780 
SCANDINAVIAN FISHES. 
30 — 36 cm., still attains a weight of about 1 kgm." 
In external form it seems to occupy an intermediate 
position between the Leuciseines and the Crucian Carp, 
which it so closely resembles in this respect that in 
some localities it bears the name of Sjoruda (Lake 
Crucian Carp). In Halland and Blekinge it is also 
called JRitda (Rita), and on the Scanian coast of the 
Sound it is known by its Danish name of Rudskalle 
(Dan. skalle, Roach). The body is deeper and, in pro- 
portion to the depth, more compressed than in the pre- 
ceding Leuciseines, the greatest depth being about Vs 6 
of the length to the middle of the caudal tin in young 
specimens, in old somewhat less than 2 / 5 C of the same. 
In this respect, however, the Rudd undergoes a change 
of growth which during youth ranges it close beside 
the Roach in a more developed state A The greatest 
thickness is about 32 — 42 % of the greatest depth. 
The least depth of the peduncle of the tail measures 
about 7 10 (8- — 11 %) of the length of the body. The 
back rises somewhat abruptly from the occiput, form- 
ing a regular curve to the beginning of the dorsal fin, 
where it bends at an obtuse angle, and then descends 
in an elongated S-shaped curve, or sometimes almost 
in a straight line, towards the base of the caudal tin. 
It is convex throughout the greater part of its length, 
but in front of the dorsal tin compressed at the mar- 
gin, as in the Roach. The belly is rather strongly 
compressed, but Hat to the ventral fins, then carinated 
to the anal aperture. It runs in an unbroken curve 
from the chin to the vent, where it forms an angular 
bend, and then rises almost in a straight line to the 
peduncle of the tail. 
The head is of moderate size, measuring about Vs 
of the length of the body b and compressed, with broad 
and almost straight forehead ' and small, blunt, flattened 
snout 6 '. The mouth is small* * and turned upwards, the 
lower jaw being somewhat longer than the upper, so that 
the tip of the chin is the most prominent point. The 
eyes are somewhat larger than in the Roach, their 
longitudinal diameter measuring in middle-sized Rudd 
about 23 % x of the length of the head. Their position 
is such that the line from the middle of the caudal tin 
to the margin of the upper jaw cuts the centre of the 
pupil; and in adult specimens the postorbital length of 
the head is equal to or a little greater than half the 
entire length thereof, but in the fry sometimes only 
about 43 % of the same. The nostrils are similar to 
those of the Roach. The gill-rakers also resemble those 
of the Roach; but the pharyngeal teeth (tig. 193) are 
set in two rows, 5 in the inner and 3 in the outer, 
their masticatory surface is coursed by transverse grooves 
on the sides and granulated (pectinated) at the margin, 
and the pharyngeal cartilage is furnished on the sides 
with oblique, transverse grooves. 
The dorsal tin occupies the same backward posi- 
tion as in the Minnow, the Owsianka, the ‘Asp’, and 
some specimens of the Dace, lying opposite, not to the 
ventral tins, as in the other Leuciseines, but to the 
space between the ventral and anal fins, as in the 
Abramidines. It begins at a distance from the tip of 
the snout measuring about 52 — 56 % of the length of 
the body; and the distance between the ventral fins 
and the same point is only about 79 % (78 %) — 84 % 
(85 %) of the former distance. The form of the fin, 
on the other hand, is the same as in the rest of our 
Leuciseines, the length of its base measuring about 
11 — 13 % (13 V 2 %)■> and its height about 20 — 17 %, of 
the length of the body. The anal fin is distinguished 
a According to the reports sent in to the Swedish Fisheries Committee of 1881 — 83 the Rudd(?) may attain a length of 1 fg Sw. feet 
(45 cm.) and a weight of 4 Sw. pounds (1,700 grammes). Day tells us of a specimen from Norfolk 3 lbs. 1 oz. (1,389 grammes) in 
weight. According to Fatio the Rudd weighs at a length of 15Y 2 cm. 45 grammes, at a length of 266 mm. 230 grammes, and at a 
length of 3 dm. more than Y 2 kilo. 
* 26—36 %. 
c 36 — 3 9 1 /2 /■> according to our measurements. 
d In a Roach 167 mm. long the greatest depth was 26'3 %, and the greatest thickness 10'8 %, of the length of the body. In a 
Rudd 63Y 2 mm. long these percentages were respectively 26'8 and ll'O. 
e About 23 — 20 / ( 1 9 ‘ 8 %) of the length of the body in Rudd 63 — 277 mm. long. 
f The breadth of the interorbital space increases with age in the specimens just mentioned from about 40 to 47 % of the length of 
the head. 
v In the same specimens the length of the snout varies individually, though generally increasing, from about 28 % (in exceptional 
cases 26 %) to 33 1 /., % of that of the head. 
h The length of the upper jaw from the middle of the tip of the snout varies in the same specimens between about 28 % (exceptionally 
27 %) and 32 % of that of the head, and the length of the lower jaw between 39 and 36 % (34 %) of the same, being in young specimens 
often equal to, in old always less than, that of the suboperculum. 
1 In our smallest specimen, 63 mm. long, the longitudinal diameter of the eye measures 32 % of the length of the head, in our 
argest specimen, 277 mm. long, 21 % of the same. 
