﻿NO. 
  1946. 
  PACIFIC 
  MEDUSAE 
  AND 
  SIPHONOPHORAE—BIOELOW. 
  25 
  

  

  fig. 
  1) 
  — 
  and 
  3 
  in 
  which 
  all 
  the 
  ,canals,16 
  in 
  each 
  case, 
  are 
  associated 
  

   with 
  large 
  tentacles. 
  In 
  general, 
  then, 
  we 
  may 
  assume 
  that 
  after 
  the 
  

   4 
  primary 
  radial 
  canals, 
  4 
  more, 
  and 
  then 
  a 
  third 
  series 
  of 
  4-6 
  more, 
  

   are 
  formed. 
  

  

  In 
  addition 
  to 
  the 
  canalar 
  tentacles 
  every 
  specimen 
  has 
  a 
  large 
  

   number 
  of 
  tentacles 
  which 
  alternate 
  with 
  the 
  canals. 
  In 
  the 
  youngest 
  

   example, 
  age 
  being 
  judged 
  by 
  the 
  condition 
  of 
  the 
  canalar 
  tentacles, 
  

   there 
  are 
  only 
  16 
  of 
  these 
  — 
  that 
  is, 
  1 
  between 
  every 
  2 
  canals. 
  They 
  

   increase 
  irregularly 
  in 
  number, 
  and 
  in 
  the 
  older 
  specimens 
  there 
  

   are' 
  usually 
  2, 
  often 
  3, 
  between 
  each 
  pair 
  of 
  tentacles. 
  The 
  largest 
  

   number 
  is 
  41, 
  in 
  an 
  example 
  with 
  17 
  canals. 
  

  

  The 
  fact 
  that 
  the 
  increase 
  of 
  tentacles 
  so 
  far 
  outstrips 
  that 
  of 
  canals 
  — 
  

   the 
  latter, 
  indeed, 
  being 
  almost 
  stationary 
  — 
  indicates 
  that 
  the 
  canals 
  

   have 
  probably 
  nearly 
  or 
  quite 
  attained 
  their 
  final 
  number. 
  Except 
  

   for 
  size, 
  the 
  tentacles 
  are 
  structurally 
  all 
  alike, 
  there 
  being 
  no 
  very 
  

   young 
  ones 
  in 
  any 
  of 
  the 
  specimens. 
  Each 
  has 
  a 
  large 
  terminal 
  

   nematocyst 
  knob 
  which 
  is 
  spherical, 
  instead 
  of 
  pear-shaped, 
  as 
  it 
  is 
  in 
  

   typa. 
  The 
  older 
  tentacles 
  curve 
  upward 
  at 
  first, 
  and 
  lie 
  in 
  furrows 
  

   of 
  the 
  exumbrella, 
  just 
  as 
  m 
  other 
  members 
  of 
  the 
  genus, 
  but 
  the 
  

   younger 
  ones 
  project 
  directly 
  from 
  the 
  margin, 
  the 
  course 
  of 
  develop- 
  

   ment 
  in 
  this 
  respect 
  being 
  precisely 
  what 
  it 
  is 
  in 
  typa 
  (Bigelow, 
  1909&). 
  

  

  Color. 
  — 
  No 
  color 
  notes 
  were 
  made 
  from 
  life. 
  After 
  preservation 
  the 
  

   gonads 
  are 
  pale 
  brownish-red. 
  But 
  it 
  should 
  be 
  noted 
  that 
  specimens 
  

   of 
  typa 
  in 
  which 
  these 
  organs 
  are 
  a 
  very 
  deep 
  chocolate 
  in 
  life 
  fade 
  

   to 
  the 
  same 
  pale 
  tint 
  after 
  preservation 
  in 
  formalin. 
  

  

  The 
  localities 
  of 
  capture 
  are 
  restricted 
  to 
  the 
  Bering 
  Sea 
  region 
  

   and 
  the 
  Sea 
  of 
  Okliotsk. 
  

  

  Genus 
  HETEROTIARA 
  Maas, 
  190S. 
  

  

  Two 
  species 
  of 
  Heterotiara, 
  anonyma 
  Maas 
  and 
  minor 
  VanhofFen, 
  

   have 
  been 
  described, 
  and 
  my 
  own 
  examination 
  of 
  considerable 
  series 
  

   of 
  both 
  (minor 
  from 
  the 
  Phihppines) 
  shows 
  that 
  they 
  are 
  undoubtedly 
  

   distinct. 
  They 
  are 
  separated 
  by 
  the 
  number 
  of 
  tentacles 
  correlated 
  

   with 
  size, 
  anonyma 
  havmg 
  12 
  tentacles 
  (or 
  less) 
  when 
  adult, 
  and 
  reach- 
  

   ing 
  a 
  height 
  of 
  20 
  mm. 
  ; 
  whereas 
  minor 
  has 
  about 
  twice 
  as 
  many 
  tenta- 
  

   cles, 
  though 
  much 
  smaller 
  (only 
  about 
  10 
  mm. 
  high). 
  The 
  Philip- 
  

   pine 
  series 
  of 
  minor 
  will 
  be 
  described 
  elsewhere. 
  The 
  present 
  col- 
  

   lection 
  contains 
  an 
  excellent 
  series 
  of 
  anonyma, 
  a 
  species 
  previously 
  

   known 
  from 
  four 
  specimens 
  only. 
  

  

  HETEOTIARA 
  ANONYMA 
  Maas. 
  

  

  Heterotiara 
  anonyma 
  Maas, 
  1905, 
  p. 
  19, 
  pi. 
  3, 
  figs. 
  19-21. 
  — 
  Bigelow, 
  1909a, 
  p. 
  216, 
  

   pi. 
  41, 
  fige. 
  12, 
  13.— 
  Vanhoffen, 
  1911, 
  p. 
  211, 
  pi. 
  22, 
  figa. 
  3, 
  4. 
  

  

  