﻿MARINE 
  POLYCHAETE 
  WORMS 
  — 
  PETTIBONE 
  337 
  

  

  p. 
  309, 
  fig. 
  107, 
  a-1.— 
  Okuda, 
  1937b, 
  p. 
  61.— 
  Annenkova, 
  1934, 
  p. 
  322; 
  1937, 
  

  

  p. 
  195; 
  1938, 
  p. 
  212.— 
  Zatsepin, 
  1948, 
  p. 
  161, 
  pi. 
  39, 
  fig. 
  6.— 
  Wesenberg-Lund, 
  

  

  1950a, 
  p. 
  57; 
  1950b, 
  p. 
  129; 
  1951, 
  p. 
  120. 
  

   Pseudopoiamilla 
  intermedia 
  Moore, 
  1905c, 
  p. 
  562, 
  pi. 
  37, 
  figs. 
  15-22; 
  1908, 
  p. 
  359. 
  — 
  

  

  Hartman, 
  1938c, 
  p. 
  25, 
  pi. 
  2, 
  fig. 
  8; 
  pi. 
  3, 
  figs. 
  1-4; 
  1948, 
  p. 
  46.— 
  Rioja, 
  

  

  1941, 
  p. 
  732. 
  

   Pseudopotamilla 
  reniformis 
  Hartman, 
  1944a, 
  pp. 
  336, 
  343, 
  pi. 
  21, 
  figs. 
  3, 
  6; 
  1945, 
  

  

  p. 
  47.— 
  Berkeley 
  and 
  Berkeley, 
  1952, 
  p. 
  116, 
  fig. 
  239. 
  

  

  Description. 
  — 
  Length 
  80-100 
  mm., 
  width 
  1-2 
  mm. 
  Collarette 
  

   with 
  middorsal 
  depression, 
  deeply 
  notched 
  dorsolaterally 
  (at 
  level 
  of 
  

   notopodia), 
  with 
  midventral 
  slit, 
  resulting 
  in 
  a 
  4-lobed 
  structm-e 
  of 
  

   pair 
  of 
  rounded 
  or 
  triangular 
  dorsal 
  lobes 
  and 
  pair 
  of 
  rounded 
  ventral 
  

   lobes 
  which 
  may 
  be 
  deflected. 
  Branchial 
  lobes 
  each 
  with 
  about 
  10 
  

   filaments 
  (5-15). 
  At 
  least 
  some 
  of 
  branchial 
  filaments 
  with 
  large 
  

   compound 
  eyes, 
  usually 
  0-3 
  per 
  filament 
  (0-8), 
  eyes 
  may 
  be 
  variable 
  

   in 
  size 
  or 
  subequal, 
  deep 
  reddish 
  in 
  alcohol. 
  Thoracic 
  setigers 
  usually 
  

   10 
  (7-14). 
  Pygidium 
  with 
  pair 
  of 
  bulbous 
  lobes 
  with 
  eye-spots. 
  

   Color: 
  In 
  alcohol: 
  Body 
  colorless, 
  branchiae 
  with 
  diffused 
  reddish 
  

   brown 
  bands 
  in 
  region 
  of 
  eyes. 
  Tube: 
  Somewhat 
  twisted, 
  horny, 
  

   translucent 
  or 
  opaque, 
  more 
  or 
  less 
  covered 
  with 
  sand 
  or 
  mud, 
  the 
  

   free 
  end 
  usually 
  flattened, 
  rolled 
  scroll-like 
  when 
  animal 
  pulls 
  inside. 
  

  

  New 
  records. 
  — 
  Arctic 
  Alaska: 
  Off 
  Point 
  Barrow 
  base, 
  up 
  to 
  7.4 
  

   miles 
  from 
  shore, 
  21.7-54.6 
  fms., 
  on 
  bottoms 
  of 
  pebbles, 
  gravel, 
  

   rocks, 
  in 
  holes 
  of 
  large 
  stones 
  (2 
  stations, 
  15 
  specimens). 
  Bering 
  

   Sea: 
  Anchorage, 
  Cape 
  Etoliu, 
  Nunivak 
  Island, 
  8 
  fms., 
  Dall, 
  1874. 
  

   Southeastern 
  Alaska: 
  Lituya 
  Bay, 
  6-9 
  fms., 
  Dall, 
  1874. 
  East 
  

   Coast 
  North 
  America: 
  Off 
  Nova 
  Scotia, 
  Maine, 
  New 
  Hampshire, 
  

   Massachusetts, 
  Rhode 
  Island, 
  Delaware, 
  10-317 
  fms., 
  U. 
  S. 
  Fish 
  

   Commission. 
  

  

  Distribution. 
  — 
  Scattered 
  records 
  in 
  the 
  Arctic: 
  Arctic 
  Alaska, 
  

   Greenland. 
  Also 
  Iceland, 
  Swedish 
  west 
  coast 
  to 
  France, 
  Mediter- 
  

   ranean; 
  Nova 
  Scotia 
  to 
  North 
  Carolina; 
  Bering 
  Sea 
  to 
  British 
  Co- 
  

   lumbia, 
  Mexico; 
  north 
  Japan 
  Sea 
  to 
  Japan. 
  In 
  low 
  water 
  to 
  317 
  

   fathoms. 
  

  

  Genus 
  Chone 
  Kroyer, 
  1856 
  

  

  Both 
  species 
  have 
  the 
  segments 
  biannulate. 
  Collarette 
  deeply 
  

   incised 
  middorsally, 
  forming 
  two 
  longitudinal-folded 
  brackets, 
  with 
  

   sides 
  smooth; 
  without 
  midventral 
  or 
  lateral 
  notches 
  (fig. 
  39, 
  a-c). 
  

   Branchial 
  filaments 
  united 
  on 
  great 
  part 
  of 
  their 
  length 
  by 
  palmar 
  

   membrane 
  (fig. 
  39, 
  m). 
  Thoracic 
  setigers 
  8. 
  Thoracic 
  dorsal 
  setae 
  

   of 
  three 
  kinds 
  — 
  limbate 
  capillary 
  setae, 
  fine 
  bayonette 
  setae, 
  and 
  

   spatulate 
  setae 
  with 
  asymmetrical 
  mucronate 
  tips 
  or 
  gently 
  rounded 
  

   (fig. 
  39,f-h). 
  Pygidium 
  with 
  anus 
  terminal, 
  with 
  rounded 
  to 
  conical 
  

   bulbous 
  dorsal 
  valve 
  (fig. 
  39, 
  d). 
  

  

  