FORMAND STRUCTURES 85
'
An interesting
pointed out "by
Schmalhausen, lies in the
homocercal tail is
only found whereanàiI-bladder o'ccur's‘ orhas been, andÏone
can readin understand
should be;
The air—bladder ,
buoys up the sh, so: that the continual*use of
to
raise the head is unnecessary. T
have loëfc
the air—bladder and the tail remains in the heterocercal condition.
'—
,
If the body is long and thin, the tail‘isless u*nd€ïgÿ_—’Çhe «
_.
—
4
.5
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_ j_
,
.g
,
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,
a:).
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-
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-
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87
r
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FIG 18.—Developme'nfof the
_
_' ’
y.,
notochord. 2—5. UpbendingÏ of nbtochord,and
Î
l., muscle bres; h.,*hypurals; u.,
parts of ùrostylè';
'
‘
‘ep.,epurals;
,
,
,
-
‘
‘
'
inuence of What the head does, atld;often remains
"‘
less straight, in; which?‘càgse ,ità‘is‘ aéalledgjdiphëfcälf=:ÎJü
The
,
and below
=
heating of the body foms1dtodagnstthesstng _
.
medium; .It‘is 11t=t1—e=ofmtata11fêdèvç‘lèpccÿintheformshke j”
-
the Cyclost0mes .aënd
°
_
the“ …larvàl ,àd p'oStlaÏVal',. stages, Wh118tstllntheegg- ,
capsule. Nor sis
WdI-ÏdÇVÔÏÔPÇd
1nthelarvalforms
,