182 
SCANDINAVIAN FISHES. 
6 specimens (2 %) had an extraordinarily short head, 
6 ,, (2 %) were very nearly short-headed, 
10 ,, (3 1 /, %) had the ridges and protuberan- 
ces of the head very strongly 
marked (transition to Coitus 
bubalis ), 
4 ,, (1 1 / 2 %) had the ridges and protuberan- 
ces of the head extremely little 
developed and also covered by 
the skin (transition to Coitus 
gobio), 
2 ,, ( 7 /io 0/ °) bad very short preopercular spi- 
nes, almost covered by the skin 
(transition to Coitus gobio). 
7 specimens (2 Vi, %) had the longest preopercular 
spine branched at the tip or 
furnished with small lateral spi- 
nes (transition to Cottus diceraus 
and ventralis), 
6 ,, (2 %) had an irregular arrangement of 
ridges on the head. 
If we noiv endeavour to find an explanation of 
the cause of similar changes of form, we obtain the 
clearest indications, here, as in other cases, by folloAv- 
ing the course of the changes due to age and investi- 
gating the expression of the external sexual differences, 
Avhile this species also affords singular proof of the 
appearance of different characters in different geogra- 
phical environments. The folloAving table is calculated 
to give information on these points: 
Cottus scorpius. 
Cottus platy- 
cepl talus. 
Uu 
o 
The Baltic. 
The \v 
inter- 
C Cjq 
CC ~ 
II 
x a 
N 
Soq 
S 2 <rs 
^ 0 
fej T' 
Bobusliin. 
Spitzbergcn, 
Ilornsund, 
July, 1864. 
O: 
Outer i 
Hudiksvn 
Greenland, 
Ivigtut Aug. 
1883. " 
quarters of 
the “A T ega,” 
1879. 
3 specimens 
ohusliin. 
5 specimens 
itzbergen. 
ll 
• a 
td 
■< cc 
So 
CC ' 
to 
CO 
July, 
1835. 
a 
cc 
Qi 
sland-belt of 
11, Nov., 1882. 
29/ 
/ 3 ' 
20/ 
i 6* 
& 
<? 
9 
cf 
9 
c? 
cP 
9 
9 
9 
& 
cf 
Length of the body expressed in millimetres 
96.5 
101.2 
150 
149 
189 
189 
201 
204 
201 
227 
299 
310 
211 
255 
,, „ head - in % 
of the 
length of the 
body 
33.5 
32.3 
33.3 
33.5 
36.o 
36.o 
32.8 
32.6 
34.3 
34.3 
33.8 
32.9 
31.5 
30.6 
,, „ ,, maxillary bones. , 
„ „ 
7- 7? 77 
7? 
12.9 
13.i 
13.6 
13.4 
14.8 
14.3 
14.6 
13.2 
12.9 
14.5 
14.7 
14.7 
12.3 
12.i 
,, .. lower jaw 
77 77 77 
16.i 
15.9 
16.0 
16.6 
18.o 
18.0 
17.i 
16.4 
16.i 
16.7 
16.7 
17.3 
19.2 
18.8 
Longitudinal diameter of the eyes „ 
„ 
7? 77 7 7 
„ 
7.6 
7.o 
6.3 
7.4 
6.9 
7.4 
5.2 
5.4 
7.4 
6.i 
5.0 
5.i 
4.3 
3.9 
Breadth of the interorbital space-. ,, ,, 
77 77 77 
„ 
3.7 
4,4 
4.i 
4.i 
4.2 
4.7 
4.4 
4.7 
3.9 
4.4 
4.3 
4.4 
7.i 
7.8 
Least depth of the tail „ „ 
77 7? 77 
„ 
5.3 
5.2 
5.3 
4.7 
5.5 
6.i 
4.9 
5.4 
5.4 
5.2 
5.7 
5.5 
3.9 
4.3 
Distance between the first dorsal fin and the 
tip of the snout „ ,, 
30. o 
30. o 
30. o 
30.2 
30.8 
31.7 
32.i 
29.9 
30.3 
30.6 
32.1 
32.2 
30. o 
27.8 
Distance between the beginning of the first 
dorsal fin and that of the second ,, „ 
77 77 
77 7 ? 77 
77 
20. o 
20.2 
19.6 
20.8 
20.9 
18.5 
21.7 
21.5 
19.2 
20.7 
23.7 
23.2 
20.5 
22.3 
Base of the second dorsal fin „ ,, 
77 77 
77 7 ? 77 
24.9 
25.7 
25.5 
26.8 
26.4 
26.4 
25.2 
26.o 
27.6 
27.3 
26.7 
27.4 
28.9 
25.5 
,, ,, anal fin. „ „ 
77 77 
,, 
17.6 
19.9 
18.6 
17.4 
19.0 
19.7 
19.4 
18.i 
18.9 
17.7 
17.o 
17.7 
24.6 
22.7 
Length of the ventral fins „ ,, 
77 77 
77 77 77 
16.5 
16.2 
19.3 
18.4 
17.4 
18.2 
15.9 
20.8 
20.3 
15.0 
16.7 
16.4 
19.9 
18.4 
Distance between the insertion of the vent- 
ral fins and the beginning of the anal fin „ „ 
77 7 7 
25.7 
24.7 
24.c 
25.2 
26.4 
25.7 
28.6 
25.o 
25.2 
29.5 
26.7 
27.7 
27.5 
28.2 
Distance between the beginning of the anal 
fin and the tip of the snout „ „ 
77 77 77 
77 
51.2 
51.0 
52.o 
51.3 
53.c 
54.2 
54.7 
52.4 
53.2 
54.6 
50.8 
54.8 
52.i 
52.3 
Length of the pectoral fins from the upper 
end of the base „ „ 
77 77 77 
20. s 
20.7 
22.0 
21.4 
22.7 
21.7 
19.9 
22.5 
22.0 
21.i 
21.4 
21.6 
26.0 
23.9 
Length of the pectoral fins from the lower 
end of the base „ „ 
77 77 
77 7 ? 77 
77 
30.i 
29. s 
30. o 
31.5 
31.2 
30. o 
30.8 
30.4 
31.3 
30.8 
32.i 
30. o 
37.4 
36.i 
Length of the maxillary bones in % of the base 
of the 
second dorsal 
fin... 
52.4 
51.2 
53.5 
50. o 
56.o 
54.0 
58.i 
50.9 
46.8 
53.2 
55.o 
53.5 
42.6 
47.7 
„ „ ,, lower jaw „ „ „ „ „ 
77 77 
77 ?> 
77 --- 
65.8 
62.2 
62.6 
59.2 
68.o 
68.o 
67.9 
63.2 
58.5 
61.i 
62.5 
62.3 
66.6 
73.9 
Least depth of the tail „ „ „ „ „ 
5 , ,, 
anal fin 
30.2 
26.2 
28.6 
27.o 
28.4 
30.8 
25.6 
30. o 
29.o 
29.5 
33.3 
30.9 
15.6 
19.o 
„ „ „ „ „ in % of the distance between 
ventral fins and the beginning of the anal fin 
the insertion 
of the 
20.7 
21.o 
21.o 
lS.o 
21.o 
22.6 
17.4 
21.5 
21.7 
17.6 
21.2 
20. o 
14.o 
15.2 
Longest ray of the first dorsal fin in % of the distance 
uing of the first dorsal fin and that of the second 
between the 
begin- 
51.9 
49.i 
57.6 
55.o 
48.i 
55.i 
53. r, 
72.7 
72.5 
56.4 
59.i 
58.3 
52.o 
54.4 
