( 491 ) 
to grow equally fast at all parts of the body, and I feel inclined to 
consider this as the reason, why for example the scales closely 
behind the head (above the pectoral fin, a place which is called the 
shoulder by some authors) remain smaller than those of the sides. 
The figures 3, 4 and 5 represent three scales of the same salmon, 
but from different places of the body and of a different size. In 
accordance herewith the number of rings is also different. To facili¬ 
tate the comparison, all the other figures of the Plates, therefore, 
were drawn from scales taken from the same place on the body 
surface, and as such was chosen the place where a line, running 
from the beginning of the dorsal fin to the anterior point of attach¬ 
ment of the pelvic fin, would cross a line running parallel to the 
lateral line about three rows of scales above it. 
Fishes of the same age but of different size have scales of diffe¬ 
rent size and different numbers of lines of growth in consequence: 
the figures 6, 7 and 4 were drawn from scales of three salmon 
reared from the same lot of eggs and which on the same date meas¬ 
ured respectively 5.1, 6.6 and 9.1 cm.; the numbers of their lines 
of growth are about 8, 12 and 16. 
The figures 8, 9 and 10 show — for completeness’ sake — that 
the growth of the scales, and the increasing of the number of lines 
on them, continues regularly in autumn with the growth of the 
fishes. So I counted: 
on the scale of a parr of 7 cm. in August , 15 lines of growth 
„ „ „ „ „ „ „ 9.5 „ „ September, 19 „ „ „ 
„ „ „ „ „ „ „ 11 „ „ October , 22 „ „ „ 
„ „ „ x ) „ „ „ „ 11.5» » November, 24 „ „ 
Scales of salmon caught in December are the last of fishes of the 
first year, which could be investigated: it becomes difficult already 
in the later autumn months to catch young salmon, and it is quite 
impossible to do so as soon as the brooks in which the parr pass 
the winter, are frozen. As soon as these brooks thaw again in early 
spring and swell with the snow melts on hills and mountains 
the young salmon return to activity and most of them profit by the 
swelling of the brooks and the descent of the water to find their 
way to the main river and thence to the sea. We will return to 
these in c, page 493. Some of the young salmon, and perhaps not 
so few, however, remain at the end of their first year in the brooks 
of the upper course, most probably at or near the places where they 
were spawned. These are: 
*) This scale is not figured. 
Proceedings Royal Acad. Amsterdam. Vol. Xll. 
