196
THE BIOLOGY OF FISHES
specimens »eXamined,*and we
can be sure that With a still
larger number of specimens the overlàpping would not
diminish but rather increase.
Other characters, number of
n—rays, shape and size of mouth and body, show the same
grading.
=—.
-
_
_
_
Such being the Character of shes, may we n0t say With
Darwin (“ Origin of Species,” ôth ed. p. 176), that
“
through
the nature of the organism and of surroundin‘gconditions,but
.
not through natural selection,” new groups have been formed
and perhaps are still being formed ? For example, underthe
species Arnoglossus latema, noted in the table above, three
separate forms can be distinguished which, some authors
might call species. And there are few groups, of Teleosts
Which
furnish similarexamples. .
_
.
'
natural selection has played any—
'
'
:dierehtia‘cionof.
difcult to decide
_
at
thati—t—
there is very
little“ denitè ,evidenCe. _In:
may ….regard. any
.
character. as*us‘èful; Why, then, should it vary
Or
ail—together
lost ?.
And in theory also, any character
'
Otharmful,like the spiral valve or the air-bladder ;
should it persist .? The truth seems to be, that the
must make the best of what is given them, whether useful
_
or
otherwise, and are able to overcome their diîculties. ’
_
The strange forms, frequently referred to in previous pages, ,
the Pipe—shes, Plectognaths,_ PediculateS, Flat—shes, and
indicate that there is a power in the living
organism beyond the reach of natural selection.
“cannot be certain either, that natural selection has
marked 01%” the species from one
until we know
-
.
something more about theelimination‘of.intermediate forms.
'
The fact that fossil
are not represented inthe present—
day fauna'is not evidence in this regard. Nor can we take
as evidence, that the Weaklings_may
,
Offspring-; the reversemay also be said. -
;
;
.
.
_
'
—
"_
‘
Though many
in natural selection as
:
one Way of
of life, very few have
tried to realise what it meansin
author