad of tough fibrous tissue. In the
angle between the distal surface of the process and the shank of the bone, is the artieular surface for

— 12 —

the anterior end of the maxillary process of the palatine. This process of the palatine is, as in Trigla,
closely bound to the dorso-mesial edge of the lachrymal, and from the adjoining edges of these two
bones a strong ligament arises and has its attachment on the dorsal surface of the maxillary. This
ligament, as already stated, apparently represents the distal half of the rostro-palatine ligament
of Scorpaena. The ethmo-maxillary ligament is represented by a short ligament that extends from
the ascending process of the maxillary to the ventral surface of the nasal, at the base of its process-
like antero-lateral corner. There is no ligamentary process either on the external or internal surface
of the bone, this doubtless being in causal relation to the slightly developed condition of the maxillo-
mandibular ligament and of that tendon of the adductor mandibulae that has its insertion on the
maxillary.

The NASAL is a flat quadrilateral bone, which rests, in large part, directly upon the dorsal
surface of the thin flat anterior portion of the antorbital cartilage. In the anterior two-thirds of its
length it suturates, in the middle line, with its fellow of the opposite side. Posteriorly it diverges
slightly from the middle line, leaving a V-shaped space between itself and its fellow of the opposite
side, this space receiving the pointed anterior end of the mesethmoid. The narrow hind end of the bone
suturates with the mesethmoid, slightly overlapping that bone externally. Laterally, the posterior
half of the bone suturates with the long anterior end of the ectethmoid, in the manner already des-
ceribed. The dorsal surface of this part of the bone is deeply grooved, near and parallel to its lateral
edge, for the second primary tube of the supraorbital lateral canal, as also already described. A narrow
wall of bone alone separates the extreme anterior end of this groove from the hind end of the nasal
incisure. The antero-lateral corner of the bone is prolonged into a short stout horn-like process which
rests upon the summit of the anterior palatine process of the ethmoid cartilage. On the lateral sur-
face of the anterior end of this process there is the large opening of the anterior primary tube of the
supraorbital latero-sensory canal, this tube opening on the outer surface by a single large pore.
The bone is traversed by the supraorbital latero-sensory canal, and lodges one organ of the line.

The lateral half of the nasal is thickened, its full length, and this thickening would seem to be
due to the fusion, with the usual dermal component of the bone, of a thin underlying plate of bone.
This underlying plate lies directly upon the cartilage of the snout, and projects slightly beyond the
overlying portion of the nasal, both anteriorly and laterally. The laterally projeceting portion of the
plate forms the floor of the nasal pit, while the anteriorly projecting portion overlaps externally the
hind edge of the ascending process ol the vomer. The antero-lateral corner of the plate lies directly
beneath but is separated by a very narrow slit from the process-like antero-lateral corner of the
dorsal, dermal portion of the bone, and here approaches and gives support to the base of the but
slightly developed anterior palatine process of the ethmoid cartilage. This latter process forms, as
in Trigla, the antero-lateral corner of the thin flat cartilage of the snout.

The ventral plate of the nasal of Peristedion thus occupies somewhat the position of the cor-
responding half of what I have described, in Trigla, as the perichondrial portion of the mesethmoid
of that fish. It also oecupies much the position of the plate that I have described, in Belone, as under-
lying the dermal component of the nasal of that fish. In Peristedion, as in Belone, it separates from
the underlying cartilage, in slightly boiled specimens, without breakage of the cartilage, and hence
would seem to be of membranous origin, but this was not carefully investigated. Two suppositions
suggest themselves regarding it. The one, that there is a predisposition in the tissues of this region
to the development of this plate, and that the plate attaches itself to the mesethmoid or nasal,

— 143 —

according as the one bone or the other covers the region; and the other, that the anterior palatine
process of the ethmoid needing support, a supporting plate is developed from the nearest bone
available.

The FRONTAL has nearly straight mesial and hind edges, lying at a right angle to each other.
It has a small ventral flange, resembling somewhat, but much smaller than that of Scomber. Posterior
to this flange, on the ventral surface of the bone, there are two slight ridges, meeting at an angle,
which form, as the similar but more developed ridges of Scomber do, the antero-mesial and antero-
lateral boundaries of the anterior end of the lateral eranial fontanelle. The frontal suturates mesially
with its fellow of the opposite side, posteriorly with the parieto-extrascapular, and laterally with
the pterotic, the postfrontal, and a small corner of the sphenotie that comes to the level of the outer
surface of the dermal bones. It is traversed by the supraorbital latero-sensory canal and lodges five
organs of that canal, which are similarly disposed to those found in Scorpaena and Trigla; that is,
the second, third and fourth organs of the line are in regular positions; the fourth and fifth organs lie
close together without intervening primary tube; and the sixth organ is asmall one lying in the small
terminal tube of the line and innervated by a nerve that first issues in the orbit and then perforates
the alisphenoid to enter the cranial cavity and perforate the frontal beneath the organ it innervates.

