﻿Oatty 
  Marine 
  Laboratory, 
  St. 
  Andrews. 
  161 
  

  

  D 
  unman 
  us 
  Bay. 
  11. 
  2. 
  92 
  in 
  the 
  collection 
  of 
  the 
  Royal 
  

   Irish 
  Museum. 
  

  

  The 
  snout 
  forms 
  a 
  blunt 
  cone, 
  with 
  slight 
  lateral 
  notches 
  

   which 
  may 
  indicate 
  sensory 
  grooves, 
  and 
  the 
  peristomial 
  

   segment 
  is 
  devoid 
  of 
  bristles. 
  The 
  mouth 
  opens 
  ventrally 
  as 
  

   a 
  large 
  aperture, 
  having 
  a 
  crescentic 
  groove 
  posteriorly 
  and 
  a 
  

   median 
  furrow 
  between 
  the 
  two 
  lateral 
  lips 
  anteriorly. 
  

   From 
  the 
  peristomial 
  segment 
  the 
  body 
  gradually 
  widens 
  to 
  

   the 
  eighth 
  or 
  ninth 
  bristled 
  segment, 
  and 
  then 
  rather 
  

   abruptly 
  dilates 
  into 
  an 
  ovoid 
  swelling 
  including 
  about 
  ten 
  

   segments, 
  when 
  it 
  again 
  contracts, 
  such 
  being 
  doubtless 
  due 
  

   to 
  the 
  mode 
  of 
  preparation. 
  The 
  segments 
  of 
  the 
  anterior 
  

   region 
  are 
  distinctly 
  marked 
  and 
  one-ringed, 
  and 
  the 
  feet 
  

   are 
  represented 
  by 
  lateral 
  ridges 
  with 
  dorsal 
  and 
  ventral 
  

   setigerous 
  processes 
  and 
  a 
  minute 
  flat 
  intermediate 
  papilla. 
  

   Anteriorly 
  the 
  feet 
  present, 
  as 
  at 
  the 
  sixth, 
  a 
  long 
  dorsal 
  

   tuft 
  of 
  capillary 
  bristles 
  and 
  a 
  shorter 
  one 
  ventrally. 
  This 
  

   arrangement 
  continues 
  toward 
  the 
  thirtieth 
  foot, 
  when 
  a 
  

   stouter 
  series 
  appear 
  — 
  at 
  first 
  simply 
  modified 
  ordinary 
  bristles 
  

   with 
  a 
  double 
  curvature 
  of 
  the 
  shaft 
  and 
  a 
  finely 
  tapered 
  tip, 
  

   the 
  ventral 
  series 
  apparently 
  preceding 
  the 
  dorsal. 
  Finally, 
  

   posteriorly 
  both 
  divisions 
  have 
  the 
  elongated 
  and 
  charac- 
  

   teristic 
  hooks. 
  These 
  have 
  long, 
  straight, 
  finely 
  striated 
  

   shafts, 
  which 
  at 
  the 
  upper 
  part 
  have 
  a 
  slight 
  curve 
  forward, 
  

   then 
  gently 
  curve 
  forward 
  to 
  the 
  sharp 
  tip. 
  The 
  striae 
  cease 
  

   about 
  the 
  middle 
  of 
  the 
  tip. 
  They 
  thus 
  differ 
  from 
  the 
  con- 
  

   dition 
  in 
  Chatozone 
  and 
  approach 
  that 
  in 
  Cirratulus. 
  

  

  A 
  species 
  (Chaetosone 
  zetlandica) 
  dredged 
  by 
  Dr. 
  Gwyn 
  

   Jeffreys 
  in 
  100 
  fathoms 
  in 
  St. 
  Magnus 
  Bay, 
  Shetland, 
  in 
  

   July 
  1867, 
  appears 
  to 
  differ 
  from 
  Ckaetozone 
  setosa. 
  It 
  is 
  a 
  

   fragment 
  about 
  ^ 
  an 
  inch 
  in 
  length 
  of 
  the 
  middle 
  and 
  poste- 
  

   rior 
  regions, 
  including 
  more 
  than 
  sixty 
  bristled 
  segments, 
  

   and 
  is 
  distinguished 
  from 
  C. 
  setosa 
  by 
  the 
  flattened 
  body, 
  

   the 
  more 
  hirsute 
  lateral 
  regions, 
  the 
  button-shaped 
  anus, 
  and 
  

   the 
  absence 
  of 
  the 
  differentiated 
  posterior 
  region 
  so 
  charac- 
  

   teristic 
  of 
  the 
  species 
  just 
  mentioned. 
  The 
  broad 
  flattened 
  

   body 
  has 
  very 
  distinct 
  segments, 
  with 
  setigerous 
  papilla? 
  

   projecting 
  as 
  conical 
  eminences 
  on 
  each 
  side. 
  The 
  posterior 
  

   end 
  seems 
  to 
  have 
  been 
  reproduced, 
  about 
  fifteen 
  segments 
  

   being 
  thus 
  added 
  with 
  the 
  large 
  button-shaped 
  pygidium 
  ; 
  

   but 
  the 
  general 
  structure 
  of 
  the 
  feet 
  remains 
  as 
  in 
  front, 
  

   and 
  it 
  differs 
  from 
  the 
  condition 
  in 
  C. 
  setosa, 
  in 
  which 
  the 
  

   modification 
  of 
  the 
  crotchets 
  in 
  the 
  posterior 
  region 
  is 
  

   characteristic. 
  

  

  Ann. 
  & 
  Mag. 
  N. 
  Hist. 
  Ser. 
  8. 
  Vol. 
  vii. 
  11 
  

  

  