large one, with one or two adjoining eminences ra th e r th a n spines. Near th e hind edge of th e orbit
there is, in medium-sized specimens, a short and somewhat b lu n t spine, which is n o t evident in the
large specimens. The only other spines found on th e head of the fish are two spines, or eminences,
on th e hind edge of th e preopercular, and two spines on th e opercular; only one of these la tte r spines
showing on th e outer surface of th e fresh head.
Between th e orbits, in medium-sized specimens, th e dorsal surface of th e skull is deeply concave
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, th e course of th e supraorbital latero-
sensory canal. The crown of th e head is flat, th e subquadrangular groove on th e occiput, so characteristic
of th e Scorpaenidae, being slightly indicated in my medium-sized specimens by two little
tuberculated and longitudinal ridges, one on either side, on th e dorsal surface of the parieto-extra-
scapular bone. These ridges are n o t evident in th e large specimens. The preorbital portion of the
skull is relatively long, low and broad, th e casque-like portion of its dorsal surface here being convex
transversely and having straight lateral edges which converge b u t slightly forward; th e casque being
two-thirds or even three-fourths as wide a t its deeply concave anterior end as it is a t th e anterior
edges of the orbits.
The curved anterior ends of th e lachrymals project forward and mesially, on either side, beyond
th e anterior end of the skull, and, with th e concave anterior end of th e casque, nearly enclose a sub-
circular space in which th e rostral lies. The anterior edge of th e lachrymal is, in all my specimens,
serrate ra th e r th a n being, as s tated by Gunther (’60), furnished with prominent spines.
The dorsal surface of th e casque is formed by the nasals, mesethmoid, ectethmoids, frontals,
postfrontals, pterotics, parieto-extrascapulars, lateral extrascapulars and suprascapulars, and also
by a small portion of th e sphenotic which comes to th e level of th e other bones and presents th e same
granulated appearance. The supraoccipital and epiotics are almost entirely, or even entirely covered
by th e overlying frontals, parieto-extrascapulars and suprascapulars.
The mesethmoid and ectethmoids come, as ju s t above stated, to th e level of th e dorsal surface
of th e other bones th a t form th e casque-like portion of th e skull, and, having th e same surface markings
as those other bones, they form w ith them a uniform and continuous surface. They each contain
th e two somewhat different components, dermo-perichondrial and endosteal, referred to when describing
these same bones in Scorpaena; b u t here, in Trigla, th e dermal portion of th e dermo-perichondrial
component is much more important.
The MESETHMOID, as seen on th e dorsal surface of th e skull, is sometimes, as Gunther
(’60) says of the corresponding bone in Trigla gumardus, a sexangular bone, once and a half as long
as broad; b u t th e two posterior corners of the bone thus described, are usually replaced, in mediumsized
specimens, by a single point, th e bone th en being pentangular. The outer surface of th e bone
is marked by granulated ridges th a t all converge toward th e central point of th e bone, and in the
substance of th e bone, and converging toward this same point, there are tapering spaces. These
spaces lie in th e dermal portion of th e bone, between th e dense outer surface of this portion of the
bone and the th in perichondrial layer, and th e concave anterior edge of th e bone is honeycombed by
th e openings of the spaces. This anterior edge of the dermal portion of the bone is grooved, th e dense
superficial layer of th e bone projecting eaves-like above th e deeper perichondrial layer. This la tte r
layer extends anteriorly slightly beyond th e dermal layer, and is there bounded, in th e middle line,
by the hind end of a narrow and low median ridge of cartilage which represents th e relatively tall
internasal ridge of Scorpaena. On either side of this ridge th e mesethmoid is bounded by the hind
edge of th e corresponding ascending process of th e vomer.
The mesethmoid is bounded, on either side, in its posterior half-or two-thirds, by th e ectethmoid,
th e hind end of the mesethmoid usually projecting beyond th e bounding portions of the ectethmoids
and there suturating with or being overlapped externally by th e frontals. The anterior half
or th ird of th e bone gives support, on either side, to th e nasal, th e mesial half of th e la tte r bone over-
lapping and lying upon a depressed lateral half of th e dorsal surface of this p a rt of th e mesethmoid.
The antero-lateral corner of th e dorsal surface of th e mesethmoid projects forward as a sharp process,
and from this process and from th e ventral surface of the overlying nasal, the ftthmn-mfl.rina.ry
ligament has its origin. This little corner or process of th e mesethmoid, together with th e adjacent
pa rts of the flat dorsal surface of the bone, thus replace functionally, in their relations to the nasal
bone and th e ethmo-maxillary ligament, th e pronounced mesethmoid process of the Scorpaenidae.
The lateral edge of th e mesethmoid, beneath th e nasal, is grooved and forms th e median wall
ànd p a rt of th e floor of th e shallow nasal pit. Posterior to th e nasal, this same grooved edge of the
mesethmoid forms th e mesial wall of the olfactory canal through th e antorbital process. Dorsal to
this groove, between i t and the th in 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 th e two ethmoid bones, which, in large specimens,
may be6ome entirely enclosed in th e mesethmoid alone, continuing posteriorly to th e hind edge of
th a t bone. I t lodges th a t p a rt of the supraorbital latero-sensory canal th a t lies between the frontal
and nasal bones, b u t contains no sensory organ, th e sensory canal thus here being secondarily and
n o t primarily enclosed in th e bone.
Under the central portion of the bone, primary ossification has begun, and, in large specimens,
extends entirely through the cartilage of th e snout. In th e central portion of this p a rt of the bone,
in three specimens th a t were bisected, there was a large cavity filled with fa tty tissue.
The ECTETHMOID has a convex dorsal surface, this convexity being so great in the posterior
portion of th e bone th a t a transverse section here has th e shape of a quadrant of a circle. The external
surface of th e 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 th e bone is th in and sharp, and projects posteriorly to form th e anterior portion of the roof of
th e orbit. I t bears th e two or three preocular spines, the postero-mesial one of these spines being
considerably longer th a n th e others. The mesial edge of the bone suturâtes, in its posterior portion,
with the frontal, and, in its anterior portion, with the mesethmoid and the hind end of the nasal.
Along th e mesial edge of th e 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 th a t larger canal, already described, th a t lies between the mesethmoid and ectethmoid and th a t
lodges th e supraorbital latero-sensory canal.
The ventral surface of the ectethmoid is large and inclines downward and mesially a t an angle
approximately of 30 0 with a horizontal plane. Along th e lateral edge of th is surface there is a stout
and irregular longitudinal ridge which projects downward and b u t slightly laterally. The anterior
half of this ridge has a somewhat rounded summit, and this p a rt of the ridge gives articulation to