﻿NO. 
  1946. 
  PACIFIC 
  MEDUSAE 
  AND 
  SIPHONOPHORAE—BIGELOW. 
  99 
  

  

  AURELIA 
  AURITA 
  (Linnaeus) 
  Lamarck. 
  

   Medusa 
  aurita 
  Linnaeus, 
  1758, 
  p. 
  660. 
  

  

  (For 
  synonymy, 
  see 
  Mayer, 
  1910, 
  pp. 
  623, 
  628.) 
  

  

  Tsuruga, 
  Japan, 
  July 
  23, 
  surface; 
  3 
  specimens, 
  65, 
  90, 
  and 
  130 
  mm. 
  

   in 
  diameter. 
  

  

  I 
  can 
  find 
  nothing 
  to 
  separate 
  these 
  specimens 
  from 
  the 
  Aurelias 
  

   of 
  the 
  New 
  England 
  coast, 
  except 
  that 
  they 
  have 
  smaller 
  subgenital 
  

   pits 
  than 
  is 
  usually 
  the 
  case 
  among 
  the 
  latter; 
  but 
  in 
  this 
  respect 
  

   they 
  agree 
  with 
  Cuban 
  specimens. 
  The 
  branching 
  of 
  the 
  canals 
  is 
  

   rather 
  regular, 
  just 
  as 
  in 
  the 
  Japanese 
  specimens 
  recorded 
  by 
  Maas 
  

   (1909, 
  var. 
  "colpota"), 
  but 
  no 
  more 
  so 
  than 
  I 
  have 
  seen 
  it 
  in 
  some 
  

   Atlantic 
  specimens; 
  in 
  fact 
  an 
  example 
  of 
  almost 
  exactly 
  the 
  same 
  

   type 
  (though 
  with 
  only 
  seven 
  rhopalia) 
  has 
  been 
  figured 
  by 
  Hargitt 
  

   (1905c) 
  from 
  Massachusetts. 
  

  

  AURELLA 
  LIMBATA 
  Brandt. 
  

  

  Plate 
  5, 
  figs. 
  1-4. 
  

  

  Aurelia 
  limbata 
  Brandt, 
  1835, 
  p. 
  26. 
  — 
  Vanhoffen, 
  1902a, 
  p. 
  43; 
  Maas, 
  19066, 
  

  

  p. 
  507. 
  

   Diplocraspedon 
  limbata 
  Brandt, 
  1838, 
  p. 
  372, 
  pi. 
  10. 
  

  

  Dutch 
  Harbor, 
  surface, 
  May 
  25; 
  16 
  young 
  specimens, 
  16-22 
  mm. 
  

   in 
  diameter. 
  

  

  Agattu 
  Island, 
  surface, 
  June 
  7; 
  1 
  specimen, 
  now 
  in 
  fragments, 
  

   about 
  200 
  mm. 
  in 
  diameter. 
  

  

  Mororan, 
  Hokkaido, 
  Japan, 
  surface, 
  July 
  5; 
  2 
  specimens 
  of 
  about 
  

   100 
  mm.; 
  1 
  very 
  fragmentary, 
  the 
  other 
  with 
  subumbrella, 
  part 
  of 
  

   margin, 
  gonads, 
  subgenital 
  pits, 
  and 
  two 
  mouth-arms 
  intact. 
  

  

  Station 
  5008; 
  surface, 
  1 
  specimen, 
  43 
  mm. 
  in 
  diameter. 
  

  

  This 
  species 
  resembles 
  aurita 
  in 
  general 
  form 
  as 
  well 
  as 
  in 
  the 
  fact 
  

   that 
  the 
  exumbrella 
  is 
  thickly 
  set 
  with 
  minute 
  tubercles, 
  giving 
  a 
  

   hoary 
  appearance. 
  The 
  subgenital 
  openings 
  are 
  of 
  moderate 
  size. 
  

  

  No 
  one 
  of 
  the 
  large 
  specimens 
  is 
  perfect; 
  but 
  the 
  two 
  most 
  im- 
  

   portant 
  features 
  from 
  the 
  systematic 
  standpoint, 
  canal 
  system 
  and 
  

   margin, 
  are 
  well 
  preserved 
  over 
  at 
  least 
  a 
  part 
  of 
  the 
  periphery, 
  in 
  all. 
  

  

  Canal 
  system. 
  — 
  In 
  the 
  large 
  specimens 
  the 
  canal 
  system 
  is 
  so 
  char- 
  

   acteristic 
  that 
  it 
  identifies 
  them 
  at 
  a 
  glance 
  (pi. 
  5, 
  fig. 
  1). 
  The 
  inter- 
  

   radial 
  groups 
  rise 
  as 
  one 
  trunk, 
  the 
  perradials 
  usually 
  as 
  three 
  trunks; 
  

   in 
  either 
  case 
  the 
  original 
  trunks 
  soon 
  divide 
  and 
  subdivide, 
  whUe 
  

   the 
  resultant 
  branches 
  anastomose 
  among 
  themselves 
  and 
  with 
  the 
  

   outer 
  portions 
  of 
  the 
  adradials, 
  until 
  the 
  entire 
  subumbrella 
  is 
  occu- 
  

   pied 
  by 
  an 
  exceedingly 
  close-meshed 
  and 
  complicated 
  canal-net, 
  in 
  

   which 
  the 
  adradials 
  are 
  conspicuous 
  by 
  the 
  fact 
  that 
  they 
  are 
  inde- 
  

   pendent 
  for 
  the 
  inner 
  two-thirds 
  of 
  their 
  length. 
  

  

  In 
  the 
  smallest 
  specimen 
  (16 
  mm.) 
  the 
  adradials 
  are 
  unbranched, 
  

   and 
  each 
  per- 
  and 
  inTerradial 
  group 
  arises 
  as 
  a 
  single 
  trunk, 
  which 
  

  

  