﻿292 
  Retrograde 
  Varieties 
  

  

  in 
  each 
  instance 
  reverted 
  to 
  the 
  varietal 
  mark 
  

   of 
  the 
  white 
  cross, 
  and 
  three-fourths 
  (77.5$) 
  

   retained 
  the 
  dark 
  heart. 
  Once 
  more 
  the 
  flowers 
  

   were 
  self-pollinated 
  and 
  the 
  visits 
  of 
  insects 
  ex- 
  

   cluded. 
  The 
  recessives 
  now 
  gave 
  only 
  reces- 
  

   sives, 
  and 
  hence 
  we 
  may 
  conclude 
  that 
  the 
  varie- 
  

   tal 
  marks 
  had 
  returned 
  to 
  stability. 
  The 
  dark- 
  

   hearted 
  or 
  dominants 
  behaved 
  in 
  two 
  different 
  

   ways. 
  Some 
  of 
  them 
  remained 
  true 
  to 
  their 
  

   type, 
  all 
  their 
  offspring 
  being 
  dark-hearted. 
  

   Evidently 
  they 
  had 
  returned 
  to 
  the 
  parent 
  

   with 
  the 
  active 
  mark, 
  and 
  had 
  reassumed 
  this 
  

   type 
  as 
  purely 
  as 
  the 
  recessives 
  had 
  reached 
  

   theirs. 
  But 
  others 
  kept 
  true 
  to 
  the 
  hybrid 
  char- 
  

   acter 
  of 
  the 
  former 
  generation, 
  repeating 
  in 
  

   their 
  progeny 
  exactly 
  the 
  same 
  mixture 
  as 
  their 
  

   parents, 
  the 
  hybrids 
  of 
  the 
  first 
  generation, 
  had 
  

   given. 
  

  

  This 
  third 
  generation 
  therefore 
  gives 
  evi- 
  

   dence, 
  that 
  the 
  second 
  though 
  apparently 
  show- 
  

   ing 
  only 
  two 
  types, 
  really 
  consists 
  of 
  three 
  dif- 
  

   ferent 
  groups. 
  Two 
  of 
  them 
  have 
  reassumed 
  

   the 
  stability 
  of 
  their 
  original 
  grandparents, 
  and 
  

   the 
  third 
  has 
  retained 
  the 
  instability 
  of 
  the 
  hy- 
  

   brid 
  parents. 
  

  

  The 
  question 
  now 
  arises 
  as 
  to 
  the 
  numerical 
  

   relation 
  of 
  these 
  groups. 
  Our 
  experiments 
  

   gave 
  the 
  following 
  results 
  : 
  

  

  