﻿NO. 
  1946. 
  PACIFIC 
  MEDUSAE 
  AND 
  SIPHONOPHORAE—BIOELOW. 
  5 
  

  

  evidently 
  the 
  result 
  of 
  the 
  contraction 
  of 
  the 
  bell 
  as 
  a 
  whole. 
  The 
  

   short 
  manubria, 
  irregular 
  aiTangement 
  of 
  the 
  sexual 
  products 
  over 
  its 
  

   wall 
  and 
  absence 
  of 
  apical 
  canal 
  and 
  ocelli 
  are 
  all 
  easily 
  distinguished. 
  

   Color. 
  — 
  In 
  formalin, 
  manubrium 
  and 
  tentacle 
  bases 
  are 
  pale 
  brown- 
  

   ish. 
  The 
  original 
  records 
  of 
  japonica 
  were 
  from 
  Todohokke 
  and 
  

   Hokkaido, 
  Japan. 
  

  

  SARSIA 
  PRINCEPS 
  (Haeckel). 
  

   Codonium 
  princeps 
  Haeckel, 
  1879, 
  p. 
  13, 
  pi. 
  1, 
  figs. 
  1, 
  2. 
  

   (For 
  synonymy, 
  see 
  Mayer, 
  1910, 
  p. 
  60.) 
  

  

  Station 
  3604, 
  southern 
  Bering 
  Sea, 
  August, 
  1895; 
  surface; 
  1 
  speci- 
  

   men, 
  about 
  30 
  mm. 
  high. 
  

  

  The 
  single 
  example 
  is 
  flattened, 
  and 
  its 
  manubrium 
  so 
  strongly 
  

   contracted, 
  that 
  it 
  is 
  a 
  mere 
  knob; 
  but 
  the 
  specihien 
  is 
  readily 
  iden- 
  

   tified 
  by 
  the 
  long 
  "still-canal" 
  and 
  by 
  the 
  irregular 
  margins 
  of 
  the 
  

   radial 
  canals 
  though 
  the 
  latter 
  are 
  somewhat 
  less 
  pronounced 
  than 
  

   in 
  a 
  specimen 
  from 
  Newfoundland 
  (1909, 
  p. 
  303), 
  as 
  well 
  as 
  by 
  its 
  

   large 
  size. 
  

  

  For 
  a 
  list 
  of 
  occurrences 
  of 
  this 
  species, 
  which 
  include 
  Newfound- 
  

   land, 
  Greenland, 
  Davis 
  Strait, 
  Spitzbergen, 
  the 
  White 
  Sea, 
  and 
  

   Barents 
  Sea, 
  see 
  Hartlaub 
  (1907, 
  p. 
  49). 
  

  

  Genus 
  HYBOCODON 
  L. 
  Agassiz. 
  

  

  The 
  medusae 
  of 
  this 
  genus 
  may 
  be 
  almost 
  indistmguishable 
  although 
  

   budded 
  off 
  from 
  hydroids 
  which 
  are 
  perfectly 
  distinct; 
  for 
  example, 
  

   the 
  medusae 
  of 
  H. 
  christinae 
  Hartlaub 
  closely 
  resemble 
  those 
  of 
  H. 
  

   prolifer 
  Agassiz, 
  but 
  the 
  hydroids 
  of 
  these 
  two 
  species 
  can 
  not 
  be 
  

   confused, 
  because 
  in 
  the 
  former 
  the 
  medusa 
  buds 
  are 
  borne 
  singly, 
  in 
  

   the 
  latter 
  on 
  stolons. 
  The 
  following 
  North 
  Atlantic 
  species 
  are 
  listed 
  

   by 
  Hartlaub 
  (1907), 
  who 
  has 
  made 
  the 
  most 
  thorough 
  study 
  of 
  the 
  

   genus: 
  pulcher 
  Saemundsson, 
  prolifer 
  L. 
  Agassiz, 
  christinae 
  Hartlaub, 
  

   gravidumhinko 
  , 
  islandicum 
  Greene, 
  and 
  ampJiipleurus 
  Haeckel; 
  but 
  

   as 
  Mayer 
  (1910) 
  has 
  noted, 
  it 
  is 
  probable 
  that 
  gravidum 
  and 
  islandi- 
  

   cum 
  are 
  synonyms 
  of 
  prolifer 
  (of 
  neither 
  of 
  them 
  is 
  the 
  hydroid 
  

   known); 
  and 
  ampJiipleurus 
  is 
  known 
  from 
  only 
  a 
  single 
  specimen 
  

   (medusa). 
  

  

  H. 
  prolifer 
  is 
  very 
  abundant 
  off 
  the 
  coasts 
  of 
  New 
  England; 
  and 
  

   medusae 
  recorded 
  under 
  that 
  name 
  have 
  been 
  taken 
  by 
  hundreds 
  in 
  

   northern 
  European 
  waters, 
  but 
  the 
  prolifer 
  hydroid 
  has 
  not 
  been 
  

   found 
  on 
  the 
  eastern 
  side 
  of 
  the 
  Atlantic. 
  

  

  Three 
  other 
  Hybocodons 
  have 
  been 
  described, 
  H. 
  unicus 
  Browne 
  

   from 
  the 
  Falkland 
  Islands 
  (medusa 
  only) 
  ; 
  H. 
  chilensis 
  Hartlaub 
  from 
  

   the 
  Chilean 
  coast 
  (hydroid 
  onl}^, 
  and 
  H. 
  occidentalis 
  Fewkes 
  from 
  

   the 
  coast 
  of 
  California 
  (medusa 
  only). 
  Chilensis 
  is 
  allied 
  to 
  the 
  

  

  