﻿MARINE 
  POLYCHAETE 
  WORMS 
  — 
  PETTIBONE 
  223 
  

  

  Evarnella 
  triannulata 
  Berkeley 
  and 
  Berkeley, 
  1942, 
  p. 
  188; 
  1943, 
  p. 
  130. 
  — 
  Hartman, 
  

   1948, 
  p. 
  13 
  (part; 
  includes 
  H. 
  muliisetosa 
  Moore 
  and 
  H. 
  extenuata). 
  — 
  Petti- 
  

   bone, 
  1949, 
  p. 
  1. 
  

  

  Description. 
  — 
  Length 
  13-68 
  mm., 
  width 
  including 
  setae 
  4-20 
  mm. 
  

   (length 
  up 
  to 
  74 
  mm. 
  — 
  Ditlevsen, 
  1937). 
  Segments 
  37-47. 
  Prosto- 
  

   mium 
  with 
  eyes 
  large, 
  anterior 
  pair 
  anterolateral, 
  slightly 
  anterior 
  to 
  

   widest 
  part 
  of 
  prostomium, 
  visible 
  dorsally. 
  Neurosetae 
  with 
  en- 
  

   larged, 
  long 
  spinous 
  regions, 
  with 
  tips 
  slightly 
  hooked, 
  with 
  small, 
  

   secondary 
  tooth 
  present 
  or 
  absent; 
  at 
  least 
  some 
  of 
  the 
  setae 
  show 
  a 
  

   remnant 
  of 
  a 
  secondary 
  tooth. 
  The 
  upper 
  and 
  lower 
  neurosetae 
  tend 
  

   to 
  be 
  unidentate 
  (not 
  always) 
  while 
  the 
  middle 
  ones 
  are 
  bidentate, 
  

   with 
  a 
  secondary 
  tooth 
  or 
  remnant 
  of 
  it 
  (in 
  specimens 
  from 
  Woods 
  

   Hole 
  region 
  only 
  a 
  few 
  neurosetae 
  have 
  a 
  secondary 
  tooth 
  or 
  remnant 
  

   of 
  one). 
  Elytra 
  with 
  numerous 
  micro 
  tubercles, 
  more 
  or 
  less 
  uniform 
  

   in 
  size, 
  conical, 
  mth 
  tips 
  blunt, 
  pointed, 
  or 
  bifid; 
  usually 
  with 
  few 
  to 
  

   fairly 
  numerous 
  macrotubercles 
  distinctly 
  set 
  off 
  from 
  elytral 
  surface, 
  

   usually 
  narrower 
  at 
  the 
  base, 
  brown, 
  smooth, 
  globular, 
  sausage- 
  

   shaped, 
  or 
  elongate 
  fusiform, 
  variable 
  in 
  number, 
  0-9 
  near 
  posterior 
  

   border, 
  0-13 
  scattered 
  near 
  center 
  of 
  elytron. 
  Elytra 
  with 
  short 
  

   fringe 
  of 
  papillae 
  on 
  external 
  border. 
  Color: 
  In 
  alcohol: 
  Without 
  

   color 
  anteriorly; 
  on 
  posterior 
  half, 
  with 
  brownish 
  transverse 
  bands 
  and 
  

   two 
  brown 
  spots 
  basallj'' 
  on 
  cirrophores 
  (in 
  specimens 
  from 
  Woods 
  

   Hole 
  region, 
  found 
  intertidally, 
  the 
  body 
  is 
  darldy 
  pigmented 
  grayish- 
  

   green 
  middorsally) 
  ; 
  antennae 
  and 
  dorsal 
  cirri 
  ringed 
  with 
  brown; 
  

   elytra 
  mottled 
  with 
  brown, 
  sometimes 
  with 
  a 
  darker 
  spot 
  posterior 
  

   and 
  medial 
  to 
  the 
  place 
  of 
  attachment; 
  the 
  micro 
  tubercles 
  may 
  be 
  

   covered 
  with 
  a 
  brown 
  extraneous 
  material, 
  giving 
  a 
  streaked 
  appearance. 
  

  

  Remarks. 
  — 
  H. 
  extenuata 
  is 
  an 
  extremely 
  variable 
  species 
  as 
  indicated 
  

   by 
  the 
  number 
  of 
  names 
  that 
  have 
  been 
  applied 
  to 
  it. 
  It 
  reaches 
  its 
  

   greatest 
  size 
  in 
  arctic 
  waters; 
  it 
  is 
  small 
  when 
  found 
  intertidally, 
  as 
  

   in 
  the 
  Puget 
  Sound 
  region 
  (up 
  to 
  23 
  mm. 
  — 
  H. 
  triannulata 
  of 
  Moore). 
  

   When 
  found 
  intertidally 
  off 
  New 
  England, 
  it 
  also 
  is 
  small 
  (about 
  26 
  

   mm.), 
  and 
  the 
  secondary 
  tooth 
  of 
  the 
  neurosetae 
  is 
  suppressed, 
  usually 
  

   with 
  only 
  a 
  remnant 
  showing 
  on 
  a 
  few 
  neurosetae, 
  the 
  rest 
  being 
  entire 
  

   (L. 
  impatiens 
  of 
  Webster). 
  In 
  the 
  collection 
  from 
  Point 
  Barrow, 
  

   where 
  it 
  was 
  the 
  most 
  abundant 
  polychaete, 
  it 
  is 
  represented 
  by 
  

   specimens 
  of 
  all 
  sizes 
  from 
  very 
  small 
  to 
  large 
  (up 
  to 
  68 
  mm.). 
  

  

  Parasites. 
  — 
  Of 
  the 
  375 
  specimens, 
  3 
  had 
  the 
  parasitic 
  copepod 
  

   Herpyllohius 
  arcticus 
  Steenstrup 
  and 
  Lutken 
  attached 
  to 
  the 
  pros- 
  

   tomium 
  (identified 
  by 
  lUg) 
  . 
  

  

  New 
  records. 
  — 
  Arctic 
  Alaska: 
  Eluitkak 
  Pass, 
  Elson 
  Lagoon 
  near 
  

   Point 
  Barrow, 
  6.6 
  fms.; 
  off 
  Point 
  Barrow 
  base, 
  up 
  to 
  15 
  miles 
  from 
  

   shore, 
  13.3-123.5 
  fms., 
  on 
  bottoms 
  of 
  mud, 
  stones, 
  masses 
  of 
  worm 
  

   tubes, 
  and 
  various 
  combinations 
  of 
  mud, 
  pebbles, 
  rocks, 
  gravel, 
  

   stones, 
  large 
  perforated 
  rocks, 
  with 
  shells, 
  bryozoans, 
  hydroids, 
  

  

  