﻿90 
  PrbF. 
  Mcintosh's 
  Notes 
  from 
  the 
  

  

  and 
  more 
  flattened 
  toward 
  the 
  base. 
  They 
  are 
  hard, 
  though 
  

   somewhat 
  brittle, 
  and 
  the 
  edge 
  ot" 
  the 
  razor 
  is 
  often 
  notched 
  

   in 
  making 
  the 
  sections. 
  

  

  Tlie 
  dorsal 
  or 
  anterior 
  edge 
  above 
  the 
  paleolse 
  is 
  smooth, 
  

   firm, 
  and 
  somewhat 
  hollow, 
  with 
  a 
  marginal 
  rim 
  which 
  

   forms 
  more 
  than 
  a 
  semicircle 
  externally, 
  and 
  ends 
  in 
  a 
  

   subulate 
  tentacle 
  ventrally. 
  A 
  notch 
  separates 
  the 
  latter 
  

   from 
  the 
  veil 
  or 
  frilled 
  membrane 
  to 
  the 
  ventral 
  surface 
  of 
  

   the 
  paleolae, 
  and 
  the 
  edges 
  of 
  the 
  muscular 
  membrane 
  bear 
  

   a 
  series 
  of 
  long 
  papillse 
  or 
  fimbriae. 
  This 
  membrane 
  is 
  not 
  

   attached 
  directly 
  to 
  the 
  ventral 
  edge 
  of 
  the 
  rows 
  of 
  paleolse, 
  

   a 
  firm 
  transversely 
  elongated 
  area 
  occurring 
  at 
  their 
  base. 
  

  

  Below 
  and 
  attached 
  to 
  the 
  foregoing 
  veil 
  is 
  a 
  dense 
  series 
  

   of 
  tentacles 
  on 
  each 
  side 
  of 
  the 
  mouth, 
  which 
  has 
  a 
  dorsal 
  

   fold 
  in 
  the 
  middle 
  line 
  and 
  a 
  transverse 
  one 
  behind 
  it. 
  In 
  

   the 
  median 
  line 
  ventrally 
  is 
  a 
  large 
  central 
  boss, 
  and 
  on 
  each 
  

   side 
  is 
  a 
  fillet 
  continued 
  upward 
  by 
  a 
  ridge 
  to 
  the 
  long 
  lateral 
  

   cirrus 
  in 
  front 
  of 
  the 
  branchise. 
  The 
  cirrus 
  is 
  crenulate, 
  

   with 
  a 
  broad 
  base 
  which 
  tapers 
  by 
  and 
  by 
  to 
  a 
  long 
  slender 
  

   process 
  with 
  a 
  slightly 
  bulbous 
  tip. 
  In 
  structure 
  this 
  shows 
  

   externally 
  the 
  cuticle 
  and 
  hypoderm 
  with 
  fibrillation, 
  whilst 
  

   internally 
  it 
  has 
  granules 
  of 
  various 
  sizes 
  — 
  probably 
  hypo- 
  

   dermic. 
  It 
  may 
  be 
  penetrated 
  by 
  the 
  perivisceral 
  fluid. 
  In 
  

   life, 
  this 
  and 
  the 
  anterior 
  cirrus 
  or 
  tentacle 
  move 
  a 
  little 
  to 
  

   and 
  fro, 
  or 
  the 
  tips 
  are 
  coiled 
  aud 
  waved. 
  

  

  When 
  withdrawing 
  itself 
  into 
  the 
  tube 
  the 
  two 
  rows 
  

   of 
  golden 
  bristles 
  slightly 
  and 
  symmetrically 
  overlap, 
  for 
  

   they 
  can 
  both 
  be 
  separated 
  and 
  approximated, 
  and 
  the 
  firm 
  

   smooth 
  area 
  adjoining 
  forms 
  a 
  platform, 
  the 
  whole 
  per- 
  

   forming 
  the 
  part 
  of 
  an 
  operculum. 
  

  

  The 
  tentacles 
  constitute 
  a 
  dense 
  mass, 
  each 
  marked 
  by 
  a 
  

   longitudinal 
  groove, 
  the 
  red 
  blood-vessel 
  running 
  in 
  themiddle 
  

   line, 
  the 
  blood 
  now 
  flowing 
  distally 
  and 
  again 
  proximally 
  

   in 
  the 
  same 
  vessel. 
  They 
  are 
  mobile 
  organs 
  and 
  undergo 
  

   constant 
  contractions 
  and 
  elongations, 
  the 
  tip 
  being 
  often 
  

   clavate 
  or 
  spathulate. 
  The 
  grooved 
  surface 
  of 
  the 
  tentacle 
  

   is 
  minutely 
  tuberculated 
  toward 
  the 
  tip, 
  probably 
  in 
  con- 
  

   nection 
  with 
  its 
  functions 
  in 
  building 
  the 
  tube 
  — 
  indeed, 
  such 
  

   elevations 
  may 
  perform 
  the 
  part 
  of 
  minute 
  suckers. 
  The 
  blood 
  

   seems 
  to 
  flow 
  to 
  the 
  tip 
  of 
  the 
  organ, 
  Avhich 
  becomes 
  deep 
  red, 
  

   reiuains 
  there 
  for 
  a 
  little, 
  and 
  then 
  is 
  sent 
  backward. 
  A 
  

   single 
  blood-vessel 
  apparently 
  with 
  similar 
  action 
  occurs 
  in 
  

   the 
  long 
  cirri. 
  

  

  The 
  body 
  is 
  from 
  1^ 
  to 
  2 
  in. 
  in 
  length, 
  gently 
  tapered 
  to 
  

   a 
  comparatively 
  broad 
  tail, 
  which 
  has 
  the 
  anal 
  appendix 
  

   passing 
  off 
  at 
  an 
  angle 
  posteriorly. 
  It 
  is 
  rounded 
  dorsally. 
  

  

  