﻿46 
  PROCEEDINGS 
  OF 
  THE 
  NATIONAL 
  MUSEUM. 
  vol.44. 
  

  

  nematocysts, 
  and 
  there 
  are 
  64 
  otocyst-clubs 
  alternating 
  with 
  the 
  

   tentacles, 
  as 
  in 
  P. 
  ruhrum. 
  Structurally 
  the 
  clubs 
  agree 
  with 
  Van- 
  

   liofFen's 
  (1902&) 
  figure 
  of 
  clubs 
  of 
  the 
  latter 
  species. 
  

  

  Color. 
  — 
  The 
  specimens 
  are 
  colorless, 
  the 
  subunibrella 
  highly 
  iri- 
  

   descent. 
  One 
  specimen 
  appeared, 
  at 
  first 
  sight, 
  to 
  have 
  a 
  reddish 
  

   tinge, 
  but 
  on 
  examination 
  it 
  proved 
  that 
  the 
  color 
  was 
  confined 
  to 
  

   the 
  exumbrella 
  surface, 
  and 
  was 
  evidently 
  an 
  accidental 
  stain. 
  In 
  

   P. 
  ruhrum 
  subumbrella 
  and 
  manubrium 
  are 
  rosy 
  red. 
  

  

  Genus 
  COLOBONEMA 
  Vanhoffen, 
  1902. 
  

  

  Colobonema 
  Maas 
  (1905).— 
  Browne 
  (1906).— 
  Bigelow 
  (1909a). 
  

   Eomoconema 
  Mayer 
  (1910) 
  part. 
  

  

  The 
  one 
  species 
  of 
  Colohonema 
  3^et 
  known 
  is 
  characterized 
  by 
  the 
  

   order 
  of 
  development 
  of 
  its 
  tentacles, 
  of 
  which 
  the 
  8 
  pcrradial, 
  the 
  16 
  

   adradial, 
  and 
  finally 
  the 
  8 
  interradial 
  appear 
  successively, 
  32 
  being 
  

   the 
  final 
  number 
  in 
  every 
  specimen 
  which 
  has 
  yet 
  been 
  examined. 
  

   Though 
  it 
  is 
  not 
  yet 
  certain 
  that 
  this 
  type 
  of 
  succession 
  is 
  peculiar 
  to 
  

   Colohonema, 
  it 
  is 
  certainly 
  unusual, 
  and 
  there 
  is 
  no 
  evidence 
  that 
  it 
  

   occurs 
  elsewhere. 
  

  

  Maas 
  (1905) 
  and 
  Mayer 
  (1910) 
  use 
  the 
  name 
  ^?//>icii7)?,, 
  believing 
  that 
  

   sericeum 
  Vanhoffen 
  is 
  identical 
  with 
  the 
  form 
  from 
  the 
  Gulf 
  of 
  Cali- 
  

   fornia 
  earlier 
  described 
  by 
  the 
  former 
  as 
  Homoeonema 
  typicum, 
  and 
  

   for 
  the 
  sake 
  of 
  uniformity 
  the 
  same 
  course 
  is 
  followed 
  here. 
  

  

  C. 
  typicum 
  Vanhoffen 
  is 
  now 
  known 
  to 
  be 
  a 
  mesoplanktonic 
  form 
  

   of 
  very 
  wide 
  distribution 
  (Bay 
  of 
  Biscay, 
  west 
  coast 
  of 
  Africa, 
  Malay- 
  

   sian 
  region, 
  Philippines, 
  eastern 
  tropical 
  Pacific, 
  and 
  northwestern 
  

   Pacific). 
  

  

  COLOBONEMA 
  TYPICUM 
  (Maas). 
  

   Homoeonema 
  typicum 
  Maas, 
  1897, 
  p. 
  22, 
  pi. 
  3, 
  figs. 
  1-3. 
  

  

  (For 
  synonymy, 
  see 
  Mayer, 
  1910, 
  p. 
  385.) 
  

  

  Station 
  4905, 
  369-0 
  fathoms 
  ; 
  1 
  specimen, 
  about 
  32 
  mm. 
  in 
  diameter. 
  

  

  Station 
  4909, 
  300-0 
  fathoms; 
  2 
  specimens, 
  40 
  and 
  30 
  mm. 
  in 
  diam- 
  

   eter. 
  

  

  Station 
  4917, 
  361-0 
  fathoms; 
  1 
  specimen, 
  about 
  35 
  mm. 
  in 
  diameter. 
  

  

  Station 
  4920, 
  440-0 
  fathoms; 
  1 
  specimen, 
  28 
  mm. 
  in 
  diameter. 
  

  

  Station 
  5066, 
  211-0 
  fathoms; 
  1 
  specimen, 
  32 
  mm. 
  in 
  diameter. 
  

  

  The 
  material 
  is 
  not 
  good 
  enough 
  to 
  add 
  much 
  to 
  the 
  earlier 
  accounts, 
  

   but 
  it 
  is 
  interesting 
  as 
  further 
  evidence 
  of 
  the 
  invariable 
  number 
  32, 
  

   of 
  tentacles, 
  of 
  which 
  the 
  interradial 
  in 
  each 
  octant 
  is 
  always 
  the 
  

   smallest; 
  and 
  because 
  one 
  specimen 
  shows 
  the 
  gonads, 
  the 
  two 
  which 
  

   are 
  intact 
  being 
  nearly 
  cylindrical, 
  narrow 
  and 
  smooth, 
  and 
  extend- 
  

   ing 
  from 
  close 
  to 
  the 
  apex 
  nearly 
  to 
  the 
  margin, 
  much 
  the 
  condition 
  

   observed 
  by 
  Maas 
  (1905). 
  No 
  otocysts 
  were 
  preserved, 
  but 
  one 
  is 
  

   intact 
  in 
  a 
  specimen 
  from 
  the 
  Philippines. 
  The 
  manubrium 
  usually 
  

   hangs 
  to 
  about 
  the 
  mid 
  level 
  of 
  the 
  bell, 
  but 
  may 
  be 
  contracted. 
  

  

  