﻿24 
  G. 
  HlilllEERT 
  FOWLEE. 
  

  

  whereas 
  the 
  original 
  ruus 
  that 
  '' 
  I 
  have 
  been 
  unable 
  to 
  meet 
  

   with 
  auy 
  generative 
  organs," 
  my 
  specimens 
  not 
  being 
  sexu- 
  

   ally 
  ripe. 
  The 
  account 
  which 
  the 
  French 
  authors 
  have 
  

   furnished 
  leads 
  one 
  to 
  await 
  their 
  figures 
  of 
  the 
  generative 
  

   organs 
  Avith 
  interest. 
  

  

  To 
  say 
  of 
  the 
  ccelom 
  that 
  "les 
  sub-divisions 
  indiquees 
  par 
  

   Fowler 
  n'existent 
  pas 
  " 
  is 
  rather 
  sweeping*, 
  in 
  the 
  face 
  of 
  the 
  

   camera 
  drawings 
  which 
  I 
  furnished 
  in 
  my 
  last 
  paper 
  on 
  the 
  

   subject; 
  but 
  as 
  our 
  authors 
  go 
  on 
  to 
  say 
  that 
  they 
  have 
  

   vainly 
  sought 
  the 
  excretory 
  canals 
  and 
  collar-pores, 
  one 
  

   begins 
  to 
  suspect 
  that 
  either 
  the 
  preservation 
  of 
  the 
  material 
  

   or 
  the 
  technique 
  of 
  the 
  microtomist 
  was 
  imperfect. 
  When 
  

   we 
  further 
  learn, 
  of 
  the 
  structure 
  which 
  I 
  regarded 
  as 
  a 
  

   probable 
  homologue 
  of 
  the 
  " 
  notochord 
  " 
  of 
  Balanoglossus 
  

   and 
  Cephalodiscus, 
  that 
  "cette 
  pretendue 
  cliorde 
  n'etait 
  

   autre 
  chose 
  que 
  I'extremite 
  anterieure 
  du 
  pedoncle," 
  one 
  can 
  

   only 
  regret 
  that 
  these 
  gentlemen 
  have 
  not 
  already 
  figured 
  

   the 
  way 
  in 
  which 
  the 
  latter 
  post-oral 
  and 
  ventral 
  structure 
  

   gets 
  across, 
  or 
  behind, 
  or 
  beside 
  the 
  mouth, 
  so 
  as 
  to 
  become 
  

   continuous 
  with 
  the 
  pre-oral 
  " 
  notochord." 
  

  

  I 
  regret 
  that 
  I 
  cannot 
  draw 
  the 
  septa 
  between 
  the 
  body- 
  

   cavities 
  more 
  clearly 
  than 
  I 
  have 
  already 
  clone, 
  but 
  at 
  least 
  

   I 
  hope 
  that 
  fig. 
  19 
  may 
  convince 
  Messrs. 
  Conte 
  and 
  Vaney 
  

   of 
  the 
  existence 
  of 
  the 
  collar-canals 
  and 
  pores. 
  This 
  figure 
  

   has 
  been 
  drawn 
  with 
  a 
  camera 
  lucida 
  from 
  five 
  successive 
  

   sections; 
  the 
  uppermost 
  exhibiting 
  the 
  external 
  opening, 
  

   the 
  next 
  two 
  the 
  collar-canal, 
  the 
  last 
  two 
  the 
  internal 
  open- 
  

   ing; 
  the 
  cell-structure 
  is 
  sufficiently 
  well 
  preserved 
  to 
  allow 
  

   one 
  to 
  see 
  that 
  the 
  cells 
  are 
  long 
  and 
  columnar 
  in 
  the 
  canal, 
  

   with 
  the 
  nuclei 
  near 
  the 
  base 
  of 
  the 
  cell 
  ; 
  but, 
  as 
  the 
  histology 
  

   as 
  a 
  whole 
  is 
  not 
  good, 
  I 
  prefer 
  to 
  represent 
  the 
  sections 
  as 
  

   "coupes 
  histologiques 
  schematiques" 
  rather 
  than 
  to 
  draw 
  

   guesses 
  at 
  cell 
  outlines, 
  which 
  are 
  moreover 
  wholly 
  unim- 
  

   portant 
  in 
  this 
  connection. 
  

  

  I. 
  The 
  Stalk 
  op 
  the 
  Adult. 
  

   In 
  a 
  series 
  of 
  transverse 
  sections 
  the 
  first 
  appearance 
  of 
  

  

  