134
THE momev OF FISHES
theSemasseshave any special Signica—nce, but they indicate
:
the activity of the leucocytes in collecting waste or discarded
,
materials and storing them in safe places, where they might
;
—
be turned to some other account.
The special glandular :l'“x =
organs, thyroid, etc., have arisen in this way.
*
The lymph shows its activity in- another imp0rtan‘t
,
direction, in the formation and conveyance of the black j
pigment, apparently as a waste product. For example, the ‘
divisions between the centra, when the vertebral column is’
ff
being segmented, are frequently indicated by pigment spots ;
,
similarly, thelOose air—bladder assembles a mass of pigment
on its surface, also the gut, the top of the head, the base of
_
the“ tail when the hypurals are forming and so on. This
'
:
:blàÇk pigmentseems everywhere a sign of the leucocytcs at *
disturbed tissues. A striking example '_
ât—gsh7
As metamor-'
'
phésiâ apprdachesïànd a vielent transformation of the "organ”s‘ 1;
tissuesis in
in masses
.
alongthe Spirial column and under the skin about the middle
,
On}the
30”); “*“It is a sudde and _Ï
,evanescent'phenomenon; the
’
through thé body
…
"
3 EXCRETORYSYSTEM
£ '-zE—1‘f%In _the excfetoryrsystemorsystemsofshestheeme
are quite
'
clear Thesohdre81dueof the food, which cannot be
ejected from the open, ,
£
waybf the reçtùm.carbohydrateS . '
,
_
ofa the food are used up in Supplying heat—
energy tothe
tissues and organs, and the carbon dioXi’de- isconveyed by
,
—_f . the blood serum to the gills, where itli—s excreted
gas.—
ïÎ;
:Butthe
waste products,-formed "from
'
g proteins or : nitrogenous compounds, must ‘aISo be get
,
=
L
'
'
"
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