-  115 
Explanation  of  Plate  76. 
All  the  figures  of  plate  76  were  drawn 
from  cover-glass  preparations, 
fixed  by  sublimate  -  alcohol 
(Schaudinn)  while  wet,  and 
stained  with  iron-hematoxylin 
(Heidenhain). 
Fig.  5  was  drawn  with  compensating 
eye-piece  6  and  immersion  lens 
1/12;  fig.  3  with  compensating 
eye-piece  4  and  immersion  lens 
1/12;  the  others  with  eye-piece 
2  and  lens  1/12.  Drawings  at 
the  level  of  the  table,  with  Zeiss 
microscope  and  Abbé  camera- 
lucida. 
Fig.  1  Resting  nucleus.  Chromatin  mas¬ 
ses  of  different  sizes  and  shapes 
at  the  edge  of  the  nuclear  mem¬ 
brane.  A  large  oval  chromatin 
granule  with  a  clear  halo  near 
the  center. 
Fig.  2  Elongated  nucleus;  beginning  of 
mitosis;  disappearance  of  nuclear 
membrane.  Rounded  and  elon¬ 
gated  chromatin  masses  at  the 
edge  of  the  membrane  and  in¬ 
side. 
Fig.  3.  Opalina  brasiliensis  showing  the 
spiral  lines  of  cilia;  they  are 
composed  of  very  small  and 
deeply  stained  granules.  The 
cilia  and  the  granulations  of  the 
endoplasm  are  not  drawn.  Lower 
nucleus  and  that  of  fig.  3  show 
the  formation  of  the  pseudo 
centrodesmosis  between  two 
granules;  fig.  3  is  more  enlar¬ 
ged. 
Fig.  4.  Later  stage  of  mitosis.  Pseudo- 
centrodesmosis  present,  going 
from  an  oval  mass  on  one  side, 
to  another  equal  one  on  the 
opposite  side. 
Fig.  5  Advanced  stage  of  division. 
Pseudo -centrodesmosis  going 
from  a  chromatin  granule  to  a 
chromatin  mass  on  the  opposite 
side.  Deeply  stained  (Iron-he¬ 
matoxylin)  and  irregularly  dis¬ 
posed  chromatin  masses.  : 
Fig.  6.  Involution  of  half  the  pséudo- 
centrodesmosis. 
Fig.  7.  Final  stage  of  mitosis.  Very 
marked  stricture.  Irregularily 
and  differently  shaped  chromatin 
masses. 
Fig.  8.  Daughter-nuclei,  still  attached  by 
slender  filament. 
Fig.  9  &  9a.  Free  daughter-nucfei  :  at 
rest.  Crescent-shaped  or  '  roun¬ 
ded  chromatin  masses  in  the 
vicinity  of  the  membrane. 
Fig.  10.  Opalina  brasiliensis  with  two 
dividing  nuclei. 
(The  details  are  not  drawn  as  the  spe¬ 
cimen  was  not  well  differentia¬ 
ted). 
Fig.  11.  Specimen  with  4  nuclei. 
