﻿MARINE 
  POLYCHAETE 
  WORMS 
  — 
  PETTIBONE 
  335 
  

  

  Description. 
  — 
  Length 
  20-80 
  mm., 
  width 
  3-4 
  mm. 
  Collarette 
  

   widely 
  separated 
  middorsally, 
  with 
  midventral 
  slit 
  and 
  lateral 
  notches, 
  

   resulting 
  in 
  4-lobed 
  structm-e; 
  ventral 
  lobes 
  closely 
  approximated, 
  

   may 
  be 
  deflected. 
  Two 
  branchial 
  lobes 
  each 
  with 
  about 
  16 
  filaments 
  

   (15-35), 
  with 
  short 
  tapering 
  tips. 
  Branchial 
  filaments 
  with 
  usually 
  

   four 
  to 
  six 
  (2-8) 
  pairs 
  of 
  eyes 
  (located 
  in 
  color 
  bands 
  of 
  filaments 
  and 
  

   may 
  easily 
  be 
  overlooked). 
  Thoracic 
  setigers 
  usually 
  8 
  (7-9). 
  Abdo- 
  

   men 
  with 
  one 
  or 
  two 
  pairs 
  of 
  eye-spots 
  between 
  parapodial 
  rami, 
  well 
  

   developed 
  toward 
  posterior 
  end. 
  Pj^gidium 
  with 
  pair 
  of 
  bulbous 
  

   lobes 
  with 
  groups 
  of 
  eye-spots 
  on 
  dorsolateral 
  sides. 
  Color: 
  In 
  

   life 
  : 
  Body 
  flesh 
  color, 
  with 
  branchial 
  filaments 
  banded 
  rusty 
  red, 
  4-7 
  

   transverse 
  bands 
  per 
  filament. 
  In 
  alcohol 
  : 
  Body 
  colorless 
  with 
  red- 
  

   dish 
  purple 
  bands 
  on 
  branchial 
  filaments. 
  Tube: 
  Cylindrical, 
  free 
  

   end 
  flexible, 
  covered 
  with 
  thin, 
  smooth 
  layer 
  of 
  mud; 
  embedded 
  part 
  

   transparent, 
  horny, 
  rigid, 
  covered 
  with 
  sand 
  grains 
  and 
  foreign 
  

   material. 
  

  

  New 
  records. 
  — 
  Arctic 
  Alaska: 
  Off 
  Point 
  Barrow 
  base, 
  up 
  to 
  15 
  

   miles 
  from 
  shore, 
  36-123.5 
  fms., 
  on 
  bottoms 
  of 
  stones, 
  mass 
  of 
  worm 
  

   tubes, 
  and 
  various 
  combinations 
  of 
  gravel, 
  stones, 
  rocks, 
  large 
  per- 
  

   forated 
  rocks, 
  with 
  worm 
  tubes 
  (8 
  stations, 
  15 
  specimens). 
  Kam- 
  

   chatka: 
  Petropavlovsk, 
  Grevnitzky, 
  1888. 
  Alaska: 
  New 
  Harbor, 
  

   Unga 
  Island, 
  under 
  stones, 
  Dall, 
  1872; 
  Albatross 
  Sta. 
  2847, 
  55°01' 
  N., 
  

   160°18' 
  W., 
  48 
  fms., 
  and 
  station 
  at 
  Kodiak, 
  1888. 
  Canadian 
  Arctic: 
  

   Foxe 
  Basin, 
  25-31 
  fms., 
  Bartlett, 
  1927. 
  East 
  Coast 
  North 
  America: 
  

   Off 
  Labrador, 
  5-6 
  fms.. 
  Blue 
  Dolphin 
  Expedition, 
  1949; 
  Bay 
  of 
  Fundy, 
  

   Maine, 
  Massachusetts, 
  15 
  fms., 
  U. 
  S. 
  Fish 
  Commission. 
  Central 
  

   America: 
  Golfo 
  Dulce, 
  west 
  Costa 
  Rica, 
  M. 
  Valerio. 
  

  

  Distribution. 
  — 
  Widely 
  distributed 
  in 
  the 
  Arctic: 
  Siberian, 
  Alaskan, 
  

   and 
  Canadian 
  Arctic, 
  Greenland, 
  Spitsbergen, 
  Novaya 
  Zemlya, 
  Kara 
  

   Sea. 
  Also 
  Iceland, 
  Faroes, 
  Norway 
  to 
  France, 
  Mediterranean; 
  

   Hudson 
  Bay 
  to 
  Massachusetts; 
  Bering 
  Sea 
  to 
  California, 
  Central 
  

   America 
  (Costa 
  Rica); 
  north 
  Japan 
  Sea 
  to 
  Japan. 
  In 
  low 
  water 
  to 
  

   230 
  fathoms. 
  

  

  Genus 
  Potaniilla 
  Malmgren, 
  1865 
  

  

  Key 
  to 
  the 
  species 
  of 
  Potamilla 
  from 
  Point 
  Barrow 
  

  

  1. 
  Without 
  branchial 
  eyes 
  P. 
  neglecta 
  

  

  With 
  compound 
  eyes 
  in 
  single 
  rows 
  on 
  branchial 
  filaments, 
  0-8 
  per 
  filament 
  

   (fig. 
  38, 
  r) 
  P. 
  reniformis 
  

  

  Potamilla 
  neglecta 
  (Sars, 
  1851) 
  

  

  Figure 
  38, 
  j-n 
  

  

  Sabella 
  neglecta 
  Sars, 
  1851, 
  p. 
  203. 
  

  

  Potamilla 
  neglecta 
  Malmgren, 
  1865, 
  p. 
  401, 
  pi. 
  27, 
  fig. 
  84. 
  — 
  Webster 
  and 
  Benedict, 
  

   1884, 
  p. 
  736.— 
  Moore, 
  1909b, 
  p. 
  145; 
  1923, 
  p. 
  242.— 
  Johansson, 
  1927, 
  p. 
  143.— 
  

  

  