790 
SCANDINAVIAN FISHES. 
Subfamily ABRAMIDIN JE. 
Dorsal fin much shorter than the anal, the base of the former measuring as a rule less than */ 3 a of that of the 
latter , which is more than 16 % of the length of the body. Length of the head less than half the distance be- 
tween the dorsal fin and the tip of the snout. No spinous ray in the dorsal or the anal fin. Ventral margin be- 
tween the ventral fins and the anal aperture sharp , but generally naked ( not covered with curved scales ) in the 
median line. Mouth without barbels. Length of the lower jaw as a ride less than 47 % of that of the base of the 
anal fin. Pharyngeal cartilage oval or elliptical, with the anterior {upper) extremity more or less obtusely pointed. 
These characters are accompanied by the well- 
known Abramidine form, a deep and compressed body 
with strongly compressed or even sharp margins, along 
which the scales are shed at certain parts of the me- 
dian line, the two outermost rows of scales being thus 
juxtaposed edge to edge, or leaving the skin at these 
parts naked. This is always the case, even in Alburnus 
and, at least partially, in Spirlinus, along the ventral 
margin between the ventral tins and the anal aperture; 
and in the true Breams the 'denudation extends, though 
with varying distinctness, to the anterior part of the 
dorsal margin behind the occiput. 
It was not without reason that Nilsson proposed 
to unite all the Scandinavian Abramidines into one 
genus. Great as the difference may appear between a, 
Bleak and a Bream, we find intermediate forms be- 
tween them composing an almost unbroken series. A 
species found in Denmark and further south, Spirlinus 
bipunctatus, has also been referred by some, for ex- 
ample by Gunther, to the genus Abramis, by others, for 
example Heckel and Siebold, to Alburnus. The near 
relationship of this subfamily to the preceding one, a re- 
lationship which in its intermediate forms arid hybrids 
defies every attempt by fixed characters to define the li- 
mits between these two groups, has caused a like diver- 
sity of opinion, the Bleak being referred by Agassiz, 
Kroyer, Nilsson, and Lilljeborg to the same genus as 
the Asp. If the systematic classification of forms so 
closely allied is to be based on natural grounds, we are 
compelled for the sake of consistency to employ as ge- 
neric characters relations which elsewhere seem to be of 
comparatively little weight. Hence Fatio established his 
new genus Spirlinus, and for the same reason we are 
obliged to divide the genus Abramis, with a view to 
obtaining an expression for the points of resemblance 
between the ‘Zarthe’ and preceding forms and the 
respects in which it differs widely from the true 
Breams. 
The genera belonging to the Scandinavian fauna 
may be distinguished as follows: 
I: Length of the head more than 1 / 3 of 
the distance between the dorsal fin and 
the tip of the snout. 
A: Base of the anal fin less than 1 / 5 of 
the length of the body and shorter 
than the head. 
a: Lower jaw most prominent. Pec- 
toral fins longer than the longest 
ray in the dorsal fin Genus Alburnus. 
b: Jaws about equally prominent. 
Pectoral fins shorter than the 
longest ray in the dorsal fin ... Genus Spirlinus. 
c: Tip of the snout most prominent. 
Pectoral fins shorter than the 
longest ray in the dorsal fin ... Genus Leucabramis. 
B: Base of the anal fin more than Vs 
of the length of the body and as 
a rule longer than * 6 the head Genus Abramis. 
II: Length of the head less than 1 / 3 of the 
distance between the dorsal fin and the 
tip of the snout Genus Pelecus. 
a Invariably less than 72 % in all the specimens measured by us. 
6 In White Bream and young Bream exceptionally equal in length to the head. 