The POSTFRONTAL is a small bone that forms the roof of the small dilatator fossa, and is
beunded mesially by the frontal, posteriorly by the pterotic, and anteriorly by the dorso-lateral
corner of the sphenotic. It is traversed by the dorsal end of the postorbital portion of the main infra-
orbital canal, and lodges one organ of that canal, innervated by the ramus oticus lateralıs.

The PARIETO-EXTRASCAPULAR forms part of the hind edge of the secondary skull, and its
hind edge is thickened and grooved, as already described. The bone suturates anteriorly with the
frontal, and laterally with the pterotic, lateral extrascapular, and suprascapular, not overlapping
dorsally the epiotic process of the latter bone. It lies directly upon the supraoceipital, the epiotic
and the adjoining cartilaginous portions of the roof of the eranium, its lateral edge forming part of the
roof of the temporal fossa. Its hind edge is traversed by the supratemporal commissure of the latero-
sensory system and lodges one organ of that commissure.

The LATERAL EXTRASCAPULAR is a small subeircular bone lying between the fronto-
parietal and lateral spinous ridges, wedged in between the pterotic, parieto-extrascapular and supra-
scapular bones. It forms part of the roof of the temporal fossa, but does not come to the lateral edge
of the skull, being shut ofl from that edge by relatively wide suturating portions of the pterotie and
suprascapular. It is traversed by the lateral portion of the supratemporal latero-sensory commis-
sure and lodges one organ of that commissure. It is not perforated by the main infraorbital canal,
as in the other fishes described, the canal here simply passing along the lateral edge of the bone,
partly enclosed in it, and there apparently being no organ of the main infraorbital line related to it.
In this Peristedion resembles Dactylopterus, as will be later described.

The SUPRASCAPULAR forms the postero-lateral corner of the dorsal surface of the skull,
and the larger part of the roof of the temporal fossa. It has a well developed opisthotie process, but
no differentiated epiotie process, that part of the bone that represents that process being relatively
short and appearing as an epiotic region rather than an epiotic process of the large body of the bone.
On the ventral surface of this epiotie region of the bone there is a small ventral process, and this
process and the adjoining portion of the mesial edge of the bone suturate with the hind end of the
suprascapular process of the epiotic. The anterior edge of this part of the bone suturates with the

— 14 —

lateral edge of the parieto-extrascapular, that bone not overlapping the suprascapular at all. The
remainder of the anterior edge of the bone suturates with the lateral extrascapular and pterotic.
The bone is traversed by the main infraorbital latero-sensory canal and lodges one organ of that
canal. Thecanalleavesthebone by a large opening on its lateral edge, near its hind end, and immed-
iately anterior to this opening, on the ventral surface of the bone, the wide stout opisthotie process
arises. Immediately postero-mesial and also immediately postero-lateral, to the hind edge of the
base of the opisthotie process, there are small articeular facets. These two facets give articulation to
two articular eminences on the dorsal edge of the supraclavicular, these eminences embracing the
hind edge of the opisthotie process of the suprascapular. From the deep layers of the hind edge of
the epiotie region of the bone there projects postero-mesially a thick plate of bone which gives support,
on its dorsal surface, to the first one of the series of dorsal plates on the body of the fish.

The SUPRACLAVICULAR is a somewhat triangular bone, the external surface of which is
slightly concave and partly covered with small granulations. On its short dorsal edge, which repre-
sents the base of the triangle, are the two little eminences, above referred to, which artieulate with
the suprascapular. Posterior to these eminences, the dorso-posterior corner of the bone is traversed
by the main latero-sensory canal, and lodges one organ of that canal. The ventral end of the bone is
pointed, instead of being expanded as in Trigla, but, as in that fish, it overlaps externally and is
bound to the dorsal end of the clavicle; and, excepting that the bone is relatively smaller than in
Trigla, there is nothing abnormal in its position or relations to the other bones.

