﻿Gatly 
  Marine 
  Laboratory 
  , 
  St. 
  Andrews. 
  155 
  

  

  crenate 
  anus 
  above 
  it. 
  The 
  colour 
  varies 
  from 
  yellowish 
  

   orange 
  to 
  deep 
  madder-brown. 
  Two 
  achsetous 
  segments 
  

   follow 
  the 
  prostomium. 
  The 
  fourth 
  segment 
  has 
  a 
  smaller 
  

   sessile 
  foot 
  than 
  the 
  succeeding 
  segments 
  and 
  bears 
  two 
  

   minute 
  tufts 
  of 
  bristles 
  which 
  have 
  the 
  same 
  structure 
  as 
  in 
  

   C. 
  tentaculatus. 
  It 
  also 
  carries 
  a 
  series 
  of 
  proportionally 
  

   large 
  filiform 
  branchial 
  cirri 
  arranged 
  in 
  two 
  lateral 
  tufts, 
  

   each 
  of 
  seven 
  or 
  eight 
  cirri 
  of 
  an 
  orange 
  colour, 
  with 
  con- 
  

   tained 
  blood-vessels. 
  These 
  coil 
  and 
  twist 
  during 
  the 
  

   progress 
  of 
  the 
  animal, 
  and 
  in 
  proportion 
  to 
  the 
  diameter 
  of 
  

   the 
  body 
  have 
  a 
  larger 
  bulk 
  than 
  those 
  of 
  C. 
  tentaculatus. 
  

  

  The 
  following 
  thirteen 
  or 
  fourteen 
  segments 
  bear 
  branchial 
  

   cirri, 
  each 
  arising 
  above 
  and 
  slightly 
  behind 
  a 
  line 
  through 
  

   the 
  middle 
  of 
  the 
  bristle-tuft. 
  Some 
  of 
  these 
  show 
  a 
  greater 
  

   amount 
  of 
  blood 
  than 
  those 
  in 
  the 
  dense 
  anterior 
  tufts. 
  

   Here 
  and 
  there 
  along 
  the 
  body 
  a 
  single 
  cirrus 
  springs 
  from 
  

   the 
  dorsal 
  arch 
  considerably 
  above 
  the 
  bristles, 
  but 
  the 
  

   posterior 
  region 
  is 
  devoid 
  of 
  them. 
  On 
  the 
  whole, 
  these 
  

   cirri 
  are 
  much 
  fewer 
  in 
  number 
  than 
  in 
  C. 
  tentaculatus, 
  and 
  

   do 
  not 
  show 
  the 
  remarkable 
  spiral 
  coils 
  so 
  characteristic 
  of 
  

   that 
  species. 
  

  

  The 
  feet 
  differ 
  from 
  those 
  of 
  C. 
  tentaculatus 
  in 
  so 
  far 
  as 
  

   they 
  are 
  more 
  prominent 
  and 
  the 
  dorsal 
  and 
  ventral 
  divisions 
  

   considerably 
  closer 
  — 
  indeed, 
  in 
  some, 
  e.g. 
  the 
  first, 
  the 
  bases, 
  

   fused 
  with 
  the 
  body-wall, 
  closely 
  approach. 
  The 
  first 
  twelve 
  

   bristled 
  segments 
  have 
  only 
  the 
  simple 
  flattened 
  tapering 
  

   bristles, 
  the 
  points 
  being 
  extremely 
  slender, 
  and 
  the 
  ventral 
  

   are 
  distinguished 
  from 
  the 
  dorsal 
  by 
  their 
  shortness 
  and 
  in 
  

   some 
  by 
  their 
  proportionally 
  broader 
  tips. 
  The 
  dorsal 
  

   slightly 
  dilate 
  from 
  the 
  base 
  to 
  the 
  middle 
  of 
  the 
  shaft, 
  then 
  

   taper 
  gradually 
  to 
  the 
  very 
  fine 
  hair-like 
  tip. 
  Parasitic 
  

   structures, 
  such 
  as 
  alga?, 
  abound 
  on 
  them, 
  and 
  render 
  them 
  

   pinnate, 
  besides 
  winding 
  round 
  them. 
  ■ 
  The 
  front 
  edge 
  of 
  

   each 
  bristle 
  is 
  minutely 
  and 
  regularly 
  spinous, 
  the 
  direction 
  

   being 
  distal. 
  At 
  the 
  thirteenth 
  foot 
  a 
  single 
  crotchet 
  appears 
  

   on 
  the 
  ventral 
  division. 
  In 
  structure 
  the 
  crotchets 
  (hooks) 
  

   dilate 
  a 
  little 
  from 
  the 
  base 
  to 
  a 
  point 
  above 
  the 
  middle, 
  

   where 
  there 
  is 
  a 
  slight 
  forward 
  curve, 
  then 
  a 
  slight 
  backward 
  

   bend 
  occurs, 
  and 
  again 
  a 
  forward 
  curve 
  to 
  form 
  the 
  hook 
  at 
  

   the 
  tip. 
  This 
  projects 
  through 
  a 
  neatly 
  rounded 
  aperture 
  in 
  

   the 
  cuticle, 
  and 
  is 
  moderately 
  acute 
  in 
  the 
  uninjured 
  forms. 
  

   In 
  the 
  sixteenth 
  foot 
  three 
  hooks 
  are 
  present, 
  and 
  four 
  in 
  the 
  

   thirtieth. 
  One 
  or 
  two 
  bristles 
  accompany 
  the 
  hooks. 
  The 
  

   crotchets 
  commence 
  in 
  the 
  dorsal 
  division 
  about 
  the 
  thirtieth 
  

   foot, 
  a 
  slender 
  sharp-pointed 
  one 
  appearing 
  in 
  the 
  twenty- 
  

   ninth, 
  or 
  perhaps 
  earlier, 
  along 
  with 
  the 
  bristles, 
  and 
  they 
  

  

  