cartilage of the palato-quadrate apparatus, while internally i t overlaps th a t cartilage and is in
contact with the hind edge of th e metapterygoid. Its hind edge is in p a rt in contact with the anterior
edge of the web of bone th a t spans the angle between th e two limbs of th e preopercular, and in p a rt
is separated from th a t web of bone b y a relatively large opening. This opening is spanned b y membrane,
and the membrane is pierced b y th e arteria hyoidea and th e ramus mandibularis externus
facialis, th e lateralis fibers of th a t nerve being accompanied b y general cutaneous ones and possibly
also by communis fibers, as ju s t above explained. No mandibularis internus foramen, between the
symplectic and quadrate, could be found.
The METAPTERYGOID is a subcircular bone slightly concave on its internal surface. I t
is bounded anteriorly by th e entopterygoid, with which it is flexibly connected by tissue; ventrally
b y the quadrate, from which it is separated by a narrow band of cartilage; and posteriorly by the
symplectic and the interspace of cartilage between th e la tte r bone and th e hyomandibular. A small
posterior process a t the dorsal end of its hind edge is in contact with and bound b y tissue to the
anterior edge of th e ventral end of the hyomandibular, and this process is pierced by a foramen
which transmits the external carotid from th e outer to th e inner surface of th e apparatus, th e artery
there falling into the arteria hyoidea. In th e ventral edge of th e process there is a notch, which,
with th e adjoining cartilage, forms a foramen which transmits th e arteria hyoidea from the outer
to the inner surface of the apparatus. The process on th e metapterygoid thus represents, as th e hind
edge of the bone in Cóttus does, th e two flanges on the hind edge of th e bpne of Scorpaena.
The QUADRATE has a large posterior process, th e thick and broad postero-ventral surface
of which rests against the dorsal surface of the ventral limb of th e preopercular, th e point of the
process passing into a pocket in th a t bone. The symplectic groove is simply a broad and shallow
depression on th e internal surface of th e dorsal edge of th e bone, immediately anterior to this process.
Dorsally the bone is bounded b y cartilage which separates i t from th e metapterygoid, and th e anterior
edge of the bone forms, with th a t of th e metapterygoid, a continuous line which is slightly convex
and lies in a nearly transverse position. The narrow band of cartilage th a t lies between the two
bones is prolonged a short distance beyond their anterior edges, there lies in a depression on the
external surface of the., entopterygoid, and is exposed on the outer surface of th e apparatus between
th e ecto- and ento-pterygoids. The anterior edge of th e quadrate overlaps internally th e hind edge
of th e ectopterygoid, b u t is itself overlapped internally by a short process a t th e ventral corner of
the la tte r bone, this la tte r process being in articular contact with th e dorsal surface of th e mesial
end of th e articular head of the quadrate. The q uadrate and ectopterygoid th u s articulate in a measure
with each other, and as the ir adjoining edges are strongly b u t flexibly bound together by tissue, and
as th e anterior edge of the metapterygoid is similarly bound to the hind edge of the entopterygoid,
a flexible joint is here formed in the hyomandibulo-palato-quadrate apparatus. The anterior prolongation
of the band of cartilage th a t lies between th e quadrate and metapterygoid crosses the
jo in t uninterruptedly, b u t being itself flexible does not interfere with th e movements of the parts.
In th e Cyprinidae, according to Sagemehl (’91, p. 582), th e palato-quadrate apparatus is also jointed,
b u t in those fishes th e joint is between th e palatine and the ecto- and ento-pterygoids and hence,
n o t similar to th e joint in Dactylopterus.
The ECTOPTERYGOID is a stout elongated bone directed antero-dorsally. Its dorso-
anterior end suturates with th e palatine, th e two bones enclosing between them a palatine remnant
of th e palato-quadrate cartilage. The dorsal edge of th e bone overlaps externally and suturates
with the ventral edge of th e entopterygoid, bounding, in its posterior portion, the short anterior prolongation
of th e palato-quadrate cartilage ju s t above described. Its hind edge overlaps both externally
and internally and articulates with the anterior edge of th e quadrate, in th e manner ju s t above
described. Near the ventro-posterior end of th e free, ventral edge of th e bone, there is a flat ridgelike
process, the function of which was n o t evident in my preparations.
The ENTOPTERYGOID is a relatively large, thin, sub-oval bone, th e anterior end of which
overlaps internally th e palatine, th e ventral edge similarly overlapping th e dorsal edge of the ectopterygoid.
Its hind edge is flexibly bound to th e anterior edge of th e metapterygoid. In a slight
depression on its outer surface, a t its ventro-posterior comer, it lodges the short anterior prolongation
of th e palato-quadrate cartilage.
The PALATINE is a sto u t irregular bone, with a short body, a right-angled maxillary process,
and a short v entral process the ventral edge of which is broadened and corrugated b u t bears no teeth.
The hind end of the bone suturates with the ectopterygoid and entopterygoid, being overlapped
externally b y the former bone and internally by th e latter. The three bones enclose between them
a small palatine remnant of th e palato-quadrate cartilage, this cartilage n o t being exposed on the
outer surface of th e apparatus. The maxillary process of the palatine is. a s tout process, the proximal
portion of which is directed antero-dorso-laterally and th e distal portion antero-ventro-mesially,
th e two pa rts lying nearly a t a right angle to each other. The dorsal surface of th e flat distal portion
of th e processJies against, and has a sliding articulation with the internal surface of’the lachrymo-
palatine process of the nasal bone, th e ventral surface of the process giving articulation to, and being
firmly bound by fibrous tissue to, the dorsal surface of th e maxillary bone. Immediately posterior
to th e surface of contact w ith th e nasal, the hind end of the flat dorsal surface of the m axillary process
has a sliding articulation with the two little articular ridges on the internal surface of the dorsal
edge of th e lachrymal.
On the internal surface of th e base of the maxillary process of the palatine, there is a Y-shaped
groove which has a wide dorsal end and from there tapers gradually downward to a point. This
V-shaped groove articulates with the anterior edge of the lateral process of th e vomer, and possibly
also with adjacent portions of the corresponding edge of th e pedicle of the ectethmoid, in the manner
already described when describing those bones. Ventral to th e groove there is, on the internal
surface of the anterior end of the ventral process of th e palatine, a concavity which gives insertion
to th e short vomero-palatine ligament and comes in contact with th e lateral surface of the head of
th e vomer when th e palato-quadrate apparatus swings inward. The dorsal edge of th e body of the
bone, and the dorsal edge of the entopterygoid immediately posterior to it, are both bound by strong
tissue to th e ventral surface of th e pedicle of the ectopterygoid, touching th a t bone when the palato-
quadrate apparatus swings inward.
The MANDIBLE contains dentary, articular and angular elements.
The dentary has th e usual V-shaped hind end, th e two limbs of th e V being of about equal
length. The ventral limb tapers gradually to a point, and its hind end lies in a deep groove along
the internal surface of th e articular. The dorsal limb of th e bone is covered with small villiform teeth
and ends in a flattened hind end which replaces functionally the dorsal end of a coronoid process,
th a t process of th e articular being wanting. On the extetnal surface of the bone there is a deep groove