﻿TUB 
  MAIOT[C 
  PHA.se 
  IN 
  ANIMALS 
  AND 
  PLANTS. 
  489 
  

  

  On 
  the 
  Maiotic 
  Phase 
  (Reduction 
  Divisions) 
  in 
  

   Animals 
  and 
  Plants.^ 
  

  

  By 
  

   J. 
  Bretlaiul 
  Farmer, 
  D.Sc, 
  F.R.S., 
  

  

  AND 
  

  

  J. 
  E. 
  S. 
  Moore, 
  A.R.C.S., 
  F.L.S. 
  

  

  With 
  riales 
  34-41. 
  

  

  Introduction. 
  

  

  i+WE 
  think 
  it 
  desirable, 
  in 
  the 
  interests 
  of 
  clearness, 
  to 
  explain 
  

   the 
  meaning 
  of 
  the 
  nomenclature 
  that 
  is 
  employed 
  in 
  this 
  

   memoir 
  in 
  connection 
  Avith 
  the 
  " 
  reduction 
  " 
  divisions. 
  

  

  We 
  propose 
  to 
  apply 
  the 
  terms 
  Maiosis 
  or 
  Maiotic 
  

   phase" 
  to 
  cover 
  the 
  whole 
  series 
  of 
  nuclear 
  changes 
  included 
  

   in 
  the 
  two 
  divisions 
  that 
  were 
  designated 
  as 
  Heterotype 
  and 
  

   Homotype 
  by 
  Flemmiug. 
  

  

  Our 
  reason 
  for 
  introducing 
  this 
  terminology 
  is 
  in 
  order 
  to 
  

   emphasise 
  the 
  fact 
  that 
  these 
  two 
  mitoses 
  invariably 
  con- 
  

   stitute 
  a 
  perfectly 
  definite 
  and 
  recognisable 
  phase, 
  and 
  one 
  

   which 
  is 
  normally 
  intercalated 
  in 
  the 
  cellular 
  life-cycle 
  of 
  ail 
  

   metazoa 
  and 
  metaphyta 
  in 
  which 
  the 
  sexual 
  union 
  of 
  gametes 
  

   takes 
  place. 
  

  

  The 
  actual 
  point 
  in 
  the 
  life-history 
  at 
  which 
  the 
  maiotic 
  

   phase 
  may 
  occur 
  is 
  not 
  identical 
  in 
  every 
  organism, 
  and 
  it 
  is 
  

  

  ' 
  This 
  paper 
  contains 
  the 
  evidence 
  on 
  wliich 
  our 
  preliminary 
  communication 
  

   to 
  the 
  lloyal 
  Society 
  in 
  May, 
  1903, 
  was 
  based. 
  Its 
  earlier 
  publication 
  has 
  

   been 
  delayed 
  by 
  the 
  pressure 
  of 
  other 
  work. 
  

  

  * 
  fiiiuaiQ, 
  reduction 
  ; 
  fitiuTiKog, 
  that 
  which 
  is 
  reduced. 
  

   VOL. 
  48, 
  PART 
  4. 
  — 
  NEW 
  SERIES. 
  36 
  

  

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