﻿NO. 
  194G. 
  PACIFIC 
  MEDUSAE 
  AND 
  SIPHONOPHORAE—BIGELOW. 
  33 
  

  

  diademata 
  from 
  Newfoundland, 
  without 
  finding 
  a 
  single 
  character 
  to 
  

   separate 
  them 
  except 
  in 
  the 
  density 
  of 
  pigmentation. 
  

  

  TIAROPSIS 
  DIABEMATA 
  L. 
  Agassiz. 
  

  

  Tiaropsis 
  diademata 
  L. 
  Agassiz, 
  1849, 
  p. 
  289, 
  pi. 
  6, 
  figs. 
  1-16; 
  pi. 
  8, 
  fig. 
  11. 
  

   (For 
  further 
  synonymy, 
  see 
  Mayer, 
  1910, 
  p. 
  258.) 
  

  

  Dutch 
  Harbor, 
  May 
  25, 
  surface; 
  22 
  specimens, 
  10-22 
  mm. 
  in 
  

   diameter. 
  

  

  Agattu 
  Island, 
  June 
  7, 
  surface; 
  8 
  specimens, 
  18-20 
  mm. 
  in 
  

   diameter. 
  

  

  The 
  material 
  is 
  in 
  excellent 
  condition. 
  

  

  For 
  the 
  sake 
  of 
  identification, 
  of 
  course, 
  one 
  of 
  the 
  first 
  questions 
  to 
  

   be 
  answered 
  was 
  to 
  what 
  extent 
  the 
  bases 
  of 
  the 
  tentacles 
  were 
  pig- 
  

   mented. 
  In 
  the 
  specimens 
  from 
  Agattu 
  Island 
  they 
  are 
  apparently 
  

   colorless, 
  seen 
  by 
  transmitted 
  light, 
  though 
  opaque. 
  But 
  when 
  

   studied 
  against 
  a 
  white 
  background 
  it 
  is 
  evident 
  that 
  the 
  entoderm 
  of 
  

   each 
  bulb 
  contains 
  pale 
  greenish, 
  or 
  in 
  some 
  cases 
  greenish-brown, 
  

   pigment, 
  in 
  a 
  roughly 
  triangular 
  mass. 
  Though 
  the 
  pigment 
  is 
  of 
  

   the 
  same 
  color 
  that 
  it 
  is 
  in 
  the 
  Atlantic 
  diademata, 
  it 
  is 
  rather 
  more 
  

   dense 
  than 
  I 
  have 
  observed 
  it 
  in 
  the 
  latter, 
  but 
  in 
  none 
  of 
  the 
  speci- 
  

   mens 
  is 
  it 
  black, 
  as 
  it 
  is 
  represented 
  m 
  multicirrhata. 
  I 
  was 
  surprised 
  

   to 
  find 
  that 
  in 
  the 
  Dutch 
  Harbor 
  series 
  there 
  was 
  no 
  pigment 
  to 
  be 
  

   seen 
  in 
  the 
  bulbs; 
  but 
  as 
  the 
  preservation 
  in 
  these 
  was 
  not 
  quite 
  so 
  

   successful, 
  I 
  do 
  not 
  feel 
  certain 
  that 
  there 
  was 
  none 
  in 
  life. 
  It 
  may 
  

   have 
  faded 
  as 
  it 
  so 
  often 
  does 
  in 
  medusae. 
  

  

  In 
  a 
  specimen 
  20 
  mm. 
  in 
  diameter 
  there 
  are 
  59, 
  64, 
  65, 
  and 
  62 
  ten- 
  

   tacles 
  in 
  the 
  four 
  quadrants, 
  a 
  total 
  (with 
  four 
  radials) 
  of 
  254, 
  all 
  

   large. 
  In 
  a 
  smaller 
  one 
  of 
  about 
  15 
  mm. 
  the 
  numbers 
  are 
  37, 
  38, 
  39, 
  

   42, 
  total 
  160, 
  among 
  which 
  large 
  and 
  small 
  rouglily 
  alternate. 
  In 
  a 
  

   specimen 
  from 
  Newfoundland 
  of 
  20 
  mm. 
  the 
  total 
  number 
  is 
  256, 
  all 
  

   large 
  : 
  apparently, 
  then, 
  the 
  final 
  number 
  is 
  about 
  250, 
  which 
  is 
  rather 
  

   more 
  than 
  Mayer 
  (1910) 
  credits 
  it 
  with. 
  

  

  In 
  the 
  length 
  of 
  the 
  gonads, 
  frilled 
  lips, 
  and 
  short 
  broad 
  peduncle 
  

   the 
  series 
  agrees 
  perfectly 
  with 
  Atlantic 
  specimens. 
  

  

  T. 
  diademata 
  has 
  been 
  recorded 
  from 
  the 
  coasts 
  of 
  New 
  England 
  

   and 
  Newfoundland, 
  where 
  it 
  is 
  often 
  very 
  abundant; 
  Greenland, 
  and 
  

   from 
  the 
  White 
  Sea 
  (Linko, 
  1899); 
  it 
  is 
  therefore 
  not 
  surprising 
  to 
  

   find 
  it 
  in 
  Bering 
  Sea. 
  

  

  The 
  more 
  deeply 
  pigmented 
  multicirrhata 
  (whether 
  species 
  or 
  

   variety) 
  is 
  known 
  only 
  from 
  the 
  northwestern 
  coasts 
  of 
  Europe.^ 
  

  

  • 
  Since 
  the 
  above 
  was 
  written 
  I 
  have 
  studied 
  excellent 
  specimens 
  from 
  Massachusetts 
  Bay 
  in 
  which 
  

   the 
  tentacular 
  bulbs 
  were 
  densely 
  pigmented 
  with 
  black 
  granules, 
  thus 
  exactly 
  reproducing 
  the 
  

   European 
  type. 
  

  

  G90T7°— 
  Proc.X.M.vol.44— 
  13 
  3 
  

  

  