‘
THE“"BODY-—II
'
147
Ÿ
the two lateral halv”es in such 'a section are usually not quite
f
symmetrical=or thesama
'
,
.
,«
'
.
-
<
_
Ï
j
The
,
segmental arrangement
on the
throughout the
,
shes,Ï the principal— chan‘ges {depending
simply on the relative; develOpnientof ,‘thegînbre 'ÊÇtmli,
,
_
muscles, directed towards the tail,éand thelfmarginal__ muscles
directed towards the head. —In sWify,
the Sharks and Mackerels; the latter = bebeîe ofmmor *
'
importancefexcept near, ithehead, whereas
deèperjfor‘ms;
[
whichmove;mOæ slowly, the marginal
'
:
larger,as in the F lat—shes.
do with'the'working;
,
,
and balancigof the body;ad-£ns, andi'the'Plectogna‘chs,’
'
_
where:an“-accideñt
,
off_ the use of its—tail, these marginal
attain to an
,
en0tmous development; .. In the ElaSmdbranchs the muscles
'
'
'
tend'to arrange themselves in groups along the vertebral
'
column, as in the Higher Vertebrates.
'
;
'
'; A10g the Sideof thebody the meeting—place
and'ventralhalves; of themuscle segments
"
_
.
by
,
?
,
=
"
probablydetachedportons0fthplnaplmusélesswhmh , ;_,,:
:
wahtihg,
mtheLamp1ey(Petromyzon),where
'
the muscles are arranged infoompartments‘,WhiÇhîf'ëh0Wÿ;
"
a
remarkable resemblance to the
‘orga'n‘s of)—other
shes (Stanniùs, 1854).
,
,
,
_
'
The distinction between smooth or non-striated and
striatedmuscle bres expresses the general di"erence between '
_
slOw, but powerful contractions and rapid but weaken
'
contractions; Yet 5many' interVening stages occur, and the
'
_,
one may_ change into the-other or into a different k1nd of
__
cell tissue.
The,àlimentary
Clupe1dsand
several :—0thér, —:'formS j has :stri‘ated
pti; jë_{:;_,
"
postlarval. stages,—} and , this pesistS_ 1nthe adultsofmanyg—f
,,
7
sm00thvanetymïä’ iÏ? Îï
is,;,“present.,'—', Hencemsomecaesthecontractœns0fthe _ ; 1j
THE“"BODY-—II
'
147
Ÿ
the two lateral halv”es in such 'a section are usually not quite
f
symmetrical=or thesama
'
,
.
,«
'
.
-
<
_
Ï
j
The
,
segmental arrangement
on the
throughout the
,
shes,Ï the principal— chan‘ges {depending
simply on the relative; develOpnientof ,‘thegînbre 'ÊÇtmli,
,
_
muscles, directed towards the tail,éand thelfmarginal__ muscles
directed towards the head. —In sWify,
the Sharks and Mackerels; the latter = bebeîe ofmmor *
'
importancefexcept near, ithehead, whereas
deèperjfor‘ms;
[
whichmove;mOæ slowly, the marginal
'
:
larger,as in the F lat—shes.
do with'the'working;
,
,
and balancigof the body;ad-£ns, andi'the'Plectogna‘chs,’
'
_
where:an“-accideñt
,
off_ the use of its—tail, these marginal
attain to an
,
en0tmous development; .. In the ElaSmdbranchs the muscles
'
'
'
tend'to arrange themselves in groups along the vertebral
'
column, as in the Higher Vertebrates.
'
;
'
'; A10g the Sideof thebody the meeting—place
and'ventralhalves; of themuscle segments
"
_
.
by
,
?
,
=
"
probablydetachedportons0fthplnaplmusélesswhmh , ;_,,:
:
wahtihg,
mtheLamp1ey(Petromyzon),where
'
the muscles are arranged infoompartments‘,WhiÇhîf'ëh0Wÿ;
"
a
remarkable resemblance to the
‘orga'n‘s of)—other
shes (Stanniùs, 1854).
,
,
,
_
'
The distinction between smooth or non-striated and
striatedmuscle bres expresses the general di"erence between '
_
slOw, but powerful contractions and rapid but weaken
'
contractions; Yet 5many' interVening stages occur, and the
'
_,
one may_ change into the-other or into a different k1nd of
__
cell tissue.
The,àlimentary
Clupe1dsand
several :—0thér, —:'formS j has :stri‘ated
pti; jë_{:;_,
"
postlarval. stages,—} and , this pesistS_ 1nthe adultsofmanyg—f
,,
7
sm00thvanetymïä’ iÏ? Îï
is,;,“present.,'—', Hencemsomecaesthecontractœns0fthe _ ; 1j