﻿242 
  PROCEEDINGS 
  OF 
  THE 
  NATIONAL 
  MUSEUM 
  vol. 
  103 
  

  

  6. 
  Antennae 
  and 
  dorsal 
  cirri 
  swollen 
  at 
  base, 
  tapering 
  to 
  narrow 
  tip 
  (fig. 
  28, 
  m) 
  . 
  

  

  Body 
  and 
  parapodia 
  usually 
  covered 
  with 
  adhesive 
  papillae 
  and 
  fine, 
  granular 
  

  

  material 
  Sphaerosyllis 
  (p. 
  255) 
  

  

  Antennae 
  and 
  dorsal 
  cirri 
  clavate 
  or 
  conical 
  (fig. 
  28, 
  k, 
  I). 
  Bodj' 
  and 
  parapodia 
  

   not 
  covered 
  with 
  papillae 
  Exogone 
  (p. 
  257) 
  

  

  7. 
  Compound 
  neurosetae 
  with 
  distal 
  blades 
  all 
  rather 
  short 
  (fig. 
  28, 
  i). 
  Pro- 
  

  

  boscis 
  with 
  a 
  distal 
  and 
  proximal 
  row 
  of 
  soft 
  papillae, 
  with 
  distal 
  circular 
  

  

  chitinous 
  margin 
  denticled 
  (fig. 
  28, 
  g, 
  h) 
  Eusyllis 
  (p. 
  259) 
  

  

  Compound 
  neurosetae 
  with 
  some 
  distal 
  blades 
  elongate 
  (fig. 
  28, 
  j). 
  Proboscis 
  

   with 
  distal 
  row 
  of 
  soft 
  papillae 
  only, 
  with 
  distal 
  circular 
  chitinous 
  margin 
  

   smooth 
  Pionosyllis 
  (p. 
  262) 
  

  

  Genus 
  Aiitolytus 
  Grube, 
  1850 
  

  

  In 
  working 
  over 
  the 
  rather 
  numerous 
  specimens 
  of 
  Autolytus 
  in 
  

   the 
  collections 
  from 
  Point 
  Barrow, 
  several 
  things 
  were 
  revealed 
  which 
  

   throw 
  light 
  on 
  the 
  confusion 
  in 
  this 
  group 
  caused 
  by 
  the 
  formation 
  of 
  

   sexually 
  dimorphic 
  stolons. 
  For 
  correct 
  description 
  of 
  any 
  species, 
  

   one 
  should 
  have 
  the 
  stem 
  form, 
  the 
  sexual 
  buds 
  in 
  the 
  process 
  of 
  

   formation 
  including 
  the 
  mature 
  sexual 
  buds 
  attached 
  to 
  the 
  stem 
  

   form, 
  and 
  the 
  mature 
  male 
  and 
  female 
  stolons 
  separated 
  from 
  the 
  

   stem. 
  Very 
  often, 
  however, 
  stem 
  forms 
  and 
  the 
  male 
  and 
  female 
  

   stolons 
  of 
  one 
  species 
  have 
  been 
  described 
  and 
  given 
  different 
  names, 
  

   while 
  sexual 
  stolons 
  and 
  stem 
  forms 
  of 
  different 
  species 
  have 
  been 
  

   given 
  the 
  same 
  name. 
  A. 
  fallax 
  Malmgren, 
  described 
  originally 
  from 
  

   specimens 
  from 
  Spitsbergen, 
  is 
  of 
  particular 
  interest. 
  Malmgren 
  

   described 
  and 
  figured 
  the 
  stem 
  form 
  -with 
  the 
  head 
  of 
  a 
  male 
  stolon 
  

   forming 
  between 
  se 
  tigers 
  13 
  and 
  14 
  and 
  indicated 
  that 
  the 
  sexual 
  

   stolons 
  were 
  not 
  known. 
  A. 
  prismaticus 
  (Fabricius), 
  described 
  

   originally 
  from 
  specimens 
  from 
  Greenland, 
  has 
  a 
  characteristic 
  color 
  

   pattern 
  of 
  three 
  dark 
  longitudinal 
  bands 
  (median 
  and 
  lateral 
  at 
  the 
  

   level 
  of 
  the 
  bases 
  of 
  the 
  dorsal 
  cirri). 
  The 
  sexual 
  stolons 
  have 
  six 
  

   unmodified 
  setigers 
  anterior^toHhe 
  setigers' 
  with 
  swimming 
  setae; 
  the 
  

   stolons 
  show 
  the 
  characteristic 
  color 
  pattern 
  of 
  the 
  stem 
  form. 
  In 
  

   the 
  absence 
  of 
  color, 
  it 
  would 
  be 
  difficult 
  to 
  distinguish 
  A. 
  prismaticus 
  

   from 
  certain 
  other 
  species 
  of 
  Autolytus. 
  It 
  apparently 
  has 
  been 
  the 
  

   usual 
  practice 
  to 
  identify 
  any 
  sexual 
  stolon 
  of 
  unknown 
  connections 
  

   that 
  has 
  six 
  anterior 
  unmodified 
  setigers 
  as 
  A. 
  prismaticus, 
  and 
  some- 
  

   times 
  to 
  identify 
  the 
  male 
  stolons 
  as 
  Polyhostrichus 
  longosetosus 
  

   Oersted 
  or 
  A. 
  longisetosus 
  (Oersted). 
  However, 
  as 
  found 
  in 
  the 
  Point 
  

   Barrow 
  material, 
  A. 
  fallax 
  is 
  the 
  most 
  common 
  species 
  of 
  Autolytus 
  

   and 
  it 
  was 
  found 
  along 
  \vith 
  A. 
  prismaticus 
  and 
  A. 
  alexandri. 
  The 
  

   majority 
  of 
  the 
  specimens 
  of 
  A. 
  Jallax 
  were 
  in 
  the 
  process 
  of 
  stolon 
  

   formation, 
  the 
  head 
  of 
  the 
  stolon 
  being 
  formed 
  between 
  setigers 
  13 
  

  

  