viewed from above, b u t this is largely due to th e marked elongation of th e brain case; for th e fossa
extends from th e hind end of the skull about halfway to the postorbital process, which is about its
normal length. At about th e middle of its length th e fossa is bridged by the narrow and tubular,
mesial one of th e two lateral extrascapular ossicles found in this fish. Posterior to this bridge, the
central portion of th e fossa is without roof, its mesial edge being slightly overhung by th e lateral
edge of th e epiotic, and its lateral edge being roofed by th e lateral one of th e two lateral extrascapular
ossicles. Anterior to th e bridge, th e fossa is wholly without roof. The posterior opening of the fossa
is roofed, as usual, by th e suprascapular and the suprascapular process of th e epiotic. The fossa
thus opens on the dorsal surface of th e skull by two large openings. In th e mesial wall of th e posterior
portion of th e fossa there is a pronounced preepiotic recess.
The SUPRATEMPORAL FOSSA is as in Scorpaena, b u t much smaller.
There are, as is well known, three SPINES on either side of th e dorsal surface of the skull,
and one on th e supraclavicular. The three spines on th e dorsal surface of th e skull form a row th a t
corresponds to th e mesial row of spines of Scorpaena, th e supraclavicular spine being th e only one
of a lateral row.
Of th e three spines th a t form the mesial row, th e anterior one lies on the dorsal surface of
the hind end of th e nasal, and, projecting backward, overhangs th e opening of th e second primary
tube of the supraorbital latero-sensory canal. The next posterior spine of th e row lies on th e dorsal
surface of th e frontal, and its relations to th e supraorbital canal show th a t it is a frontal spine. I t
lies, however, near the postorbital comer of th e frontal, considerably anterior to its hind edge, this
position th u s differing considerably from th a t of the frontal spine in either Scorpaena or Sebastes.
The base of th e spine, in Cottus, overlies th a t p a rt of th e supraorbital canal th a t lies
between th e fifth and sixth tubes of th a t line, and projects backward toward th e seventh tube or
between th a t tu b e and th e fifth tube. The sixth tu b e anastomoses with the main infraorbital canal,
and it was double in each of th e two specimens examined, th e fifth tube being also double in one
specimen. There is no spinous interorbital ridge related to th e frontal spine.
From th e base of the frontal spine a strong ridge begins, th e occipital ridge of Jordan and
Evermann’s (’98) descriptions, and running backward in a curved course across th e posterior portion
of the frontal and then across th e parieto-extrascapular, ends, a t th e hind end of th e la tte r bone,
in a s tout spine. This spine lies pa rtly above b u t mostly posterior to th e supratemporal canal, its
position thus n o t definitely indicating whether it is a parietal or a nuchal spine. I t is however, in all
probability, a spine developed in relation to th e parietal bone, and hence a parietal spine, the ridge
th a t terminates in it th en being a parietal ridge.
The parietal ridges of opposite sides lie relatively widely apart, and th a t p a rt of th e dorsal
surface of th e skull th a t lies between them is flat, and corresponds to the subquadrangular groove
on th e vertex of Scorpaena; b u t here, in Cottus, there is, aside from the presence of parietal spinous
ridges, no indication whatever of a groove; for the region is not depressed and there are no anterior
and posterior bounding ridges whatever.
The supraclavicular spine projects posteriorly from th e dorso-posterior corner of the supraclavicular,
ventral to the section of latero-sensory canal th a t traverses th e bone.
The MESETHMOID is, in all my specimens, a relatively delicate bone th a t extends b u t slightly
into th e underlying cartilage. I t has, on either side, a short stout m esethmoid process which is directed
antero-laterally and gives attachment', on its outer end, to the ethmo-maxillary ligament. Thé latero-
posterior, or ventro-latero-posterior, surface of the process gives support to a process on the hind end
of the nasal bone, the la tte r bone being strongly bound to the mesethmoid process by fibrous tissues.
The ECTETHMOID has a body of delicate perichondrial bone, and a s tout lateral process
which corresponds to th e wing and arm together of the bone in Scorpaena. On the ventral edge of
this lateral process there is a single large condylar eminence, which gives articulation to the lachrymal
alone, the palatine not anywhere coming into articular relations with the ectethmoid. Lateral to this
articula r eminence, th e ventro-lateral corner of th e lateral process is free. On th e antero-dorsal
surface of th e bone there is a short b u t relatively large process which projects antero-mesially and gives
support, on its summit, to the lateral end of a lateral process on the hind end of the nasal, this process
of th e nasal being strongly bound to th e ectethmoid process by fibrous tissues. Between this ectethmoid
process and th e mesethmoid process, the lateral process of the nasal bridges th e hind end of
th e olfactory depression, lying between th e two nasal apertures. In Scorpaena scrofa, as already
stated , this nasal process of th e ectethmoid of Cottus is apparently represented by an eminence, or
sh o rt spine, sometimes b u t n o t always found on the ectethmoid of th a t fish.
The VOMER has a short dorsal limb formed of thin bone, of perichondrial appearance, which
comes into contact posteriorly with th e perichondrial portions of the three ethmoid bones. A raised
portion on the ventral surface of th e anterior end of th e bone bears a band of villiform teeth which
extends, uninterruptedly, from one side to th e other.
The PREMAXILLARY has large ascending and articular processes, the former resting on the
dorsal surface of the rostral, and th e la tte r articulating w ith the maxillary, as in Scorpaena. The body
of th e bone is shorter th a n in Scorpaena, extending b u t half the length of the maxillary and ending
practically a t the hind edge of its own postmaxillary process; th e posterior half of th e body of the
bone of Scorpaena being represented, in Cottus, by tough gristly tissue. The oral surface of the bone
of Cottus is furnished nearly its full length with small villiform teeth.
The MAXILLARY has a stout, right-angled ascending process which articulates with the
premaxillary and, through the intermediation of a pad of semi-cartilaginous tissue, with the dorsal
limb of the vomer. The antero-mesial (proximal) end of th e ligamentary process is well-developed
and gives insertion to th e ethmo-maxillary ligament. The postero-lateral (distal) end of the process
is represented by a slight eminence which gives insertion to the maxillo-mandibular ligament, this
ligament having a course, and an insertion on the articular, similar to th a t in Scorpaena. Between
these two ends th e ligamentary process is b u t slightly if a t all developed, b u t th e dorsal surface of
the shank of th e bone here gives articulation to the enlarged anterior end of th e maxillary process
of the palatine. The ventral edge of the anterior end of the lachrymal here also comes into slight
oont^ct w ith the maxillary, b u t the lachrymal is here bound to the palatine alone, and is n ot supported
by, and bound to the maxillary, as in Scorpaena.
The NASAL has, as already stated, a lateral process on its hind end, this process giving to the
hind end of the bone an expanded appearance. This expanded hind end of the bone is bound mesially
to th e mesethmoid process, and laterally to the nasal process on the dorso-anterior surface of the
«ctethmoid, thus bridging a p a rt of the nasal pit. The bone is traversed by the supraorbital latero-
sensory canal and lodges one organ of th a t line. No p a rt of the canal traverses the process th a t
bridges the nasal sac.