( 497 ) 
months,may have elapsed, since their departure and since they ceased 
to take food, — it is even possible that they spent a considerably 
longer period still, without taking food in the normal way, which 
is done by the older salmon only in the sea, as is well known. 
Hence it is possible that the growth of the fish itself and of its 
scales has also been suspended for so long a time. If we wish 
to consider the length of the periods and the regularity in the alterna¬ 
tion of the stay in freshwater and salt, we have to reckon with all 
these possibilities; hence one cannot be surprised if the picture of 
the growth, which the scale presents, is often not easy to under¬ 
stand. Personally as yet I have no great experience in the matter 1 ) 
as I could not include in my investigations either the scales of 
kelts or those of very big and old salmon which, probably, do 
not ascend the Rhine for the first time. 1 investigated, however, a 
single, so-called small, and a single, so-called large, summer salmon 
and I shall give here a summary description of their scales. 
The figures 19 and 19« are from the scale of a small summer-salmon 
of 84 cm., which was caught in August at one of our seine-fisheries. 
The scale shows the formation of the first year in rather good 
development. The number of rings formed in that first year is 16 — 18, 
if we count them in oblique direction from the centre to the rounded 
corner where the lateral and front (in the drawing the under) margins 
meet. The section grown in the second year consists of two parts: 
first (going from the interior to the exterior) 14—15 rather regular 
rings, which are slightly broader than those of the first year and 
which represent, with the latter, the growth in fresh water; then 
^—11 somewhat less regular rings, the most interior of which are 
considerably broader: they are the first rings formed in the sea. 
Roundabout that division a few very narrow rings are to be seen, 
which represent the growth of the winter at the end of the second 
year. In the third year about 15 nearly equally broad rings have 
been formed and roundabout these a group of 3—4 narrow rings, 
with here and there perfectly parellel margins, which seem to indicate 
the growth of the winter of that year. In the same way the growth 
of the fourth year is formed by 25—27 such rings and the growth 
the third winter passed in the sea by a band of from 4 to 5 
narrower rings with nearly parallel margins. Finally that part of 
the 5th year, which lasts from winter until August, is represented 
1 ) Johnston (1. c.) describes the scales of such salmon; what he tells us about 
the “spawning marks” which are to be seen on the scales of older salmon is 
very interesting and in any case is worth being compared with what the scales of 
Rhine-salmon will show under the same circumstances. 
