﻿282 
  PROCEEDINGS 
  OF 
  THE 
  NATIONAL 
  MUSEUM 
  tol.io3 
  

  

  C^nus 
  Prionospio 
  Malmgren, 
  1867 
  

   Prionospio 
  malmgreni 
  Clapar^de, 
  1868 
  

  

  Figure 
  32, 
  i-k 
  

  

  Prionospio 
  malmgreni 
  ClaparMe, 
  1868, 
  p. 
  333, 
  pi. 
  22, 
  fig. 
  3 
  (fide 
  Fauvel, 
  1927). 
  — 
  

   Ehlers, 
  1913, 
  p. 
  511.— 
  Fauvel, 
  1927, 
  p. 
  61, 
  fig. 
  21, 
  a-e.— 
  Annenkova, 
  1937, 
  

   p. 
  171; 
  1938, 
  p. 
  174.— 
  Hartman, 
  1948, 
  p. 
  36.— 
  Wesenberg-Lund, 
  1951, 
  

   p. 
  70. 
  — 
  Berkeley 
  and 
  Berkeley, 
  1952, 
  p. 
  29, 
  figs. 
  54, 
  55. 
  

  

  Spiophanes 
  tenuis 
  Verrill, 
  1879b, 
  p. 
  176. 
  

  

  Prionospio 
  tenuis 
  Verrill, 
  1882, 
  p. 
  370. 
  — 
  Hartman, 
  1944a, 
  pp. 
  336, 
  340, 
  ? 
  pi. 
  19, 
  

   fig. 
  7; 
  not 
  1945, 
  p. 
  32 
  ( 
  = 
  P. 
  treadwelli 
  Hartman, 
  1951). 
  

  

  Description. 
  — 
  Length 
  up 
  to 
  25 
  mm., 
  width 
  1 
  mm. 
  Prostomium 
  

   dilated 
  anteriorly, 
  with 
  anterior 
  border 
  rounded, 
  narrowing 
  posteriorly, 
  

   extending 
  in 
  obtuse 
  crest 
  to 
  setiger 
  2 
  (to 
  4) 
  . 
  Four 
  eyes, 
  two 
  smaller, 
  

   two 
  much 
  larger 
  (may 
  be 
  lacking) 
  . 
  Two 
  long 
  palps, 
  usually 
  missing 
  

   (in 
  alcohol). 
  A 
  short, 
  eversible, 
  somewhat 
  lobulated 
  proboscidial 
  

   region. 
  Branchiae 
  four 
  pairs, 
  on 
  setigers 
  2-5, 
  completely 
  separated 
  

   from 
  dorsal 
  lamellae, 
  pairs 
  1 
  and 
  4 
  longer, 
  pinnate, 
  somewhat 
  decid- 
  

   uous, 
  pairs 
  2 
  and 
  3 
  shorter, 
  smooth, 
  triangular. 
  Dorsal 
  postsetal 
  

   lamellae 
  of 
  first 
  setiger 
  small, 
  much 
  larger 
  and 
  triangular 
  on 
  next 
  

   four 
  setigers, 
  then 
  diminishing 
  in 
  size, 
  becoming 
  reduced 
  beginning 
  

   on 
  setigers 
  8 
  or 
  9; 
  ventral 
  postsetal 
  lamellae 
  oval, 
  rounded. 
  Hooded, 
  

   multidentate 
  crotchets 
  beginning 
  about 
  setigers 
  12-16 
  in 
  neuropodia 
  

   and 
  about 
  setiger 
  40 
  in 
  notopodia. 
  Beginning 
  on 
  setiger 
  7, 
  slightly 
  

   elevated 
  transverse 
  folds 
  between 
  dorsal 
  lamellae, 
  continuing 
  on 
  next 
  

   6-14 
  segments. 
  Pygidium 
  with 
  longer, 
  unpaired 
  dorsal 
  cirrus 
  and 
  

   two 
  smaller 
  lateral 
  ones. 
  Without 
  color 
  in 
  alcohol. 
  

  

  Remarks. 
  — 
  The 
  types 
  of 
  Prionospio 
  tenuis 
  Verrill 
  from 
  Cape 
  Cod 
  

   Bay 
  were 
  examined 
  and 
  are 
  herein 
  referred 
  to 
  P. 
  malmgreni. 
  There 
  

   are 
  four 
  pairs 
  of 
  branchiae, 
  the 
  first 
  and 
  fourth 
  pairs 
  pinnate, 
  the 
  sec- 
  

   ond 
  and 
  third 
  pairs 
  shorter, 
  smooth. 
  

  

  New 
  records, 
  — 
  Arctic 
  Alaska: 
  Off 
  Point 
  Barrow 
  base, 
  4 
  miles 
  from 
  

   shore, 
  29 
  fms., 
  on 
  bottom 
  of 
  gravel, 
  small 
  stones 
  (1 
  station, 
  2 
  speci- 
  

  

  FiGURE 
  32. 
  — 
  Orbiniidae: 
  a, 
  Scoloplos 
  armiger, 
  dorsal 
  view 
  anterior 
  end; 
  i, 
  same, 
  parapodium 
  

   from 
  thoracic 
  region, 
  posterior 
  view; 
  c, 
  same, 
  parapodium 
  from 
  abdominal 
  region, 
  anterior 
  

   view; 
  d, 
  ty 
  same, 
  crenulate 
  neurosetae 
  from 
  thoracic 
  region. 
  Spionidae:/, 
  Spio 
  filicornis, 
  

   dorsal 
  view 
  anterior 
  end 
  (palps 
  missing); 
  g, 
  same, 
  parapodium 
  from 
  anterior 
  region, 
  

   anterior 
  view; 
  h, 
  same, 
  hooded 
  bidentate 
  crotchet; 
  i, 
  Prionospio 
  malmgreni, 
  dorsal 
  view 
  

   anterior 
  end; 
  /, 
  same, 
  branchiae 
  on 
  setigers 
  2-S 
  (one 
  of 
  each 
  pair 
  shown); 
  k, 
  same, 
  hooded 
  

   multidentate 
  crotchet; 
  /, 
  Polydora 
  caulleryi, 
  dorsal 
  view 
  anterior 
  end 
  (palps 
  missing); 
  

   m, 
  same, 
  parapodium 
  of 
  modified 
  fifth 
  setigerous 
  segment; 
  «, 
  same, 
  special 
  hooks 
  from 
  

   setiger 
  5; 
  o, 
  same, 
  notopodium 
  of 
  posterior 
  setiger, 
  with 
  conical 
  bundle 
  awl-shaped 
  

   setae; 
  p, 
  same, 
  anal 
  disc 
  of 
  pygidium, 
  lateral 
  view; 
  q, 
  same, 
  hooded 
  bidentate 
  crotchet, 
  

   f, 
  Ntrinides 
  sp., 
  dorsal 
  view 
  anterior 
  end; 
  s, 
  same, 
  parapodium 
  from 
  anterior 
  region. 
  

   (For 
  explanation 
  of 
  symbols, 
  see 
  p. 
  210.) 
  

  

  