﻿Gatty 
  Marine 
  Laboratory, 
  St. 
  Andrews. 
  153 
  

  

  congenial 
  to 
  the 
  animal 
  than 
  with 
  mud, 
  which 
  at 
  least 
  

   enables 
  it 
  to 
  separate 
  the 
  long 
  coiled 
  filaments. 
  

  

  The 
  peristomial 
  segment 
  is 
  somewhat 
  narrower 
  than 
  the 
  

   two 
  which 
  follow, 
  and 
  each 
  of 
  which 
  has 
  various 
  transverse 
  

   creases 
  or 
  wrinkles. 
  These 
  are 
  devoid 
  of 
  bristles, 
  hooks, 
  or 
  

   other 
  appendages. 
  The 
  first 
  setigerous 
  segment 
  follows 
  the 
  

   foregoing 
  and 
  is 
  broader 
  than 
  its 
  successors. 
  The 
  foot 
  is 
  

   represented 
  in 
  the 
  lateral 
  region 
  only 
  by 
  dorsal 
  and 
  ventral 
  

   setigerous 
  processes, 
  which 
  bear 
  tnfts 
  of 
  capillary 
  bristles. 
  

   Moreover, 
  near 
  the 
  junction 
  with 
  the 
  segment 
  behind 
  and 
  

   nearly 
  on 
  a 
  level 
  with 
  the 
  upper 
  bristles 
  is 
  a 
  long 
  coiled 
  

   branchia. 
  The 
  capillary 
  bristles 
  have 
  somewhat 
  stout 
  shafts 
  

   and 
  long, 
  flattened, 
  tapering 
  tips, 
  with 
  a 
  narrow 
  border 
  of 
  

   spines 
  directed 
  distally. 
  The 
  four 
  or 
  five 
  bristled 
  segments 
  

   which 
  follow 
  are 
  broader 
  than 
  those 
  next 
  them, 
  but 
  all 
  have 
  

   the 
  capillary 
  bristles 
  dorsally 
  and 
  ventrally. 
  In 
  the 
  groove 
  

   between 
  the 
  second 
  and 
  third 
  bristled 
  segment 
  a 
  second 
  and 
  

   smaller 
  branchia 
  occurs, 
  the 
  base 
  arising 
  a 
  little 
  above 
  the 
  

   level 
  of 
  the 
  dorsal 
  bristle-tuft. 
  The 
  same 
  takes 
  place 
  in 
  the 
  

   groove 
  between 
  the 
  third 
  and 
  fourth 
  and 
  between 
  the 
  fifth 
  

   and 
  sixth. 
  The 
  branchiae 
  and 
  tentacles 
  vary 
  in 
  size 
  according 
  

   to 
  the 
  degree 
  of 
  development, 
  those 
  in 
  process 
  of 
  reproduc- 
  

   tion 
  being 
  small, 
  whilst 
  the 
  older 
  examples 
  are 
  thick. 
  All 
  

   are 
  minutely 
  ringed, 
  probably 
  from 
  muscular 
  fibres. 
  

  

  The 
  strong 
  hooks 
  commence 
  in 
  the 
  ventral 
  series 
  of 
  the 
  

   large 
  examples 
  from 
  Plymouth 
  at 
  the 
  sixty-second 
  bristled 
  

   segment, 
  though 
  they 
  vary 
  in 
  this 
  respect, 
  some 
  commencing 
  

   at 
  the 
  forty-fifth, 
  others 
  at 
  the 
  sixtieth. 
  The 
  hooks 
  are 
  at 
  

   first 
  slender, 
  but 
  soon 
  become 
  robust, 
  the 
  neck 
  curving 
  

   backward 
  and 
  then 
  forward 
  at 
  the 
  tip, 
  and 
  probably 
  they 
  are 
  

   the 
  main 
  agents 
  in 
  securing 
  a 
  firm 
  hold 
  of 
  the 
  burrow. 
  

   Their 
  appearance 
  in 
  the 
  dorsal 
  division 
  is 
  somewhat 
  later, 
  

   viz. 
  between 
  the 
  ninety-first 
  and 
  ninety-fifth 
  bristled 
  seg- 
  

   ments. 
  In 
  both 
  cases 
  the 
  foregoing 
  figures 
  differ 
  from 
  those 
  

   of 
  von 
  Marenzeller 
  and 
  De 
  St. 
  Joseph. 
  The 
  former 
  states 
  

   that 
  the 
  first 
  ventral 
  hooks 
  appear 
  in 
  C. 
  tentaculalus 
  between 
  

   the 
  thirty-third 
  and 
  forty- 
  fifth 
  segments, 
  and 
  the 
  dorsal 
  

   between 
  the 
  fortieth 
  and 
  forty-fourth 
  ; 
  whereas 
  in 
  Cirra- 
  

   tulus 
  chiajii 
  the 
  ventral 
  appear 
  between 
  the 
  twenty-first 
  and 
  

   twenty-third 
  and 
  the 
  dorsal 
  between 
  the 
  fortieth 
  and 
  forty- 
  

   fourth. 
  The 
  variation 
  in 
  regard 
  to 
  the 
  appearance 
  of 
  these 
  

   structures 
  in 
  British 
  examples 
  of 
  C. 
  tentaculatus 
  would 
  also, 
  

   as 
  De 
  St. 
  Joseph 
  observes, 
  lead 
  to 
  some 
  doubt 
  as 
  to 
  specific 
  

   identity 
  based 
  on 
  this 
  feature. 
  

  

  An 
  examination 
  of 
  two 
  examples 
  of 
  Cirratulus 
  (Audouinia) 
  

   filigerus 
  from 
  Naples 
  shows 
  that 
  in 
  one 
  the 
  anterior 
  tentacles 
  

  

  