﻿Gatty 
  Marine 
  Laboratory, 
  St, 
  Andrews. 
  159 
  

  

  red 
  streak 
  (vessel) 
  . 
  It 
  tinges 
  spirit 
  green 
  ? 
  giving 
  out 
  a 
  dark 
  

   green 
  exudation 
  like 
  dark 
  specimens 
  of 
  Cirratulus. 
  

  

  De 
  Quatrefages 
  thought 
  that 
  the 
  buccal 
  segment 
  was 
  in 
  

   abeyance 
  (" 
  L'anneau 
  buccal 
  a 
  presque 
  entierement 
  disparu"), 
  

   yet 
  not 
  only 
  the 
  mouth-parts, 
  but 
  the 
  bases 
  of 
  the 
  great 
  

   tentacles 
  are 
  close 
  to 
  the 
  peristomium. 
  The 
  large 
  tentacles 
  

   are 
  prominent 
  organs, 
  with 
  a 
  deep 
  groove 
  on 
  their 
  ventral 
  

   surface; 
  and 
  as 
  the 
  edges 
  of 
  these 
  are 
  crenated, 
  they 
  in 
  all 
  

   probability 
  approach 
  in 
  function 
  to 
  those 
  of 
  Polydora 
  and 
  

   other 
  Spionidte. 
  Above 
  and 
  behind 
  the 
  tentacles 
  is 
  a 
  

   branchia, 
  and, 
  as 
  a 
  rule, 
  three 
  others 
  follow, 
  each 
  on 
  the 
  

   dorsal 
  arch 
  of 
  its 
  segment, 
  and 
  with 
  a 
  diminishing 
  distance 
  

   transversely 
  between 
  the 
  bases. 
  They 
  are 
  of 
  moderate 
  

   length, 
  and 
  in 
  some 
  have 
  a 
  tendency 
  to 
  form 
  curves 
  and 
  a 
  

   few 
  coils. 
  

  

  Behind 
  the 
  tentacles 
  are 
  indications 
  of 
  five 
  segments, 
  but 
  

   whether 
  the 
  imperfect 
  first 
  of 
  these 
  should 
  be 
  regarded 
  

   as 
  an 
  independent 
  one 
  may 
  be 
  an 
  open 
  question. 
  The 
  four 
  

   following 
  have 
  dorsal 
  and 
  ventral 
  bristles 
  of 
  a 
  simple 
  tapering 
  

   kind, 
  minutely 
  serrated 
  along 
  the 
  anterior 
  edge. 
  These 
  and 
  

   the 
  next 
  are 
  all 
  narrow 
  segments, 
  and 
  differ 
  in 
  this 
  respect 
  

   from 
  those 
  which 
  follow. 
  The 
  foot 
  is 
  represented 
  by 
  a 
  

   dorsal 
  and 
  a 
  ventral 
  setigerous 
  papilla, 
  with 
  a 
  ridge 
  between.. 
  

   The 
  type 
  of 
  foot, 
  however, 
  changes 
  at 
  the 
  seventh, 
  where 
  the 
  

   characteristic 
  crotchets 
  occur 
  dorsally 
  and 
  ventrally. 
  On 
  

   their 
  first 
  appearance 
  these 
  organs 
  have 
  a 
  slight 
  forward 
  

   curve 
  of 
  the 
  shaft 
  as 
  far 
  as 
  the 
  distal 
  third, 
  where 
  a 
  back- 
  

   ward 
  curve 
  takes 
  place. 
  The 
  shaft 
  shows 
  only 
  a 
  slight 
  

   dilatation 
  from 
  the 
  base 
  upward 
  for 
  a 
  short 
  distance, 
  re- 
  

   maining 
  nearly 
  of 
  the 
  same 
  diameter 
  to 
  the 
  neck, 
  where 
  it 
  

   bends 
  backward 
  and 
  again 
  forward 
  at 
  the 
  tip 
  (PI. 
  V. 
  fig. 
  2 
  a)~ 
  

   The 
  latter 
  in 
  certain 
  antero-posterior 
  views 
  presents 
  a 
  median 
  

   rib 
  and 
  two 
  lateral 
  wing-like 
  areas, 
  but 
  probably 
  this 
  appear- 
  

   ance 
  is 
  due 
  to 
  the 
  thicker 
  tissue 
  in 
  the 
  centre 
  and 
  the 
  thinner 
  

   and 
  slightly 
  expanded 
  lateral 
  regions. 
  In 
  lateral 
  view 
  the 
  

   hollow 
  of 
  the 
  distal 
  hook 
  appears 
  to 
  be 
  scooped 
  out 
  like 
  an 
  

   old 
  snuff-spoon, 
  but 
  there 
  is 
  no 
  knob 
  at 
  the 
  anterior 
  base 
  as. 
  

   in 
  D. 
  concharum. 
  These 
  hooks 
  increase 
  gradually 
  in 
  

   strength 
  though 
  not 
  in 
  length 
  in 
  both 
  divisions 
  of 
  the 
  foot 
  

   posteriorly, 
  and 
  their 
  number 
  toward 
  the 
  tip 
  of 
  the 
  tail 
  

   diminishes, 
  but 
  they 
  are 
  of 
  proportionally 
  great 
  size, 
  and 
  

   thus 
  in 
  contrast 
  with 
  those 
  of 
  D. 
  concharum* 
  Two 
  occur 
  in 
  

   the 
  dorsal 
  and 
  three 
  in 
  the 
  ventral 
  division 
  just 
  in 
  front 
  

   of 
  the 
  tail, 
  but 
  the 
  number 
  is 
  variable. 
  The 
  alterations 
  of 
  

   the 
  contour 
  of 
  the 
  tips 
  of 
  the 
  hooks 
  would 
  indicate 
  that 
  

   they 
  have 
  special 
  functions 
  in 
  connexion 
  with 
  the 
  tube, 
  and 
  

  

  