ON POLYZOA AND SHELL—FISÈES.
17
"
brief, its circumstances are different from those, for instance,
of a sh with pelagic eggs.
_
-
In this group, therefore, we see that, while the more minute
and lower forms are beyond the interference of man, certain of
the larger and higher species can be notably diminished.
So
“
far as can be ascertained, however, the species found on the
bottom of the open sea
are as abundant as in former ages, and
_
constitute an important element in the nourishment of the
_
ground—feeding shes, such as the cod.
'
Ÿ
T_he wealth of oceanic life receives a considerable increment
;
from the Polyzoa, which are either tufted plant—like forms or
…
calcareous crusts on stones and sea—weeds.
The group, how—
ever, is not a conspicuous one in the pelagic fauna, though the
,
larvæ certainly occur in abundance, and for many months of
the year. The sea—mats (Flustræ) are especially plentiful on
some shing—grounds, and, besides the larvæ which increase the
'
:
pelagic life, the arboreScent tufts give shelter to other forms on
which shes feed.
,
'
In the offshore as well as the inshore areas, in shallows and
Î_
__
in very great depths, at the surface, in mid—water and on the
î
_
bottom, the group
of the shell-shes is everywhere disseminated.
The vast resources of the sea in this respect cannot be over—
estimated.
For the present purpose the class maybe dividcd
ïf
into two groups, viz., (1) the pelagic, and (2) those frequenting
=Î_Â-Î
the bottom.
-
_
î;
The
pteropods, heteropods, and the pelagic stages of
demerSal forms—both univalve and bivalve—are universally
g
distributed from the Arctic to the Antarctic seas.
Thus Ghana
Lihzacina form conspicuous elements of the pelagic food of
;
the right whale in the Arctic seas, while the tropical and
;?
sub—tr0pical pteropods are even.more numerous.
That these
and their allies are a favourite food of shes is well known,
:_
though it is less generally understood that even ducks feed on
:_.
them in the
Mixed with the purely pelagic
;
mollusks are immense numbers of the larval stages (veligers)
:_'
of bivalves and univalves, besides sea—slugs and their allies,
and they are found during every month of the year, most
.
î
numerously in spring and summer. The neighbourhood of a
% > ‘
M. B.
-
2
_
17
"
brief, its circumstances are different from those, for instance,
of a sh with pelagic eggs.
_
-
In this group, therefore, we see that, while the more minute
and lower forms are beyond the interference of man, certain of
the larger and higher species can be notably diminished.
So
“
far as can be ascertained, however, the species found on the
bottom of the open sea
are as abundant as in former ages, and
_
constitute an important element in the nourishment of the
_
ground—feeding shes, such as the cod.
'
Ÿ
T_he wealth of oceanic life receives a considerable increment
;
from the Polyzoa, which are either tufted plant—like forms or
…
calcareous crusts on stones and sea—weeds.
The group, how—
ever, is not a conspicuous one in the pelagic fauna, though the
,
larvæ certainly occur in abundance, and for many months of
the year. The sea—mats (Flustræ) are especially plentiful on
some shing—grounds, and, besides the larvæ which increase the
'
:
pelagic life, the arboreScent tufts give shelter to other forms on
which shes feed.
,
'
In the offshore as well as the inshore areas, in shallows and
Î_
__
in very great depths, at the surface, in mid—water and on the
î
_
bottom, the group
of the shell-shes is everywhere disseminated.
The vast resources of the sea in this respect cannot be over—
estimated.
For the present purpose the class maybe dividcd
ïf
into two groups, viz., (1) the pelagic, and (2) those frequenting
=Î_Â-Î
the bottom.
-
_
î;
The
pteropods, heteropods, and the pelagic stages of
demerSal forms—both univalve and bivalve—are universally
g
distributed from the Arctic to the Antarctic seas.
Thus Ghana
Lihzacina form conspicuous elements of the pelagic food of
;
the right whale in the Arctic seas, while the tropical and
;?
sub—tr0pical pteropods are even.more numerous.
That these
and their allies are a favourite food of shes is well known,
:_
though it is less generally understood that even ducks feed on
:_.
them in the
Mixed with the purely pelagic
;
mollusks are immense numbers of the larval stages (veligers)
:_'
of bivalves and univalves, besides sea—slugs and their allies,
and they are found during every month of the year, most
.
î
numerously in spring and summer. The neighbourhood of a
% > ‘
M. B.
-
2
_