12
THE BIOLOGY OF FISHES
ventrale, being neaier the ground,are stilloft'ener used as
tactilèorholding“organS.
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Thèse adaptations will be described more fully insucceeding pages. The signicant point is, that the ns were
not made for these purposes;
They
the beatig
of 'a soft, muscular body against a resisting medium,” rst
to the one side, then to the other;
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skin—fold or
membrane thus pressed out along the marginS then became
occupied ___in various partsby horny bres “or scaly rays,
which helped to balance the sh. The later adaptations
have come from the particular use of the ns in the directions
mentioned.
As
geological time is now reckoned, the
adaptations we see in shes of the present day are all of recent
origin… These Sheshave iiOt made
but their
intelligence hasbeen at”Workin Using and-deve10ping them in
particular directions;
f
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f
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In doing so, we can. readin Seeçthat the shes were
departing from the normal use and type, and were probably
at a disadvantage in the beginnig.in the struggle for life.‘
To
to a stone or bufÿ the head in sand when watchful
enemies are pursuing would seem a precarious Way of escap—
_
ing. The long pectoral ns of the Flying—sh are of no
in swimming, perhaps even a hindrance. But related species
which have shorter ns, also delight in leaping into the air,
and there is no doubt that the aptitude has come in reality
from the great strength of the tail… Thé ‘Î_ Wings ”have
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been" developed in=the air, from 3 the;
_jSh,‘f and,
—
‘
f
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€
"
.
Wherit One—part ;chafngeé,ï__-othçrs, ;çhange‘ with it
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sh takesÏtoÏÏ-ïsWirnming
another: to Clinging
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on to stoesor
clear that the
.
moulding pressure ofgthe water 3must reàct-On the formin
«
manygdierent ways
grasp the complèXity
and— variety of ithÿeÏ
”let
think-of ‘àn intermediate
type;
of
simple body
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Herring, and en—deavour to picture
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“how, by coming under? dierent bondit—ions, fresh or Salt
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water,f pressure, etc.,— or; by“: accidents; and then by.using the
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