﻿Miscellaneous. 
  291 
  

  

  composed 
  of 
  two 
  distinct 
  glands, 
  opening 
  outwards 
  in 
  the 
  two 
  

   appendages 
  placed 
  on 
  the 
  margin 
  of 
  the 
  anus. 
  

  

  These 
  glands, 
  which 
  are 
  situated 
  on 
  the 
  two 
  sides 
  of 
  the 
  hody 
  of 
  

   the 
  animal, 
  have 
  the 
  form 
  of 
  an 
  elongated 
  tube 
  terminating 
  crecally 
  

   about 
  the 
  fifth 
  anal 
  segment. 
  They 
  present 
  an 
  anterior 
  and 
  a 
  

   posterior 
  portion. 
  The 
  former 
  constitutes 
  the 
  gland 
  properly 
  so 
  

   called, 
  the 
  latter 
  its 
  excretory 
  canal. 
  The 
  glandular 
  part 
  occupies 
  

   about 
  two 
  thirds 
  of 
  the 
  total 
  length 
  of 
  the 
  organ 
  ; 
  its 
  outer 
  surface 
  

   is 
  rugged, 
  and 
  covered 
  with 
  an 
  irregular 
  network 
  of 
  intercrossing 
  

   muscular 
  fibres. 
  The 
  gland 
  itself 
  is 
  occupied 
  by 
  a 
  single 
  large 
  cavity 
  

   filled 
  with 
  the 
  secreted 
  substance 
  ; 
  its 
  wall 
  is 
  formed 
  by 
  a 
  pavement- 
  

   epithelium 
  consisting 
  of 
  small 
  cells 
  charged 
  with 
  fine 
  granulations, 
  

   which 
  is 
  bounded 
  externally 
  by 
  a 
  thick 
  and 
  very 
  resistant 
  basement- 
  

   membrane. 
  The 
  excretory 
  canal 
  is 
  clearly 
  indicated, 
  externally 
  

   by 
  the 
  disappearance 
  of 
  the 
  muscular 
  network, 
  and 
  internally 
  by 
  

   that 
  of 
  the 
  lining 
  cells, 
  and 
  at 
  the 
  same 
  time 
  by 
  the 
  considerable 
  

   diminution 
  of 
  the 
  thickness 
  of 
  the 
  walls. 
  It 
  opens, 
  as 
  already 
  

   stated, 
  in 
  the 
  anal 
  appendage 
  of 
  the 
  same 
  side. 
  

  

  These 
  terminal 
  appendages, 
  as 
  is 
  well 
  known, 
  are 
  formed 
  by 
  a 
  

   single 
  lanceolate 
  joint, 
  bristling 
  with 
  hairs, 
  and 
  terminated 
  by 
  a 
  

   long 
  and 
  strong 
  spine. 
  M. 
  Fabre*, 
  who 
  regarded 
  these 
  singular 
  

   Myriopoda 
  as 
  young 
  specimens 
  of 
  Gryptops, 
  took 
  these 
  two 
  append- 
  

   ages 
  for 
  the 
  rudiments 
  of 
  the 
  anal 
  limbs. 
  

  

  Each 
  appendage 
  is 
  traversed 
  by 
  a 
  cavity, 
  the 
  diameter 
  of 
  which 
  

   is 
  greater 
  than 
  that 
  of 
  the 
  execretory 
  canal 
  ; 
  at 
  its 
  extremity, 
  at 
  

   the 
  very 
  base 
  of 
  the 
  terminal 
  spine, 
  there 
  is 
  an 
  aperture 
  destined 
  to 
  

   afford 
  a 
  passage 
  to 
  the 
  product 
  of 
  secretion. 
  The 
  liquid 
  secreted 
  

   by 
  the 
  gland 
  is 
  remarkable 
  for 
  its 
  great 
  viscosity 
  ; 
  it 
  does 
  not 
  

   mix 
  either 
  with 
  water 
  or 
  glycerine. 
  On 
  coming 
  in 
  contact 
  with 
  

   the 
  air 
  it 
  hardens 
  rapidly. 
  

  

  It 
  is 
  easy 
  to 
  ascertain 
  that 
  the 
  product 
  of 
  secretion 
  is 
  conveyed 
  

   out 
  by 
  the 
  orifices 
  of 
  the 
  terminal 
  appendages 
  ; 
  in 
  fact, 
  on 
  making 
  

   the 
  animal 
  fall, 
  we 
  note 
  that 
  it 
  remains 
  suspended 
  from 
  the 
  object 
  

   from 
  which 
  it 
  has 
  been 
  precipitated 
  by 
  an 
  extremely 
  delicate 
  

   thread. 
  This 
  thread 
  issues 
  from 
  the 
  body 
  of 
  the 
  animal 
  by 
  the 
  

   aperture 
  of 
  the 
  appendages 
  above 
  described, 
  appendages 
  which, 
  

   consequently, 
  constitute 
  true 
  spinnerets. 
  These 
  threads 
  would 
  be 
  

   perfectly 
  comparable 
  with 
  those 
  of 
  Araneida 
  if 
  they 
  possessed 
  the 
  

   same 
  elasticity 
  ; 
  but 
  they 
  are 
  plainly 
  distinguished 
  from 
  them 
  by 
  

   their 
  fragility, 
  which 
  cannot 
  be 
  better 
  compared 
  than 
  to 
  that 
  of 
  a 
  

   thread 
  of 
  glass. 
  

  

  It 
  appears 
  from 
  my 
  observations 
  : 
  (1) 
  That 
  Scolopendrella 
  im- 
  

   maculata 
  possesses 
  a 
  glandular 
  apparatus 
  destined 
  to 
  secrete 
  a 
  

   liquid 
  capable 
  of 
  hardening 
  in 
  the 
  air 
  and 
  of 
  forming 
  threads 
  very 
  

   like 
  those 
  spun 
  by 
  the 
  Spiders 
  ; 
  (2) 
  that 
  the 
  anal 
  appendages 
  consti- 
  

   tute 
  true 
  spinnerets. 
  — 
  Gornptes 
  Rendus, 
  January 
  14, 
  1889, 
  p. 
  100. 
  

  

  * 
  Loccit. 
  p. 
  311, 
  fig. 
  25. 
  

  

  