﻿418 
  Prof. 
  MIntosh 
  on 
  the 
  

  

  it 
  probably 
  inhabits 
  similar 
  sandy 
  flats 
  at 
  and 
  beyond 
  the 
  

   margin 
  of 
  low 
  water 
  on 
  many 
  shores 
  — 
  in 
  company 
  with 
  

   Vahncinia 
  armandi, 
  Glycera, 
  Aricia, 
  Spio, 
  Lanice 
  conchilega, 
  

   and 
  the 
  crustacean 
  and 
  molluscan 
  fauna 
  characteristic 
  of 
  

   such 
  sites. 
  

  

  It 
  is 
  a 
  slender 
  annelid, 
  150 
  mm. 
  to 
  200 
  mm. 
  in 
  length, 
  

   pale 
  pinkish 
  anteriorly, 
  dull 
  greyish 
  green 
  (from 
  the 
  glands 
  

   of 
  the 
  digestive 
  chamber) 
  posteriorly. 
  The 
  snout 
  is 
  eyeless, 
  

   remarkably 
  flattened, 
  translucent, 
  and 
  thinned 
  at 
  the 
  edges, 
  

   like 
  a 
  pointed 
  spatula. 
  Behind 
  a 
  constriction 
  on 
  each 
  side 
  

   of 
  the 
  head 
  a 
  long 
  tentacle 
  occurs, 
  the 
  anterior 
  surface 
  of 
  

   "which 
  has 
  rows 
  of 
  elongated 
  papillae 
  of 
  a 
  somewhat 
  cylindrical 
  

   outline. 
  The 
  segments 
  of 
  the 
  body 
  are 
  numerous, 
  and 
  they 
  

   gradually 
  diminish 
  posteriorly 
  and 
  terminate 
  in 
  a 
  broad 
  

   papilla 
  with 
  a 
  cirrus 
  at 
  each 
  side, 
  a 
  little 
  beyond 
  the 
  anus. 
  

  

  The 
  body 
  is 
  divided 
  into 
  two 
  well-marked 
  regions, 
  in 
  the 
  

   first 
  of 
  which 
  (besides 
  the 
  head) 
  are 
  nine 
  double 
  pairs 
  of 
  

   bristles, 
  and 
  in 
  this 
  respect 
  it 
  approaches 
  the 
  Heterospio 
  

   lonyissima 
  of 
  Prof. 
  Ehlers"^, 
  which 
  also 
  has 
  nine 
  anterior 
  

   segments. 
  The 
  inferior 
  groups 
  are 
  simple, 
  delicate, 
  and 
  

   tapering, 
  and 
  they 
  have 
  a 
  larger 
  free 
  portion 
  and 
  a 
  more 
  

   pronounced 
  terminal 
  curve 
  than 
  the 
  superior 
  series. 
  Both 
  

   have 
  lateral 
  expansions 
  or 
  wings, 
  which, 
  however, 
  are 
  wider 
  

   in 
  the 
  superior 
  bristles 
  and 
  most 
  pronounced 
  posteriorly. 
  

   The 
  latter 
  are 
  also 
  more 
  numerous. 
  

  

  The 
  ninth 
  series 
  of 
  bristles 
  has 
  undergone 
  special 
  modifi- 
  

   cation. 
  Each 
  of 
  the 
  four 
  broad 
  fan-shaped 
  groups 
  consists 
  

   of 
  slender 
  translucent 
  bristles 
  with 
  dilated 
  tips 
  and 
  filiform 
  

   processes. 
  The 
  enlargement 
  at 
  the 
  tip 
  seems 
  to 
  be 
  formed 
  

   by 
  a 
  modification 
  of 
  the 
  wings, 
  and 
  various 
  degrees 
  of 
  

   development 
  can 
  be 
  traced 
  in 
  them 
  : 
  thus 
  in 
  one 
  of 
  those 
  

   next 
  the 
  few 
  simple 
  bristles 
  (with 
  broad, 
  wings) 
  which 
  

   correspond 
  with 
  the 
  anterior 
  tufts, 
  the 
  dilatation 
  at 
  the 
  tip 
  

   being 
  comparatively 
  slight. 
  Next 
  the 
  foregoing 
  a 
  larger 
  tip 
  

   is 
  found, 
  and 
  then 
  the 
  well-marked 
  series 
  occurs, 
  the 
  axis 
  or 
  

   shaft 
  tapering 
  to 
  a 
  fine 
  point 
  near 
  the 
  tip, 
  while 
  the 
  wings 
  

   continue 
  as 
  broad 
  margins, 
  and 
  coalesce 
  into 
  the 
  translucent 
  

   expansion 
  with 
  the 
  filiform 
  process. 
  In 
  the 
  dorsal 
  group 
  

   there 
  is 
  only 
  a 
  tendency 
  to 
  the 
  formation 
  of 
  the 
  simple 
  

   bristles 
  at 
  each 
  end 
  of 
  the 
  row, 
  the 
  rest 
  consisting 
  of 
  those 
  

   with 
  the 
  enlarged 
  translucent 
  tips. 
  The 
  bristles 
  of 
  this 
  

   segment 
  would 
  appear 
  to 
  be 
  homologous 
  with 
  the 
  special 
  

   forms 
  in 
  the 
  third 
  segment 
  in 
  Disoma, 
  the 
  fourth 
  in 
  the 
  

   Cluetopteridse, 
  and 
  the 
  filth 
  iu 
  Polydora, 
  and 
  probably 
  are 
  of 
  

  

  * 
  Zeitscb. 
  f. 
  w. 
  Zool. 
  Bd. 
  xxv. 
  p. 
  60. 
  

  

  