317.  Sexual  reprodnction.  Antheridia. — The  antheridia  are  short  cells
which  are  formed  by  one  of  the  ordinary  cells  dividing  into  a  number  of
disk-shaped  ones  as  shown  in  fig.  147.    The  protoplasm  in  each  antheridium


Fig.  146.
Zoogonidia  of  oedogonium  escaping.
At  the  right  one  is  germinating  and
forming  the  holdfasts,  by  means  of  which
these  algae  attach  themselves  to  objects
for  support.    (After  Pringsheim.)


ISO  MORPHOLOGY.
farm*  two  tpennatoioldt  (Mmettmes  only  one)  whtch  are  of  the  Mme  fonn  at
t)ie  zaogonidia  but  tmaller,  and  yellowish  instead  of  gnen.  In  some  species
a  motile  body  intermedi-
ate  in  size  and  color  be-
tween the  spermatoioids
and  zoogonidia  is  tint
fbnned,  which  after
swimming  around  comei
to  rest  on  the  oogonium,
or  near  it,  and  develops
what  is  called  a  "  dwarf
male  pl?nt  "  from  which
the  reai  spermatozoid  is
produced.
81S.  Oogonla.  —  The
oogonia  are  Ibnned  di.
