the united lachrymal and palatine bones in a manner th a t will be described when describing those
bones. I t may however here be stated th a t 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 elsewhere.
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 th a t 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
th a t bone. With the latero-ventral surface of the process the palatine articulates. 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 comer 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 downward
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 ectethmoid 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 th a t it is
represented in th a t part of th a t surface th a t 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 comer, is certainly the homologué of the rounded angle in the lateral edge of
the wing of Scorpaena, and the anterior end of the anterior, single portion of the articular ridge of
Trigla must be the homologue of th a t process-like portion of the bone of Scorpaena that gives articulation
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 th a t 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 corresponding
ectethmoid, and its floor is perforated by a circular opening which is closed ventrally by
the underlying parasphenoid. Prom 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-musele canal. Immediately
lateral to the opening th a t leads from the orbit into the anterior eye-muscle canal, there is,
m 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 th a t 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 ectethmoid. 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 comer 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 articulation 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 articulating with the latter process by an articular surface a t the base of its maxillary
process.
Between the summit of the anterior palatine process of the ethmoid cartilage and the projecting
antero-lateral comer 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