191 
“Linnean Transactions ” by Count Daldorff,* giving an account of 
this fish and its singular habits. It can move for some distance 
on land and even up inclined surfaces. The author himself found 
one “in the act of ascending a palm tree that grew near a pond. 
It had reached the height of five feet above the water and was 
still going up further when he stopped it with his hand.” You 
._ will ask how the fish manages to climb in this way. It is by 
means of the spines on the opercle or gill-flap and the spines of 
the anal fin, which are all long and sharp. The fish first fixes 
the opercular spines in the bark of the tree, and by the help of 
these draws up the posterior part of the body, and then in like 
manner fixes the anal spines. The opercular spines are then 
released, and by a side movement of the head those on the other 
side are fixed higher up and so on; the right and left opercle 
taking their turns as the head is moved first to one side and then 
the other. What the object of the fish is in these vagaries I have 
no idea. It may be to get at some food it had a taste of formerly, 
or it may be from a sheer love of gymnastics. Anyhow, the habit 
must have been of long standing. What led to it in the first 
instance it is impossible to say, but, once formed, the spines 
would probably become gradually longer and stronger by use, 
combined with inheritance of the habit from a line of ancestors 
reaching back for a countless number of generations.t 
But I must pass on now to speak of the remarkable case of an 
altered instinct, accompanied no doubt by some slight alteration 
of structure, which I before briefly referred to, as one in which 
we know almost to a certainty what occasioned it. It is the case 
* Vol. iii., p. 62, 1797. 
+ A doubt has been entertained by some whether the climbing of 
trees is a constant habit of this fish, or whether “the ascent witnessed 
by Daldorff” may not have been “accidental.” (See Romanes’ Animal 
Inielligence, p. 249.) But it could hardly so generally have got the 
‘name of the 7Z7ee-climber had it not been the regular habit of the 
species, 
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