﻿22 
  PROCEEDINGS 
  OF 
  THE 
  NATIONAL 
  MUSEUM. 
  vol.44. 
  

  

  true, 
  which 
  distuigiiishes 
  the 
  Atlantic 
  spechnens 
  of 
  typa 
  from 
  their 
  

   Indian 
  Ocean 
  representative 
  (Vanlioffen) 
  and 
  from 
  simulans; 
  that 
  

   is, 
  the 
  presence 
  of 
  a 
  funnel-shaped 
  apical 
  depression 
  in 
  the 
  former 
  

   and 
  its 
  absence 
  in 
  the 
  latter. 
  I 
  should 
  not 
  lay 
  stress 
  on 
  this, 
  were 
  

   it 
  not 
  that 
  Fewkes's 
  example 
  of 
  typa 
  shows 
  it 
  very 
  clearly. 
  And 
  

   when 
  specimens 
  from 
  the 
  same 
  general 
  locality, 
  but 
  captured 
  some 
  

   30 
  years 
  apart, 
  have 
  so 
  trifling 
  a 
  character 
  well 
  developed, 
  it 
  can 
  

   liardly 
  be 
  looked 
  on 
  as 
  an 
  individual 
  variation. 
  The 
  probable 
  

   explanation 
  is 
  that 
  typa, 
  a 
  form 
  of 
  very 
  wide 
  distribution, 
  has 
  local 
  

   varieties. 
  And 
  this 
  is 
  not 
  at 
  all 
  an 
  unreasonable 
  assumption, 
  since 
  it 
  

   is 
  probable 
  that 
  Calycopsis, 
  though 
  belonging 
  to 
  the 
  Mesoplankton, 
  

   has 
  a 
  fixed 
  stage. 
  C. 
  chuni 
  is 
  distinguished 
  from 
  typa 
  not 
  only 
  by 
  the 
  

   number 
  of 
  tentacles, 
  but 
  by 
  a 
  less 
  regular 
  arrangement 
  of 
  the 
  genital 
  

   folds, 
  and, 
  according 
  to 
  Vanhoffen, 
  by 
  the 
  red 
  color 
  of 
  its 
  tentacles. 
  

  

  In 
  horchgrevinki, 
  accordmg 
  to 
  both 
  Browne 
  (1910) 
  and 
  Vanhoffen 
  

   (1911), 
  there 
  are 
  8 
  canals, 
  4 
  radial, 
  and 
  4 
  interradial 
  centripetal, 
  and 
  

   up 
  to 
  16 
  tentacles. 
  The 
  gonads 
  are 
  restricted 
  to 
  the 
  upper 
  part 
  of 
  

   the 
  manubrium. 
  In 
  small 
  specimens, 
  10-18 
  mm. 
  high, 
  the 
  genital 
  

   products 
  suggest 
  transverse 
  folds 
  (Vanhoffen), 
  but 
  in 
  large 
  ones, 
  

   20 
  mm. 
  high, 
  they 
  lie 
  in 
  irregularly 
  arranged 
  pockets 
  (Browne), 
  

   though 
  probably 
  the 
  difference 
  is 
  one 
  of 
  terms 
  of 
  description 
  only. 
  

   Vanhoffen 
  (1911) 
  has 
  suggested 
  that 
  lorchgrevinlci 
  is 
  a 
  young 
  stage 
  

   of 
  typa, 
  stating 
  that 
  the 
  restriction 
  of 
  the 
  sex 
  products 
  to 
  the 
  base 
  of 
  

   the 
  manubrium 
  is 
  evidence 
  of 
  immaturity. 
  But 
  this 
  does 
  not 
  

   necessarily 
  follow. 
  On 
  the 
  contrary, 
  the 
  fact 
  that 
  all 
  the 
  specimens 
  

   of 
  this 
  species 
  agree 
  in 
  their 
  general 
  stages 
  of 
  development, 
  though 
  

   taken 
  at 
  far 
  separated 
  localities 
  (south 
  of 
  Bouvet 
  Island, 
  and 
  near 
  

   Cape 
  Adare), 
  and 
  especially 
  that 
  Browne 
  (1910) 
  observed 
  large 
  ova, 
  

   as 
  well 
  as 
  gonads 
  emptied 
  of 
  their 
  contents, 
  suggests 
  that 
  we 
  are 
  

   dealing 
  with 
  a 
  small, 
  simply 
  organized 
  Antarctic 
  species. 
  If 
  not, 
  

   advancing 
  development 
  would 
  seem 
  to 
  lead, 
  not 
  to 
  typa, 
  but 
  to 
  a 
  

   stage 
  resembling 
  higelowi, 
  which 
  agrees 
  with 
  horchgrevinki 
  in 
  having 
  

   more 
  tentacles 
  than 
  canals, 
  and 
  in 
  the 
  number 
  of 
  canals. 
  It 
  is 
  true 
  

   that 
  it 
  has 
  more 
  tentacles 
  (about 
  48, 
  large 
  and 
  small, 
  in 
  the 
  one 
  

   known 
  specimen), 
  and 
  that 
  the 
  gonads 
  are 
  transversely 
  folded, 
  but 
  

   both 
  these 
  features 
  would 
  naturally 
  result 
  from 
  progressive 
  develop- 
  

   ment 
  of 
  horchgrevinki. 
  Whether 
  these 
  two 
  "species" 
  are 
  finally 
  

   united, 
  more 
  extensive 
  material 
  alone 
  can 
  show. 
  

  

  In 
  the 
  several 
  species 
  of 
  Calycopsis 
  so 
  far 
  considered, 
  the 
  lip, 
  though 
  

   more 
  or 
  less 
  folded, 
  has 
  a 
  smooth 
  margm 
  without 
  projections 
  or 
  

   papillae 
  of 
  any 
  kind, 
  but 
  in 
  a 
  series 
  in 
  the 
  present 
  collection 
  it 
  is 
  not 
  

   only 
  extensively 
  folded, 
  but 
  is 
  studded 
  with 
  a 
  marginal 
  row 
  of 
  stalked 
  

   nematocyst 
  knobs, 
  a 
  structural 
  character 
  so 
  distinctive 
  that 
  it 
  alone 
  

   would 
  warrant 
  the 
  institution 
  of 
  a 
  new 
  species. 
  And 
  the 
  structure 
  

   of 
  the 
  gonads 
  is 
  likewise 
  characteristic. 
  In 
  the 
  proportionate 
  number 
  

  

  