18 
these rays is, in the cod, subject to no small variation. In the Great Belt 
you may thus in the first dorsal fin count, now 12, now 16 rays, generally 
however 13 or 14. The number of rays in the second dorsal fin varies 
between 15 and 22, and in the third between 15 and 20. In the first and 
second anal fin there is a variation of respectively 16—23 and 15—19. 
When a cod has become 1—2 inches long, and perhaps already before, 
this number of rays does not change any more in it; it is consequently 
independent of age, dwelling-place, and, as it seems, also of sex. As the 
number of the rays, as I have said, is subject to no small individual 
variation, it would, in analogy with what is known from other species of 
fish, be quite likely that this variation and its limits would not be the same 
in different races of cod. If there were, e. g., one race in the Cattegat and 
another in the North Sea, it might probably be seen by an examination of 
the number of their rays. 
So ail the rays were counted in 76 cod from the Great Belt and 25 
from Fsbjerg, and the result was for 
1. dorsal fin m the Great Belt as a rule 13—15, at Esbjerg 13—15 rays, 
VÆRE SEE — 17—20, — 17—20 — 
BRUNE MEE — 17—19, — 17—19 — 
anset — 17—21, — 17—21 — 
2. — - — 16—18, — 16—18 — 
consequently so exactly alike that I very soon gave up finding any difference 
in race on that point. 
Besides the characters the zoologists have tried to use as marks of 
different races of the cod, I have heard others mentioned by the fishermen, 
of which, however, some might be said before-hand to be no characters 
of race, but only signs of the fish being more or less fat, or of quite indi- 
vidual variations. One of the more striking circumstances to which my 
attention was called, was that "some cod have a tongue, others have none”. 
I have never been quite able, however, to discover the difference between 
fish with and without a tongue; for the -phenomenon, certainly, depends 
only on the manner in which the cod opens its mouth when it dies. Some- 
times the tongue protrudes far in the mouth, sometimes it lies pressed down 
and is less visible. Krøyer has also known this, but like myself he attaches 
little importance to it. 
Another, more remarkable, thing is that the cod in certain waters 
north of Funen is almost always infested with the well known worms in 
the flesh (Ascaris). 
Worms, certainly, may be met with at all places and at all times of 
the year; in the Great and the Little Belt, however, there is not one out of 
a hundred cod which has worms. But in the above mentioned waters, at 
Endelave and west of Samsø, according to the fishermen's statements, nearly 
every cod is infested with them; and not with a few worms, there are many 
