788 
SCANDINAVIAN FISHES. 
length to the end of the middle caudal rays, and the 
greatest thickness is about half the greatest depth. The 
least depth is about 8 % (7 '8 — 8'2 %) of the length. 
The back is broad and convex, the belly more com- 
pressed, forming between the ventral fins and the anal 
aperture a sharp carina, covered with a row of curved 
scales. 
The length of the head is about 23 — 21 % of that 
of the body. It is apparently a general rule that in 
the young and the males the length of the head is 
greater, in adult females less, than the greatest depth 
of the body. In form the head is almost exactly si- 
milar to that of the Bleak, but in old specimens its 
upper surface, along the middle of the forehead and 
the crown, is depressed and plane. The eyes are ver- 
tically set, rather large, and situated almost entirely in 
the anterior half of the head, the postorbital part mea- 
suring about 43 or 44 % of the entire length of the 
head. In specimens 5 — 8 cm. long the longitudinal 
diameter of the eyes, which is slightly greater than or 
equal to the vertical diameter, measures about 33 — 31 
% of the length of the head, and is always perceptibly 
greater than the length of the snout. The tip of the 
snout is sharp (shallow), but broad (truncate), with a 
shallow sinus to receive the point of the lower jaw. 
The cleft of the mouth is turned sharply upwards and 
rather large; but in consequence of its obliquity the 
hind extremity of the maxillaries scarcely extends, when 
the mouth is closed, to the perpendicular from the an- 
terior margin of the eyes. The lips are thin. The 
length of the upper jaw from the middle of the tip of 
the snout is about 7 % (6*6 — 7*2 %) of that of the body, 
or about 30 % (29‘2 — 32‘2 °/o) of that of the head. The 
length of the lower jaw, which is generally about equal 
both to the breadth of the interorbital space and the 
length of the suture between the suboperculum and the 
operculum, measures about 8% % (8’5 — 8‘7 %) of the 
length of the body, or about 38 1 / 2 % (37'5 — 40 %) of 
that of the head. The nostrils lie rather near the up- 
per anterior corner of the orbits. The gill-openings 
are fairly large, the branchiostegal membranes coalesc- 
ing with the isthmus in about a line with the hind 
margin of the preoperculum. The outer row on the 
front of the first branchial arch contains 11 — 13 pointed 
gill-rakers, small and close-set below, larger and more 
scattered above. The pharyngeal teeth are slender and 
almost straight, with hooked tip and pectinated masti- 
catory surface. They are sometimes set, according to 
Heckel, Maslowsky, and Siebold, in two rows; but 
in all the specimens examined bv us they formed a 
single row. The pharyngeal cartilage is elliptical, but 
its hind (lower) extremity is raised, as in the preceding 
Leuciscines, in an inverted canaliculate form. 
The fins are of the normal Leuciscine type. The 
dorsal fin begins at a distance from the tip of the snout 
measuring about half (49 — 52 %) of the length of the 
body. The length of its base is about 7g (12—11 %), 
and its height about 1 / 7 (16 — 1 3 3 / 4 %), of the same length. 
The anal fin is perceptibly longer and, especially in 
old specimens, lower, and begins further back in the 
females than in the males. The distance between it 
and the tip of the snout measures in the males about 
55 or 56 in the females about 57V 2 — 597 2 of the 
length of the body. Its base is about 16—14 % (in 
exceptional cases 13 %), and its height in young spe- 
cimens about 14 %, in old 13 — 12 %, of the same length. 
Its length marks the approximation to the Abramidines, 
for whereas in all the preceding Cyprinoids the least 
depth of the tail is more than 2 / 3 of the length of the 
base of the anal fin — though exceptions may occur 
among young Minnows — in Leucaspius delineatus the 
said ratio is less than 2 / 3 (about 50 — 61 %). The cau- 
dal fin undergoes a similar change of growth, the length 
of the middle caudal rays being in young specimens 
about 12 %, in old about 10 — 9 x / 2 %, of that of the 
body. The longest caudal rays (in the inferior lobe) 
measure about 22 or 23 % of the length of the body. 
This fin is also subject to individual variation, an ex- 
ceptional circumstance among the Cyprinoids, the num- 
ber of the branched rays being either 16 or 17. The 
pectoral fins are obliquely pointed and comparatively 
short (16 or 15 % of the length of the body). The 
ventral fins are almost triangular, and their length is 
about 14 or 13 % (in exceptional cases 11 %), of that 
of the body. The distance between the ventral fins 
and the tip of the snout measures about 41 — 45 %, the 
preabdominal length about 20 — 22 V 2 %, and the post- 
abdominal length about 14 or 15 % (cf) — 17 or 18 % 
($), of the length of the body. 
The anal aperture calls to mind the corresponding 
organ in the Minnow and the ‘Bitterling’ (see above). 
It is more prominent and tubiform than in the Minnow, 
especially in the females, and is furnished on each side 
with an oblong, compressed papilla. 
The scales are thin, deciduous, and rather large, 
their number in an oblique transverse row above the 
