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ADAPTATION ;
,
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269
bilities of the Other creatures of the deep. 'Many other
shes, for example, the
Cottids, have loose
aps of skin above their heads, but they arenot.known to
use them as a lure.
Possibly they are rendered less con—
spicuous among the seaweed where they live, so that the
unsuspecting prey approaches them and are then captured .
by a short but quick eËort.
;
"
,
.
,
_
Noteworthy examples of_ the adaptation of various
structures to one and the same end are given by the shes
which attach themselves to solid objects for some reason
or
another.
In. therapid streams‘. of the
the
Anabantoids use their movable spines to anchor themselves
to stones, but the Loricariid'æ ofCeritraland South Arnerica,
‘
‘
,
which have no spineS, use their mouth as a
and keep,
such rm hold they cannot be pulled off without difculty.
'
It is by this means that they manage to reach up to great
heights, over 11,000 feet, among the Andes; Still more
remarkable is the behaviour of the Globe—sh(Tetrodo) -
of East India.
It is a voracious and ‘predatory Lsh_ in Spite ,
,
of its diminutive size{about, 3 Îind—les), and is able to inate . .,
its body like Drodon 'IÏO 3ŸÔîd—bË-Ïng carried ,:awäy by the
,
stones,
ithas piled up, and ,
'
sweljls out
body; lil;eïâballdOn î It
so yammedm ;
between
Stones thér:it remains just
‘
without
,
_
Another f0rm of attachment
adhésive
'
bellyof the sh, and this would
be the most natural
apparatus for the purpose—_. of _stemming a Current, And if
structures
_,
arose and developed on account of their utility
_
Wèï
expect to nd it in the freshwater forms, but it
in” marine forms.
The
appr0achito‘
the condition inffrésh Water is Gastromyzon of .NorthîBorne'o
in which the whole ve'ntral surface of the belly,_=
pectorals at {the sidGS:fin
and the…venträs behind,
'for_ms a large suçker5and is used by the sh 120
'
stones: in ' the
mountain.
"
_
Pseud€chenis, 1ÏVÇS
_
in lÏ:h<î
_