﻿258 
  PROCEEDINGS 
  OF 
  THE 
  NATIONAL 
  MUSEUM 
  vol, 
  103 
  

  

  Key 
  to 
  the 
  species 
  of 
  Exogone 
  from 
  Point 
  Barrow 
  

  

  I. 
  Antennae 
  subequal. 
  Tentacular 
  cirri 
  rudimentary, 
  reduced 
  to 
  small 
  knobs 
  

  

  (fig. 
  28, 
  0- 
  Dorsal 
  cirri 
  lacking 
  on 
  setiger 
  2. 
  Upper 
  compound 
  setae 
  with 
  

  

  rather 
  short 
  pointed 
  blades 
  E. 
  naidina 
  

  

  Median 
  antenna 
  more 
  than 
  4 
  times 
  length 
  of 
  lateral 
  antennae 
  (fig. 
  28, 
  k). 
  

   Tentacular 
  cirri 
  only 
  slightly 
  smaller 
  than 
  the 
  lateral 
  antennae 
  or 
  dorsal 
  

   cirri. 
  Dorsal 
  cirri 
  present 
  on 
  all 
  setigerous 
  segments. 
  Upper 
  compound 
  

   setae 
  with 
  long 
  pointed 
  blades 
  E. 
  dispar 
  

  

  Exogone 
  naidina 
  Oersted, 
  1845 
  

  

  Figure 
  28, 
  I 
  

  

  Exogone 
  naidina 
  Oersted, 
  1845, 
  p. 
  20, 
  pi. 
  2. 
  — 
  Augener, 
  1939, 
  p. 
  140. 
  — 
  Zatsepin, 
  

   1948, 
  p. 
  116, 
  pi. 
  31, 
  fig. 
  8. 
  

  

  Exogone 
  gemmifera 
  Pagenstecher, 
  1862, 
  p. 
  267, 
  pi. 
  25; 
  pi. 
  26, 
  figs. 
  1, 
  2, 
  6-8. 
  — 
  

   Mcintosh, 
  1908, 
  p. 
  151, 
  pi. 
  59, 
  figs. 
  5, 
  6.— 
  Southern, 
  1914, 
  p. 
  17.— 
  Eliason, 
  

   1920, 
  p. 
  11.— 
  Fauvel, 
  1923, 
  p. 
  305, 
  fig. 
  117, 
  a-d.— 
  Annenkova, 
  1934, 
  p. 
  322; 
  

   1938, 
  p. 
  154.— 
  Rioja, 
  1943, 
  p. 
  223, 
  figs. 
  38-46.— 
  Gorbunov, 
  1946, 
  p. 
  38.— 
  

   Thorson, 
  1946, 
  p. 
  35, 
  fig. 
  8.— 
  Berkeley 
  and 
  Berkeley, 
  1948, 
  p. 
  79, 
  fig. 
  118.— 
  

   Hartman 
  and 
  Reish, 
  1950, 
  p. 
  13. 
  

  

  Description. 
  — 
  Length 
  3.5-5 
  mm., 
  width 
  without 
  setae 
  0.3 
  mm., 
  

   segments 
  32-36. 
  Palps 
  form 
  rounded 
  mass, 
  1.4-2 
  times 
  length 
  of 
  

   prostomium. 
  Antennae 
  shorter 
  than 
  palps, 
  subequal 
  or 
  median 
  one 
  

   slightly 
  longer, 
  clavate, 
  inserted 
  anterior 
  to 
  eyes 
  in 
  almost 
  a 
  straight 
  

   line. 
  Tentacular 
  cirri 
  very 
  small, 
  reduced 
  to 
  small 
  knobs. 
  Dorsal 
  

   cirri 
  lacking 
  on 
  setiger 
  2. 
  Neurosetae 
  of 
  each 
  parapodium 
  consisting 
  

   of 
  one 
  simple, 
  cm-ved 
  upper 
  seta, 
  one 
  upper 
  composite 
  seta 
  with 
  

   longer 
  pointed 
  blade, 
  and 
  four 
  or 
  five 
  composite 
  setae 
  with 
  short, 
  

   hooked 
  blades. 
  Female 
  (21 
  fathoms, 
  September 
  15, 
  1948) 
  without 
  

   special 
  swimming 
  setae, 
  with 
  large 
  eggs 
  attached 
  to 
  ventral 
  surface 
  

   (between 
  segments 
  1 
  1-25, 
  one 
  to 
  three 
  per 
  segment) 
  medial 
  to 
  ventral 
  

   cirri 
  and 
  between 
  parapodia. 
  Another 
  female 
  (57 
  fathoms, 
  October 
  

  

  II, 
  1949) 
  with 
  eggs 
  on 
  ventral 
  surface 
  of 
  segments 
  13-21 
  (mostly 
  

   four 
  per 
  segment) 
  ; 
  eggs 
  large, 
  nearly 
  touching. 
  (Swimming 
  setae 
  on 
  

   females 
  with 
  internal 
  ova, 
  absent 
  in 
  females 
  with 
  ova 
  attached 
  to 
  

   ventral 
  surface, 
  two 
  eggs 
  per 
  segment 
  — 
  Thorson, 
  1946.) 
  

  

  New 
  records. 
  — 
  Arctic 
  Alaska: 
  Off 
  Point 
  Barrow 
  base, 
  16.7-123.5 
  

   fms., 
  up 
  to 
  16 
  miles 
  from 
  shore, 
  on 
  bottoms 
  of 
  rocks, 
  stones, 
  worm 
  

   tubes, 
  and 
  various 
  combinations 
  of 
  mud, 
  gravel, 
  stones, 
  rocks, 
  large 
  

   perforated 
  rocks, 
  with 
  worm 
  tubes, 
  bryozoans, 
  hydroids; 
  on 
  female 
  

   Hyas 
  coarctatus 
  alutaceus 
  (14 
  stations, 
  82 
  specimens). 
  

  

  Distribution. 
  — 
  Alaskan 
  and 
  Siberian 
  Ai-ctic; 
  Denmark, 
  Ireland, 
  

   Great 
  Britain 
  to 
  Madeira, 
  Mediterranean; 
  Bering 
  Sea 
  to 
  Mexico; 
  

   north 
  Japan 
  Sea. 
  In 
  low 
  water 
  to 
  123.5 
  fathoms; 
  sexual 
  stages 
  at 
  

   surface. 
  

  

  