﻿Gatiij 
  Marine 
  Luhoratoru, 
  St. 
  Andrews. 
  89 
  

  

  region 
  of 
  the 
  body 
  not 
  yet 
  having 
  been 
  reproduced, 
  whilst 
  

   the 
  caudal 
  process 
  is 
  fully 
  developed. 
  

  

  Tlie 
  lamellar 
  hooks 
  have 
  six 
  teeth 
  from 
  the 
  crown 
  down- 
  

   ward, 
  then 
  a 
  finely 
  spinous 
  process 
  (like 
  a 
  large 
  tooth 
  with 
  

   serrations), 
  below 
  which 
  is 
  a 
  notch 
  directed 
  upward, 
  and, 
  

   lastly, 
  the 
  rounded 
  prow, 
  which 
  is 
  nearly 
  in 
  a 
  line 
  with 
  the 
  

   face 
  of 
  the 
  hook. 
  The 
  shaft 
  of 
  the 
  hook 
  is 
  short 
  and 
  

   comparatively 
  broad. 
  

  

  The 
  tube 
  is 
  gently 
  curved 
  and 
  finely 
  tapered, 
  especially 
  

   in 
  the 
  smaller 
  specimens, 
  and 
  composed 
  of 
  fine 
  sand- 
  

   grains 
  neatly 
  cemented 
  together, 
  the 
  tubes 
  of 
  young 
  forms 
  

   especially 
  having 
  very 
  minute 
  grains. 
  In 
  the 
  'Porcupine' 
  

   Expedition 
  of 
  1869 
  empty 
  tubes 
  apparently 
  of 
  this 
  species 
  

   were 
  formed 
  of 
  ti-ansversely 
  arranged 
  and 
  neatly 
  cemented 
  

   sponge-spicules. 
  In 
  specimens 
  from 
  deep 
  water, 
  80-130 
  

   fathoms, 
  in 
  Hardanger 
  Fjord 
  and 
  oft" 
  Leavig 
  in 
  Norway 
  the 
  

   tabes 
  at 
  first 
  formed 
  of 
  fine 
  sand-grains 
  were 
  for 
  some 
  

   distance 
  afterwards 
  formed 
  of 
  spongc-spicules 
  placed 
  trans- 
  

   versely. 
  

  

  In 
  extremities 
  a 
  Nemertean 
  (one 
  of 
  the 
  Aopla) 
  will 
  occa- 
  

   sionally 
  thrust 
  itself 
  in 
  the 
  mouth 
  of 
  the 
  tube, 
  driving 
  the 
  

   annelid 
  before 
  it 
  and 
  compressing 
  it 
  in 
  the 
  posterior 
  region 
  

   of 
  the 
  tube. 
  

  

  The 
  third 
  species, 
  Lagis 
  koreni, 
  Malmgren, 
  has 
  often 
  been 
  

   mistaken 
  for 
  Pec^i/za/'za 
  belgica. 
  In 
  this 
  generally 
  distributed 
  

   form 
  the 
  head 
  is 
  provided 
  with 
  a 
  transverse 
  series 
  of 
  fifteen 
  

   lustrous 
  golden 
  paleolge 
  on 
  each 
  side. 
  Each 
  is 
  a 
  flattoied, 
  

   hollow, 
  chitinous 
  process 
  tapering 
  to 
  a 
  delicate 
  tip, 
  which 
  is 
  

   always 
  more 
  or 
  less 
  curved 
  toward 
  the 
  dorsum, 
  the 
  con- 
  

   cavity 
  of 
  the 
  curve 
  or 
  coil 
  being 
  minutely 
  crenulate, 
  as 
  if 
  

   from 
  a 
  thinner 
  tissue 
  on 
  that 
  side. 
  Moreover, 
  the 
  point 
  of 
  

   those 
  in 
  the 
  middle 
  of 
  the 
  series 
  is 
  continued 
  as 
  a 
  long 
  and 
  

   delicate 
  process 
  — 
  generally 
  coiled. 
  The 
  outer 
  in 
  each 
  series 
  

   is 
  short, 
  broad 
  at 
  the 
  base, 
  and 
  with 
  a 
  long 
  tapering 
  tip 
  — 
  

   not 
  coiled. 
  The 
  paleoUe 
  are 
  finely 
  striated 
  longitudinally, 
  

   and 
  also 
  marked 
  by 
  transverse 
  lines. 
  The 
  second 
  external 
  

   paleola 
  has 
  its 
  transverse 
  lines 
  arranged 
  in 
  distinct 
  ringed 
  

   belts, 
  and 
  not 
  scattered 
  indiscriminately. 
  In 
  viewing 
  the 
  

   paleolse 
  of 
  each 
  side 
  as 
  a 
  whole, 
  the 
  distal 
  curve 
  of 
  the 
  outer 
  

   forms 
  is 
  more 
  marked 
  than 
  that 
  of 
  the 
  inner 
  forms, 
  and 
  the 
  

   inner 
  are 
  deeply 
  set 
  in 
  the 
  tissues 
  and 
  moved 
  by 
  powerful 
  

   muscles, 
  whereas 
  the 
  external 
  paleolte 
  are 
  less 
  deeply 
  im- 
  

   planted. 
  The 
  bases 
  of 
  the 
  paleolse 
  have 
  a 
  slight 
  obliquity, 
  

   being 
  directed 
  downward 
  and 
  outward 
  on 
  each 
  side. 
  In 
  

   transverse 
  section 
  the 
  flattened 
  hollow 
  condition 
  of 
  the 
  

   paleolae 
  is 
  apparent. 
  Moreover, 
  they 
  become 
  much 
  thinner 
  

  

  