﻿158 
  Prof. 
  M'lntosh's 
  Notes 
  from 
  the 
  

  

  with 
  young 
  Arenicola, 
  the 
  little 
  boring 
  Sipunculus, 
  Pholoe, 
  

   and 
  swarms 
  of 
  Polydora 
  ciliata 
  at 
  the 
  East 
  Rocks, 
  St. 
  An- 
  

   drews, 
  the 
  body, 
  in 
  spirit, 
  is 
  rounded 
  in 
  front, 
  but 
  the 
  poste- 
  

   rior 
  third 
  is 
  more 
  or 
  less 
  flattened, 
  as 
  in 
  Heterocirrus. 
  The 
  

   colour 
  of 
  the 
  two 
  regions 
  also 
  differs, 
  that 
  in 
  front 
  being 
  

   pale 
  greyish, 
  whilst 
  the 
  posterior 
  is 
  brownish 
  red. 
  The 
  

   bristled 
  segments 
  are 
  about 
  35 
  in 
  number. 
  The 
  snout 
  is 
  

   formed 
  as 
  in 
  the 
  adult, 
  with 
  the 
  mouth 
  considerably 
  behind, 
  

   and 
  the 
  tentacles 
  and 
  the 
  branchiae 
  are 
  well 
  developed. 
  The 
  

   two 
  rounded 
  papillae 
  at 
  the 
  vent 
  are 
  more 
  distinct 
  than 
  in 
  

   the 
  adult. 
  The 
  characteristic 
  hooks 
  show 
  that 
  whilst 
  the 
  

   flattened 
  posterior 
  region 
  simulates 
  that 
  of 
  Heterocirrus 
  ater, 
  

   the 
  form 
  is 
  essentially 
  different. 
  

  

  No 
  feature 
  in 
  Guernsey 
  and 
  Herm 
  is 
  more 
  interesting 
  in 
  

   the 
  littoral 
  region 
  than 
  the 
  abundance 
  of 
  boring 
  forms 
  in 
  the 
  

   coating 
  of 
  Lithothamnion 
  on 
  the 
  surface 
  of 
  the 
  hard 
  gneiss, 
  

   especially 
  at 
  low 
  water. 
  Amongst 
  them 
  is 
  the 
  next 
  form, 
  

   viz. 
  Dodecaceria 
  ater, 
  De 
  Quatrefages 
  (which 
  is 
  not 
  a 
  variety 
  

   of 
  Dodecaceria 
  concharum, 
  which 
  also 
  occurs 
  in 
  the 
  fissures 
  

   of 
  the 
  rocks 
  in 
  long 
  galleries 
  curved 
  in 
  various 
  ways). 
  

   Langerhans 
  * 
  and 
  De 
  St. 
  Joseph 
  consider 
  this 
  only 
  a 
  variety 
  

   of 
  D. 
  concharum, 
  but 
  so 
  marked 
  a 
  variety, 
  especially 
  in 
  regard 
  

   to 
  the 
  structure 
  of 
  the 
  hooks, 
  merits 
  in 
  the 
  meantime 
  special 
  

   separation. 
  It 
  may 
  be 
  that 
  Langerhans 
  had 
  not 
  the 
  present 
  

   form 
  before 
  him, 
  for 
  his 
  figure 
  of 
  the 
  hooks 
  of 
  D. 
  concharum 
  

   is 
  good. 
  The 
  head 
  of 
  this 
  species 
  is 
  rather 
  elongated, 
  like 
  

   that 
  of 
  Phyllodoce, 
  slightly 
  tapered 
  and 
  smoothly 
  rounded 
  iu 
  

   front, 
  and 
  with 
  two 
  dark 
  patches 
  of 
  minute 
  eyes 
  in 
  the 
  

   median 
  dorso-lateral 
  region, 
  the 
  snout 
  in 
  front 
  of 
  these 
  

   generally 
  being 
  pale 
  in 
  the 
  preparations, 
  whilst 
  that 
  behind 
  

   is 
  dark. 
  The 
  mouth 
  opens 
  ventrally 
  a 
  short 
  distance 
  behind 
  

   the 
  tip 
  of 
  the 
  snout, 
  as 
  in 
  other 
  forms, 
  and 
  not 
  at 
  the 
  tip 
  as 
  

   De 
  Quatrefages 
  observes. 
  

  

  The 
  body 
  is 
  1-2 
  inches 
  long, 
  rounded 
  or 
  slightly 
  flattened 
  

   in 
  front, 
  more 
  distinctly 
  flattened 
  after 
  the 
  anterior 
  third, 
  

   and 
  often 
  forming 
  a 
  broad 
  oar-like 
  region 
  posteriorly 
  before 
  

   abruptly 
  narrowing 
  toward 
  the 
  tip, 
  which 
  presents 
  a 
  papilla 
  

   on 
  each 
  side 
  of 
  the 
  vent. 
  It 
  is 
  slightly 
  tapered 
  toward 
  the 
  

   snout 
  and 
  the 
  segments 
  throughout 
  are 
  distinctly 
  marked, 
  

   their 
  antero-posterior 
  diameter 
  being 
  larger 
  iu 
  front 
  than 
  

   behind, 
  though 
  the 
  first 
  four 
  or 
  five 
  bristled 
  segments 
  are 
  

   narrow. 
  The 
  colour 
  is 
  of 
  a 
  very 
  dark 
  blackish 
  green 
  

   throughout, 
  the 
  tentacles 
  being 
  pale 
  green, 
  with 
  a 
  central 
  

  

  * 
  Zeitschr. 
  f. 
  w. 
  Zool. 
  Bd. 
  xxxiv. 
  p. 
  96. 
  

  

  