﻿MARINE 
  POLYCHAETE 
  WORMS 
  — 
  PETTIBONE 
  285 
  

  

  Distribution. 
  — 
  Widely 
  distributed 
  in 
  the 
  Arctic: 
  Siberian 
  and 
  

   Alaskan 
  Arctic, 
  Davis 
  Strait, 
  Greenland, 
  Spitsbergen, 
  Novaya 
  Zemlya. 
  

   Also 
  Iceland, 
  Faroes, 
  Norway 
  to 
  France; 
  Hudson 
  Bay 
  to 
  Massachu- 
  

   setts; 
  Bering 
  Sea 
  to 
  central 
  California; 
  Japan. 
  In 
  low 
  water 
  to 
  211 
  

   fathoms; 
  sm-face. 
  

  

  Genus 
  Nerinides 
  Mesnil, 
  1896 
  

   Nerinides 
  sp. 
  

  

  Figure 
  32, 
  r, 
  s 
  

  

  Two 
  small 
  specimens 
  obtained 
  from 
  plankton 
  10 
  feet 
  from 
  shore, 
  

   agreeing 
  in 
  some 
  respects 
  with 
  the 
  description 
  of 
  N. 
  cantabra 
  Rioja 
  

   (Fauvel, 
  1927, 
  p. 
  31). 
  Length 
  16 
  mm., 
  width 
  1 
  mm., 
  segments 
  57. 
  

   Prostomium 
  rounded 
  anteriorly, 
  tapering 
  posteriorly, 
  with 
  middorsal 
  

   crest 
  extending 
  on 
  first 
  setiger, 
  with 
  four 
  eyes, 
  one 
  pair 
  larger, 
  a 
  

   raised 
  area 
  just 
  posterior 
  to 
  eyes 
  (median 
  antenna?), 
  with 
  two 
  large, 
  

   thick 
  palps 
  (fig. 
  32, 
  r). 
  Dorsal 
  and 
  ventral 
  postsetal 
  lamellae 
  distinct, 
  

   dorsal 
  ones 
  may 
  be 
  slightly 
  undulate, 
  ventral 
  ones 
  entire, 
  not 
  notched 
  

   (fig. 
  32, 
  s). 
  Branchiae 
  begin 
  on 
  setiger 
  2, 
  continuing 
  to 
  near 
  posterior 
  

   end, 
  fused 
  to 
  upper 
  part 
  of 
  dorsal 
  lamellae. 
  Body 
  with 
  low 
  transverse 
  

   dorsal 
  ridges 
  between 
  bases 
  of 
  branchiae. 
  First 
  setiger 
  with 
  both 
  

   dorsal 
  and 
  ventral 
  setae. 
  Notopodia 
  with 
  only 
  capillary 
  setae, 
  being 
  

   extra 
  long 
  in 
  posterior 
  region. 
  Neuropodia 
  with 
  capillary 
  setae 
  and 
  

   hooded 
  bidentate 
  crotchets 
  beginning 
  around 
  setiger 
  20. 
  Pygidium 
  

   with 
  4-lobed 
  membranous 
  appendage. 
  Without 
  color 
  in 
  alcohol. 
  

  

  Family 
  Cirratulidae 
  

  

  Body 
  more 
  or 
  less 
  cylindrical, 
  attenuated 
  at 
  both 
  ends, 
  with 
  

   numerous, 
  short, 
  compact, 
  nearly 
  similar 
  segments. 
  Prostomium 
  

   small, 
  usually 
  without 
  appendages, 
  with 
  or 
  without 
  eyes. 
  Pair 
  of 
  large 
  

   grooved 
  spioniform 
  palps 
  (fig. 
  33, 
  d) 
  or 
  with 
  more 
  or 
  less 
  numerous 
  

   grooved 
  tentacular 
  fiilaments 
  inserted 
  on 
  dorsal 
  surface 
  of 
  an 
  anterior 
  

   segment 
  (fig. 
  33, 
  a). 
  Branchiae 
  simple, 
  filamentous, 
  long, 
  con- 
  

   tractile, 
  inserted 
  above 
  notopodia 
  on 
  few 
  to 
  many 
  segments 
  (may 
  

   be 
  absent). 
  Parapodia 
  biramous, 
  lobes 
  scarcely 
  projecting 
  (fig. 
  33, 
  

   6). 
  Setae 
  usually 
  simple, 
  some 
  capillary, 
  others 
  acicular 
  crotchets 
  

   (fig. 
  33, 
  c) 
  . 
  Without 
  dorsal, 
  ventral, 
  or 
  anal 
  cirri. 
  Proboscis 
  smooth, 
  

   unarmed. 
  May 
  have 
  epitokous 
  pelagic 
  form 
  at 
  time 
  of 
  reproduction. 
  

   Usually 
  in 
  mud; 
  some 
  (Dodecaceria) 
  in 
  calcareous 
  matrix. 
  

  

  Represented 
  by 
  two 
  genera 
  and 
  two 
  species 
  from 
  Point 
  Barrow. 
  

   Both 
  genera 
  have 
  prostomium 
  conical, 
  buccal 
  segment 
  and 
  two 
  fol- 
  

   lowing 
  segments 
  achaetous, 
  more 
  or 
  less 
  fused 
  to 
  prostomium, 
  with 
  

   lateral 
  filamentous 
  branchiae 
  beginning 
  just 
  anterior 
  to 
  first 
  setigerous 
  

   segment, 
  continuing 
  on 
  large 
  number 
  of 
  segments. 
  

  

  