﻿NO. 
  1946. 
  PACIFIC 
  MEDUSAE 
  AND 
  SIPHONOPHORAE—BIGELOW. 
  

   The 
  series 
  affords 
  the 
  following 
  numerical 
  data 
  : 
  

  

  1. 
  UNION 
  BAY. 
  

  

  2. 
  PUGET 
  SOUND. 
  

  

  3. 
  SPECIMEN 
  FROM 
  NAPLES. 
  

  

  Thus 
  the 
  numerical 
  proportion 
  between 
  tentacles 
  and 
  canals 
  is 
  

   variable 
  according 
  as 
  more 
  or 
  fewer 
  bulbs 
  develop 
  into 
  tentacles. 
  

  

  In 
  specimens 
  up 
  to 
  190 
  mm. 
  in 
  diameter 
  Torrey 
  found 
  the 
  tentacles 
  

   more 
  numerous 
  than 
  the 
  radial 
  canals 
  (about 
  120), 
  and 
  in 
  one 
  55 
  mm. 
  

   in 
  diameter 
  fi-om 
  San 
  Diego 
  there 
  were 
  90 
  canals; 
  in 
  the 
  Puget 
  Sound 
  

   series 
  studied 
  by 
  Murbach 
  and 
  Shearer 
  (1903) 
  there 
  were 
  about 
  as 
  

   many 
  tentacles 
  as 
  canals 
  (about 
  100 
  of 
  each 
  in 
  specimens 
  70 
  mm. 
  

   broad) 
  besides 
  numerous 
  laiobs. 
  

  

  The 
  general 
  "habitus" 
  has 
  often 
  been 
  described, 
  and 
  its 
  chief 
  

   variations 
  have 
  been 
  tabulated 
  by 
  Mayer 
  (1910). 
  

  

  The 
  shape 
  of 
  the 
  tentacular 
  bulbs 
  is 
  important, 
  because 
  of 
  its 
  

   bearing 
  on 
  the 
  status 
  of 
  A. 
  macrodactylum. 
  In 
  most 
  cases 
  they 
  are 
  

   somewhat 
  triangular, 
  tapering, 
  slightly 
  narrower 
  at 
  their 
  junction 
  

   with 
  the 
  margin 
  than 
  just 
  below, 
  circular 
  in 
  cross 
  section, 
  and 
  in 
  side 
  

   view 
  we 
  see 
  that 
  they 
  cover 
  very 
  little, 
  if 
  any, 
  of 
  the 
  exumbrella. 
  On 
  

   some 
  of 
  the 
  largest 
  tentacles, 
  however, 
  the 
  bulbs 
  are 
  so 
  much 
  thicker 
  

   that 
  they 
  do 
  cover 
  a 
  considerable 
  amount 
  of 
  the 
  exumbrella, 
  and 
  it 
  

   would 
  take 
  only 
  a 
  slight 
  increase 
  in 
  this 
  respect 
  to 
  equal 
  the 
  small 
  

   tentacles 
  in 
  A. 
  macrodactylum; 
  but 
  none 
  have 
  distinct 
  clasps. 
  The 
  

   bulbs 
  of 
  half-grown 
  tentacles 
  are 
  fusiform. 
  

  

  The 
  excretory 
  papillae 
  are 
  very 
  prominent, 
  one 
  associated 
  with 
  

   every 
  tentacle, 
  and 
  even 
  with 
  the 
  youngest 
  knob, 
  from 
  which 
  it 
  

   appears 
  that 
  in 
  development 
  knob 
  and 
  papilla 
  are 
  formed 
  at 
  about 
  

   the 
  same 
  time. 
  After 
  preservation 
  the 
  mouth 
  is 
  wide 
  open 
  in 
  all 
  our 
  

   specimens; 
  nor 
  does 
  it 
  give 
  any 
  clue 
  to 
  its 
  normal 
  ability 
  to 
  expand, 
  

  

  