…1 1 1
…
_
-
'
85
MAN’S INFLUENCE ON.LOWER FORMS—SPONGES;
as in the modern._
In the warmer areas, again, the water
teems with the minute phosphorèscent
’
'
The Cilioagellates, such as Peridinium and C'eratium,
occur in great abundance throughout the year. In the warmer
—
months these and the pelagic Infusoria (ag. Tintiômus) are
especially conspicuous at the surface.
Their multiplication
__
and that of other free and parasitic Infusorians—upon Which
many simple forms and even
shes feed——is beyond the sphere
of human inuence.
_
_
_
Amongst the lower invertebrates we meet with a group
which in itself has been the source of a special shery, ViZ. the '
From time immemorial the Levant and for a less
__
period the Bahamas and Florida have furnished large supplies.
_
Moreover, comparatively little care has been taken to propagate
\—
them by articial means, and yet so nicely do all the ‘su1‘round—
Î
ingS t them to cOntinue the race that, after all these years,
110
sign of extinction is apparent. The fragments left
'
on
the
rocks or stones as well as the pelagic larvæ which represent __
them in the water around have sufced to ll up the .gaps
caused by the sponge—shérmen.
_
_
_
__
The non—commercial kinds of sponge,
on the other hand,
_
‘aréfree from special pursuit, being only captured by trawls
_
:
.
and
'
hooks to be again returned to the sea. The lacerated ;
.
fragments! or their contained eggs and larvæ enable each species ‘;
to keep up its numbers in all our seas. Storms, moreover,
“
on the beach, but neither the one loss nor the other
‘_
affects their'abundance;. Nature persistently carries- out
_
: measures
of economy
from age to age, and no more cOnspicuous
of this eXists than the wide-Spread disintegration‘ of
_
rocks
and the denSest
by the ceaseleSs borings
_
°“PŒaüonmrePmmm€nüy
than in- the“»hydroid »
dfthe
maJ°“‘W°“helæeThelmmensepmfuswof…sü:ch zoophÿtes ,