OF THE - BODY—H
153 .
.“ photogens,” which, by
'
the
way,— have
no
necesëary
connection with phœphorus. The presence of halOgensor
even of ammonia in the water may have the effect—of stimu—
lating these substances to radiant activity, but they are more
active under certain “conditions of temperature and s‘urroundings than under
The larvæ of shes, though
without any denite mucus organs, mày…becomelunnoius
simply from sudden impulses given to the water : (Ryder,i880)..
.
_
_
J
…
g
,
,
î
The production of these substances is_well—known among
the lower forms of life,,Bacteria,
insecte,
etc., whether they live in air, water, or other media… Among
shes it was formerly believed to occur only«among those
living in the ab‘ysses of , the oceans and the luminosity was-=
-
.suPposed to be useful, in place of the light rays, in attracting
mates and repelling enemies, etc., but this view. has proved
crroneous, On”the Valdivia expedition, Chun
.d6ep=seash as soon as it was caught into the photographie
dark room, and,-Wasin most cases unable “to detect any
light entt_èd from—.;them—
.
:
’
be Commonest
:inÎg'shes which live
,;_no great depths.—_
:_to
*
Burekhardt(rgoo)
of Sharks, including
which,ate =th
the
_—
:Thèfren'iar‘lç . ,
able Harpodon, which when caught beœm6s’brilliahtlÿ
"
luminescent all over the body, lives in the riVers and
estuaries of India.
Photoblepharon, a still moreremarkàble
form, lives in freshwater quarries and ancient crat€rs of the
Malay Archipelago. In his work
_
on
the Valdivia shes
__,
Brauer found that the luminous organs were not
tothecepest and
‘
,
.
'
conclusions_havebee conrmed andextended
,
by Hjort_,froni
of his: expedition “across the
Atlantic in: He states that.mahy
ï
,
'
brought up from the abyssal region in_;a,
,
dition—without :.any special ; luminouS
_lumi—3
nosity being connected Simply__with the
,