﻿452 
  Prof. 
  M'Intosh 
  on 
  the 
  

  

  muscular 
  fibres, 
  "which 
  diverge 
  superiorly 
  aud 
  inferiorly; 
  

   the 
  circumferential 
  region 
  is 
  cellulo-granular, 
  and 
  the 
  tip 
  is 
  

   granular, 
  with 
  a 
  few 
  palpocils. 
  A 
  cup-shaped 
  form 
  is 
  often 
  

   assumed 
  by 
  the 
  blunt 
  tip, 
  as 
  the 
  central 
  fibres 
  are 
  emi- 
  

   nently 
  contractile, 
  and 
  thus 
  give 
  a 
  sucker 
  action 
  to 
  the 
  

   extremity. 
  In 
  some 
  views 
  the 
  muscular 
  fibres 
  acting 
  on 
  

   the 
  sucker-tip 
  seem 
  to 
  be 
  separated 
  from 
  the 
  hypoderm 
  of 
  

   the 
  process. 
  Moreover, 
  in 
  the 
  living 
  animal 
  the 
  very 
  fine 
  

   palpocils 
  cover 
  the 
  tip 
  like 
  a 
  series 
  of 
  motionless 
  microscopic 
  

   cilia. 
  Further, 
  the 
  walls 
  of 
  the 
  papillae 
  have 
  a 
  few 
  con- 
  

   stricting 
  fibres, 
  which 
  are 
  the 
  chief 
  agents 
  in 
  elongating 
  

   them. 
  After 
  pressure 
  has 
  continued 
  for 
  a 
  short 
  time 
  various 
  

   cells, 
  mucous 
  globules, 
  and 
  granules 
  begin 
  to 
  appear 
  at 
  the 
  

   sides 
  and 
  palpocils 
  on 
  the 
  summit. 
  Strings 
  of 
  mucus 
  also 
  

   shoot 
  out, 
  enclosing 
  small 
  bacillary 
  cells. 
  Within 
  the 
  hypo- 
  

   derm 
  of 
  the 
  tentacle 
  is 
  a 
  well-marked 
  circular 
  muscular 
  coat, 
  

   surrounding 
  a 
  thick 
  longitudinal 
  layer, 
  which 
  is 
  arranged 
  in 
  

   regular 
  fasciculi, 
  and 
  possessing 
  a 
  raphe 
  at 
  the 
  attachment 
  

   of 
  the 
  fibres 
  of 
  the 
  vessels 
  at 
  each 
  pole, 
  that 
  for 
  the 
  artery 
  

   opposite 
  the 
  papillae 
  being 
  most 
  distinct. 
  

  

  In 
  the 
  central 
  chamber 
  of 
  the 
  tentacle 
  are 
  two 
  vessels, 
  an 
  

   afferent 
  and 
  efferent. 
  The 
  afferent 
  blood-vessel 
  is 
  the 
  smaller 
  

   and 
  lies 
  a 
  little 
  on 
  one 
  side 
  of 
  the 
  pole 
  opposite 
  the 
  papillose 
  

   margin. 
  Its 
  wall 
  on 
  section 
  presents 
  the 
  peculiar 
  striated 
  

   appearance 
  seen 
  in 
  the 
  anterior 
  dorsal 
  vessel 
  of 
  the 
  body, 
  and 
  

   such 
  is 
  probably 
  due 
  to 
  the 
  same 
  longitudinal 
  fibres. 
  Both 
  

   during 
  life 
  and 
  in 
  the 
  preparations 
  it 
  is 
  firm 
  and 
  elastic, 
  and 
  

   in 
  contrast 
  with 
  the 
  widely 
  dilated 
  efferent 
  vessel. 
  The 
  

   latter 
  is 
  not 
  easily 
  made 
  out 
  unless 
  in 
  good 
  preparations, 
  a 
  

   suspensory 
  band 
  from 
  the 
  centre 
  (or 
  raphe) 
  of 
  the 
  papillose 
  

   region 
  being 
  attached 
  to 
  it, 
  and 
  then 
  proceeding, 
  like 
  a 
  

   membranous 
  septum, 
  to 
  the 
  opposite 
  pole. 
  A 
  series 
  of 
  very 
  

   distinct 
  transverse 
  mesenteries 
  or 
  dissepiments, 
  again, 
  exist 
  

   in 
  the 
  tentacle, 
  at 
  regular 
  intervals 
  and 
  almost 
  to 
  the 
  tip 
  of 
  

   the 
  organ. 
  

  

  The 
  tentacles 
  are 
  reproduced 
  with 
  considerable 
  rapidity. 
  

   About 
  the 
  third 
  day 
  after 
  removal 
  the 
  new 
  organs 
  appeared 
  

   on 
  each 
  side 
  as 
  short 
  blunt 
  processes 
  into 
  which 
  the 
  blood 
  

   entered. 
  In 
  other 
  specimens 
  they 
  were 
  about 
  twice 
  the 
  

   breadth 
  of 
  the 
  head, 
  but 
  had 
  not 
  yet 
  begun 
  to 
  develop 
  

   papillae. 
  A 
  distinct 
  artery 
  and 
  vein 
  are 
  apparent 
  in 
  those 
  

   about 
  as 
  long 
  as 
  the 
  head, 
  but 
  even 
  though 
  they 
  are 
  three 
  or 
  

   four 
  times 
  as 
  long 
  no 
  capillary 
  branches 
  are 
  apparent, 
  the 
  

   blood 
  rushing 
  in 
  by 
  the 
  artery 
  to 
  return 
  by 
  the 
  vein. 
  When 
  

   only 
  one 
  tentacle 
  is 
  being 
  reproduced 
  the 
  activity 
  in 
  the 
  

   circulation 
  of 
  the 
  entire 
  (i. 
  e. 
  the 
  old) 
  organ 
  is 
  very 
  great, 
  

  

  