<s>
An	O
ocelloid	B-Algorithm
is	O
a	O
subcellular	O
structure	O
found	O
in	O
the	O
family	O
Warnowiaceae	O
(	O
warnowiids	O
)	O
,	O
which	O
are	O
members	O
of	O
a	O
group	O
of	O
unicellular	O
organisms	O
known	O
as	O
dinoflagellates	O
.	O
</s>
<s>
The	O
ocelloid	B-Algorithm
is	O
analogous	O
in	O
structure	O
and	O
function	O
to	O
the	O
eyes	O
of	O
multicellular	O
organisms	O
,	O
which	O
focus	O
,	O
process	O
and	O
detect	O
light	O
.	O
</s>
<s>
The	O
ocelloid	B-Algorithm
is	O
much	O
more	O
complex	O
than	O
the	O
eyespot	O
,	O
a	O
light-sensitive	O
structure	O
also	O
found	O
in	O
unicellular	O
organisms	O
,	O
and	O
is	O
in	O
fact	O
one	O
of	O
the	O
most	O
complex	O
known	O
subcellular	O
structures	O
.	O
</s>
<s>
The	O
ocelloid	B-Algorithm
was	O
originally	O
described	O
in	O
1884	O
.	O
</s>
<s>
Ocelloids	B-Algorithm
contain	O
subcomponents	O
analogous	O
to	O
eye	O
structures	O
including	O
the	O
lens	O
,	O
cornea	O
,	O
iris	O
,	O
and	O
retina	O
.	O
</s>
<s>
The	O
hyalosome	O
serves	O
as	O
the	O
refractive	O
lens	O
of	O
the	O
ocelloid	B-Algorithm
;	O
it	O
is	O
surrounded	O
by	O
a	O
layer	O
of	O
mitochondria	O
serving	O
as	O
the	O
cornea	O
and	O
has	O
constrictive	O
rings	O
analogous	O
to	O
the	O
iris	O
.	O
</s>
<s>
Using	O
single-cell	O
genomics	O
and	O
electron	O
microscopy	O
techniques	O
,	O
the	O
ocelloid	B-Algorithm
has	O
been	O
shown	O
to	O
consist	O
of	O
multiple	O
membrane-bound	O
organelles	O
with	O
distinct	O
endosymbiotic	O
origins	O
deriving	O
from	O
multiple	O
lineages	O
of	O
peridinin-containing	O
plastids	O
.	O
</s>
<s>
Due	O
to	O
the	O
strong	O
structural	O
resemblance	O
between	O
the	O
ocelloid	B-Algorithm
and	O
metazoan	O
eyes	O
,	O
it	O
has	O
long	O
been	O
speculated	O
that	O
the	O
ocelloid	B-Algorithm
functions	O
as	O
a	O
photoreceptor	O
;	O
however	O
,	O
this	O
is	O
difficult	O
to	O
determine	O
experimentally	O
because	O
warnowiids	O
cannot	O
be	O
cultured	O
in	O
the	O
laboratory	O
,	O
and	O
isolates	O
from	O
natural	O
habitats	O
degrade	O
quickly	O
.	O
</s>
<s>
It	O
has	O
been	O
shown	O
that	O
the	O
morphology	O
of	O
the	O
ocelloid	B-Algorithm
changes	O
in	O
response	O
to	O
environmental	O
illumination	O
,	O
that	O
the	O
ocelloid	B-Algorithm
structure	O
can	O
be	O
disrupted	O
by	O
exposure	O
to	O
extremely	O
bright	O
light	O
,	O
and	O
that	O
it	O
contains	O
proteins	O
with	O
sequence	O
similarity	O
to	O
known	O
light-sensitive	O
proteins	O
.	O
</s>
<s>
It	O
has	O
been	O
speculated	O
that	O
the	O
ocelloid	B-Algorithm
aids	O
in	O
detecting	O
prey	B-Application
,	O
possibly	O
other	O
dinoflagellates	O
.	O
</s>
<s>
Ocelloids	B-Algorithm
are	O
considered	O
a	O
synapomorphic	O
character	O
for	O
the	O
warnowiids	O
-	O
that	O
is	O
,	O
they	O
are	O
present	O
in	O
all	O
warnowiids	O
and	O
presumed	O
present	O
in	O
the	O
common	O
ancestor	O
,	O
but	O
are	O
not	O
present	O
in	O
the	O
closest	O
extant	O
relatives	O
,	O
the	O
polykrikoid	O
dinoflagellates	O
.	O
</s>
<s>
The	O
molecular	O
evidence	O
is	O
compelling	O
that	O
ocelloids	B-Algorithm
are	O
composed	O
of	O
multiple	O
endosymbionts	O
:	O
mitochondria	O
and	O
at	O
least	O
one	O
type	O
of	O
plastid	O
.	O
</s>
<s>
Ocelloids	B-Algorithm
are	O
likely	O
to	O
be	O
homologous	O
to	O
much	O
less	O
complex	O
plastid-containing	O
eyespots	O
found	O
in	O
other	O
,	O
distantly	O
related	O
dinoflagellates	O
.	O
</s>
