﻿NOTES 
  ON 
  RHABDOPLKURA 
  NORMANI, 
  ALLMAN. 
  29 
  

  

  Dr. 
  Masterman's 
  paper 
  ^ 
  on 
  the 
  budding 
  of 
  Cephalodiscus, 
  but 
  

   I 
  am 
  unable 
  to 
  bring 
  tlie 
  two 
  sets 
  of 
  observations 
  into 
  

   accord. 
  There 
  is 
  no 
  doubt 
  tliat 
  Masterman's 
  picture 
  of 
  the 
  

   stalk 
  in 
  Cephalodiscus 
  is 
  correct 
  in 
  exhibiting 
  two 
  cavities 
  

   bounded 
  by 
  a 
  thickish 
  membrane 
  (as 
  in 
  his 
  pi. 
  i, 
  fig. 
  18)^ 
  

   whatever 
  may 
  be 
  the 
  correct 
  interpretation 
  of 
  these 
  struc- 
  

   tures. 
  There 
  is 
  equally 
  no 
  doubt 
  that 
  my 
  fig. 
  2 
  is 
  also 
  

   correct 
  (interpretations 
  excepted) 
  in 
  showing 
  the 
  coelom 
  of 
  

   the 
  stalk 
  divided 
  completely 
  by 
  a 
  septum. 
  But 
  Masterman 
  

   interprets 
  the 
  cavities 
  in 
  Cephalodiscus 
  as 
  " 
  blood-^' 
  sinuses, 
  

   whereas 
  my 
  specimens 
  lead 
  me 
  to 
  believe 
  that 
  the 
  central 
  

   core 
  of 
  the 
  Rhabdopleura 
  septum 
  is 
  continuous 
  with 
  the 
  lining 
  

   of 
  the 
  alimentary 
  caual. 
  Unfortunately 
  buds 
  smaller 
  than 
  

   that 
  described 
  in 
  detail 
  above 
  proved 
  to 
  be 
  too 
  minute 
  to 
  

   allow 
  of 
  definite 
  conclusions 
  being 
  drawn/ 
  and 
  the 
  prelimi- 
  

   nary 
  remarks 
  of 
  MM. 
  Conte 
  and 
  Vaney 
  are 
  too 
  brief 
  and 
  

   vague 
  to 
  settle 
  the 
  matter 
  (op. 
  cit., 
  p. 
  749). 
  

  

  Cephalodiscus 
  and 
  Rhabdopleura 
  agree 
  in 
  the 
  precocious 
  

   formation 
  of 
  the 
  epistome, 
  in 
  the 
  continuity 
  of 
  the 
  stalk- 
  

   coelom 
  with 
  that 
  of 
  the 
  bud, 
  and 
  in 
  the 
  presence 
  of 
  a 
  nerve- 
  

   like 
  stripe 
  of 
  ectoderm 
  on 
  the 
  stalk. 
  

  

  EXPLANATION 
  OF 
  PLATE 
  3, 
  

  

  Illustrating 
  Dr. 
  G. 
  Herbert 
  Fowler's 
  "Notes 
  on 
  Rhabdo- 
  

   pleura 
  Normani, 
  Allman." 
  

  

  Note. 
  — 
  As 
  in 
  my 
  previous 
  paper 
  (op, 
  cit. 
  supra), 
  Uie 
  trunk-ccelom 
  lias 
  been 
  

   drawn 
  all 
  round 
  Ihe 
  alimentary 
  canal 
  on 
  the 
  aullioritj 
  ol' 
  Prof. 
  Lankesler's 
  

   observations 
  on 
  livinjj 
  specimens, 
  although 
  in 
  my 
  shrunken 
  specimens 
  it 
  is 
  

  

  ^ 
  A. 
  T. 
  Masterman, 
  'Trans. 
  Roy. 
  Soc. 
  Edin.,' 
  xxxis, 
  p. 
  507. 
  

  

  ^ 
  At 
  the 
  same 
  time, 
  the 
  structures 
  are 
  large 
  enough 
  to 
  allow 
  of 
  accurate 
  

   determination 
  in 
  material 
  specially 
  preserved 
  ; 
  mine 
  had 
  been 
  roughly 
  pre- 
  

   served 
  (ajiparently 
  merely 
  in 
  strong 
  alcohol), 
  for 
  the 
  sake 
  of 
  the 
  Lopliophelia 
  

   on 
  which 
  it 
  grew; 
  as 
  it 
  was 
  "Challenger" 
  material, 
  thirty 
  years' 
  preservation 
  

   has 
  not 
  improved 
  it. 
  

  

  