Dismissing  as  entirely  unnecessary  and  untenable,  the  proposed  sub-
stitution by  Professor  Haeckel  of  an  intervening  kingdom  of  the  Protista,
it  has  been  elected  here  to  fall  back  upon  the  old  lines,  and  to  indicate  as
nearly  as  may  be,  the  most  salient  features  of  distinction  adopted,  though
perhaps  somewhat  arbitrarily,  in  this  volume  for  the  separation  of  the
animal  and  vegetable  series.  The  purpose  of  this  treatise  being  the
description   and   exposition  of  the    structure  and  life-history  of   those

*  The  presence  of  nucleus-like  bodies  in  the  Foraminiferal  type  Hafyphysema  Tumancvnczii,
Bwbk.  {Squamulina  scapula^  Carter)  has  likewise  been  noted  and  figured  by  the  present  author  in  an
article  on  the  nature  and  affinities  of  this  species,  published  in  the  '  Annals  and  Magazine  of  Natural
History '  for  July  1878  ;  such  discovery  being  confirmed  by  Professor  £.  Ray  Lankester's  subsequent
investigation  of  this  form  reported  in  the  '  Quarterly  Journal  of  Microscopical  Science '  for  October
1879.
46  THE  SUB-KINGDOM  PROTOZOA.
