Slightly mesial to the ridge th a t forms the lateral boundary of the groove on the vertex, near
the middle of its length, and a t the anterior edge of the parieto-extrascapular bone, another cranial
ridge begins. Running a t first parallel to the lateral bounding ridge of the groove on the vertex, this
other ridge soon curves latero-posteriorly onto th e bounding ridge, near its hind end, and so leaves
the groove on the vertex a t its postero-lateral corner. I t then curves again into the direction of the
bounding ridge, here lying posterior to th e groove on the vertex, and continues either parallel to and
slightly mesial to the line prolonged of the bounding ridge of the groove, or as a direct posterior continuation
of th a t ridge. I t soon terminates in a spine, this spine rising from the dorsal surface of the
parieto-extrascapular slightly postero-mesial to the central point of the body of th a t bone, and lying
directly superficial to th a t section of the supratemporal latero-sensory canal th a t is lodged in the
bone. This spine is the parietal spine of Jordan & Gilbert’s diagram of Sebastodes, and i t lies approximately
a t the hind end of the parietal p a rt of the parieto-extrascapular bone. The ridge to which the
spine is related is then the parietal spinous rid g e , and this ridge is n o t the one th a t forms th e lateral
boundary of th e groove on th e vertex, th a t ridge being an independent one, without related spine.
Immediately posterior to th e parietal spine, or immediately lateral to its base, another cranial
spinous ridge begins, and running postero-laterally to th e hind edge of the parieto-extrascapular
there terminates in the nuchal spine; this spine thus lying a t the hind edge of th e extrascapular
p a rt of the parieto-extrascapular.
Emery (’85), in his figure of th e skull of Scorpaena scrofa, shows b u t a single spine on the
parieto-extrascapular, th e spine and bone both being called by him, the external occipital.
In th e several specimens of Scorpaena porcus th a t were examined in this connection, the
anterior end of the parietal spinous ridge, instead of beginning close to the lateral bounding ridge of
th e groove on the vertex, begins well within th e groove, sometimes even near the middle of th e corresponding
half of th e groove. I t leaves the groove a t its postero-lateral corner, as in Scorpaena
scrofa, b u t it is much taller, relatively to th e lateral bounding ridge of th e groove, th a n in th a t fish.
I t thus forms the apparent lateral boundary of th e posterior portion of th e groove, and th e groove
has n o t the evenly subquadrangular appearance th a t it has in' Scorpaena scrofa.
The frontal, parietal and nuchal spines of Scorpaena form the three posterior members of a
row of four spines, th e anterior member of which is th e nasal spine, lying a t the hind end of th e nasal
bone. There is thus, in this row, a spine a t or near the hind edge of each of the four dermal elements
th a t form th e mesial portion of each half of the dorsal surface of the skull; th e four spines forming
a mesial row of spines.
The remaining spines of Jordan and Gilbert’s diagram of Sebastodes are the preocular, supraocular
and postocular, all three of which are found in Scorpaena. The preocular spine of this la tte r
fish lies on th e free, orbital edge of th e ectethmoid, near its dorso-mesial end, and forms the hind end
of a ridge on th e dorsal surface of the ectethmoid which runs, from in front, upward backward and
slightly laterally. The supraocular and postocular spines rise from the dorsal surface of the lateral
edge of the frontal, both lying posterior to th e middle point of th e orbit, and both of them projecting
postero-laterally in th e direction of th e lateral edge of the frontal.
From th e base of each of these three ocular spines, a ridge runs postero-mesially, the three
ridges converging, approximately, toward th e point where th e fourth tube of the supraorbital latero-
sensory canal leaves th a t canal to ru n backward and mesially to unite with its fellow of the opposite
side and thus form the supraorbital, or frontal commissure of th e latero-sensory system. The point
where this commissure leaves the main canal lies anterior and slightly mesial to the antero-lateral
corner of the groove on th e vertex, and th e course of the commissure, on either side, is approximately
marked by th e anterior bounding ridge of the groove. This la tte r ridge begins a t the median opening
of the commissure and from there runs antero-laterally, immediately posterior to the commissure,
to become confluent with the frontal spinous ridge a t th e base of the frontal spine, as
already described. The frontal and commissural ridges, as well as the three ocular ridges, thus
all radiate approximately from th e point where the frontal commissure arises from the supraorbital
canal. The parietal ridge, also, radiates from this same point; and still another ridge, a slight one,
extends from this point, postero-laterally, across the postero-lateral p a rt of the frontal, and leads
directly toward b u t does n o t quite reach the anterior end of the pterotic spinous ridge, to be later
described. There are thus seven ridges radiating approximately from a certain point on the dorsal
surface of th e skull, all of them apparently in some way related to certain of the cranial spines. But
what these relations may be, or what the significance of the ridges, I can not determine, excepting
th a t they would seem to indicate some center of formative action a t the point from which they radiate.
With th e exception of the frontal and parietal ridges they seem not to have heretofore been described.
The preocular spine, it is to be noted, has two ridges related to it, one on the frontal and the other
o n th e ectethmoid, th e la tte r being the more important.
In Scorpaena porcus, the comissural ridge runs directly across th e h ind end of the frontal ridge,
th is la tte r ridge abutting against the former one, almost a t right angles to it, a t a point slightly mesial
to the base of th e frontal spine and there apparently ending. The commissural ridge and not the frontal
ridge thus here bears th e frontal spine, th e commissural ridge turning sharply backward a t its lateral
end, and immediately terminating in the backwardly directed spine. This arrangement of ridge and
spine is a definite characteristic of all my specimens of Scorpaena porcus, while the former arrangement
is equally characteristic of all those of my specimens of Scorpaena scrofa in which there are
three postfrontal spines, described below. . Where there are, in Scorpaena scrofa, b u t two of these
la tte r spines, the relations of the two ridges here in question, to each other and to the frontal spine,
are intermediate in character.
In addition to th e above described spines, all of which are mentioned by Cuvier and Valenciennes
(’29, vol. 4, p. 291), there are, on the dorsal surface of the head of Scorpaena scrofa, a certain
number of other spines, all of which, excepting two, those on the lateral extrascapulars, are also
mentioned by Cuvier and Valenciennes. Three of these spines are small, and lie on th e postfrontal
bone; one near th e antero-mesial corner of the bone, one a t th e postero-mesial corner and one a t the
postero-lateral corner. The three spines radiate, in general direction, from the antero-lateral corner
•of th e bone, and on th a t corner there is a small b u t pronounced tubercle. Joining this tubercle and the
antero-mesial spine there is a small b u t definite ridge, th e other two spines having no related ridges.
In Scorpaena porcus, in all th e specimens examined, there were in this group of postfrontal spines,
b u t one or two spines; the one spine, where it alone was found, being usually bifid. The presence of
the three postfrontal spines thus seems to be a definitive characteristic of Scorpaena scrofa, b u t in
certain of my specimens of this fish there are b u t two spines, as in Scorpaena porcus. These postfrontal
spines must be th e bifid spines of Jordan & Evermann’s (’98) descriptions.
Postero-mesial to this little group of postfrontal spines, a ridge begins on th e pterotic, and
running postero-laterally to the hind end of th a t bone ends in a strong spine. Posterior to, and in
.the line prolonged of this spinous ridge, a ridge begins on the suprascapular, and running along the