750 
SCANDINAVIAN FISHES. 
at the inferior extremity. It may be easily detached 
from its place. 
The body is covered with very thin, oblong, and 
imbricated scales, which are deeply inserted in the skin 
and thus appear externally to be very small. One of 
the larger scales above the lateral line in a Tench 4 
dm. long is 9 mm. in length and 5 mm. in breadth, 
but only the hindmost 2 mm. project out of the follicle. 
The nucleus lies far forward in the covered part. A 
great number of radiating grooves run from the nucleus 
in all directions to the margin of the scale (the most 
numerous and densest to the hind margin); and the 
tine, numerous, concentric striae encircle the nucleus, 
running parallel to the margin of the scale. The scales 
and follicles are clothed with a fairly thick, soft, and 
slimy epidermis. The lateral line bends down in front, 
and then runs straight along the body, about equally 
distant from the back and belly. It contains about 
100 scales. Above the line there lie about 30 scales, 
below it about 20, in an oblique row from the be- 
ginning of the dorsal fin. 
The height of the dorsal tin is greater than the 
length of its base: the former measures in adult spe- 
cimens about 18 % (17 — 19 %) and the latter about 
13 x / 2 % (12 — 15 %) of the length of the body. The 
distance between this tin and the tip of the snout is 
about 48 % (47 — 49 %) of the length of the body, or 
about twice as long as the dorsal margin of the ped- 
uncle of the tail (between the dorsal and caudal tins). 
Its first four rays are simple; but the first ray is al- 
ways so short that it does not even project above the 
skin; the second ray is also short and in old specimens 
difficult of detection, the third about half as long as 
the fourth, which is only slightly shorter than the se- 
cond or third among the branched rays. These last 
two rays are the longest in the tin. Sometimes, how- 
ever, even the fourth ray may be branched; and simple 
or branched, but narrow rays may lie inserted here 
and there between the branched rays, which are other- 
wise as a rule 8 in number. 
The anal fin is of exactly the same structure as 
the dorsal and of essentially the same form; but its 
base is still shorter in proportion to its height. The 
latter measures about 14 % (13 — 15 Vs %) of the length 
of the body, the former about 8 % (7 — 9 %) of the 
same. The beginning of the tin lies at a distance from 
the tip of the snout of about 63 % (60 — 64 %) of the 
length of the body. The vent is usually separated 
from the beginning of the anal fin by a distance about 
equal to the diameter of the eyes (a little more or less). 
The caudal tin is broad and slightly concave at 
the end, almost truncate when expanded. The length 
of its middle rays, measured from the point where the 
scales end, is about 14 % (157s — 13 x / 4 %), that of its 
longest lateral rays about 16 % (18 — 1 5 x / 2 %), of the 
length of the body. 
The paired tins are broad and obliquely oval. The 
most distinct external differences between the sexes find 
expression in the dimensions of these tins. In young 
Tench and in the males the ventral fins are longer than 
the pectoral tins, in adult females shorter. The length 
of the pectoral tins is about 1 6 x / 2 % (16 — 18 %) of that 
of the body: the length of the ventral tins is in the 
females less than 17 % (15 — 16 %), in the males more 
than 17 % (about 18 %) of the same. It is also a rule 
that in the females the ventral fins, when laid back, do 
not extend to the vent, while in the males their tips 
reach beyond it. In the males too, the second ray in 
these tins is very thick and broad. The distance be- 
tween the ventral tins and the tip of the snout is about 
42 % (39 x / 2 — 44 %) of the length of the body, their 
position being generally farther back in the females. 
The coloration of the Tench adapts itself to the 
water in which the fish lives. In clear water the whole 
body is yellowish green on a golden ground, with tine, 
golden dots at the tip of each scale. The top of the 
head is darker than the back, the latter in its turn 
darker than the sides, which fade below into the whitish 
yellow colour of the belly. This last colour also ex- 
tends to the lower parts of the head and of the gill- 
covers. All the fins are light green. The iris is cop- 
pery red. — When the fish has been so long out of the 
water that life is extinct, the colour is entirely changed. 
The body is now dark green. The back, and in parti- 
cular the top of the head, are blackish green. The tine, 
golden dots have vanished. The belly is yellow. The 
tins are dark purplish red or nearly black. These last 
organs are also the first parts of the body to change 
colour. — When the Tench lives on a muddy bottom, 
it presents the appearance shown in our figure. When 
it is found in the forest tarns, where the water is ge- 
nerally very dark, the entire upper part of the body is 
black, as though dipped in ink, only the belly being 
somewhat lighter. A not uncommon variety is the Golden 
Tench, of a spotted or plain orange colour. This form 
is often kept in fish-ponds both in Germany and England. 
