'25o
-.
THE SEAS
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*
_
rotation oflife as are exhibited in our waters are absent.
_
'
In many parts of the world, Ïhowever, there
dry and
rainy periods, monsoons, and other weather conditions
»
that alternate with unfailing regularity during the year
and it. is morethan probable that these secular changes
may have their eñect upon the life in the sea.
.
There are at any rate in tropical, as well as temperate,
waters animals which, if not giving an index of the season
of the year, show without fail,, by their spawning habits,
the times of the lunar. months.
It is quite a common
occurrence to nd that marine animals“ will breed at certain
the moon…
It,has been shown that” our
common oyster has atendency to “
spat
”
in much greater
.
‘
numbers during the week following the full and new moon '
than- at-any… other time.
In Egyptian Waters also there
is a sea urchin that breeds-during the nightswhen the moon
-
‘
is”qu. But
cases of
this kind is supplied by a small marine worm from the
tropical-seas.nearrSamoa-inthe Pacic Ocean—, the “ Palolo
»
.
Worm ” (Eunice viridis). .This worm can be regarded as a
,
veritable sea calendar.
All the year round it liVes in holes
andcrevices among rocks andcoral'grow—th on the sea
bottom (Plate 89). 'Buttrue to the Very day, each year
the worms come to the surface of the sea in Vast
.
for their wedding dance.
This occurs at dawn just for two
days in each of the months, October and November, the
day before, and the day on which, the moon is in its last
quarter; the worms are most numerous— on the second
day,
when the surface
of theocean appears covered with
them.
it is not
Whole Worm_
joins_in
‘
the spawning swarm.
The hinder portion of the Worth
becomes specially modied to carry the 'sexuà.l”products.
On the morning of the , great…dayeach
créeps back—
wards out of its burrow,‘and when. the modied
is