784 
SCANDINAVIAN FISHES. 
(varying between 23 and 25 %), and the greatest thick- 
ness at most about 1 / 9 (varying between 8 and 1 1 V 2 
%), of the length of the body to the end of the middle 
caudal rays; but in gravid females (see the figure) the 
former ratio may rise to 2 7 1 / 2 %. The least depth of 
the tail is about 7io (varying between 9 and 107 2 %) 
of the length of the body. 
The back is arched at the occiput, but elsewhere 
slopes almost in a straight line, both backwards and 
forwards from its apex at the beginning of the dorsal 
fin. Just in front of this fin it is very slightly 
compressed at the margin, but with this exception it 
is convex or even (behind the dorsal fin) flat. The 
belly descends from the chin in a regular curve, rather 
sharp in gravid females; and the ventral margin is 
broad and flatly convex, but furnished between the 
ventral fins and the anal aperture 1) in the median 
line with a distinct, but low carina, composed of curved 
scales of a special type, and 2) at the boundary be- 
tween it and the sides with a similar carina, usually 
less prominent, but sometimes quite distinct, which runs 
back on each side from the outer angle of the insertion 
of the ventral fin. 
The head is middle-sized, but laterally compressed, 
its length being in young specimens somewhat greater, 
in old less, than the greatest depth of the body, and 
varying between 24 and 22 % of the length of the 
latter. The cheeks are flat and perpendicular; the up- 
per surface is straight and slightly convex or almost 
flat with a gentle slope in a forward direction; and 
the breadth of the interorbital space measures in young- 
specimens 31 % of the length of the head, but rises in 
old to at least 35 % of the same. The eyes are set 
high on the sides of the head, and are comparatively 
small, being about equal in size to those of the Tench. 
They invariably lie in the anterior half of the head, 
for the postorbital length thereof measures in young- 
specimens about 56 %, in old about 63 % of its entire 
length from the tip of the snout. In young specimens 
about 16 cm. long the length of the eyes, which is al- 
ways somewhat greater than their vertical diameter, is 
about 21 — 20 % of that of the head. In specimens 
18 — 22 cm. long this proportion has sunk to 18 or 
17 %, and in specimens 44 — 66 cm. long the length 
of the eyes is only about 14 — 1 2 1 / 2 % of that of the 
head. The length of the snout, which is shallow and 
wedge-shaped, tapering to a sharp edge in front, mea- 
sures about 28 % (27 — 29 %) of that of the head. The 
lines of the mouth are characterized principally by the 
sinus at the tip of the snout, into which the more or less 
knob-shaped point of the lower jaw fits when the mouth 
is closed. On each side of this sinus the labial mar- 
gin forms a somewhat arcuate projection, thus giving 
to the margin of the upper jaw on each side the elong- 
ated S-shape pointed out by Nilsson. The lower jaw 
expands in a similar manner on the sides in front; 
and the fleshy lips, especially the lower, are tumid at 
the corners of the mouth. The intermaxillaries cannot 
be protruded beyond the tip of the snout; yet the gape 
is large in consequence of the length of the jaws, which 
is greater, compared with the size of the head, than 
in any other Scandinavian Cyprinoid", the length of 
the upper jaw from the tip of the snout being about 
38 % (36 — 39 %) of that of the head, and the length 
of the lower jaw about 48 % (45 — 51 %) of the same. 
There is no free tongue; but the middle part of the 
hyoid apparatus in front (the glossohyoid region) is 
fleshy and soft. The nostrils are set on a level with 
the upper orbital margins, about twice as near to the 
eye as to the tip of the snout. The gill-openings are 
large, the broad branchiostegal membranes not coalesc- 
ing with the isthmus until they reach the perpendicular 
from the hind margin of the eyes. Nine or ten short 
and scattered gill-rakers, compressed at the tip or with 
faint signs of digitation (cf. the Ide), compose the outer 
row on the front of the first branchial arch. The outer 
margin of the pharyngeals is furnished with 7 or 6 
pointed and still shorter gill-rakers. The long pha- 
ryngeals (fig. 194) are armed, as mentioned above, with 
two rows of simple, but strong teeth, hooked at the 
tip. The pseudobranchiae lie high on the inner surface 
of the hyomandibular bone, in the hollow on each side 
above the ‘carp-tongue’, and in some cases are there- 
fore difficult of detection, though well-developed. 
All the fins save, in some degree, the ventrals are 
distinguished by a more or less incised, pointed form. 
The dorsal fin begins at a distance from the tip of the 
snout measuring on an average 47 V 2 % (46 1 / 2 — 48 7 2 %) 
of the length of the body. Its base occupies about 7io 
(9'3 — 114 %) of the same length, and its height is in 
young specimens about 1 8 1 / 2 %, in old about 16 %, of 
the same. The anal fin, which lies further back in the 
Compared with the length of the body, however, the jaws .of the Goldfish are equally long. 
