BIHANG TILL K. SV. VET.-AKAD. HANDL. BAND 24. AFD. IV. N:08. 27 
Out of 68 specimens (34 I, 34 Q) | Out of 58 specimens (35 &, 20 2) 
of C. gobio | of C. poecilopus 
. 2 specimens (1 5,1 2) had 15 rays | 6 specimens (3 7,3 2) had 16 rays 
7 Hand (GIT, AKS rRejga 1] 3 vel (208 TRR) HRT 
44 > (23 7:21 92) a» 17 > | 19 > (181576) rnNI8 
Niörssjor förguerejds nisl) | Rv aagölkta ; 90 
The measurements of the height of the fins show that 
they are higher in C. gobio and also usually highest in the 
young specimens. In this respect also C. gobio seems to re- 
present the juvenile stage. There is no distinct difference 
in sex as to the height of the fins, but the males in C. poeci- 
lopus seem to have followed another course of development. 
While the fins in all the specimens of C. gobio and in the 
females of C. poecilopus evidently diminish in height, in the 
males of O. poecilopus they always remain of about the same 
height, or they show in some cases a tendency to become 
higher, a circumstance, which, we shall find, corresponds to 
the course of the development of the paired fins. 
In the anal fin of the males there appears to be about 
the same state of things as in the dorsal fins. This becomes 
longer with age, being also longer in C. poecilopus than in 
C. gobio. The females show, however, a different develop- 
ment, the fins of these diminishing in length and more dis- 
tincily so in C. poecilopus than in C. gobio. A difference in 
sex thus appears in specimens of any size; the fins are longer 
in the nfales. C. poecilopus represents here a male stage 
and an adult one. 
The number of rays varies as follows: In OC. gobio be- 
tween 10 and 13, in C. poecilopus between 13 and 15, show- 
ing that there exists in this respect a more marked distinc- 
tion between the forms than appears in the dorsal fins. 
Out of 68 specimens (34 I, 34 2) Out of 58 specimens (38 >, 20 2) 
of C. gobio | of C. poecilopus 
5 specimens (1 5,4 2) had 10 rays | 16 specimens (12 sz, 4 2) had 13 rays 
20 > (10Z, 10/0) > LA NRA > (TRISS) IA 
37 > (SEIN rr RR 8 > (ÖP of SACD | eg (VARE 
6 > (SIA Sv LO) Eb EN [SV 
In its variations of height the anal fin pursues quite an 
opposite course to that of the dorsal fins. In both forms the 
anal fin becomes higher with age, and it is higher in the 
