MIGRATION OF FISI—IES
'
benet to the birds.
On the one hand, they are urgedï0n:,_
‘
by. the constitutional fever within ; on the other, they are
enticed forwards by What lies at the end- of the journey.
This is wanting in the shes ; the urge isthere but
inducemerit or reward.
If an Eel could foreseeæwhatlaÿ
‘
before it in the depths of the Atlantic, would it1u“ndertzækç:
the journey ?
'
…
-
We may say, then, that the migrations. of shes cannot
,
be regarded as adaptations, as we apply that term to birds.
_
They are On a lower level, .more primitive and crude. 5111
allprobability they are an inheritance from remote ances‘tors,
Which the shes from lack of s'uîcient intelligence perhaps
_
have not been able to overcome.
'. '
it should be noted thatthe birds do
contradictory phenomena; the migrations are always” to
avoid the severity of the external conditions. We might
sayithis of the summer spawners' among shes ; but
and conditi0ns are to be
and the eXtreme cases,
Salmon and Eel, seem wilfully -to be 'seeking thè‘most
dangerous and most deadly’ conditions
'
,
'
Many eorts have been made to
-’ _
“Off shes With;the external-conditions, temperature,sahmty,
‘
light, etc;;ïandïit‘is probable
hassomemueœ , :
but the problem has
essential
to
distihguish Îf’the food concentratlonsand
.
:_
wanderings from the sp‘a'Wning:migrations—;,a
'
easy as at rst
{:.
feeding
cases 1f not
the : actual
changesmmeabohsm
Which give. the stimulus
ounds andcond1tmns Ï
(Pat—on; 1900)
Î-î
.
mthngnththtgtdfmthngThltt
'
benet to the birds.
On the one hand, they are urgedï0n:,_
‘
by. the constitutional fever within ; on the other, they are
enticed forwards by What lies at the end- of the journey.
This is wanting in the shes ; the urge isthere but
inducemerit or reward.
If an Eel could foreseeæwhatlaÿ
‘
before it in the depths of the Atlantic, would it1u“ndertzækç:
the journey ?
'
…
-
We may say, then, that the migrations. of shes cannot
,
be regarded as adaptations, as we apply that term to birds.
_
They are On a lower level, .more primitive and crude. 5111
allprobability they are an inheritance from remote ances‘tors,
Which the shes from lack of s'uîcient intelligence perhaps
_
have not been able to overcome.
'. '
it should be noted thatthe birds do
contradictory phenomena; the migrations are always” to
avoid the severity of the external conditions. We might
sayithis of the summer spawners' among shes ; but
and conditi0ns are to be
and the eXtreme cases,
Salmon and Eel, seem wilfully -to be 'seeking thè‘most
dangerous and most deadly’ conditions
'
,
'
Many eorts have been made to
-’ _
“Off shes With;the external-conditions, temperature,sahmty,
‘
light, etc;;ïandïit‘is probable
hassomemueœ , :
but the problem has
essential
to
distihguish Îf’the food concentratlonsand
.
:_
wanderings from the sp‘a'Wning:migrations—;,a
'
easy as at rst
{:.
feeding
cases 1f not
the : actual
changesmmeabohsm
Which give. the stimulus
ounds andcond1tmns Ï
(Pat—on; 1900)
Î-î
.
mthngnththtgtdfmthngThltt