The PARASPHENOID has the shape shown in the figures. The ascending process of either
side rises at about the posterior quarter of the length of the bone, and is a thin triangular plate that
lies transversely to the axis of the bone instead of parallel to that axis. The point of the triangle is
directed upward and the base downward, and from this base of the triangle a thin flange of bone
extends forward along the lateral surface of the bone. The mesial edge of the triangle is thickened
somewhat, is directed dorso-latero-posteriorly and terminates in a sharp point; and this thiekened
part alone of the triangle would seem to be the homologue of the entire ascending process of the bone
in the other fishes so far described, for it alone lies between the anterior edge of the posterior
portion of the body of the bone and the hind end of its thickened interorbital portion. The triangular
plate can accordingly be considered as a thin flange of bone that arises from the lateral surface of the
ascending process proper; this flange projecting laterally and slightly posteriorly, and, at the ventral
end of the process, being bent forward, in a rounded angle, and then continued forward as a flange
that projects laterally and sliehtly ventrally from the ventral edge of the lateral surface of the inter-
orbital portion of the bone.

On the dorsal surface of the interorbital portion of the parasphenoid, two thin laminae of bone
arise, and converging posteriorly, unite, slightly anterior to the ascending processes of the bone, to
form a median tooth-like process. The triangular space between the two laminae lodges, as in Trigla,
the ventral end of the cartilage of the interorbital septum, the hind end of the process giving attach-
ment to membrane that represents the leg of the basisphenoid; that bone being wanting in Peristedion.
On the dorsal surface of the posterior portion of the parasphenoid there is a median longitudinal
raised portion which is deeply grooved on its dorsal surface. This raised portion fills the hypophysial
fenestra, the groove on its dorsal surface forming part of the floor of the myodome. The hypophysial
fenestra extends-backward slightly beyond the anterior edge of the basioeccipital.

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Zoologica Heft IMl.

Verzeichnis der bisher erschienenen Hefte der Zoologica:-

Heft 1 Haha o Di ee Tierwelt in 1 Broeren Meerestiefen und ihre Be DRURER zu der Oberflächen-
DE fauna, Mit 5 farb. Doppeltafeln. 1880. 20,—.
I 2 _Strubell, Ad, Untersuchungen über den Bau und die Entwicklung des Rübennematoden Heterodera
ARueh Schachtii Schmidt. "Mit 2 2. T. ‚farb. Tafeln. 1888. 10,—.

Vanhöffen,
Heckert, G. A, eansehloridirn Paradoxum. an Dietaling der LEE a eban
” geschichte des Distomum macorostomum. Mit 4 z. T. farb. Tafeln. 1889. 20,—
Mr 5 'Schewiakoff, 'W., Beiträge zur Kenntnis der holotrichen Ciliaten. Mit 7 farb. Tafeln. 1889. 32,—.
6 Braem, Fr., Untersuchungen über die. Bryozoen des süßen Wassers. Mit 15 zT. farb. Tafeln und
' zahlreichen Illustr. im Text. 1890. 80,—.

cephalen. 2 Teile. Mit 10 Doppeltafeln. 1891—92. 92,—.

Haase, E., Untersuchungen über die Mimicry auf Grundlagen ‚eines natürlichen. Systems der Papilioniden.
22. "Bände. Mit 14 farb. nach ‚der Natur gezeich. u. lithogr. Tafeln. 1891—1892. 90,—.

{ Herbst, ©, Beiträge zu Kenntnis der Chilopoden. Mit 5 Doppeltafeln. 1891. 24,—.
ee _ Leichmann, G Beiträge zur Naturgeschichte der Isopoden. Mit 8 Tafeln. 1891. 24,—

Sehmeil, 0, Deutschlands freilebende Süßwasser- EREEPORRR. I. Gyelapidan., Mit 8 z. T. farb. Tafeln
und 3 Illustr. im Texte. 1892. 5,— ns):
12 } Frenzel, Joh., Untersuchungen über die ee EHER Argentiniens, ni ‚Die Protozoen, E

A L Lig. 1—. Mit. 10° farb. Tafeln. 1892. 56.— ? nr
Kohl, Ko Rudimentäre Wirbeltieraugen. I. Mit 9 farb. Doppeltateln. 1892. 73,—.

