THE FOOD QUESTION
311
Pütter Comes to the conclusion, then, that by far the
greater quantity
the food of Copepods must come from
the dissolved organic substances in the water. This is
not taken into the digestive tract but penetrates through
the surface of the body, just as the oxygen does.
,
Since
Vitamines (A) have been found in these Crustacea, he
suggests that the Diatoms may be “useful in supplying these
accessory substances. As already remarked, these-views of
‘Pütter cannot be lightly rejected,but we must await further
investigation before giving up the old belief that the Diatoms
and other algæ form the “grass,” from which the esh Of
the Copepbds- and Other animals arises. _, -
*
to the food of very youngshes, the informa—
tion given by M. -Leboür (1921,1924) is veryinst’ructive.
Dealing mainly with the earliest stages of the Herring, this
author shows that the diet is varied.
Up to a —lengthof
,
-
12 mm. the larval Herring prefers the more satisfying
larval Molluscs, especially Gastropods, if it can get them,
but it certainly takes quantities of the unicellular organismS,
Diatoms_1and' InfùsOria. f—AS it
however,—»it'passes to
an} eXclusivdy "CoÂp‘6pod diet and
here: fairly catholic in
its tastes; ’ Thesi—z—eof- the mouthis probably the determining factor in its choice of food, and it is of interest to note
that as the young post—larval Herring sink down from the
surface they seem totake less food.
Thus -moref than'hàlf
'
those from near the” bottom and froni 'midwa‘rter were empty,
and only a little more thana third were empty from the
.
surface.”
This is just the stage when the jaws are ossifying
and “when the little sh has difculty in taking in food
;(s_eeâChap. V).
»
‘
7: 'The adult Herring is also not very particular ; it is not
form.
It is not above eating
young
Sand—”cds and other young sh, even its Own.fry,
but to satisfy its_Voracious appetite it nds the thick
“
soup
”
of Copepods more suitable. Herdman has found that the
_
Summer'Herring off the Isle of Manfeed mainly, if not
_
'Wholly, on Temora. ' This, Copepod 'may be So =abundant
'
as to cause large patches of a red colOur' on
surface
311
Pütter Comes to the conclusion, then, that by far the
greater quantity
the food of Copepods must come from
the dissolved organic substances in the water. This is
not taken into the digestive tract but penetrates through
the surface of the body, just as the oxygen does.
,
Since
Vitamines (A) have been found in these Crustacea, he
suggests that the Diatoms may be “useful in supplying these
accessory substances. As already remarked, these-views of
‘Pütter cannot be lightly rejected,but we must await further
investigation before giving up the old belief that the Diatoms
and other algæ form the “grass,” from which the esh Of
the Copepbds- and Other animals arises. _, -
*
to the food of very youngshes, the informa—
tion given by M. -Leboür (1921,1924) is veryinst’ructive.
Dealing mainly with the earliest stages of the Herring, this
author shows that the diet is varied.
Up to a —lengthof
,
-
12 mm. the larval Herring prefers the more satisfying
larval Molluscs, especially Gastropods, if it can get them,
but it certainly takes quantities of the unicellular organismS,
Diatoms_1and' InfùsOria. f—AS it
however,—»it'passes to
an} eXclusivdy "CoÂp‘6pod diet and
here: fairly catholic in
its tastes; ’ Thesi—z—eof- the mouthis probably the determining factor in its choice of food, and it is of interest to note
that as the young post—larval Herring sink down from the
surface they seem totake less food.
Thus -moref than'hàlf
'
those from near the” bottom and froni 'midwa‘rter were empty,
and only a little more thana third were empty from the
.
surface.”
This is just the stage when the jaws are ossifying
and “when the little sh has difculty in taking in food
;(s_eeâChap. V).
»
‘
7: 'The adult Herring is also not very particular ; it is not
form.
It is not above eating
young
Sand—”cds and other young sh, even its Own.fry,
but to satisfy its_Voracious appetite it nds the thick
“
soup
”
of Copepods more suitable. Herdman has found that the
_
Summer'Herring off the Isle of Manfeed mainly, if not
_
'Wholly, on Temora. ' This, Copepod 'may be So =abundant
'
as to cause large patches of a red colOur' on
surface