﻿360 
  ME. 
  E. 
  A. 
  BATHEE 
  ON 
  THE 
  

  

  however, 
  though 
  it 
  favoured 
  v. 
  Zittel's 
  view, 
  did 
  not 
  agree 
  with 
  

   it 
  at 
  all 
  points. 
  Wishing 
  to 
  put 
  the 
  keystone 
  to 
  my 
  argument, 
  I 
  

   therefore 
  requested 
  Prof. 
  v. 
  Zittel 
  to 
  send 
  me 
  some 
  sketch 
  or 
  dia- 
  

   gram, 
  that 
  I 
  might 
  publish 
  it 
  on 
  his 
  authority 
  as 
  an 
  illustration 
  to 
  

   my 
  paper. 
  With 
  a 
  courteous 
  generosity 
  for 
  which 
  I 
  cannot 
  suffi- 
  

   ciently 
  thank 
  him, 
  he 
  replied 
  by 
  sending, 
  not 
  only 
  a 
  further 
  eluci- 
  

   dation 
  of 
  his 
  description, 
  but 
  also 
  the 
  specimens 
  themselves. 
  Owing 
  

   to 
  a 
  mistake 
  in 
  the 
  postal 
  address, 
  the 
  specimens 
  were 
  in 
  England 
  

   for 
  six 
  weeks 
  before 
  they 
  came 
  into 
  my 
  hands 
  ; 
  I 
  was 
  therefore 
  

   unable 
  to 
  incorporate 
  their 
  evidence 
  with 
  my 
  previous 
  arguments. 
  

   I 
  should 
  have 
  thought 
  it 
  unnecessary 
  to 
  trouble 
  the 
  Society 
  with 
  

   any 
  remarks 
  of 
  mine 
  upon 
  these 
  specimens, 
  had 
  not 
  circumstances 
  

   abundantly 
  proved 
  the 
  great 
  need 
  for 
  a 
  published 
  figure 
  with 
  

   detailed 
  description 
  : 
  for, 
  be 
  it 
  remembered, 
  science 
  was 
  acquainted 
  

   with 
  the 
  bare 
  conclusions 
  of 
  Beyrich 
  and 
  v. 
  Zittel 
  before 
  de 
  Loriol 
  

   and 
  Carpenter 
  attacked 
  the 
  subject. 
  

  

  The 
  specimens 
  so 
  kindly 
  lent 
  to 
  me 
  by 
  Prof. 
  v. 
  Zittel 
  consist, 
  of 
  eight 
  

   dorsal 
  cups, 
  more 
  or 
  less 
  perfect, 
  of 
  Eugeniacrinus 
  caryophyllatus, 
  

   from 
  the 
  " 
  Weisser 
  Jura 
  e 
  " 
  (Quenstedt) 
  of 
  Engelhardtsberg, 
  N. 
  of 
  

   Streitberg. 
  The 
  fossils 
  are 
  partially 
  silicified, 
  and 
  weathering 
  and 
  

   acids 
  have 
  removed 
  all 
  portions 
  not 
  so 
  preserved. 
  Thus 
  the 
  external 
  

   shell 
  of 
  each 
  first 
  radial, 
  both 
  inside 
  and 
  out 
  and 
  along 
  the 
  suture- 
  

   line, 
  remains 
  like 
  a 
  box. 
  The 
  bounding 
  surfaces 
  of 
  the 
  canals 
  

   which 
  penetrated 
  the 
  once 
  solid 
  radials 
  were 
  equally 
  exposed 
  to 
  the 
  

   silicifying 
  fluid 
  : 
  hence 
  the 
  canals 
  remain 
  as 
  a 
  system 
  of 
  branching 
  

   tubes 
  passing 
  through 
  the 
  space 
  of 
  the 
  now 
  hollow 
  radials 
  *. 
  In 
  no 
  

   specimen 
  is 
  the 
  system 
  quite 
  intact 
  : 
  some 
  of 
  the 
  best 
  are 
  represented 
  

   in 
  figures 
  1-4, 
  and 
  an 
  accurate 
  description 
  of 
  each 
  specimen 
  so 
  figured 
  

   is 
  given 
  in 
  the 
  explanation 
  of 
  the 
  engravings 
  (facing 
  p. 
  362). 
  From 
  

   the 
  various 
  evidence 
  of 
  these 
  specimens 
  is 
  reconstructed 
  the 
  perfect 
  

   figure 
  (fig. 
  5). 
  It 
  is 
  thus 
  seen 
  that 
  v. 
  Zittel's 
  account 
  is 
  absolutely 
  

   correct. 
  The 
  axial 
  canal 
  of 
  the 
  stem 
  passes 
  up 
  into 
  the 
  radial 
  

   circlet, 
  and 
  gradually 
  widens 
  ; 
  at 
  a 
  short 
  distance 
  below 
  the 
  floor 
  of 
  the 
  

   calycal 
  cavity 
  it 
  gives 
  off 
  5 
  interradial 
  branches 
  ; 
  these 
  soon 
  bifurcate, 
  

   and 
  the 
  adjacent 
  secondary 
  branches 
  converge. 
  Before 
  they 
  meet, 
  

   each 
  secondary 
  branch 
  gives 
  off 
  towards 
  the 
  periphery 
  of 
  the 
  dorsal 
  

   cup 
  a 
  very 
  short 
  side-branch 
  ; 
  this 
  side-branch 
  connects 
  the 
  secon- 
  

   dary 
  branch 
  from 
  which 
  it 
  springs 
  with 
  a 
  ring-canal, 
  which 
  con- 
  

   tained 
  the 
  interradial 
  and 
  intraradial 
  commissures. 
  Prom 
  the 
  level 
  

  

  * 
  [Note, 
  April 
  25, 
  1889. 
  This 
  mode 
  of 
  preservation 
  is 
  peculiar 
  but 
  not 
  

   unique 
  ; 
  a 
  dorsal 
  cup 
  of 
  Miller 
  icrinus, 
  sp., 
  in 
  the 
  British 
  Museum 
  (49210), 
  

   said 
  to 
  come 
  from 
  Nattheim, 
  shows 
  the 
  canals 
  in 
  the 
  same 
  way. 
  Replacement 
  

   of 
  calcite 
  by 
  silica, 
  though 
  not 
  impossible, 
  is 
  by 
  some 
  considered 
  improbable. 
  

   Results 
  so 
  nearly 
  the 
  same 
  as 
  to 
  be 
  undistinguishable 
  might 
  be 
  obtained 
  from 
  

   the 
  interpenetration 
  of 
  the 
  reticular 
  calcareous 
  tissue 
  of 
  the 
  Echinoderm 
  

   skeleton 
  by 
  silica, 
  and 
  the 
  subsequent 
  removal 
  of 
  the 
  calcite. 
  The 
  brilliant, 
  

   opaque 
  whiteness 
  of 
  the 
  present 
  specimens, 
  and 
  the 
  texture 
  of 
  their 
  surface, 
  

   favours 
  this 
  explanation. 
  Such 
  a 
  process 
  can 
  only 
  have 
  taken 
  place 
  soon 
  after 
  

   death, 
  before 
  any 
  infiltration 
  of 
  calcite 
  had 
  taken 
  place. 
  The 
  silica 
  in 
  the 
  

   specimen 
  of 
  Miller 
  icrinus 
  is, 
  in 
  places, 
  distinctly 
  crystalline 
  ; 
  but 
  this 
  may 
  be 
  

   due 
  to 
  secondary 
  changes.] 
  

  

  