800 
SCANDINAVIAN FISHES. 
fins, to the beginning of the anal fin, it is straight. 
The forepart of the back, as well as the top of the 
head, is transversely convex; but towards the beginning 
of the dorsal fin it grows more and more compressed, 
while behind this fin the dorsal margin is again con- 
vex or even fiat. Along the median line of the dorsal 
margin there runs, however, interrupted only by the 
dorsal fin, “a thin keel, with the appearance of a coarse 
thread laid under the skin. This keel begins on the 
head vertically above the anterior margin of the eyes, 
and ends at the caudal fin” (Ekstrom). The anterior 
part of the keel, almost to the dorsal fin, is naked; 
but at this point one or two scales generally begin to 
overlap the margin with their lateral part. Behind the 
dorsal fin, on the other hand, the keel itself consists 
of curved scales. The belly in front of the ventral fins 
is convex or flat underneath, but between these fins 
and the anal aperture sharp, with the median line scale- 
less. At the sides of the straight base of the anal fin 
the lowest scales project, forming a groove in which 
this fin may be partially concealed. 
The length of the head measures in adult speci- 
mens (19 — 34 cm. long) about 227 2 — 2 1 V 2 % of that 
of the body. Just in front of the eyes it is more or 
less tumid; but the most characteristic point in its ap- 
pearance is the prolongation of the snout, as in the 
Haddock or the Houting. The projecting tip of the 
snout is obtusely rounded, and the length of the snout 
measures in young specimens about 29 % of that of 
the head, in old as much as 35 % of the same, being- 
less in the former than the breadth of the interorbital 
space, but in the latter at least equal to or, generally, 
someAvhat greater than this breadth. In the former 
too the length of the snout is somewhat less, but in 
the latter perceptibly greater, than that of the upper 
jaw from the middle of the tip of the snout. The 
mouth thus acquires a position quite ventral and al- 
most horizontal, but is fairly large, so large, according 
to Artedi, that the middle finger may be inserted with 
ease into the mouth of large specimens, the upper jaw 
being then protruded as if from a thumb-stall. The 
lower jaw, which articulates below the centre of the eyes, 
measures about 36 — 33 % of the length of the head. 
The lips are rather thick. The eyes are of moderate 
size, their longitudinal diameter varying in the above- 
mentioned adult specimens between 23 V 2 and 18 % of 
the length of the head, or between V 2 and 2 /a of the 
postorbital length of the same. The postorbital part 
occupies between 44 and 50 % of the entire length of 
the head, the eyes being thus situated sometimes en- 
tirely, and always principally, in the anterior half of 
the head. The nostrils, set almost on a level with the 
upper orbital margin, are farther from the eyes than 
in the preceding forms; but the distance between the 
posterior nostril and the eye is never more than half 
of that between the anterior and the tip of the snout. 
The gill-openings are large, the branchiostegal mem- 
branes coalescing with the isthmus close beside each 
other and in about a line with the posterior margin 
of the eyes. The gill-rakers in the outer row on the 
first branchial arch are not very close-set (15 or 16) 
and triangular in shape, the upper and lower ones 
pointed, the middle ones blunter and with a tendency 
to ramification at the tip. The outer anterior margin 
of the pharyngeals is set with 10 — 12 small spines. 
The pharyngeals are comparatively short, and their an- 
terior (lower) arm is deeply grooved (bilobate) at the 
inferior margin. The pharyngeal teeth, which have 
been described above, are in other respects, both in 
form and arrangement, not unlike those of the Roach. 
The shape of the dorsal fin also reminds us most 
of the Roach, but it is somewhat more pointed, as in 
Abramis, and the base is comparatively shorter. Its 
position is given above. The base measures about 1 / 10 
(10 — 10'6 %), and the height about 19 — 1 6 1 / 2 %, of the 
length of the body. The distance between the anal fin 
and the tip of the snout occupies in young specimens 
about 62 %, in old sometimes nearly 66 %, of the length 
of the body. The base of this fin measures in all our 
specimens 18 — 19 % (according to Dybowski sometimes 
only 1 7 x / 2 %) of the length of the body, and its great- 
est height in the males about V 9 , in the females about 
7 10 , of the same. The caudal fin is deeply forked, its 
middle rays measuring about 7V 2 — Q l / 2 % of the length 
of the body, and about 1 / s of that of the longer (the 
inferior) caudal lobe. 
The pectoral fins are obtusely pointed, the second 
or third ray being the longest. Their greatest length 
is about 15 or 16 % (in a few males nearly 17 %) of 
the length of the body. The preabdominal length is 
about 22 — 24 % (in a few females 24 V 2 %), and the 
postabdominal length about 20 — 20 V 2 % (in a few fe- 
males 21 %), °f the length of the body. In percentage 
of the same length the distance between the ventral 
fins and the tip of the snout is about 43 — 45 (in a 
few females nearly 46), and the length of these fins in 
