766 
SCANDINAVIAN FISHES. 
The gill-rakers in the outer row on the first branchial 
arch are 10 in number, flat at the tip, and divided into 
two or three digitate branches. The pharyngeal teeth 
(fig. 190) are set, as mentioned above, in two rows, 5, 
as a rule, in the inner row, and 3 smaller teeth in the 
outer one. During the shedding of the teeth, however, 
these numbers are altered, and we find, on the one 
hand, new and more or less undeveloped teeth (at first 
cucullate), lying loose in the gums or beginning 
to fix themselves, and on the other hand, old teeth 
more or less completely detached from their alveoli. 
The masticatory surface of the largest (middle and 
posterior) teeth -in the inner row does not become quite 
distinct until the fish has attained some considerable 
size. The front tooth in this row (as well as the first, 
the two first, or even all three teeth in the outer and 
smaller row) is straighter and conical or cylindrical, 
the remaining teeth being hooked at the tip. 
The dorsal fin begins at a distance from the tip 
of the snout that in young specimens measures about 
48 or 49 % of the length of the body, in old 50 or 
51 % thereof. Its origin generally lies above the middle 
of the insertions of the ventral fins; but on examining 
a number of specimens we find a variation even in this 
respect. The height of this fin is greater than its length, 
the former measuring on an average 18 — 16 % of the 
length of the body, and the length of its base 11 or 
12 % of the same. The margin is obliquely truncate, 
with more or less rounded corners, at least in front; 
and the fin leans slightly backwards. The beginning 
of the anal fin lies at a distance from the tip of the 
snout that in young specimens and the males varies 
between 60 and 65 %>, in the females between about 
67 and 68 % of the length of the body, though this 
measurement is also subject to individual variations. 
The height of the fin varies between 13 and 15 % of 
the length of the body, the length of its base between 
10 and 12 % of the same. When it is folded, the mar- 
gin is deeply concave; when expanded, almost straight, 
though even then the concavity is quite perceptible. 
The length of the rays in proportion to each other is 
usually such that the tips of the third and fourth rays, 
which are the longest, extend to the tip of the last ray, 
when the fin is completely folded. The caudal fin is 
forked, with pointed corners, the lower lobe being 
hardly any longer than the upper. The length of the 
middle caudal rays occupies in young specimens about 
12 — 10 % of that of the body, in old about 8 — 7 % 
thereof, and measures in the former about 1 / 2 , in the 
latter about 2 / 5 , of that of the longest rays in the fin. 
The pectoral fins are of oblong shape, with rounded 
tip when laid back; their length varies between about 
1 7 a / 2 and 15 % of that of the body. The ventral fins 
are broader and more rounded. The distance between 
the latter fins and the tip of the snout measures in old 
specimens about 45 or 46 %, in young specimens about 
43 % , of the length of the body, the distance between 
the foremost point in their insertions and the corre- 
sponding point in the insertions of the pectoral fins 
(the preabdominal length) in old specimens about 23 or 
24 %, in young about 21 or 22 %, of the same length, 
and the distance between the former point and the be- 
ginning of the anal fin (the postabdominal length) in 
old specimens about 21 — 24 %, in young about 18 %, 
of the same. The leno-th of the ventral fins themselves 
O 
is about 1 3 1 / 2 — 14V 2 % of that of the body. 
The scales are of the same shape as in the pre- 
ceding species, but their texture is somewhat firmer, 
with denser and coarser radiating grooves, which render 
their hind margin more distinctly crenulated. The la- 
teral line, which slopes slightly at first, runs almost 
parallel to the ventral margin, and lies much nearer to 
the belly than to the back. It contains in most cases 
about 57 scales, the greatest number in any Scandi- 
navian Leuciscus. Above the lateral line there are 8 
or 9 rows of scales, and below it 4 or 5, counting 
from the dorsal and ventral fins to the lateral line, and 
excluding the scales of the line itself. Between the vent 
and the lateral line there are 5 or 6 rows of scales. 
It is only during the spawning-season that any ex- 
ternal difference between the sexes can easily be dis- 
tinguished. During this period the scales of the male 
are furnished with a rim, consisting of a row of clear, 
yellowish, verrucose tubercles, with dark tip, which are 
wanting in the female, and disappear as soon as the 
spawning is over. 
The coloration of the Ide is subject to considerable 
variations; but the most striking alteration in its dress de- 
pends on the time of year. In spring the Ide wears 
its spawning-dress, and the prevailing ground-colour is 
brassy yellow, which gleams through the green pigment 
wherewith the scales, especially at their insertions, are 
coated. This pigment grows darker towards the back, 
which is almost plain grayish green, and lighter, gra- 
dually disappearing, towards the belly. The head is 
above of the same colour as the back, but somewhat 
