﻿Gatty 
  Marine 
  Laboratory, 
  St. 
  Andrews. 
  171 
  

  

  bristles, 
  then 
  a 
  slight 
  constriction 
  takes 
  place 
  at 
  the 
  level 
  of 
  the 
  

   cuticle, 
  the 
  tip 
  being 
  broad 
  and 
  more 
  or 
  less 
  striated, 
  but 
  ter- 
  

   minating 
  in 
  a 
  long 
  hair-like 
  process. 
  The 
  perfect 
  crotchet 
  

   or 
  hook 
  is 
  best 
  seen 
  in 
  the 
  posterior 
  region 
  of 
  about 
  fifteen 
  

   segments, 
  the 
  shaft 
  dilating 
  a 
  little 
  from 
  the 
  soft 
  base 
  up- 
  

   ward, 
  then 
  narrows 
  about 
  the 
  level 
  of 
  the 
  skin, 
  from 
  which 
  

   a 
  noticeable 
  forward 
  bend 
  occurs, 
  the 
  long 
  stout 
  tip 
  ending 
  

   in 
  a 
  blunt 
  point. 
  The 
  whole 
  organ 
  is 
  striated 
  to 
  the 
  point 
  

   and 
  somewhat 
  resembles 
  a 
  miniature 
  scalpel 
  which 
  has 
  a 
  

   curve 
  backward 
  (PI. 
  VII. 
  fig. 
  11). 
  The 
  direction 
  of 
  these 
  

   crotchets 
  is 
  at 
  first 
  slightly 
  backward, 
  but 
  by-and-by 
  they 
  

   project 
  transversely 
  outward, 
  and 
  in 
  four 
  or 
  five 
  of 
  the 
  

   terminal 
  segments 
  they 
  are 
  directed 
  forward 
  — 
  doubtless 
  in 
  

   connexion 
  with 
  their 
  functions 
  in 
  mud 
  or 
  sandy 
  mud. 
  

  

  Cirratulus 
  norvegicus 
  ? 
  

  

  A 
  form 
  dredged 
  off 
  Drobak, 
  Christiania 
  Fjord, 
  in 
  30-100 
  

   fathoms, 
  in 
  1879, 
  somewhat 
  resembles 
  Cirratulus 
  tessellatus 
  in 
  

   so 
  far 
  as 
  the 
  dorsal 
  divisions 
  of 
  the 
  anterior 
  feet 
  approach 
  

   each 
  other 
  dor 
  sally, 
  and 
  in 
  some 
  are 
  raised, 
  so 
  that 
  the 
  spaces 
  

   between 
  the 
  lateral 
  lines 
  at 
  the 
  base 
  of 
  the 
  feet 
  are 
  narrow 
  in 
  

   front 
  and 
  gradually 
  widen 
  in 
  their 
  course 
  backward. 
  More- 
  

   over, 
  a 
  considerable 
  amount 
  of 
  dark 
  pigment 
  characterizes 
  

   the 
  anterior 
  dorsal 
  region 
  and 
  also 
  occurs 
  along 
  the 
  poste- 
  

   rior 
  lip 
  of 
  the 
  gaping 
  mouth. 
  

  

  The 
  head 
  has 
  the 
  form 
  of 
  a 
  small 
  blunt 
  cone, 
  sometimes 
  

   constricted 
  posteriorly, 
  and 
  when 
  the 
  button-shaped 
  proboscis 
  

   is 
  extruded, 
  as 
  in 
  the 
  majority 
  of 
  the 
  specimens, 
  it 
  projects 
  

   upward 
  and 
  forward, 
  or, 
  in 
  complete 
  extrusion, 
  upward. 
  

  

  The 
  body 
  is 
  probably 
  between 
  1 
  and 
  2 
  inches 
  in 
  length, 
  

   flattened 
  anteriorly, 
  and 
  somewhat 
  rounded 
  posteriorly. 
  It 
  

   is 
  tapered 
  rather 
  abruptly 
  anteriorly, 
  but 
  does 
  not 
  appear 
  to 
  

   be 
  much 
  tapered 
  posteriorly, 
  only 
  a 
  slight 
  diminution 
  taking 
  

   place 
  in 
  the 
  preparation 
  ; 
  but 
  such 
  may 
  be 
  an 
  incomplete 
  

   specimen. 
  It 
  terminates 
  posteriorly 
  in 
  a 
  pouting 
  button- 
  

   shaped 
  vent, 
  which 
  is 
  produced 
  ventrally 
  into 
  a 
  process 
  with 
  

   a 
  median 
  fissure 
  and 
  a 
  fillet 
  on 
  each 
  side 
  of 
  it 
  (PI. 
  VII. 
  fig. 
  12). 
  

   The 
  ventral 
  surface 
  is 
  flattened, 
  sometimes 
  with 
  a 
  median 
  

   ridge 
  and 
  two 
  lateral 
  elevations, 
  though 
  in 
  a 
  few 
  neither 
  is 
  

   visible. 
  The 
  buccal 
  and 
  two 
  achaetous 
  segments 
  follow 
  the 
  

   head, 
  and 
  in 
  one 
  example 
  each 
  has 
  a 
  dorso-lateral 
  frill, 
  it 
  

   may 
  be 
  from 
  imperfect 
  preservation. 
  Every 
  example 
  presents 
  

   two 
  short 
  lappets 
  (or, 
  it 
  may 
  be, 
  the 
  bases 
  of 
  tentacles) 
  

   interposed 
  between 
  the 
  converging 
  lateral 
  lines 
  of 
  the 
  feet 
  

   nearly 
  opposite 
  the 
  first 
  bristle-bundles. 
  A 
  series 
  of 
  long 
  

  

  