'
SWIMMING “ANIMALS
î05
Seal
—
vitulz‘na) ;and the Grey Seal (Halicizærus .
grypu3).
Neither of these furnish the beautiful sealskin
of
commerce,
this
product only being-obtained fr0m
,
certain distinct speciesknCwn as“… fur »Seals ”
-oi°- “
sea
'
beatrs.”
-
-
,
,
_
.
,
.
»
"
:
Seals feed mostly on sh, .and are commonly a nuisance
in the estuaries Of someof the Scottish salmonrivers, where
they do
damage
the net shees for'the‘5salmon;
Some species feed on -shellsh -:and êother’ small '
marine
_
animals.
The
walrus uses
its— longf ivory tu‘sks fordigging in the sand-andgravel to turn up the- shellsh
on which it feeds.
_
.
r
:
'
-
'
'
'
_' CUTTLEFISHES AND SQUIDS
Amongst invertebrate animals there is only one group
which can be .clas5ed as true swimming
These are
the. cuttleshes and squids, which belong to the family
known as Cephalopods.
This name_is derived from tw0
Greek words meaning
“
head ” and “
foot,” and originates
from the fact that actually the feet or
surround
the head.
_
j
'
backbone-less animals known as Molluscs, and are closely
allied therefore to
though
admittedly the externaL--res‘<äfhblance is not obvio_us-.
In
many ways—they are the most highly evolved of the back—,
and are remarkable for possessing eyes
similar in almost all respects to thOSe of the higher animals
.
.
such as sh and mammals.
Both the cuttlesh and the squid possess ten tentacleS
armed With suckers. Two of these teŒacles are very much
'
longer.than theothers
bewit‘hdrawn into a cavity -
near the head. -_ In this respect they di‘er from theirfnear —