412 
SCANDINAVIAN FISHES. 
at most V 3 of the total length of the head, or °/u of 
the postorbital length of the head, and is always less 
than the length of either of the pectoral fins or than 1 / i 
of the greatest depth of the body". It extends along the 
dorsal edge for a distance that, measured in a straight 
line, is equal to 72 — 1\% of the length of the body. In 
the first third of the tin the rays are of fairly uniform 
length, only slightly increasing in length posteriorly, and 
the longest rays, the length of which is 9 or 10 % of that 
of the body, are set at about the middle of the fin. All 
the anterior rays are simple; but in the posterior part of 
the fin the rays branch, though very irregularly — from 
5 to 20 of these branched rays may be found, often 
scattered in the posterior part of the fin''. The anal fin, 
which in shape and structure resembles the dorsal minus 
its first third, measures from about 52 to 53 x / 2 % of the 
length of the body. In front of its beginning the post- 
abdominal bone projects in an anal spine, which in 
young specimens is distinct and pointed, but in older 
ones grows blunt and is hidden by the skin. The vent 
and, just behind it, the urogenital opening lie at the 
ventral margin itself, about half- wav between the be- 
ginning of the anal fin and the insertion of the ventral 
fins — thus comparatively far from the former. The 
ventral fins are symmetrical in position, being set just 
in front of the perpendicular from the upper (anterior) 
end of the insertion of the pectoral fins. They are 
almost equal in length, varying in young specimens 
between 5 '/ 2 % (on the blind side sometimes 5 %) and 
6 % of the length of the body. As a rule the first two 
rays are simple, the others branched. The pectoral fins, 
on the other hand, are more dissimilar in form and 
length, that of the eye side being obliquely pointed and 
that of the blind side more evenly obtuse, and the for- 
mer measuring in young females 11 — 12 1 / 2 % of the 
length of the body, in young males about 13 % thereof, 
while the latter measures about 8V 2 or 9 % of the same 
length. In the pectoral fins too, the first (uppermost) 
two rays are simple — on the blind side, in most young 
specimens, the lowest two as well. The median length 
of the caudal fin is fairly equal to the length of the 
pectoral fin on the eye side — except in the males, where 
the pectoral fins are somewhat longer — as well as to 
the distance between the middle of its base and the end 
of the dorsal fin. In young specimens the hind margin 
of this fin is evenly concave, while in old specimens it 
forms a double curve or an elongated S-shape. The 
fin contains 13 multifid rays, and 3 supporting rays at 
each margin; but at least in old specimens the two 
longest supporting rays, the tips of which extend out 
to each corner of the caudal fin, are also branched. 
The whole body and the head, with the exception 
of the fleshy lips and the nasal cavities, are covered 
with cycloid scales, some of them ordinary, but still 
small, and as usual smaller on the front part of the 
body than behind, and some of them still more nume- 
rous, accessory scales between the former. These acces- 
sory scales also cover the whole of the caudal fin, the 
outer side of the pectoral fin of the eye side, and at 
least the base of the ventral fin of the same side, as 
well as the greater part of the dorsal and anal fins. 
The lateral line forms a fairly high, but often irregular 
arch above the pectoral fin, behind the point of which 
it adopts a straight course almost along the middle of 
the sides of the body, and advances over the caudal 
fin, though it branches just in front of the base of this 
fin, one branch running straight out between the 7th 
and 8th or 8th and 9th branched rays' (counting from 
a In four females we have found the distance between the dorsal fin and the tip of the snout to be greater than the least depth of 
the tail, bu( in a inale it is less than this depth. 
6 If we denote the branched rays by Roman figures, the formula for the dorsal and anal fins in five specimens is as follows: 
Length of the body 
in millimetres. 
Dorsal tin. 
Anal fin. 
337 
81 + XX 
55 + XIX 
357 
83 + I + 5 + XIII 
55 -t- I + 3 + XVII 
3(12 
91 + XI 
59 + I + 9 + VIII 
393 
96 + V 
67 + XI 
455 
78 + I + 4 + XVI 
36 + II + 11 + I + 3 + XXI 
c At the middle of the length of these rays it generally branches again, and follows the lower side of one of the rays and the upper 
side of the other; but these branches eventually join each other again. See our figure of the young Halibut (Plate XVII, fig. 1). 
