﻿FOURTH 
  REPORT 
  OF 
  THE 
  DIRECTOR 
  I907 
  1 
  65 
  

  

  sion. 
  In 
  the 
  present 
  seas 
  all 
  gastropods 
  of 
  truly 
  parasitic 
  habit 
  

   are 
  parasites 
  on 
  the 
  Echinoderma, 
  the 
  class 
  to 
  which 
  the 
  crinoids 
  

   belong. 
  Crinoids 
  are 
  few 
  today 
  and 
  appear 
  to 
  be 
  relatively 
  free 
  

   from 
  these 
  attachments, 
  but 
  their 
  allies, 
  the 
  starfish 
  and 
  sea 
  

   urchins, 
  are 
  still 
  beset 
  by 
  the 
  gastropods, 
  often 
  so 
  reduced 
  by 
  the 
  

   degeneration 
  of 
  their 
  condition 
  as 
  to 
  be 
  scarcely 
  recognizable. 
  

   This 
  far-reaching 
  and 
  general 
  condition 
  of 
  depravity 
  would 
  seem 
  a 
  

   direct 
  inheritance 
  of 
  the 
  ancient 
  conditions 
  we 
  have 
  portrayed. 
  1 
  

  

  Crinoids 
  and 
  Starfish 
  

  

  We 
  have 
  some 
  very 
  interesting 
  instances 
  of 
  association 
  be- 
  

   tween 
  the 
  crinoids 
  and 
  the 
  ophiuran 
  Onychaster 
  flex- 
  

   i 
  1 
  i 
  s 
  Meek 
  & 
  Worthen. 
  Three 
  of 
  these 
  are 
  here 
  figured, 
  one 
  a 
  

   copy 
  from 
  Wachsmuth 
  and 
  Springer's 
  figure 
  ofActinocrinus 
  

   multiramosus 
  W. 
  & 
  Sp., 
  the 
  others 
  drawn 
  from 
  specimens 
  

   in 
  the 
  possession 
  of 
  Mr 
  Fred 
  Braun. 
  In 
  the 
  first 
  the 
  starfish 
  has 
  

   encircled 
  with 
  its 
  arms 
  the 
  dome 
  of 
  the 
  crinoid, 
  mouth 
  downward 
  

   in 
  such 
  an 
  attitude 
  as 
  to 
  suggest 
  though 
  probably 
  not 
  to 
  demonstrate 
  

   that 
  it 
  was 
  diligently 
  attending 
  to 
  the 
  waste 
  of 
  the 
  crinoid. 
  As 
  the 
  

   arms 
  of 
  the 
  crinoid 
  have 
  been 
  broken 
  away 
  the 
  act 
  of 
  the 
  starfish 
  

   is 
  exposed 
  in 
  all 
  its 
  nakedness. 
  In 
  the 
  specimens 
  of 
  the 
  Onychaster 
  

   with 
  Barycrinus 
  hoveyi 
  Hall, 
  the 
  arms 
  of 
  the 
  two 
  creatures 
  

   have 
  become 
  completely 
  entangled 
  and 
  fixation 
  for 
  feeding 
  purposes 
  

   at 
  least 
  is 
  entirely 
  effective. 
  In 
  respect 
  to 
  the 
  end 
  sought 
  and 
  

   attained 
  this 
  condition 
  is 
  one 
  of 
  parasitism 
  but 
  one 
  still 
  subject 
  to 
  

   the 
  control 
  of 
  the 
  individual. 
  There 
  seems 
  no 
  reason 
  to 
  assume 
  

   that 
  the 
  starfish 
  is 
  here 
  endeavoring 
  to 
  suck 
  the 
  life 
  out 
  of 
  the 
  

   crinoid 
  itself 
  and 
  it 
  would 
  be 
  going 
  further 
  than 
  the 
  facts 
  justify 
  to 
  

   interpret 
  this 
  demonstration 
  solely 
  as 
  an 
  act 
  of 
  feeding 
  like 
  that 
  of 
  

   the 
  common 
  starfish 
  of 
  today 
  in 
  its 
  attacks 
  upon 
  the 
  oyster. 
  

  

  I 
  quote 
  here 
  some 
  remarks 
  from 
  Wachsmuth 
  and 
  Springer's 
  

   North 
  American 
  Crinoidea 
  Camerata 
  [1897, 
  p. 
  566], 
  concerning 
  the 
  

   relations 
  of 
  Platyceras 
  and 
  Onychaster 
  to 
  the 
  high 
  domed 
  crinoid 
  

   Actinocrinus 
  multiramosus. 
  

  

  Of 
  this 
  large 
  and 
  beautiful 
  species 
  we 
  obtained 
  at 
  Indian 
  Creek 
  

   and 
  Canton 
  over 
  forty 
  specimens, 
  most 
  of 
  them 
  in 
  excellent 
  pre- 
  

   servation, 
  with 
  the 
  arms 
  attached; 
  and 
  it 
  is 
  very 
  remarkable 
  that 
  

   nearly 
  one 
  half 
  of 
  them 
  have 
  either 
  a 
  Platyceras 
  attached 
  to 
  the 
  

  

  'The 
  brothers 
  Sarasin 
  have 
  described 
  a 
  very 
  interesting 
  case 
  of 
  the 
  parasitic 
  attachment 
  

   of 
  a 
  limpetlike 
  Platyceras 
  to 
  a 
  living 
  starfish, 
  in 
  which 
  the 
  former 
  by 
  an 
  extension 
  of 
  its 
  

   mouth 
  into 
  a 
  snout 
  which 
  penetrates 
  the 
  test 
  of 
  the 
  starfish, 
  sucks 
  out 
  the 
  nutritious 
  fluids 
  

   Ergebniss 
  einer 
  Forschungsreise 
  auf 
  Ceylon, 
  v. 
  I\, 
  While 
  the 
  parasitic 
  condition 
  between 
  

   che 
  limpets 
  and 
  crinoids 
  of 
  the 
  Paleozic 
  was 
  elastic, 
  this 
  is 
  fixed 
  and 
  beyond 
  repair. 
  Other 
  

   living 
  snails 
  parasitic 
  on 
  the 
  allies 
  of 
  the 
  crinoids 
  are 
  interestingly 
  described 
  in 
  the 
  Natur- 
  

   wissenschaftliche 
  Wochenschrift, 
  January 
  17, 
  1904. 
  

  

  