,
THE
OF FISHES
*
-
-
215 1
maxillaries, the Condition found,in higher Vèrtebratè'sff :It
seems
more probable that, the pailato'—quadràte originay
formed part of the;skùH ;-=—at_ any
gives a better
working hypothesis to explain,the;dierences
'
Teleosts and the _Elasmobrar1’ch3.
the -,ï '
quadrateelemet separated fromthÏe
f
'
'
remained— attached to it in front.; in the latter (Sharksaud
Rays) both descend6d from the skull'.—
wecan
represett‘he change as_the result of the“
'
o£ life of theyoung stages, ',
.
.
.
‘
;
With regard to the
can be added to whathas
i
been«said. ioÿreÿîous_ Chapters. If we acceptthefsküflf Ôf '
Ï
the
'
Èalæospondylùsÿ as the s1mplestand
'
__
moSt pr1m1t1ve,1t
to asso'éia‘te the
_
coditi0of the
the modeof 'repro_=
f
,
and developmentof these forms, j Certain it is_,,ï7__
,
that among the Telecats, where the amount of yolkincreäséâ
'
,
and the .eggs are demersal, the
of Ï -
'
th 1…y1f…hmp…
-
-
{
: -,
f
’ï
:
»
thattheprmüveGanodshketheDîP@lalsoërpôss,tèäsédfâ”îïi :_j_'
the socalledSp1ralvalveandanml‘bladderTheÈlasm0
_
]
have
=
The arrangement of the-shes
,
fgenealogi0al tree follows in the main the 1ineàdevèlopedhÿf
,
“Toodward (1891) With regard to the origin of the
modern
from ' the
_
(Isospondy)= add
thfom thM Eugnathidæ and Semionotidæ -
;
(Pmtospondyh)
_
It—;is buta short step backwards
these
Ï—iÇÈalæoniscîdæ; fth,e {: early…
aSE1asmobran0hand
=
'
the! Helocephahweïeof the; s…;ageThesurvmg
=
?
tnelyreœntægmanaqu1teunconnectedw1ththeme»th
Ti}:
Which_ïw_ith'theancœnt1pnmwerecompietely ; ;;}gÿf