TROUT AND GRAYLING. 65 
are able to find in it. He found by experiment that when Loch 
Leven trout are taken to different parts of the country, they very 
soon lose a good many of their characteristic features, and a 
number that were introduced into Gloucestershire took to them- 
selves the same colouring as the ordinary brown trout to be found 
in the neighbourhood. It is also a known fact that when the 
ordinary brown trout is introduced into salt or brackish waters it 
assumes the silvery coat of the sea trout, and it is soon very 
difficult to distinguish one form from the other. Another very 
strong argument in favour of Dr. Francis Day’s idea is that in 
New Zealand, where the ordinary fresh water trout of England has 
been introduced into the rivers, it has apparently taken up 
some of the habits of the sea trout, has put on a beautiful silvery 
coat, and goes down the rivers into the sea at certain seasons of the 
year. 
There are two other very peculiar kinds of trout that are certainly 
worthy of passing mention, and they are a race of tailless trout that 
are found in Loch Islay, and the hunchbacked trout found in 
the streams on Plinlimmon and the adjacent parts of Wales. It 
is supposed that as these latter fish are only found in small 
streams with numerous cascades in them, the eggs are in some 
way injured by the falling water, and the fish are consequently 
born with crooked spines. 
The grayling is in many ways very dissimilar to the trout. It 
is very different in shape—the head is much smaller, it has com- 
paratively a small mouth, with only very small and few teeth com- 
pared with the trout. It has a remarkably large dorsal fin in pro- 
portion to its size, a very forked tail, and it also has a very large 
air bladder. The pupil of the eye is pear-shaped instead of the usual 
circular shape. Its colour is a beautiful silvery grey, and it some 
times has numerous black spots all over its body and dorsal fin, but 
these are often very scarce ; its back is a very dark greenish colour, 
and in certain lights greyish lines are visible running down its sides. 
These grey lines are supposed, I don’t know with how much 
truth, to be the origin of its name, grayling (grey lines, grayling). 
‘Scientifically, it is known as Sa/no thyma/llus, because it is supposed 
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