GENERAL CHARACTERISTICS
5
slenderness of the body at the
the tail is a sure sign
of a good swimmer. Then follows the broad, and long
caudal n, as it is called.
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Even this torpedo form, however, sh0wS many variations,
,
as we can see at once from the shape of the tail. In the Cod
(Fig. 2) the tail is abby and square-cut at the end. In
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moving, this kind of tail beats from side to side and the Whole
body undulates,- even the head. The resistance the Cod
presents to the Water mustbe considerable, and. it isot to
be classed among the most rapid swimmers. '
In the Herring
(Fig. 1) the tail is forked. and from this as well as the
position of the ns we may conclude that the sh swings
«or twists its body in moving. In the Mackerel family (Fig.
62) the tail n is more deeply forked and looks for all the
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ll.,1àteralline; b., barbel,
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;
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,
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(Fronf—Ehfenbaumû '
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world just like
that the dierent
are 'sdæ_11n1;ed
that the
whole apparatus forms a shaft
directly
on the Skull and driving the sh forward with great velocity.
]udging from the ease with which the Bonito keeps up with
Ships, its'speed has been estimated at 16 to 20 knots
hour.
In the Sharks and ‘Dog—shes we nd another sort
of tail.
Thé upper lobe of the fork is very much. larger than ,
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lower arid moves like a seùll from the”,
Of a boat.
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Herie”also the body‘and head muSt*fock'and"sWingfr01n”side .
’
to:Side;—3nd the speed ofm‘0St Sharks is probably
ably= less than that of a Bonito; As will be mentioned
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,
evensmallershès‘than theBonitdàré
»
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and ütàèhth‘emselVŒ-to
.
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