818 
SCANDINAVIAN FISHES. 
Abvamis Heckelii , Sel. Longch., Fne Beige , p. 217. 
Hybrid between Abramis brama and Leuciscus rutiJus, Gthr, 
Cat. Brit. 9 fits., Fish., vol. VII, p. 214; Lillj. (p. p.), Sv ., 
Norg. Fn., Fisk., vol. Ill, p. 287. 
Of this form, which according to Siebold attains 
a length of about 31 cm. (to the extreme tips of the 
caudal lobes), we have been in a position to examine 
three specimens 17 — 22 cm. long (to the end of the 
middle caudal rays), all three taken in Dalecarlia by 
Dr. Steffenburg, and two others, resp- 20 and 32 
cm. long, from the Helge River (Scania). Instead of a 
description at length we shall here give those average 
measurements of the first-mentioned three specimens 
which express the most important relations of form. 
Length of the body expressed in millimetres. 
Length of the head in % of the length of the body 
Greatest depth of the body „ „ ,, „ „ „ „ 
Greatest thickness of the body i „ „ „ „ „ „ „ „ 
Least depth of the tail „ „ „ „ „ „ ,, „ 
Distance between the dorsal tin and the tip of the snout ,, ,, „ „ „ „ „ „ 
Length of the base of the dorsal fin „ „ „ „ „ „ „ „ 
„ „ „ longest ray of the dorsal fin „ „ „ „ „ „ „ „ 
Distance between the anal fin and the tip of the snout „ „ ,, „ „ „ „ „ 
Length of the base of the anal fin „ „ „ „ „ „ „ „ 
„ „ „ longest ray of the anal fin „ „ „ „ „ „ „ „ 
„ „ „ middle rays of the caudal fin „ „ „ „ ,, „ ,, ,, 
,, ,, 5, longest rav ,, ,, ,, ,, - ,, ,, „ ,, ,, ,5 ,, ,, 
55 55 55 pectoral fins — — — ,, ,, ,, ,, ,, ,, ,, ,, 
„ „ „ ventral „ „ „ „ „ „ „ „ „ 
Distance between the ventral fins and the tip of the snout „ „ „ „ „ „ „ „ 
Preabdominal length „ „ „ „ „ „ „ „ 
Postabdominal ,, — — ,, ,, ,, ,, ,, ,, ,, „ 
Length of the peduncle of the tail behind the perpendicular from the termination of the base of the anal fin „ „ „ „ „ „ „ „ 
Diameter of the eyes... ,, „ „ „ „ „ „ head 
Length of the snout „ „ „ ,, „ „ „ ,, 
Breadth of the interorbital space „ „ „ ,, ,, „ „ „ 
Length of the upper jaw from the tip of the snout ,, „ „ „ ,, „ „ „ 
55 55 55 lower ,, ,, ,, ,, ,, 5, ,, ,, ,, 
„ ,, „ suboperculum at the upper margin „ „ „ „ „ „ „ „ 
193 
21.9 
31.8 
(9.3) 
10.5 
49.7 
13.5 
(23.0) 
62.8 
17.2 
(15.5) 
9.4 
(25.4) 
(18.1) 
(16.5) 
42.8 
20.9 
(20.5) 
15.9 
23.9 
(30.3) 
37.5 
29.5 
35.2 
35.6 
The characters of the Roach here find expression 
in the comparatively short lower jaw and pectoral fins, | 
in the forward position of the dorsal fin and its com- 
paratively long base, and in the comparatively great 
postabdominal length. The influence of the Bream type 
may be traced, on the other hand, not only in the 
great depth of the body and, relatively, of the pe- 
duncle of the tail, but also in the height of the dorsal 
and anal fins and in the comparatively great preab- 
dominal length. 
Bloch described this form from Swedish Pomerania, 
Heckel and Siebold from Central Germany and Austria, 
Nordmann from the Lower Danube, Valenciennes from 
France, Selys-Longchamps from Belgium, Yarrell and 
Gunther from England. According to Thompson it 
also occurs in Ireland; but this statement seems to re- 
quire further corroboration, for, as Day" has remarked, 
the Roach does not belong to the Irish fauna. In Swe- 
den this hybrid had as yet been found, to the best of 
our knowledge, only in Dalecarlia and, according to 
Lilljeborg, in the Klar Elf, until we received very re- 
cently (May, 1893), through Fisherman Billing of Kris- 
tianstad, two splendid specimens from the broad below 
that town on the lower course of the River Helge. 
The German name of Letter (Leader) has been con- 
ferred on this hybrid as well as on several other more 
or less singular fishes that occur in solitary specimens 
among a shoal of some common species, and are there- 
fore supposed to pilot their comrades. A catch of this 
kind. is enough to give the fisherman hope of a plenti- 
ful take of Bream. 
Like the Cyprinoid hybrids in general this form 
too is prolific, the spawning-season occurring in Ger- 
many, according to Siebold, at the end of April. 
Fish. Gt. Brit., Irel ., vol. II, p. 195. 
