192
'
THE BIOLOGY OF FISHES
mentions them.
These vary according as the sh live in
open or in secluded waters.
In general, the specimens
from
the'open waters have a more elongated shape With a larger
number of vertebræ,_ but smaller number of pectoral rays,
etc. ;
those living in quieter waters have a thicker body,
thus a smaller number of vertebræ, and a larger number
of pectoral rays. The correlations seem very apparent if
we suppose the inherited balance and hence the movements
-
of the:young to have a determining inuence on the number
of vertebræ and other characters.
Is it not conceivable,
that‘theshape and movements of the mother—sh inuence
the activity of the Offspring. within—in fact, take the place
of the genotypes ?
.
—
,
In his painstaking- -endeavours to distinguish between
the inherited and the acquired characters ]ohs. Schmidt has
.
also,made : extensive experiments on Zoarces.
Thus, two
differentÎ-sets of parents from different regions were
_
.
transferred tothe Same external conditions (1920) and the
‘
number
of vertebræ in the ospring compared. The latter
retained the character of their parents, and
has taken this result as evidence of the dominatinginuenc<ê
'
_
Of; , the genotypical inheritance; But, for the reasons
'
mentioned above, we may question whether the external
Ï
-
,
conditions areïeliminated in this
,
surely the body
cavity of the mother—sh fmaybe regarded as an external
‘
inuence on the movements0f the young »? =
…
.
;
'
More convincing :is,t_he- denite__ evidence he= brings
'
forward
has
: marked eéçfonthenuœbaof
fIg=theacase
foundÏj’that;
'
of Ï=fh*éfèsame
'
*
.parents—g—hÏgher
an'increase_"inÏthe number
,
he obtained a similar
.
_
result,
interesting: experiment=was that in which
.
fhe
eggs from the
.
différent temperatures ..
,
,
_
number of vertebræ Camelfrom-the intermedi'atef‘tempetaturC
_
_
__
and
at
and still mor-eat
—_
;;
;
._
:,
5
_
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