is traversed by th e main infraorbital canal, and lodges one organ of th a t canal. The hind corner of
th e bone may be either sharp or rounded, and as it forms a slight eminence in th e dermis may be
considered as th e la st spine of th e lateral row. The occipito-supraclavicular ligament is inserted on
the internal surface of the supraclavicular, in the usual manner.
L A T E R A L S U R F A C E O F T H E B R A I N C A S E .
The lateral surface of th e b rain case of Scorpaena is inclined a t an angle of 45 °, approximately,
to the horizontal plane. Its ventral half is crossed transversely, from above downward and backward,
b y the elongated, fusiform and prominent swelling of th e bulla acustica. Anterior to this
swelling, there is, on the ventral half of th e lateral surface of th e brain case, a depressed region which
lies on th e prootic and parasphenoid. The posterior and larger p a rt of this depressed surface is filled
b y and gives attachment to a large tough pad of connective and muscular tissue, which is continuous,
across th e middle line, with a similar pad on th e other side, th e two together representing the anterior
transversus dorsalis muscle. The lateral border of th e pad of either side gives a ttachment to a short
muscle which has its insertion on the epibranchial of th e second arch, and is th e obliquus dorsalis of
th a t arch; th e two short muscles, one on either side, together with th e intervening pad, forming a
single mass, as in Scomber. The posterior transversus dorsalis is a th in band of muscle extending
from the th ird and fourth epibranchials of one side transversely across to th e corresponding bones of
th e other side.
Anterior to th e anterior transversus dorsalis, th e infrapharyngobranchial of the first arch is
attached to the side wall of the skull; and, anterior to th a t element, th e posterior portion of the
adductor arcus palatini has its origin. The surface of origin of this la tte r muscle begins immediately
ventral to the trigeminus opening of the trigemino-facialis chamber, there lying p a rtly on th e prootic
and p a rtly on th e ascending process of th e parasphenoid. From there it extends downward and forward
along th e anterior portion of th e la tte r process, and th en tu rn s directly forward, occupying a
depressed region along th e lateral edge of th e body of the parasphenoid and extending forward across
the o rbit to th e antorbital process of th e skull. From this long surface of origin th e broad and relatively
th in muscle extends latero-ventrally and has its insertion mainly on th e palato-quadrate arch, as will
be later more fully described, its posterior portion, however, having its insertion on th e inner surface
of th e th in flange of bone th a t forms th e anterior edge of th e hyomandibular. The muscle thus acts
in p a rt as an adductor hyomandibularis, b u t it is widely and wholly separate, both a t its origin and
insertion, from th e la tte r muscle, properly so-called.
Immediately dorsal to th e anterior end of the bulla acustica is th e opening usually called the
facial foramen, b u t this so-called foramen is, as in Scomber, th e facialis opening of th e trigemino-
facialis chamber. Posterior to this opening, and extending across the lateral surface of th e skull to
its hind edge, there is a large, shallow, and, in certain specimens, distinctly pyramidal depression
which lies on th e prootic, opisthotic and exoccipital bones. The depression is subtriangular in outline,
th e base of th e triangle being formed by th e dorsal edge of th e anterior portion of the bulla, th e posterior
edge by a p a rt of th e postero-lateral edge of th e skull, and th e antero-dorsal edge by a low ridge
th a t runs downward and forward across th e lateral surface of th e brain case, approximately in the
line prolonged of the opisthotic process of the suprascapular. The center of th e depression, somewhat
pointed in certain specimens, lies within th e arch of th e external semicircular canal, ventral
to th a t canal, and in this th e depression corresponds to the sub temporal fossa of Sagemehl’s
descriptions of the Cyprinidae, but, as described immediately below, it does not correspond with th a t
fossa in th e muscles to which it gives origin. The anterior corner of th e depression is connected by
a shallow groove with the facialis opening of the trigemino-facialis chamber, this groove lodging
th e nervus sympatheticus and th e ramus anterior of the nervus glossopharyngeus. In the postero-
ventral corner of th e depression is th e vagus foramen, and slightly anterior to th a t foramen, near
th e ventral edge of th e depression, is th e glossopharyngeus foramen, both of these foramina perforating
th e exoccipital.
Dorsal to th e subtriangular depression above described, the posterior half or three-fifths of
th e dorsal half of th e lateral surface of th e skull is markedly flat. Anterior to this flat portion, there
is a large and deep fossa, on the prootic and pterotic bones, the fossa lying immediately antero-
ventral to the elongated facet for th e posterior articular head of the hyomandibular, and antero-
dorsal to th e arch of th e external semicircular canal. The anterior border of this fossa is formed by
a strong flat process of th e prootic, this process lying directly dorsal to the facialis opening of the
trigemino-facialis chamber and immediately posterior to th e rounded oval and relatively deep facet
for the anterior articular head of the hyomandibular. P a rtly in the dorsal portion of this fossa and
p a rtly on th e process th a t forms its anterior border, the two internal levators of th e branchial arches
a n d th e external levators of th e first three branchial arches have their origins. The external levator
of th e first arch was little more th a n a band of membrane on one side of the head of th e single
specimen examined in this respect; and on this same side of th e head of this one specimen the external
levator of the th ird arch was wholly wanting, while on th e other side it was a slender muscle much
smaller th a n any of the others. The several muscles all arise together, as a group, the internal levators
arising in a line th a t lies immediately postero-ventral to th e line of origin of the external muscles.
The levator internus anterior lies internal to the other muscles, and is a s to u t one which bellies
considerably immediately beyond its origin, the belly of the muscle completely filling th a t large
p a rt of the fossa th a t lies ventral to th e surface of origin of the muscles. This large p a rt of the
fossa thus seems to have been formed by th e compressive action of this muscle, and not in relation
to the points of origin of th e several muscles of th e group.
On the flat surface of th e skull posterior to this fossa, and also pa rtly in th e subtriangular
depression, th e adductor hyomandibularis and adductor operculi have a large surface of origin. These
two muscles are n o t contiguous a t their origins, th e surface of origin of the adductor operculi lying
slightly posterior to and being slightly larger th a n th a t of the adductor hyomandibularis. Dorsal
to these two muscles, in a long and narrow line along the dorso-lateral edge of th e skull, th e levator
operculi has its origin. Immediately posterior to the surface of origin of the adductor operculi, in a
narrow line near the hind edge of the skull, th e external levator of th e fourth arch has its origin,
this fourth levator, in the one specimen examined, having its insertion on the fourth arch and not
o n the inferior pharyngeal bone. Posterior to this fourth levator, and in contact w ith it, a flat muscle
has its origin, and running posteriorly has its insertion on the dorsal portion of the clavicle, thus
corresponding to th e fifth levator of my descriptions of Scomber. This fifth levator would seem to
be th e homologue of the muscle th a t Herrick considers (’99, p. 117), in Menidia, as th e trapezius
musele. I t would seem as if it must also be the homologue of the muscle described by Sagemehl
{’84 b, p. 49), in the Charaeinidae, as the Attractor of th e shoulder girdle, th a t muscle being said to
arise from the skull and to have its insertion on the supraclavicular. Vetter concluded th a t
a trapezius muscle is wanting in Teleosts, as Herrick himself states.