﻿86 
  PROCEEDINGS 
  OF 
  THE 
  NATIONAL 
  MUSEUM. 
  vol. 
  44. 
  

  

  Family 
  ATOLLIDAE 
  Bigelow. 
  

  

  Family 
  COLLASPIDAE 
  » 
  Haeckel. 
  

  

  Genus 
  ATOLLA 
  Haeckel, 
  1880. 
  

  

  The 
  general 
  anatomy 
  of 
  this 
  peculiar 
  genus 
  is 
  now 
  well 
  known, 
  

   thanks 
  to 
  Maas 
  (1897, 
  1903, 
  1904&) 
  and 
  Vanhoffen 
  (1902a); 
  but 
  the 
  

   specific 
  relationships 
  of 
  its 
  members 
  are 
  still 
  unsettled, 
  because 
  the 
  

   characters 
  which 
  have 
  been 
  used 
  to 
  separate 
  the 
  various 
  closely 
  

   allied 
  "species," 
  are 
  all 
  more 
  or 
  less 
  subject 
  to 
  individual 
  variation. 
  

  

  The 
  characters 
  used 
  by 
  Vanhoffen 
  to 
  separate 
  species 
  are 
  the 
  

   presence 
  or 
  absence 
  of 
  radiai 
  furrows 
  in 
  the 
  central 
  disk; 
  whether 
  

   the 
  furrows, 
  if 
  present, 
  are 
  broad 
  or 
  narrow; 
  the 
  presence 
  or 
  absence 
  

   of 
  exumbral 
  warts; 
  and 
  the 
  size 
  of 
  the 
  septal 
  nodes. 
  But 
  I 
  have 
  

   found 
  that 
  it 
  is 
  impossible 
  to 
  draw 
  any 
  sharp 
  line 
  between 
  specimens 
  

   with 
  broad 
  and 
  those 
  with 
  narrow 
  radial 
  furrows;, 
  and 
  the 
  present 
  

   series 
  shows 
  that 
  the 
  size 
  of 
  the 
  septal 
  nodes 
  is 
  so 
  variable 
  that 
  it 
  

   can 
  not 
  be 
  a 
  specific 
  character. 
  There 
  remain 
  then 
  only 
  the 
  presence 
  

   or 
  absence 
  of 
  radial 
  furrows, 
  and 
  of 
  exumbral 
  knobs. 
  Mayer 
  notes 
  

   that 
  the 
  former 
  is 
  not 
  a 
  sharp 
  difference, 
  because 
  there 
  may 
  be 
  faint 
  

   sinuosities 
  on 
  the 
  margin 
  of 
  the 
  central 
  disk, 
  without 
  any 
  true 
  radial 
  

   furrows; 
  so 
  that 
  he 
  suggests 
  that 
  the 
  two 
  forms, 
  wyvillei 
  with 
  fur- 
  

   rows 
  and 
  hairdii 
  with' 
  a 
  smooth 
  disk 
  may 
  be 
  merely 
  varieties 
  of 
  a 
  

   single 
  species. 
  

  

  Vanhoffen 
  recognized 
  five 
  species, 
  hairdii, 
  valdiviae, 
  verriUii, 
  chuni, 
  

   and 
  wyvillei; 
  but 
  Mayer 
  reduces 
  these 
  to 
  three, 
  hairdii 
  with 
  smooth 
  

   disk, 
  wyvillei 
  with 
  radial 
  furrows, 
  and 
  chuni, 
  in 
  which 
  the 
  lappets 
  are 
  

   sprinkled 
  with 
  exumbral 
  papillae; 
  a 
  reduction 
  which 
  seems 
  war- 
  

   ranted. 
  Chuni 
  has 
  now 
  been 
  recorded 
  by 
  Browne 
  (1910) 
  from 
  the 
  

   Antarctic, 
  and 
  Hartlaub 
  (1909a) 
  has 
  recently 
  described 
  another 
  

   species, 
  A. 
  tenilla 
  from 
  the 
  Greenland 
  Sea; 
  but 
  this 
  is 
  probably 
  the 
  

   young 
  either 
  of 
  hairdii 
  or 
  of 
  wyviUei. 
  

  

  ATOLLA 
  WYVILLEI 
  Haeckel. 
  

  

  Atolla 
  wyvillei 
  Haeckel, 
  1880, 
  p. 
  488; 
  1881, 
  p. 
  113, 
  pi. 
  29, 
  fig. 
  1-9.— 
  Vanhoffen, 
  

   1902a, 
  p. 
  13, 
  pi. 
  5, 
  fig. 
  22.— 
  Bigelow, 
  1909a, 
  p. 
  39, 
  pi, 
  8, 
  fig. 
  1; 
  pi. 
  9, 
  

   fig. 
  3; 
  pi. 
  10, 
  figs. 
  8, 
  9. 
  

  

  Collaspis 
  achilis 
  Haeckel, 
  1880, 
  p. 
  489. 
  

  

  Atolla 
  alexandri 
  Maas, 
  1897, 
  p. 
  81, 
  pi. 
  11, 
  fig. 
  2; 
  pi. 
  14, 
  fig. 
  4, 
  5. 
  

   (For 
  full 
  synonymy 
  see 
  Mayer, 
  1910, 
  p. 
  566.) 
  

  

  Station 
  4758, 
  300-0 
  fathoms; 
  1 
  specimen. 
  

   Station 
  4759, 
  300-0 
  fathoms; 
  2 
  specimens. 
  

   Station 
  4760, 
  300-0 
  fathoms; 
  3 
  specimens. 
  

   Station 
  4764, 
  1130-0 
  fathoms; 
  1 
  specimen. 
  

   Station 
  4765, 
  300-0 
  fathoms; 
  1 
  specimen. 
  

  

  1 
  Untenable, 
  because 
  Collasjria 
  is 
  a 
  synonym 
  of 
  AtoUa. 
  

  

  