4 Kohl, ©., Rudimentäre Wirbeltieraugen. II. Mit ‚6 farb. Doppeltafeln. - 1893. 2—
A; UN.K Kohl, O., Rudimentäre Wirbeltieraugen. Nachtrag. 1895. 12, —.

und Dllustr. im Texte. 1893. 40,—.

des. Distomenkörpers. Mit 9 farb. Doppeltafeln. A89n., 80.

geschichte dieser Tiergruppe. -Ontogenie. Mit 19 Tafeln und 20 Textfiguren. 1895. 64,—.
2 Nagel, w. As, Vergleichend en und anatomische Untersuchungen über den Geruchs- und Ge-

Ne Physiologie. Mit 7 z. T. farb. Tafeln. 1894. 42,—
$ 19. . Chun, ©, Atlantis. Biologische Studien üb. pelagische nen: M. ee er u. 8 einf, ‚Taf. 1896. 128,—.

Zoologische Ergebnisse der v.d. Ges. für Erdkunde in Berlin ausgesandten Grönlandsexpedition. 1) Dr.
. E. Vanhöffen: Untersuchungen üb. Arachnactis albida Sars. 2) Ders.: Die grönländ. Ctenophoren. M.1 Tat.

Ä Tintinnen. Mit 1 Tafel. Zusammen 12,—. 5) Dr. H. Lenz: Grönländische Spinnen. Mit 9 Holzschnitten.
6)Dr. Kramer: Grönländische Milben. M.3Holzschn. 7) Dr. Sommer: Drei Grönländerschädel, M. 1 Taf.9,—.
8) E. Rübsaamen: Mycetophiliden etc. Mit 2 Tafeln. 9) W. Michaelsen: Grönländische Anneliden, 12,—.
Schmeil, 0% Deutschlands freilebende Süßwasser-Copepoden. III. Centropagidae. Mit 12 z. T. farb.
"Tafeln und Illustrationen im Text. 1896. 50,—. ? '

2a .Schmeil, DR, Deutschlands freilebende Süßwasser-Copepoden. Nachtrag zu den Familien der Gyelopiden
und ae Mit 2 Tafeln. 1898. 12,—.

Komplett. Mit 51 z. T. farb. Tafeln. 132,—.

7a, Kaiser, Joh, Beiträge ‚zur Kenntnis der Anatomie, Histologie und Entwicklungsgeschichte. der Acantor-

chmeil, 0. Deutschlands freilebende Süßwasser- Copepoden. IT. ‚Harpacticidae. -Mit8z.T. farb. ‚Tafeln.
Looss, 'A., Die Distomen unserer Fische und Terösohe, "Neue Untersuchungen über Ba und Bu

i Leche, W., Zur re ya des Zahnsystems der Saugetiere, arte ein Beifiag zur Anne

schmaekssinn und ihre Organe mit einleitenden: BE aus der SE EDBSEBEHIED. vergleichenden Sinnes-

er Be 3) Dr. H. Lohmann: Die Appendikularien der Expedition. Mit 1 Tafel. 4) Prof. Dr. K. Brandt: Die

Bin

”

Heft 23.

24,
25.
26.
27.
28.
2,
30.
31.

BU

33.
34.
35.
36.

37.

38.
39.
40.

41.
42.

43.
44.

45.

4b.

47.

48.

49.

50.

51.

92:

53.

54.

99.
56,

Verzeichnis der bisher erschienenen Hefte ‚der Zoologien: Br
(Fortsetzung.)

Thiele, J., Studien über pazifische Spongien. 2 Teile mit 13 Tafeln und 1 alt 1898. | = -
Stoller, J. H., On the organs of respiration of the oniseidae. 1899. Mit 2 Tafeln. 7.—. Re Ye
Wasmann, E., S. J., Die psychischen Fähigkeiten der Ameisen. 2. Aufl. 1908. Mit. Sue 300
Pagenstecher, A., Die Lepidopterenfauna d, Bismarck-Archipels. I. Die Tagfalter. M. 2kol. Tal. 1899. 2 — 2 2
Miltz, O., Das Auge der Polyphemiden. Mit 4 kolor. Tafeln. 1899. 18, ar
Pagenstecher, A., Die Lepidopterenfauna d.Bismarckarchip. II. Die Nachtfalter. M. 2 kol. Tat. 1900. a
Müller, G. W., Deutschlands Süßwasser-Ostracoden. Mit 21 Tafeln, 1900. 60,—. OT RE -
Michaelsen, W., Die holosomen Ascidien des magalhäensisch-südgeorg. Gebiets. Mit 3 Tal. 1900. Bm En
Handrick, K., Z. Kenntnis d. Nervensyst. u. d. Leuchtorg. v. Argyropelecus hemigymnus. M. 6 Taf. 1901. 8 I
Heymons, R., Die Entwickelungsgeschichte der Scolopender. Mit 8 Tafeln. 1901. 52,—.
Woltereek, R., Trochophora-Studien. I. Mit 11 Tafeln und 25 Textfiguren. 1902. Beer
Bösenberg, W., Die Spinnen Deutschlands. Mit 43 Tafeln. 1901—1903. 95,—.

