﻿FROM 
  THE 
  RADIOLARLAN 
  MARLS 
  OF 
  BARBADOS. 
  649 
  

  

  But 
  as 
  the 
  depths 
  assigned 
  to 
  Cystechinus 
  rest 
  solely 
  on 
  the 
  records 
  

   of 
  the 
  ' 
  Challenger/ 
  and 
  as 
  the 
  depths 
  given 
  by 
  this 
  expedition 
  have 
  

   been 
  seriously 
  questioned, 
  it 
  becomes 
  necessary 
  to 
  consider 
  how 
  far 
  de- 
  

   pendence 
  can 
  be 
  placed 
  upon 
  them. 
  In 
  the 
  preface 
  to 
  the 
  narrative 
  

   of 
  the 
  ' 
  Challenger' 
  expedition 
  the 
  following 
  statement 
  is 
  made*: 
  — 
  

   "With 
  respect 
  to 
  the 
  depths 
  assigned 
  to 
  the 
  zoological 
  specimens, 
  it 
  

   may 
  be 
  well 
  to 
  state 
  that 
  the 
  naturalists 
  of 
  the 
  expedition 
  have 
  

   simply 
  recorded 
  the 
  greatest 
  depth 
  to 
  which 
  the 
  dredge 
  or 
  trawl 
  was 
  

   believed 
  to 
  have 
  descended 
  at 
  each 
  station. 
  It 
  will 
  be 
  evident 
  that 
  

   the 
  instrument 
  may 
  have 
  been 
  occasionally 
  dragged 
  into 
  slightly 
  

   deeper 
  or 
  shallower 
  water 
  than 
  was 
  recorded 
  by 
  the 
  sounding-line, 
  

   and, 
  what 
  is 
  of 
  greater 
  consequence, 
  the 
  trawl 
  or 
  dredge 
  may 
  have 
  

   caught 
  animals 
  while 
  sinking 
  through 
  the 
  water 
  or 
  being 
  hauled 
  up 
  

   again. 
  In 
  the 
  great 
  majority 
  of 
  cases 
  there 
  is 
  little 
  difficulty 
  in 
  

   deciding 
  which 
  animals 
  were 
  dredged 
  from 
  the 
  bottom 
  and 
  which 
  

   were 
  caught 
  by 
  the 
  instrument 
  in 
  surface 
  or 
  subsurface 
  waters. 
  

   With 
  some 
  fish, 
  Crustaceans, 
  Medusas, 
  and 
  other 
  groups, 
  however, 
  

   there 
  is 
  considerable 
  difficulty 
  ; 
  in 
  these 
  cases 
  the 
  organization 
  is 
  often 
  

   a 
  guide, 
  and 
  the 
  specialist 
  who 
  has 
  made 
  a 
  careful 
  study 
  of 
  the 
  group 
  

   to 
  which 
  the 
  species 
  belongs 
  is 
  best 
  able 
  to 
  form 
  an 
  opinion 
  as 
  to 
  

   the 
  depth 
  at 
  which 
  the 
  specimens 
  were 
  probably 
  captured. 
  These 
  

   circumstances 
  should 
  therefore 
  always 
  be 
  borne 
  in 
  mind 
  when 
  the 
  

   depths 
  at 
  which 
  animals 
  have 
  lived 
  are 
  being 
  discussed, 
  and 
  only 
  

   after 
  careful 
  consideration 
  should 
  it 
  be 
  inferred 
  that 
  they 
  were 
  

   procured 
  at 
  the 
  depths 
  assigned 
  to 
  them 
  in 
  the 
  lists." 
  This 
  warning 
  

   has 
  been 
  repeated 
  t 
  equally 
  emphatically 
  in 
  a 
  review 
  in 
  the 
  ' 
  Athe- 
  

   naeum/ 
  which 
  contains 
  strong 
  internal 
  evidence 
  o£ 
  the 
  authorship 
  of 
  

   Prof. 
  Moseley 
  ; 
  the 
  validity 
  of 
  the 
  conclusions 
  based 
  by 
  Mr. 
  J. 
  J. 
  

   Quelch 
  on 
  the 
  recorded 
  depths 
  of 
  some 
  reef- 
  corals 
  from 
  below 
  the 
  

   30-fathom 
  line 
  is 
  absolutely 
  denied, 
  as 
  in 
  the 
  cases 
  in 
  question 
  

   " 
  the 
  dredge 
  ranged 
  while 
  down 
  from 
  30 
  fathoms 
  or 
  1 
  fathom 
  or 
  10 
  

   fathoms 
  to 
  greater 
  depths, 
  but 
  there 
  is 
  no 
  proof 
  at 
  all 
  that 
  it 
  did 
  not 
  

   pick 
  up 
  the 
  corals 
  at 
  the 
  least 
  depth 
  encountered." 
  But 
  with 
  

   Echinoids, 
  and 
  especially 
  with 
  edentulate 
  Spatangoids, 
  which 
  must 
  

   have 
  lived 
  on 
  or 
  burrowing 
  through 
  the 
  ooze, 
  there 
  can 
  be 
  no 
  doubt 
  

   that 
  they 
  were 
  derived 
  from 
  the 
  bottom, 
  though 
  the 
  pumice, 
  palm 
  

   fruits, 
  leaves, 
  &c. 
  associated 
  with 
  them 
  at 
  Station 
  205 
  were 
  probably 
  

   picked 
  up 
  near 
  the 
  surface. 
  Very 
  few 
  particulars, 
  however, 
  have 
  

   been 
  given 
  by 
  the 
  ' 
  Challenger 
  ' 
  reporters 
  as 
  to 
  the 
  range 
  of 
  depth 
  

   crossed 
  during 
  the 
  day's 
  run 
  ; 
  but 
  had 
  this 
  been 
  serious 
  it 
  could 
  hardly 
  

   have 
  escaped 
  notice. 
  The 
  only 
  case 
  in 
  which 
  an}^ 
  serious 
  discrep- 
  

   ancy 
  might 
  have 
  occurred 
  is 
  that 
  off 
  the 
  Philippine 
  Islands 
  ; 
  and 
  it 
  is 
  

   not 
  likely 
  there, 
  as 
  the 
  dredge 
  was 
  dropped 
  in 
  1050 
  fathoms, 
  and 
  

   the 
  depth 
  had 
  increased 
  to 
  2100 
  fathoms 
  at 
  the 
  next 
  Station. 
  

  

  Cystechinus 
  crassus 
  was 
  probably 
  an 
  inhabitant 
  of 
  a 
  less 
  depth 
  

   than 
  either 
  of 
  the 
  previously 
  described 
  species 
  of 
  the 
  genus, 
  as 
  is 
  

   indicated 
  by 
  the 
  greater 
  thickness 
  of 
  the 
  plates 
  of 
  the 
  test. 
  Loven 
  

  

  * 
  Ibid. 
  vol. 
  i. 
  pt. 
  i. 
  pp. 
  xi, 
  xii. 
  

  

  t 
  Athenasum, 
  No. 
  3116, 
  July 
  16, 
  1887, 
  p. 
  87. 
  

  

  