﻿MARINE 
  POLYCHAETE 
  WORMS 
  — 
  PETTIBONE 
  241 
  

  

  to 
  several 
  chitinous 
  teeth. 
  Reproduction 
  direct 
  (epigamy) 
  or 
  by 
  

   stolons, 
  sometimes 
  having 
  sexual 
  dimorphism; 
  with 
  swimming 
  capillary 
  

   setae 
  at 
  maturity. 
  

  

  Represented 
  by 
  6 
  genera 
  and 
  11 
  species. 
  

  

  Key 
  to 
  the 
  genera 
  of 
  Syllidae 
  from 
  Point 
  Barrow 
  

  

  1. 
  Without 
  ventral 
  cirri. 
  Palps 
  reduced, 
  united, 
  turned 
  under 
  on 
  ventral 
  side 
  

  

  of 
  prostomium 
  (except 
  for 
  forked 
  palps 
  of 
  male 
  stolon; 
  fig. 
  29, 
  a). 
  Antennae 
  

   and 
  dorsal 
  cirri 
  smooth 
  or 
  faintly 
  annulated. 
  Reproduction 
  by 
  stolons; 
  

   stem 
  forms 
  produce 
  by 
  transverse 
  fission, 
  singly 
  or 
  in 
  chains, 
  sexually 
  

  

  dimorphic 
  male 
  and 
  female 
  forms 
  with 
  swimming 
  setae 
  Autolytus 
  — 
  2 
  

  

  With 
  ventral 
  cirri 
  (fig. 
  28, 
  d) 
  . 
  Palps 
  better 
  developed, 
  free 
  or 
  fused 
  4 
  

  

  2. 
  Prostomium 
  normal, 
  with 
  4 
  dorsal 
  eyes 
  in 
  trapezoidal 
  arrangement, 
  with 
  3 
  

  

  antennae, 
  short 
  fused 
  palps; 
  2 
  pairs 
  tentacular 
  cirri 
  (fig. 
  29, 
  a). 
  Without 
  

   swimming 
  setae. 
  Pharynx 
  long, 
  more 
  or 
  less 
  sinuous, 
  usually 
  with 
  a 
  crown 
  

  

  of 
  teeth 
  Stem 
  form 
  or 
  stock 
  of 
  Autolytus 
  (p. 
  242) 
  

  

  Prostomium 
  abnormal, 
  with 
  4 
  large 
  eyes 
  (usually 
  2 
  dorsolateral 
  and 
  2 
  ventro- 
  

   lateral) 
  ; 
  2-3 
  pairs 
  tentacular 
  cirri 
  (fig. 
  29, 
  c-f) 
  . 
  Body 
  divided 
  into 
  an 
  anterior 
  

   unmodified 
  region, 
  a 
  middle 
  region 
  with 
  long 
  swimming 
  setae 
  and 
  well- 
  

   developed, 
  paddlelike 
  parapodia, 
  and 
  with 
  or 
  without 
  a 
  posterior 
  unmodified 
  

   region. 
  Without 
  pharynx 
  Sexual 
  stolons 
  of 
  Autolytus 
  — 
  3 
  

  

  3. 
  Prostomium 
  with 
  3 
  antennae 
  (very 
  long 
  median 
  one 
  and 
  pair 
  of 
  small 
  frontal 
  

  

  ones) 
  and 
  pair 
  of 
  anterior 
  bifurcate 
  palps; 
  1 
  pair 
  tentacular 
  cirri 
  very 
  long, 
  

   similar 
  to 
  median 
  antennae 
  (these 
  may 
  be 
  the 
  dorsal 
  cirri 
  of 
  the 
  first 
  setiger 
  

   or 
  of 
  a 
  small, 
  knoblike 
  achaetous 
  lobe; 
  fig. 
  29, 
  e,f). 
  Testes 
  and 
  sperm 
  con- 
  

   fined 
  to 
  anterior 
  unmodified 
  region. 
  

  

  Male 
  form 
  of 
  Autolytus 
  (Polybostrichus) 
  (p. 
  242) 
  

   Prostomium 
  with 
  3 
  subequal 
  antennae, 
  without 
  palps; 
  none 
  of 
  tentacular 
  

   cirri 
  especially 
  elongate 
  (fig. 
  29, 
  c, 
  d). 
  Most 
  of 
  body 
  filled 
  with 
  eggs; 
  eggs 
  

   carried 
  in 
  large 
  sac 
  on 
  ventral 
  surface 
  (gestation). 
  

  

  Female 
  form 
  of 
  Autolytus 
  (Sacconereis) 
  (p. 
  242) 
  

  

  4. 
  Dorsal 
  cirri 
  distinctly 
  moniliform 
  throughout 
  body 
  (fig. 
  28, 
  c) 
  . 
  Palps 
  separate 
  

  

  for 
  their 
  entire 
  length 
  or 
  fused 
  basally. 
  Reproduction 
  direct 
  or 
  by 
  single 
  

   stolons. 
  Sexual 
  stolons 
  (Chaetosyllis) 
  : 
  Small 
  prostomium, 
  with 
  2 
  pairs 
  

   eyes, 
  pair 
  short 
  moniliform 
  antennae; 
  without 
  tentacular 
  cirri; 
  1 
  anterior 
  

   unmodified 
  segment, 
  a 
  middle 
  region 
  with 
  long 
  swimming 
  setae, 
  and 
  few 
  

  

  unmodified 
  posterior 
  segments 
  Syllis 
  (p. 
  252) 
  

  

  Dorsal 
  cirri 
  smooth 
  or 
  indistinctly 
  articulate 
  (may 
  be 
  more 
  or 
  less 
  articulate 
  

   anteriorly) 
  . 
  Palps 
  fused 
  at 
  base 
  only 
  or 
  throughout 
  .__ 
  5 
  

  

  5. 
  Palps 
  fused 
  for 
  nearly 
  their 
  entire 
  length 
  (fig. 
  28, 
  k-m). 
  Body 
  very 
  small. 
  

  

  Antennae 
  and 
  dorsal 
  cirri 
  short, 
  not 
  moniliform. 
  One 
  pair 
  tentacular 
  cirri 
  

   (may 
  be 
  rudimentary). 
  Reproduction 
  generally 
  direct, 
  with 
  swimming 
  

   setae 
  at 
  maturity; 
  eggs 
  and 
  larvae 
  fixed 
  to 
  dorsal 
  or 
  ventral 
  surface 
  of 
  

  

  female 
  6 
  

  

  Palps 
  fused 
  at 
  base 
  only 
  (fig. 
  28, 
  g). 
  Body 
  larger. 
  Antennae 
  and 
  dorsal 
  

   cirri 
  longer, 
  smooth 
  (antennae 
  and 
  anterior 
  dorsal 
  cirri 
  may 
  be 
  indistinctly 
  

   articulate, 
  especially 
  distally). 
  Two 
  pairs 
  tentacular 
  cirri. 
  Reproduction 
  

   direct, 
  with 
  swimming 
  setae 
  at 
  maturity 
  7 
  

  

  