88
_
THE—' BIOLOGY OF FISHES
The, n—rays are also affected ; they do not get a chance to
develop, one may say, in the" Sharks. In the Eels and Eel—
like shes they are very short, or also absent. Whilst in the
_
Salmon and Herring tribes they are only of moderâæ_lèngÈh
as a mle, and the radials are formed well outin the embryonic
__
,
'
_
(Fig. 19, 3). Broàder ns are met With in the more“
‘
slowly moving larvæ, Carangoids, ScombroidS-; and Perches,
D
,
,
LL
V
'
_
'
Flc
I.
Herring _from
Ehrenbaum);
(from Ehrenbaûm) ;
3. Harriotta, a deep-sea C11imær'id
(from Goode and Bean); D, dorsal n _; LL, lateral'line , V, ventral n(
'
and the —rays become strongef and ossied as spines, in
,
-"
the rst dorsal*n'above
Ï
._
'
-‘_j
-
_' .The movements of thebody thus detbrnne‘ thestruëture
and position of the ns, and as the
.;
growth, the ns may alter position
character} As
'
Goodrichhas shown in the case of
the-posterior
,
part_of a n :may ceàse to :grow Whilst new—radials may
r
develop" in:—front; The…_-young Mackerels have-: uniform;
_
,
‘
continuous second dorSal and anal ns, but as the tail