﻿1874.] 
  ' 
  Challenger' 
  Soundings 
  in 
  the 
  Southern 
  Sea. 
  35 
  

  

  and 
  transparent, 
  and 
  each 
  of 
  the 
  pores 
  which 
  penetrate 
  it 
  is 
  surrounded 
  

   by 
  a 
  raised 
  crest, 
  the 
  crest 
  round 
  adjacent 
  pores 
  coalescing 
  into 
  a 
  roughly 
  

   hexagonal 
  network, 
  so 
  that 
  the 
  pore 
  appears 
  to 
  lie 
  at 
  the 
  bottom 
  of 
  an 
  

   hexagonal 
  pit. 
  At 
  each 
  angle 
  of 
  this 
  hexagon 
  the 
  crest 
  gives 
  off 
  a 
  

   delicate 
  flexible 
  calcareous 
  spine, 
  which 
  is 
  sometimes 
  four 
  or 
  five 
  times 
  the 
  

   diameter 
  of 
  the 
  shell 
  in 
  length. 
  The 
  spines 
  radiate 
  symmetrically 
  from 
  

   the 
  direction 
  of 
  the 
  centre 
  of 
  each 
  chamber 
  of 
  the 
  shell, 
  and 
  the 
  sheaves 
  

   of 
  long 
  transparent 
  needles, 
  crossing 
  one 
  another 
  in 
  different 
  directions, 
  

   have 
  a 
  very 
  beautiful 
  effect. 
  The 
  smaller 
  inner 
  chambers 
  of 
  the 
  shell 
  

   are 
  entirely 
  filled 
  with 
  an 
  orange-yellow 
  granular 
  sarcode 
  ; 
  and 
  the 
  large 
  

   terminal 
  chamber 
  usually 
  contains 
  only 
  a 
  small 
  irregular 
  mass, 
  or 
  two 
  

   or 
  three 
  small 
  masses 
  run 
  together, 
  of 
  the 
  same 
  yellow 
  sarcode 
  stuck 
  

   against 
  one 
  side, 
  the 
  remainder 
  of 
  the 
  chamber 
  being 
  empty. 
  JNo 
  defi- 
  

   nite 
  arrangement, 
  and 
  no 
  approach 
  to 
  structure, 
  was 
  observed 
  in 
  the 
  

   sarcode, 
  and 
  no 
  differentiation, 
  with 
  the 
  exception 
  of 
  round 
  bright-yellow 
  

   oil-globules, 
  very 
  much 
  like 
  those 
  found 
  in 
  some 
  of 
  the 
  Radiolarians, 
  

   which 
  are 
  scattered 
  apparently 
  irregularly 
  in 
  the 
  sarcode. 
  We 
  never 
  

   have 
  been 
  able 
  to 
  detect 
  the 
  least 
  trace 
  of 
  pseudopodia 
  in 
  any 
  of 
  the 
  large 
  

   number 
  of 
  Globigerince 
  which 
  we 
  have 
  examined, 
  nor 
  any 
  extension, 
  in 
  any 
  

   form, 
  of 
  the 
  sarcode 
  beyond 
  the 
  shell. 
  

  

  Major 
  Owen 
  (op. 
  cit.) 
  has 
  referred 
  the 
  Globigerina 
  with 
  spines 
  to 
  a 
  

   distinct 
  species, 
  under 
  the 
  name 
  of 
  G. 
  hirsuta. 
  I 
  am 
  inclined 
  rather 
  to 
  

   believe 
  that 
  all 
  Globigerince 
  are, 
  to 
  a 
  greater 
  or 
  less 
  degree, 
  spiny, 
  when 
  the 
  

   shell 
  has 
  attained 
  its 
  full 
  development. 
  In 
  specimens 
  taken 
  with 
  the 
  

   tow-net 
  the 
  spines 
  are 
  very 
  usually 
  absent 
  ; 
  but 
  that 
  is 
  probably 
  on 
  

   account 
  of 
  their 
  extreme 
  tenuity 
  ; 
  they 
  are 
  broken 
  off 
  by 
  the 
  slightest 
  

   touch. 
  In 
  fresh 
  examples 
  from 
  the 
  surface 
  the 
  dots 
  indicating 
  the 
  origin 
  

   of 
  the 
  lost 
  spines 
  may 
  almost 
  always 
  be 
  made 
  out 
  with 
  a 
  high 
  power. 
  

   There 
  never 
  are 
  spines 
  on 
  the 
  Globigerince 
  from 
  the 
  bottom, 
  even 
  in 
  the 
  

   shallowest 
  water. 
  Two 
  or 
  three 
  very 
  marked 
  varieties 
  of 
  Globigerina 
  

   occur 
  j 
  but 
  I 
  certainly 
  do 
  not 
  think 
  that 
  the 
  characters 
  of 
  any 
  of 
  them 
  can 
  

   be 
  regarded 
  as 
  of 
  specific 
  value. 
  

  

  There 
  is 
  still 
  a 
  good 
  deal 
  of 
  obscurity 
  about 
  the 
  nature 
  of 
  Orbulina 
  

   universa, 
  an 
  organism 
  which 
  occurs 
  in 
  some 
  places 
  in 
  large 
  proportion 
  in 
  the 
  

   Globigerina-ooze. 
  The 
  shell 
  of 
  Orbulina 
  (PI. 
  II.) 
  is 
  spherical, 
  usually 
  about 
  

   •5 
  millimetre 
  in 
  diameter, 
  but 
  it 
  is 
  found 
  of 
  all 
  smaller 
  sizes. 
  The 
  texture 
  

   of 
  the 
  mature 
  shell 
  resembles 
  closely 
  that 
  of 
  Globigerina, 
  but 
  it 
  differs 
  in 
  

   some 
  important 
  particulars. 
  The 
  pores 
  are 
  markedly 
  of 
  two 
  different 
  sizes, 
  

   the 
  larger 
  about 
  four 
  times 
  the 
  area 
  of 
  the 
  smaller. 
  The 
  larger 
  pores 
  are 
  

   the 
  less 
  numerous 
  ; 
  they 
  are 
  scattered 
  over 
  the 
  surface 
  of 
  the 
  shell 
  with- 
  

   out 
  any 
  appearance 
  of 
  regularity 
  ; 
  the 
  smaller 
  pores 
  occupy 
  the 
  spaces 
  

   between 
  the 
  larger. 
  The 
  crests 
  between 
  the 
  pores 
  are 
  much 
  less 
  ^regular 
  

   in 
  Orbulina 
  than 
  they 
  are 
  in 
  Globigerina 
  ; 
  and 
  the 
  spines, 
  which 
  are 
  of 
  

   great 
  length 
  and 
  extreme 
  tenuity, 
  seem 
  rather 
  to 
  arise 
  abruptly 
  from 
  

   the 
  top 
  of 
  scattered 
  papillae 
  than 
  to 
  mark 
  the 
  intersections 
  of 
  the 
  crests. 
  

  

  d 
  2 
  

  

  