﻿MARINE 
  POLYCHAETE 
  WORMS 
  — 
  PETTIBONE 
  249 
  

  

  ments, 
  with 
  body 
  regions 
  of 
  6 
  anterior, 
  27-30 
  middle, 
  9-10 
  posterior 
  

   setigers, 
  tapering 
  gradually 
  posteriorly. 
  Prostomium 
  short, 
  wide, 
  

   with 
  a 
  pair 
  of 
  eyes 
  dorsolateral, 
  a 
  larger 
  pan- 
  ventrolateral, 
  all 
  with 
  

   lenses; 
  palps 
  bifurcated 
  about 
  basal 
  third, 
  the 
  two 
  branches 
  subequal; 
  

   very 
  long, 
  stout 
  median 
  antenna 
  and 
  very 
  small 
  lateral 
  antennae 
  

   anterior 
  and 
  medial 
  to 
  dorsal 
  pair 
  of 
  eyes. 
  Three 
  pairs 
  tentacular 
  

   cirri 
  with 
  anterior 
  dorsal 
  pair 
  similar 
  to 
  dorsal 
  cirri, 
  anterior 
  ventral 
  

   pair 
  shorter 
  than 
  prostomial 
  length, 
  posterior 
  dorsal 
  pair 
  very 
  large, 
  

   similar 
  to 
  median 
  antenna, 
  with 
  a 
  pair 
  of 
  achaetous 
  knobs 
  at 
  their 
  

   ventral 
  bases. 
  Dorsal 
  cirri 
  of 
  anterior 
  setigers 
  about 
  as 
  long 
  as 
  body 
  

   width, 
  those 
  of 
  modified 
  region 
  about 
  as 
  long 
  as 
  the 
  elongated, 
  paddle- 
  

   like 
  parapodial 
  lobes, 
  those 
  of 
  posterior, 
  taillike 
  region 
  short, 
  digitiform. 
  

   Shallow 
  semicircular 
  epaulettes 
  on 
  tentacular 
  segment 
  only. 
  Color: 
  

   In 
  alcohol: 
  Rusty 
  brown, 
  darkest 
  on 
  anterior 
  part 
  or 
  colorless 
  except 
  

   anterior 
  part. 
  In 
  life 
  : 
  Yellowish 
  green. 
  Taken 
  in 
  plankton, 
  near 
  shore, 
  

   September 
  10, 
  1949; 
  dredged 
  in 
  27 
  fathoms 
  February 
  18, 
  1950. 
  

  

  Remarks. 
  — 
  As 
  referred 
  to 
  under 
  the 
  systematic 
  discussion 
  of 
  

   Autolytus, 
  the 
  stem 
  form 
  of 
  A. 
  jallax 
  has 
  been 
  incorrectly 
  referred 
  to 
  

   A.'proliferhj 
  KugmQv 
  (1913, 
  1928) 
  and 
  Wesenberg-Lund 
  (1947, 
  1950). 
  

   The 
  two 
  may 
  be 
  distinguished 
  by 
  the 
  different 
  positions 
  of 
  the 
  sexual 
  

   buds, 
  the 
  greater 
  length 
  of 
  the 
  dorsal 
  cirri 
  in 
  A. 
  prolifer, 
  and 
  the 
  color 
  

   markings. 
  The 
  sexual 
  stolons 
  of 
  A. 
  jallax 
  have 
  been 
  confused 
  with 
  

   A. 
  prismaticus 
  (see 
  discussion 
  above). 
  

  

  New 
  records.— 
  -Arctic 
  Alaska: 
  Eluitkak 
  Pass, 
  Elson 
  Lagoon 
  near 
  

   Point 
  Barrow, 
  5-6.6 
  fms., 
  mud, 
  in 
  tubes 
  associated 
  with 
  hydroid 
  

   Lafoeina 
  maxima 
  Levinsen; 
  Point 
  Barrow 
  base, 
  washed 
  ashore, 
  on 
  

   same 
  hydroid; 
  off 
  Point 
  Barrow 
  base, 
  5-75.5 
  fms., 
  up 
  to 
  8 
  miles 
  

   from 
  shore, 
  on 
  bottoms 
  of 
  mud, 
  stones, 
  and 
  various 
  combinations 
  of 
  

   mud, 
  gravel, 
  stones, 
  rocks, 
  large 
  perforated 
  rocks, 
  with 
  bryozoans, 
  

   hydroids 
  including 
  Lafoeina 
  maxima, 
  and 
  shells 
  (16 
  stations, 
  85 
  

   specimens); 
  sexual 
  stages 
  from 
  plankton 
  near 
  shore 
  to 
  75.5 
  fms. 
  (7 
  

   stations, 
  22 
  specimens). 
  Cape 
  Smyth, 
  Point 
  Barrow 
  Expedition, 
  

   winter, 
  1883 
  (1 
  male, 
  2 
  females 
  with 
  egg 
  sacs). 
  East 
  Coast 
  North 
  

   America: 
  Off 
  Labrador, 
  25-60 
  fms., 
  Blue 
  Dolphin 
  Expeditions, 
  1949, 
  

   1951. 
  

  

  Distribution. 
  — 
  Widely 
  distributed 
  in 
  the 
  Arctic: 
  Alaskan 
  and 
  

   Canadian 
  Arctic, 
  Greenland, 
  Spitsbergen, 
  Franz 
  Josef 
  Land, 
  Novaya 
  

   Zemlya. 
  Also 
  Faroes; 
  Labrador. 
  In 
  low 
  water 
  to 
  75.5 
  fathoms; 
  

   sexual 
  stolons 
  in 
  plankton. 
  

  

  Autolytus 
  prismaticus 
  (Fabricius, 
  1780) 
  

  

  Figure 
  29, 
  a, 
  b 
  

  

  Nereis 
  prismatica 
  ? 
  MuUer, 
  1776, 
  p. 
  218.— 
  Fabricius, 
  1780, 
  p. 
  302; 
  1799, 
  p. 
  177, 
  

  

  pi. 
  4, 
  figs. 
  17-20. 
  

   ? 
  Polybostrichus 
  longosetosus 
  Oersted, 
  1843, 
  p. 
  183, 
  pi. 
  5, 
  figs. 
  62, 
  67, 
  71. 
  

  

  