﻿NO. 
  1946. 
  PACIFIC 
  MEDUSAE 
  AND 
  SIPHONOPHORAE—BIGELOW. 
  45 
  

  

  Station 
  4763, 
  300 
  fathoms; 
  18 
  specimens. 
  

  

  Station 
  4764, 
  1130-0 
  fathoms; 
  2 
  specimens. 
  

  

  Station 
  4766, 
  300-0 
  fathoms; 
  10 
  specimens. 
  

  

  Station 
  4767, 
  300-0 
  fathoms; 
  12 
  specimens. 
  

  

  Station 
  4774, 
  557-0 
  fathoms; 
  1 
  specimen. 
  

  

  Station 
  4775, 
  200-0 
  fathoms; 
  24 
  specimens; 
  excellent 
  condition. 
  

  

  Station 
  4800, 
  300-0 
  fathoms; 
  14 
  specimens. 
  

  

  Station 
  5030, 
  1800-0 
  fathoms; 
  4 
  specimens; 
  fragmentary. 
  

  

  Most 
  of 
  the 
  specimens 
  are 
  in 
  good 
  condition, 
  except 
  that 
  the 
  

   tentacles 
  are 
  broken 
  short 
  off. 
  The 
  series 
  ranges 
  in 
  height 
  from 
  

   5-19 
  mm. 
  Up 
  to 
  the 
  present 
  time 
  only 
  two 
  specimens 
  of 
  tliis 
  species 
  

   have 
  been 
  recorded, 
  oAe 
  young 
  (Maas, 
  1893, 
  8 
  mm.), 
  the 
  other 
  frag- 
  

   mentary 
  (Maas, 
  19046). 
  

  

  In 
  general 
  outline 
  the 
  specimens 
  are 
  thimble-shaped, 
  with 
  deep 
  

   bell 
  cavity, 
  and 
  thin 
  gelatinous 
  substance 
  (pi. 
  3, 
  fig. 
  4) 
  ; 
  most 
  of 
  them 
  

   are 
  about 
  as 
  broad 
  as 
  high, 
  but 
  several 
  are 
  proportionately 
  broader, 
  

   though 
  in 
  good 
  condition. 
  Probably 
  the 
  differences 
  m 
  this 
  respect 
  

   between 
  different 
  specimens 
  are 
  due 
  to 
  varying 
  states 
  of 
  contraction. 
  

  

  The 
  exumbrella 
  is 
  marked 
  by 
  a 
  regular 
  series 
  of 
  meridional 
  furrows, 
  

   nmning 
  from 
  apex 
  to 
  margm, 
  thirty-two 
  in 
  every 
  large 
  specimen 
  in 
  

   which 
  I 
  could 
  count 
  them; 
  the 
  subumbrella 
  is 
  extremely 
  muscular. 
  

  

  Manubrium. 
  — 
  The 
  manubrium 
  is 
  flask-shaped, 
  sessile, 
  without 
  a 
  

   trace 
  of 
  peduncle, 
  the 
  mouth 
  surrounded 
  by 
  four 
  pointed 
  lips 
  (pi. 
  3, 
  

   fig. 
  8). 
  

  

  In 
  the 
  original 
  specimen 
  of 
  liaeckeli 
  the 
  eight 
  gonads 
  extended 
  the 
  

   whole 
  length 
  of 
  the 
  radial 
  canals, 
  formmg 
  several 
  irregular 
  thicken- 
  

   ings 
  on 
  each. 
  Very 
  much 
  the 
  same 
  condition 
  is 
  to 
  be 
  seen 
  also 
  in 
  

   our 
  small 
  specimens, 
  6-8 
  mm. 
  high 
  (pi. 
  3, 
  fig. 
  5), 
  in 
  which 
  each 
  canal 
  

   bears 
  from 
  2-4 
  sexual 
  swellings, 
  connected 
  or 
  not 
  according 
  to 
  their 
  

   age. 
  But 
  the 
  sexual 
  centers 
  do 
  not 
  remain 
  independent, 
  for 
  as 
  growth 
  

   progresses, 
  sex-tissue 
  is 
  developed 
  along 
  almost 
  the 
  entire 
  length 
  of 
  

   each 
  canal, 
  connecting 
  them 
  in 
  a 
  continuous 
  ridge 
  (pi. 
  3, 
  fig. 
  6), 
  which 
  

   finally 
  takes 
  on 
  a 
  wavy 
  form 
  (pi. 
  3, 
  fig. 
  7). 
  The 
  development 
  of 
  the 
  

   gonads 
  is 
  very 
  irregular, 
  not 
  only 
  in 
  different 
  specimens, 
  but 
  often 
  in 
  

   the 
  different 
  canals 
  of 
  a 
  given 
  specimen, 
  and 
  the 
  largest 
  gonads 
  were 
  

   found 
  in 
  a 
  specimen 
  only 
  14 
  mm. 
  high. 
  Another 
  feature 
  adding 
  to 
  

   their 
  irregularity 
  is 
  that 
  in 
  all 
  the 
  large 
  specimens 
  the 
  sexual 
  pro- 
  

   ducts 
  had 
  been 
  shed 
  over 
  the 
  distal 
  end 
  of 
  each 
  gonad, 
  as 
  is 
  made 
  

   noticeable 
  by 
  a 
  difference 
  in 
  color, 
  the 
  distal 
  part 
  being 
  white 
  instead 
  

   of 
  brownish-yellow. 
  

  

  Marginal 
  organs. 
  — 
  In 
  every 
  specimen, 
  large 
  and 
  small, 
  which 
  was 
  

   m 
  good 
  enough 
  condition 
  to 
  show 
  the 
  stumps 
  of 
  the 
  tentacles, 
  there 
  

   are 
  64, 
  that 
  is, 
  8 
  perradials 
  and 
  7 
  subradials 
  in 
  each 
  octant; 
  and 
  

   the 
  same 
  is 
  true 
  in 
  P. 
  ruhrum. 
  Between 
  the 
  bases 
  of 
  the 
  tentacles 
  

   the 
  margin 
  is 
  thickened, 
  forming 
  rounded 
  prominences 
  crowded 
  with 
  

  

  