374 
SCANDINAVIAN FISHES. 
toothless. The branch of the blind side is only slightly 
changed in the articular (posterior) part, but the an- 
terior or dental part is much shortened, deeper than 
long, of an irregular quadrilateral shape, toothless in 
front, and behind, in the toothed part, curved out- 
wards — somewhat as in Mugil — - and still farther back 
raised into a process which meets, and is united by 
strong ligaments to, the hind part of the intermaxillary 
bone. The branch of the lower jaw on the blind side 
is thus much deeper, but shorter than that on the eye 
side, its depth being about V 2 the least depth of the 
tail or twice the longitudinal diameter of the eye. There 
are on each side three round, upper pharyngeals — the 
middle one being considerably larger than the other 
two — and one oblong, lower pharyngeal. All of them 
are set with movable, cardiform teeth, like the jaw- 
teeth. The gill-openings are small; the opening on the 
blind side extends up to the top of the insertion of 
the pectoral tin, but on the eye side only to the lower 
end of this insertion. The opercula have rounded, smooth 
margins and are entirely covered with a thick, scaly 
skin, but under their rims protrudes the margin of the 
smooth, scaleless branchiostegal membrane. The two 
branchiostegal membranes are united underneath, and 
surround the anterior lower point of the clavicular bones, 
at the point where the latter are united to each other 
and to the lower posterior prong of the urohyoid (basi- 
branchiostegal) bone. The latter bone is shaped, as in 
most of the Flatfishes, like a joiner’s square, the end 
of the anterior (longer) prong being attached to the 
under surface of the hyoid bone, and the posterior prong 
pointing in a downward direction and united by a liga- 
ment to the top of the lower junction of the clavicular 
bones. Thus, the two clavicular bones and the uro- 
hyoid bone are united in front into a point, which is 
generally covered underneath by the co.alescent branchio- 
stegal membranes. There are usually 6 or l a branchio- 
stegal rays on each side, sharply bent, and covered 
by the opercula. The outer (distal) part of the first 
branchiostegal ray on one side is coalescent with the 
corresponding part of the same ray on the other side. 
The eyes are oblong, and less prominent than in the 
rest of the Scandinavian Flatfishes. The upper eye lies 
half its own length in front of the lower, which is 
situated above and close to the corner of the mouth. 
The distance between the eyes is about equal to the 
longitudinal diameter of the iris. The pupil is round, 
without any intruding excrescence from the iris. The 
skin of the body may be drawn over the eye in the 
form of an eyelid. The nostrils are more or less per- 
fectly tubular. The nostrils of the eye side are set 
close to each other and near the anterior margin of the 
lower eye, close to the mouth, the anterior being per- 
fectly tubular, the posterior larger, with the tube slit 
behind. The nostrils of the blind side, on the other hand, 
are far apart, the posterior being situated fairly high 
above the corner of the mouth and the anterior about 
half-way between the posterior and the tip of the snout. 
The surface of the body is even, and covered on 
both sides with imbricate, oblong scales, rounded at the 
corners and distinctly ciliated behind. The scales cover 
the surface of the eye side of the head entirely, but 
only two-thirds of the surface of the blind side, the 
anterior third of this side of the head (the mouth and 
snout), as well as a part of the base of the dorsal fin and 
the margins of the operculum of this side, being thickly 
strewn with soft tubercles or warts, with a crest of short, 
hairlike cirri at the tip. The fin-rays are also covered 
with scales, at least for some distance from the base. 
The rays of the vertical fins are each furnished with 
several rows of more or less pointed scales, and on the 
eye side this covering extends almost out to the tips 
of the rays. The paired fins are covered with scales 
only on the outer surface of the rays and for about 
half their length. On the blind side too, the covering 
of scales does not extend so far out on all the fins, 
and the ventral fin of this side (sometimes the pectoral 
as well) is generally scaleless. Behind the head the 
lateral line is distinct and perfectly straight, or slightly 
curved in the abdominal region, where it also lies nearer 
the dorsal than the ventral margin. But the cephalic 
system of the lateral line is indistinct, with the ex- 
ception of the dorsal branch, which curves upwards and 
forwards in an arch on the occiput. The vent lies very 
far forward, between the ventral fins and just in front 
of the beginning of the anal fin, entirely on the blind 
side, but close to the ventral margin. Just behind the 
vent lies the genital opening, and between them we find 
a dermal flap, which is sometimes erected in the shape 
of an acute-angled triangle. 
The dorsal fin is fairly low, somewhat higher in 
the males than in the females, its longest rays measur- 
ing about 20 — 23 % of the greatest depth of the body, 
91 — 92 % of the least depth of the body or 40 — 45 % 
Gottsche has sometimes found 8 branchiostegal rays. 
