ECONOMY‘OÈ THE
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3567
cdntînua‘cio of the, skin on the lower margîn of the eye and
can be draWn,up like a
Here it-may” bezusedias
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a protection against the rays‘ of.light when the
near the surface… And
deŸeloped «nictita‘ting membraneoftheSun—sh(MOÏa) .
Acco‘rdingto
musclew1thve
radiating, —Ope_rng0r
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and South America
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î
upper adva 16W‘ef,:by—à
cbjûCt—ivà;and‘*the‘ —î
pupil beneath_is 1i—keWisk:—COnetced
upperandÿîIÔWérÿ
…
part:_(Fig; ‘7‘3);,
.…
mosy,…has twdkid‘s
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“the -air:ând*the
(lOWŒ') for:- the… water.- HOW this
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peCuliarity Ÿcoùl‘dahe “arisen,' eXcèptî under the law ‘j‘of
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action
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fa ..!_£;.l;à;
* 6CmmnNævovsSmm
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fmmtheeg1rmnghas;bæntheïayerthatiecmved
have sunk in from ’Èhe‘ surfaceandarenowformed,hläethe
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sense organs, from an inpushi‘ng or depression
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cell—layer in» the erbryo.‘ Instead of being ”în separate”
parts, however, like the muscles and organe, the depression
forme. a continüous groove along"the mici-dorsal
turned into
canal or Sol—id columnof ce11‘sÿ:
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of the
Then
the sides grow
the top: -andshuto'thecordom
heneaœstthesurfacelntheC1upd8thatlsmîheeaÿ
stages
Thespmalnervesconnectedmthth@àerentsegŒnü