﻿STRUCTUEE 
  AND 
  CLASSIFICATION 
  OF 
  THE 
  ARAOHNIDA. 
  203 
  

  

  structure 
  of 
  Limulus 
  and 
  that 
  of 
  Scorpio 
  is 
  found 
  in 
  the 
  

   hinder 
  region 
  of 
  the 
  alimentary 
  canal. 
  Scorpio 
  is 
  here 
  

   provided 
  with 
  a 
  single 
  or 
  double 
  pair 
  of 
  renal 
  exci'etoi'y 
  

   tubes, 
  which 
  have 
  been 
  identified 
  by 
  earlier 
  authors 
  with 
  

   the 
  Malpighian 
  tubes 
  of 
  the 
  Hexapod 
  and 
  Myriapod 
  insects. 
  

   Limulus 
  is 
  devoid 
  of 
  any 
  such 
  tubes. 
  We 
  shall 
  revert 
  to 
  this 
  

   subject 
  below. 
  

  

  7. 
  Ovaries 
  and 
  Spermaries; 
  Gronocoels 
  and 
  Gono- 
  

   ducts. 
  — 
  The 
  scorpion 
  is 
  remarkable 
  for 
  having 
  the 
  special- 
  

   ised 
  portion 
  of 
  coelom, 
  from 
  the 
  walls 
  of 
  which 
  egg-cells 
  or 
  

   sperm-cells 
  are 
  developed 
  according 
  to 
  sex, 
  in 
  the 
  form 
  of 
  

   a 
  simple 
  but 
  extensive 
  network. 
  It 
  is 
  not 
  a 
  pair 
  of 
  simple 
  

   tubes, 
  nor 
  of 
  dendriform 
  tubes, 
  but 
  a 
  closed 
  network. 
  The 
  

   same 
  fact 
  is 
  true 
  of 
  Limulus, 
  as 
  was 
  shown 
  by 
  Owen 
  (7j 
  in 
  

   regard 
  to 
  the 
  ovary, 
  and 
  by 
  Benham 
  (14) 
  in 
  regard 
  to 
  the 
  

   testis. 
  This 
  is 
  a 
  very 
  definite 
  and 
  remarkable 
  agreement, 
  

   since 
  such 
  a 
  reticular 
  gonocosl 
  is 
  not 
  found 
  in 
  Crustacea 
  

   (except 
  in 
  the 
  male 
  Apus). 
  Moreover 
  there 
  is 
  a 
  significant 
  

   agreement 
  in 
  the 
  character 
  of 
  the 
  spermatozoa 
  of 
  Limulus 
  

   and 
  Scorpio. 
  The 
  Crustacea 
  are 
  — 
  with 
  the 
  exception 
  of 
  the 
  

   Cirrhipedia 
  — 
  remarkable 
  for 
  having 
  stiff, 
  motionless 
  sperma- 
  

   tozoids. 
  In 
  Limulus 
  Lankester 
  found 
  (15) 
  the 
  spermatozoa 
  

   to 
  possess 
  active 
  flagelliform 
  " 
  tails," 
  and 
  to 
  resemble 
  very 
  

   closely 
  those 
  of 
  Scorpio, 
  which, 
  as 
  are 
  those 
  of 
  most 
  terrestrial 
  

   Arthropoda, 
  are 
  actively 
  motile. 
  This 
  is 
  a 
  microscopic 
  point 
  

   of 
  agreement, 
  but 
  is 
  none 
  the 
  less 
  significant. 
  

  

  In 
  regard 
  to 
  the 
  important 
  structures 
  concerned 
  with 
  the 
  

   fertilisation 
  of 
  the 
  egg, 
  Limulus 
  and 
  Scorpio 
  diff^er 
  entirely 
  

   from 
  one 
  another. 
  The 
  eggs 
  of 
  Limulus 
  are 
  fertilised 
  in 
  the 
  

   sea 
  after 
  they 
  have 
  been 
  laid. 
  Scorpio, 
  being 
  a 
  terrestrial 
  

   animal, 
  fertilises 
  by 
  copulation. 
  The 
  male 
  possesses 
  ela- 
  

   borate 
  copulatory 
  structures 
  of 
  a 
  chitinous 
  nature, 
  and 
  the 
  

   eggs 
  are 
  fertilised 
  in 
  the 
  female 
  without 
  even 
  quitting 
  the 
  

   place 
  where 
  they 
  are 
  formed 
  on 
  the 
  wall 
  of 
  the 
  reticular 
  

   gouoccel. 
  The 
  female 
  scorpion 
  is 
  viviparous, 
  and 
  the 
  young 
  

   are 
  produced 
  in 
  a 
  highly 
  developed 
  condition 
  as 
  fully 
  formed 
  

   scorpions. 
  

  

  