﻿334 
  PROCEEDINGS 
  OF 
  THE 
  NATIONAL 
  MUSEUM 
  vol. 
  los 
  

  

  of 
  setae, 
  dorsal 
  uncinigerous 
  tori 
  and 
  ventral 
  capillary 
  setae. 
  A 
  

   median 
  ciliated 
  faecal 
  groove 
  runs 
  length 
  of 
  body, 
  ventral 
  in 
  abdom- 
  

   inal 
  region 
  and 
  crossing 
  to 
  dorsal 
  surface 
  in 
  thoracic 
  region. 
  Tube 
  

   cylindrical, 
  permanent 
  or 
  more 
  or 
  less 
  transitory, 
  gelatinous, 
  mem- 
  

   branous, 
  or 
  horny, 
  covered 
  or 
  not 
  with 
  mud, 
  sand, 
  gravel, 
  debris 
  of 
  

   shells. 
  

  

  Represented 
  by 
  five 
  genera 
  and 
  seven 
  species 
  at 
  Point 
  Barrow. 
  

   All 
  the 
  genera 
  have 
  large 
  branchial 
  plumes 
  composed 
  of 
  two 
  similar 
  

   semicircular 
  lobes; 
  branchial 
  filaments 
  without 
  large 
  subterminal 
  

   eyes, 
  without 
  dorsal 
  appendages. 
  First 
  setigerous 
  segments 
  with 
  

   limbate 
  notosetae 
  only; 
  neurosetae 
  begin 
  on 
  setiger 
  2. 
  Abdominal 
  

   region 
  with 
  numerous 
  segments. 
  

  

  Key 
  to 
  the 
  genera 
  of 
  SaheUidae 
  from 
  Point 
  Barrow 
  

  

  1. 
  Ventral 
  tori 
  of 
  thorax 
  with 
  row 
  of 
  uncini 
  of 
  the 
  avicular 
  form 
  (fig. 
  38, 
  /; 
  in 
  

  

  Sabella 
  and 
  Potamilla 
  with 
  additional 
  row 
  of 
  hoelike 
  setae, 
  fig. 
  38, 
  t) 
  . 
  Col- 
  

   larette 
  well 
  developed. 
  Branchial 
  filaments 
  with 
  or 
  without 
  eyes, 
  united 
  

  

  at 
  base 
  only, 
  with 
  palmar 
  membrane 
  poorly 
  developed 
  or 
  lacking 
  2 
  

  

  Ventral 
  tori 
  of 
  thorax 
  with 
  crotchets 
  with 
  long 
  manubrium 
  (fig. 
  39, 
  t; 
  without 
  

   tori 
  in 
  Myxicola). 
  Branchial 
  filaments 
  without 
  eyes, 
  united 
  along 
  a 
  large 
  

   part 
  of 
  their 
  length 
  by 
  a 
  well-developed 
  palmar 
  membrane 
  (fig. 
  39, 
  w) 
  — 
  3 
  

  

  2. 
  Dorsal 
  thoracic 
  setae 
  all 
  limbate, 
  some 
  long 
  with 
  straight 
  borders, 
  others 
  short 
  

  

  with 
  wide 
  borders 
  (fig. 
  38, 
  c) 
  Sabella 
  (p. 
  334) 
  

  

  Dorsal 
  thoracic 
  setae 
  of 
  two 
  kinds, 
  some 
  limbate, 
  others 
  spatulate 
  (fig. 
  38, 
  m, 
  n) 
  

  

  Potamilla 
  (p. 
  335) 
  

  

  3. 
  Uncinigerous 
  tori 
  projecting, 
  with 
  short, 
  lateral 
  rows 
  of 
  uncini. 
  Collarette 
  

  

  well 
  developed 
  (fig. 
  39, 
  a-c). 
  Dorsal 
  thoracic 
  setae 
  of 
  two 
  kinds, 
  limbate 
  

  

  and 
  spatulate 
  (fig. 
  39, 
  /, 
  g) 
  4 
  

  

  Without 
  projecting 
  uncinigerous 
  tori, 
  abdominal 
  uncini 
  in 
  almost 
  complete 
  

   transverse 
  band 
  (fig. 
  39, 
  p). 
  Collarette 
  poorly 
  developed, 
  represented 
  by 
  

   a 
  triangular 
  ventral 
  lobe 
  (fig. 
  39, 
  o). 
  Dorsal 
  thoracic 
  setae 
  all 
  capillary, 
  

   limbate 
  Myxicola 
  (p. 
  340) 
  

  

  4. 
  Posterior 
  segments 
  without 
  ventral 
  depression 
  Chone 
  (p. 
  337) 
  

  

  Posterior 
  segments 
  about 
  10, 
  with 
  ventral 
  suckerlike 
  disc, 
  large 
  ventral 
  de- 
  

   pression 
  with 
  flared 
  sides 
  (fig. 
  39, 
  n) 
  Euchoiie 
  (p. 
  339) 
  

  

  Genus 
  Sabella 
  Linn^, 
  1767 
  (sensu 
  Malmgren, 
  1865) 
  

  

  Sabella 
  crassicornis 
  Sars, 
  18.51 
  

  

  Figure 
  38, 
  a-i 
  

  

  Sabella 
  crassicornis 
  Sars, 
  1851, 
  p. 
  202.— 
  Malmgren, 
  1865, 
  p. 
  399, 
  pi. 
  27, 
  fig. 
  83.— 
  

  

  Moore, 
  1909b, 
  p. 
  144.— 
  Johansson, 
  1927, 
  p. 
  119.— 
  Hartman, 
  1942a, 
  p. 
  78; 
  

  

  1948, 
  p. 
  46.— 
  Berkeley 
  and 
  Berkeley, 
  1943, 
  p. 
  130; 
  1952, 
  p. 
  114, 
  figs. 
  236, 
  

  

  237.— 
  Zatsepiu, 
  1948, 
  p. 
  161, 
  pi. 
  39, 
  fig. 
  4. 
  

   Sabella 
  fabricii 
  Kroyer, 
  1856, 
  p. 
  20.— 
  Fauvel, 
  1927, 
  p. 
  300, 
  fig. 
  103, 
  a-g.— 
  Augener, 
  

  

  1928, 
  p. 
  800.— 
  Annenkova, 
  1934, 
  p. 
  322; 
  1937, 
  p. 
  195; 
  1938, 
  p. 
  211.— 
  Wesen- 
  

  

  berg-Lund, 
  1950b, 
  p. 
  128; 
  1951, 
  p. 
  118. 
  

   Sabella 
  spetsbergensis 
  Malmgren, 
  1865, 
  p. 
  399, 
  pi. 
  29, 
  fig. 
  93. 
  

   Sabella 
  spitzbergensis 
  Webster 
  and 
  Benedict, 
  1887, 
  p. 
  750. 
  

  

  