Stromer v. Reichenbach, E., Die Wirbel der Landraubtiere, ihre Morphologie und Susternatinche Be
deutung. Mit 5. Tafeln. 1902. 48,—. n ß

Leche W., Entwicklungsgesch. d. Zahnsystems d. Säugetiere. II. ‚Pilsen: HA: Brinaceidae. ‚Mur Tat.
und 59 Textfiguren. 1902. 24,—. SE;

Illig, K. G., Duftorgane der männl. Schmetterlinge. Mit 5 Taf. 1902. 24,—. ERDE
Schauinsland, H., Beitr. z. Entwickelungsgesch. u. Anatom. d. Wirbeltiere I. II. III.M. 56 6 Tat. 1903. a ea =

Zur Strassen, Otto L., Geschichte der T-Riesen von Ascaris ee As, 5 Taten u. 9. Text- Ha:
a BON 76,—. Et

miraeh C., nr zur Morphologie Bi Arthropoden. 1]. Ein Beihraf zur Kenntnis ‚der Pepaen.
Mit 7 Tafeln und 98 Textfiguren. 1904, 64,—. 3

Escherich, K., Das System der a Mit 4 arg und 67 ne 1905.

W. Michaelsen. Mit 23 Tafeln und 2 Textfiguren. 1905. 80, ;
Fischer, G., Vergleichend-anatomische Untersuchungen über den Bronchialbaum der von Mit 5 Tateln e
und 2 Textfiguren. 1905. 28,—. ka
Wagner, W., Psychobiologische'Studien an Hummeln. Mit 1 Tafel und 136 a ER 1906-1907, 6,
Kupelwieser, H., Untersuchungen über den feineren Bau a die Metamorphose das Cvphonautes.

Mit 5 Tafeln und 8 Textfiguren. 1906. 24,—.
Borcherding, Fr., Achatinellen- Fauna der Sandwich-Insel Molokai. Mit 10 Tafeln und W Karte von

Molokai, 1906. 75,—.
Leche, W,, Zur Entwicklungsgeschichte des Zahnsystems der Säugetiere. II. STR, H.:2: erden 2

Solenodontidae und Chrysochloridae. Mit 4 Tafeln und 108 Textliguren. 1907. 40,—. RR. Fe ”
Schwabe, J., Beiträge zur Morphologie und Histologie der tympanalen Sinnesapparate der RE,

Mit 5 Tafeln und 47 Textabbildungen. 1906. 50,—. .
Leiber, Ad., Vergleichende Anatomie der Spechtzunge. Mit 6 Tafeln und 13 Terifignnen: 40,—
Braem, F., Die geschlechtliche Entwiekelung von Fredericella sultana nebst Beobachtungen über‘ ai

weitere Lebensgeschichte der Kolonien. Mit 7 Tafeln und 4 Textfigur. 1908. 32,—. ; ;
Hilzheimer, M., Beitrag zur Kenntnis der - nordafrikanischen Schakale, nebst Bemerkungen über

deren Verhältnis zu den Haushunden, insbesondere nordafrikanischer und altägyptischer Hunderassen.

Mit 10 Tafeln und 4 Tabellen, 36.— ee;
Kennel, J. v., Die paläarktischen Tortrieiden. Eine monographische Darstellung. Mit 24 Tafeln,

einer Stammtafel und mehreren Textfiguren. Lieferung ‘1. 100 Seiten mit 6 Tafeln, für die Abon-

nenten auf die „Zoologica‘‘ 20,—, für die übrigen Besteller 24,—.,

Kahle, W., Die Paedogenesis der Cecidomyiden. Mit 6 Tafeln und 38 Textfiguren. 2
Thiele, Joh., Revision des Systems der Chitonen. I. Teil. Mit 6 Tafeln und ‘5 Textfiguren.
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