SALMONS. 
833 
than in its fellows of the same age. In average cal- 
culations, however, such individual exceptions may be 
regarded as eliminated, and the said classification is 
observed, generally speaking, even in popular phraseo- 
logy, the first group containing the Laxyngel , Salmon- 
fry (length under 70 mm.), the second group the Stir- 
rar, Parr j length ^ rara 'j, the third group the Fo- 
reller or Stenbit | length ^ inni '|, the fourth group 
the Oring ar or Borting | length ^ mm ‘ J, the fifth 
group the full-grown Laxar or Salmon (length > 450 
mm.). The average percentages calculated as expres- 
sions of the different relations of form in these groups, 
lead us to very singular results". Out of 59 distinct 
relations of form' 41 follow a fixed course in their 
changes of growth, i. e. they either decrease with in- 
creasing age (as for example the average length of the 
head in proportion to that of the body), or increase 
with age (as for example the average postabdominal 
length in proportion to the length of the body). 
In order to obtain an expression for those common 
variations of the Salmons which are due to external 
sexual differences, we have compared 17 males of the 
different stages of growth with 17 females of about the 
same size as the males and with the sexual organs about 
equally ripe. The result is that 16 of the said 41 changes 
of growth run in the same direction as the sexual 
difference between male and female, i. e. a change of 
growth that shows decreasing percentages with increas- 
ing age answers to a sexual difference with greater 
percentages in the males than in the females, and vice 
versa. The two examples cited above appear in the 
following percentages : 
Average 
Pry. 
Parr. 
For ell. 
Oring. 
Lax. 
c? 
9 
Length of the body expressed in millimetres 
48 
108 
179 
318 
595 
218 
218 
„ head in % of the length of the body . 
25. o 
23.o 
22.5 
21.9 
20.9 
23.4 
21.8 
Postabdominal length „ „ ,, ,, „ „ „ „ 
16.9 
19.7 
19.7 
20.4 
21.2 
19.6 
20.9 
The parallelism between the numerical alterations 
l) in the first five columns and 2) in the last two 
columns, may ' evidently be expressed as follows: the 
younger Salmon are to the older as the males to the 
females. 
If Ave noAV examine the difference of form betAveen 
the tAvo Scandinavian Salmon species that have received 
most general recognition, Salmo trutta and S. solar avc 
arrive at exactly the same result: the difference between 
the averages for the said characters runs from the Grd- 
lax (S. trutta) to the BlanJdax (S. salar ) in the same 
direction as the averages for the changes of groAvth and 
also for the external sexual differences. Some of the most 
important of these characters may here be tabulated. 
A 
y e r a 
g e 
Pry. 
■> 
Parr. 
Forell. 
Oring. 
Lax. 
c? 
9 
1 
Salmo 
trutta 
47 
108 
182 
313 
5871 
Length of the body expressed in 
millimetres.. 
I 
218 
218 
1 
Salmo 
salar 
50 
109 
161 
403 
609| 
„ „ „ head 
.. in % of the 
length of the body 
Salmo 
trutta 
25.2 
23.5 
22.6 
22.o 
22.o \ 
23.4 
21.8 
55 55 5 ? 55 
- „ „ „ „ 
77 77 77 77 
Salmo 
salar 
24.6 
23.5 
22.2 
20.i 
20.2 f 
Postabdominal length 
Salmo 
trutta 
16.5 
19.8 
19.7 
20.3 
21.21 
19.6 
20.9 
55 5 ) 
-- 77 77 77 77 
„ „ „ „ 
Salmo 
salar 
17.7 
19.5 
19.5 
21.3 
21.i | 
Length of the maxillaries 
Salmo 
trutta 
9.8 
9.2 
9.i 
9.o 
8.6) 
9.G 
8.6 
55 55 55 55 
-- 77 55 75 77 
77 75 77 57 
Salmo 
salar 
8.i 
8.0 
7.6 
7.o 
7.o f 
Least depth of the tail 
Salmo 
trutta 
9.5 
9.i 
9.4 
8.7 
8.7 1 
8.7 
8.4 
)! n n » » 
-- „ „ „ „ 
55 55 55 55 
Salmo 
salar 
8.4 
8.o 
8.2 
7.i 
6. 9 J 
Length of the middle caudal rays „ „ „ „ 
55 55 55 5 ) 
Salmo 
trutta 
11.4 
9.0 
8.o 
7.7 
7.7) 
ft 1 
„ » „ „ „ „ 
77 77 77 77 
55 55 55 55 
Salmo 
salar 
8.8 
7.i ■ 
0.7 
5.5 
5.8 | 
Least depth of the tail 
■ 77 77 77 77 
preabdominal length 
Salmo 
trutta 
36.3 
32.4 
32.7 
30. o 
30.i) 
30. o 
29.4 
55 77 77 77 77 
- 77 77 77 77 
55 ?5 
Salmo 
salar 
30.4 
27.8 
28.i 
23.6 
23.2 1 
° As we cannot give here all the particulars of our investigations, we refer the reader to our Kritislc Forteckning ofver de i Rilcs- 
museum befintliga Salmonider, Vet.-Akad. Handli, Bd. 21, No. 8. 
