56 Alf Wollebæk. [No. 12 
Water-layers of the same nature, — viz: with a salinity of 
34—35 0 and å temperature of about 69 C. —, as that in which 
Pandalus borealis is found in the Fastland fiords, are to be met 
with along the whole extent of our coast as well as in the boreal- 
aretic regions. And the mere fact that Pandalus borealis has been 
shown to oceur in large numbers in å long succession of fiords 
along the whole extent of our coast and in the sea outside is clear 
proof that the species cannot be regarded as eut off strietly 
speaking in the fiords of southern Norway from its own peculiar 
area of distribution. We find the boundary for its area of 
distribution to lie at the mouth of the Kattegat and in the interior 
of the fiords. 
Composition of the bottom: In the deeper portions of 
the fiords where Pandalus borealis is caught in large quantities the 
bottom is covered with considerable deposits of fine soft mud. It 
is the barriers of the fiords which render these accumulations of fine 
mud possible. The masses of sediment which in the course of 
time are carried out to sea sink slowly to the bottom and there 
aceumulate. The finer the particles of mud are the slower they 
sink, and they are consequently carried further out towards the sea. 
At the barriers of the fiords their progress is to å great extent 
arrested, and the mud is thus gradvally stored up in the deeper 
portions. 
However it is not merely on this soft mud-bottom that Pan- 
dalus borealis i8 met with. It is found too, close in under the 
mountain sides, on å stony bottom and among corals; and oceasion- 
ally, as at the spawning time, may even be found there in quan- 
tities. 
Consequently although these Carids are at all seasons of the 
year found chiefly on å soft muddy bottom, it does not necessarily 
follow that any special form of bottom, or in any case that å soft 
muddy bottom, is an absolute essential for their occurrence. Un- 
doubtedly å bottom of this nature is their most characteristic abode; 
still it must be admitted that it is only on bottom of this kind that 
with modern appliances fishing can be effectively carried on.  When- 
ever Pundalus borealis has been found in abundance amidst corals 
we must asceribe the discovery to chance. In ordinary cases å 
prawnp-trawl would be at once torn to pieces on such å bottom. 
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