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CHAPTER IX
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Feeding of Marine Animals
FOOD is the rst necessity of life, and nowhere is the struggle
to obtain it keenerthan in the'sea ; every pOssible source
Of food has been exploited byone type of animal or another,
so that the study of the multitudinous devices for obtaining
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food of one sort or another which have been evolVed as a
result of the keen struggle for existence forms one of the
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most fascinating branches of marine biology.
The food in the sea may be divided into two groups;
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there are the dissolved salts and gases in sea water, such as
the manurial nitrates _and phosphates, carbonic acid gas,
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etc., whichiorm the‘food of plant life, both large‘ seaweeds
and microscopical diatonis ; and there are the actual plants
and animals
bOth living and dead, and also
while in the prOcess of disin‘tegration by bactéria._ It is the '
organic substances-orc which these are made up—as opposed
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to the inorganic salts in the sea Water—”which form the food
of the animals.
divided into three groups of
substances, fats, proteins and carbohydrates, all three of
which—together with minute traces of those little known,
but all-important, substances known as Vitamins—are
essential to the life Of the animal, though the
proportions vary for different kinds of
Aeoording
to a German scientist named Pütter, theanimals also obtain
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nou-rishment from dissolved organic substances in the water,
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but this so”mewhat fascinating theory has never been— fully
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proved.
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One may roughly divide animals into herbivores, carni—
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