'
64
-
THE SEAS
-
.
'
ing small bivalve5.
Several kinds of worms habitually live
,
,
in sand, while of crustaceans the commonest are the
swimming crabs, which have the terminal joint of the £th
pair of legs atten'ed and paddle—shaped, enabling them-to
,
swim upwards.
Especiay adaptedfora buried existence
_
is the masked crab, Corystes (Fig. 10), which lives with
—
only the extreme tip of its long, upward1y directed feelers
exposed.
Each of these has two rows of sti hairs which,
_
'
_
_
\
when the feelers are placed
,
——_'
together, interlock so that
'.
_'
'
\
‘
a
channel is formed down
.'
.
-
'
which water can be drawn.
'
Other devices for obtaining
.
‘
-
‘
' water for respiration while
.’ î'
“'
burrowing are the long
s
_
siphons of_ the bivalves,
\
and the rows of vibrating
,
_/' 3 l:{ \
spines Which keep up a cir—
\;
/‘%
culation of water through
,
.—
\'Ç'
7__
the burrows of Astropecteri
_
an%
the burrowmg urchulis.
,
,
-
__
u:
\
urrowers
are
a so
'(
typical ofamuddy bottom.
‘
_
'\
.?‘,
There are
anemones
of
__
,
,
'
\=
_/
Which only the mouth and=
_
Fm_. Io._——The Masked Grab, Corystcs,
tentades appear above the
1
which
lives in sand (slightly reduced).
mud, & VELI΀tV of WOIH1S
'
which burrow- or live in parchment—‘like tubes and also
scavengers like the interesting
mouse, Aphrodite,- which
attains ‘a lengthof six or seven inches and has a broad back
'
covered with mouse—coloured felting beneath which are scales,
,
'
while from the sides of the body Spring clusters of spines
…
and beautiful iridescent hairs-. _"IÏhe» big sea cucumber or.
trepang (H0l0thuria): {Pla-te 23), lives chiey- in mudä