'
136
THE BIOLOGY OF FISHES
_
‘
mes0nephros is formed in other shes (Kishinouye, 1923).
In these as in the other Scombroids the scales are very small,
and the same is the case when large quantities of lymph are
°
present under the skin, as in the Eels, Angler, etc.
As mentioned above, the wandering cells may convey
their bur'dens into the abdominal cavity or ventral cœlom,
and this has apparently led to a second kind of excretory
"organ peculiar to shes.
In many forms (namely,
branchs with a few exceptions, Sturgeon, Protopterus, the
Teleost Mormyriclæ and Salmonidæ) abdominal pores are
present opening to the exterior near the anal aperture, and
these may also serve for the extrusion of the eggs;
-
We come now to the true kidneys which stand
in-close
cannection with the blood circulation. The rst portion to
,
-
.
lies},_under the anterior vertebræ near the Skull
î
of
a long…duct leading
Ï
’backwardsïon each:Side
end
the Cydostonies and,_îTunñies,=
'
above,_this
“
pronephros
”
persists
gin
_
many shes its character Changes at an early period—and there
is'still some obscurity with regard to its mode of origin'an‘d'
how far it serves as a functional kidney. In some forms at
'
'
any rate the duct does not appear till late in the larval
'
development. In the at-sh Symphurus, and in the Pipe—
shes (Huot, 1902) the kidneys and duct are only developed
:
on the right side, and this seems to indicate that they have
been formed later than the air—bladder, which has been
'
able_to displace them to the one side (Fig. 30).
'
'
'
.
kidney '(mesonephros) of other shes
"
,
’
andlies_posteriorly in the
,
î'
,îbddy,
of; the original ductS coming from the
,
,
head kidney:
capillaries which go to its forma'-'
'
tion
dorsal_aorta ;' that is to say, the blood
'
has topàss through the gills before it realches
As“ already mentioned, the _venousblœd c0ming ,from‘ the
'
_
caudal region passes through
kidneys in 'the'.Elasmoè
_
_
branchS, Dipnoi, and a few Tele0sts, butin other- Tele0$ts
' :
,
the “verrous system, has little, if anything, todo With the
136
THE BIOLOGY OF FISHES
_
‘
mes0nephros is formed in other shes (Kishinouye, 1923).
In these as in the other Scombroids the scales are very small,
and the same is the case when large quantities of lymph are
°
present under the skin, as in the Eels, Angler, etc.
As mentioned above, the wandering cells may convey
their bur'dens into the abdominal cavity or ventral cœlom,
and this has apparently led to a second kind of excretory
"organ peculiar to shes.
In many forms (namely,
branchs with a few exceptions, Sturgeon, Protopterus, the
Teleost Mormyriclæ and Salmonidæ) abdominal pores are
present opening to the exterior near the anal aperture, and
these may also serve for the extrusion of the eggs;
-
We come now to the true kidneys which stand
in-close
cannection with the blood circulation. The rst portion to
,
-
.
lies},_under the anterior vertebræ near the Skull
î
of
a long…duct leading
Ï
’backwardsïon each:Side
end
the Cydostonies and,_îTunñies,=
'
above,_this
“
pronephros
”
persists
gin
_
many shes its character Changes at an early period—and there
is'still some obscurity with regard to its mode of origin'an‘d'
how far it serves as a functional kidney. In some forms at
'
'
any rate the duct does not appear till late in the larval
'
development. In the at-sh Symphurus, and in the Pipe—
shes (Huot, 1902) the kidneys and duct are only developed
:
on the right side, and this seems to indicate that they have
been formed later than the air—bladder, which has been
'
able_to displace them to the one side (Fig. 30).
'
'
'
.
kidney '(mesonephros) of other shes
"
,
’
andlies_posteriorly in the
,
î'
,îbddy,
of; the original ductS coming from the
,
,
head kidney:
capillaries which go to its forma'-'
'
tion
dorsal_aorta ;' that is to say, the blood
'
has topàss through the gills before it realches
As“ already mentioned, the _venousblœd c0ming ,from‘ the
'
_
caudal region passes through
kidneys in 'the'.Elasmoè
_
_
branchS, Dipnoi, and a few Tele0sts, butin other- Tele0$ts
' :
,
the “verrous system, has little, if anything, todo With the