orbital to the postfrontal, th e canal here forming a continuous suborbital ring, instead of being
interrupted as in Scorpaena. The orbital edges of th e lachrymal and two suborbitals are broadened
to form a flat, curved and delicate suborbital shelf.
The lachrymal articulates, by its dorsal edge, with th e ectethmoid. Its ventro-anterior corner
rests upon, and is firmly bound to th e ligamentary process of th e maxillary, th e dorso-mesial portion
of its anterior edge resting upon th e dorsal surface of th e maxillary process of th e palatine. A t the
hind end of this surface of contact with th e palatine a short s tout ligament connects th e two bones.
Posterior to the point of attachment of this ligament, between it and th e articular surface for the
ectethmoid, th e large anterior primary tube of the main infraorbital canal opens on th e external
surface of th e bone. The second and th ird tubes of th e main infraorbital caUal issue from th a t canal
as it traverses th e lachrymal, the fourth tube issuing between th e lachrymal and first suborbital,
as in Scorpaena. The anterior edges of the second and th ird tubes, one or both, are produced in
short sharp spines, these being th e only spines on th e infraorbital chain of bones. The fifth tube
opens on the lateral surface of the second suborbital bone, and the prolonged hind end of th e dorsal
edge of this tube reaches and is bound to the preopercular. The sixth tube lies between th e dorsal
edge of th e second suborbital and the ventral end of th e first postorbital, the seventh tube lying
between th e two postorbitals, and th e eighth tube between th e second postorbital and the postfrontal.
The hyomandibulo-palato-quadrate apparatus does n o t differ in any important respect from
th a t of Scorpaena. The opercular process of th e hyomandibular is not so long as in Scorpaena. The
preopercular has five spines on its hind edge; b u t th e second spine from th e dorsal edge of th e bone,
instead of the first one, is th e longest, and there is no supplementary spine either a t th e base of this
spine or a t th e base of th e dorsal spine, as there is in Scorpaéna. The quadrate has a posterior process,
th e posterior surface of which is applied against and firmly bound to th e ventral end of th e preopercular.
On th e inner surface of th e quadrate there is a symplectic groove which lodges th e ventral
portion of th e 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: b u t these
flanges of Sebastes do n o t meet to form a dorsal prolongation of the hind edge of th e bone, and there
is no continuation of the flanges along th e dorso-anterior edge of th e bone, as in Scorpaena. The
ectopterygoid and entopterygoid differ b u t little from those of Scorpaena. The palatine is relatively
shorter th a n in Scorpaena, and its ventral process is n o t so ta ll as in th a t fish. The opercular, sub-
opercular and interopercular are as in Scorpaena.
The mandible has articular, angular and d entary elements, closely resembling those of Scorpaena.
I I I . C o t t u s o c t o d e c i m o s p i n o s u s.
The skeleton of the head of Cottus octodecimospinosus differs considerably, in several important
respects, from th a t of Scorpaena and Sebastes.
1. S K U L L .
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
th an those of Scorpaena and Sebastes, the brain case being little more th an a thin shell of bone.
The postorbital process of the skull is á short broad pyramidal process which lies a t the anterior
two-fifths, approximately, of th e length of the brain case, and in th e 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, b u t these two surfaces here lie in nearly th e 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, th e orbital opening of th e brain case is very large.
The postorbital corner of th e frontal lies in th e 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 th e prootic and sphenotic bones,
and it bears a large circular facet for th e 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 b u t much more rounded edge running postero-ventrally toward the hind end of
th e brain case. Between these two edges and the base of the skull there is a flat smooth and raised
portion of th e lateral surface of th e brain case, the flat bulla acústica forming the rounded dorso-
posterior edge of th e surface.
Anterior to this flat surface and to the postorbital process, there is a depressed region which
forms th e orbital surface of th e brain case. Dorso-posterior to th e flat surface there is, on the lateral
surface of the brain case, a large triangular subtemporal depression, similar to b u t more extensive
th an th é one in Scorpaena, th e depression here reaching almost to the dorsal edge of the lateral surface
of th e skull. Anterior to this subtemporal depression, between it and the postorbital process,
there is a shallow groove, which apparently represents th e fossa there found in Scorpaena. In the
postero-ventral corner of th e subtemporal depression is the vagus foramen, the glossopharyngeus
foramen lying slightly anterior to it a t the ventral edge of the depression; both foramina perforating
th e 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 th e facialis opening of a trigemino-facialis chamber. Dorsal, or dorso-anterior to the
dorsal corner of th e subtemporal depression is the small oval facet for the posterior articular head
of the hyomandibular, this facet lying wholly on the pterotic.
The DILATATOR FOSSA is small, lies directly anterior to the posterior articular facet
for th e hyomandibular, and almost directly dorsal to th e anterior articular facet for th a t bone.
The fossa lies partly in th e sphenotic and p a rtly in the pterotic, and is roofed by th e pterotic alone,
th e 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 th e , lateral surface of the skull, between the opisthotic leg of the suprascapular and
the posterior process of the pterotic. The usual opening, on the posterior surface of the skull, between
th e opisthotic leg of th e suprascapular 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 epiotic and
the opisthotic leg of the suprascapular, b u t mainly to th e marked broadening of the la tte r leg. When
th e suprascapular is removed the hind end of the fossa‘is found to be fairly large, and to lie a t the
extreme dorso-lateral corner of the hind end of the skull. The fossa, thus exposed, seems short when