'
,
ADAPTATIONŸ
273;
male and by this means the embryo receiVes nourishment
_
through a placenta. In Aspredo— ofthe Guianas it“ is, the '
females that undergo this change andnourish the eggs.
,
The origin of the skin fold in
have,
_
-
come about in the following
shes :haVe'
.
narrow bodies and have
derived; from
‘
others With
deeper bodies (Clùpeids)
Hereg«the;ribs
absent and the
a
-
.
lateral
We nd it again in other shes, such as, the
'
Sand-eel(Ammodytes),which apparently fnak;e no rÏ_lSC{Of it, ,
,
The
;
of the eggs, sitting‘bn them like a beh, develops hi)lloîävs and
of the pectofal=-rays. In,
the)eggs togethergandikeepthem
_
;
in
mass-. The
none‘the less
_
wonderful because we ascbe it— to the regulative laW of
action and reaction.
What is perhaps still
j
'
'
isthat these hollow‘sand
other
:
Ç-e5i:ii—cÿ
thus
ñtiÇîÊ_?—Ëo 0fthlïuse
1
*
phenomenonfromthewewthatthe hermonessümulate :
,
theseand0therparts0fthebody todevelopasthese‘mal
*
3. nmnoNs CONNECTËDÇWITH_ HREN .—
:
,
The necessary elements of- a iesîairat‘ory «organ consmt gÿî
__
simply , of; a separating membrane"between blood On the
orie;,side and. a medium_ containing— Oxygen on the other.
Ÿ
;
It13notessenal that-the organ should take the form of
'
,
Ÿ
gillsHence We nd that inshes almostany part may on
?
occasmnserve the purpŒe- For,
Rÿdef -<1-893)7
‘
'
'
the. young fry:0fg thc.Embioiœi@$
'
°
;
..are
süîälièd;Wh:blœd_—_Capillaries
serve
:
=…
—
'asJ respirafofÿi6rsà—rjisieÿi’ln:mariÿ
!
"
canalareusedf0rr“
'
:
the purpose-,
_
.
,
,
:;
'
'
.
T
'
.