﻿^f^ 
  15 
  1904 
  

  

  STRUCTUEE 
  AND 
  CLASSIFICATION 
  OF 
  THE 
  ARACflNIDA. 
  165 
  

  

  The 
  Structure 
  and 
  Classification 
  of 
  the 
  

   Arachnida. 
  

  

  By 
  

   E. 
  Ray 
  I^ankester, 
  M.A., 
  I.I..D., 
  F.R.S., 
  

  

  Director 
  of 
  the 
  Natural 
  History 
  Departments 
  of 
  the 
  Britisli 
  Museum. 
  

  

  (Reprinted 
  by 
  kind 
  permission 
  of 
  the 
  proprietors 
  from 
  tlie 
  tentli 
  edition 
  of 
  

   the 
  ' 
  Encyclopaedia 
  Britannica.') 
  

  

  /- 
  Arachnida 
  is 
  the 
  name 
  given 
  in 
  1815 
  by 
  Lamarck 
  (Greek 
  

   o/oaxvrj, 
  a 
  spider) 
  to 
  a 
  class 
  whicli 
  he 
  instituted 
  for 
  the 
  recep- 
  

   tion 
  of 
  the 
  spiders, 
  scorpions, 
  and 
  mites 
  previously 
  classified 
  

   by 
  Linnaeus 
  in 
  the 
  order 
  Aptera 
  of 
  his 
  great 
  group 
  Insecta. 
  

   Lamarck 
  at 
  the 
  same 
  time 
  founded 
  the 
  class 
  Crustacea 
  for 
  

   the 
  lobsters, 
  crabs, 
  and 
  water-fleas, 
  also 
  until 
  then 
  included 
  

   in 
  the 
  order 
  Aptera 
  of 
  Linnaeus. 
  Lamarck 
  included 
  the 
  

   Thysanura 
  and 
  the 
  Myriapoda 
  in 
  his 
  class 
  Arachnida, 
  The 
  

   Insecta 
  of 
  Linnseiis 
  was 
  a 
  group 
  exactly 
  equivalent 
  to 
  the 
  

   Arthropoda 
  founded 
  a 
  hundred 
  years 
  later 
  by 
  Siebold 
  and 
  

   Stannius. 
  It 
  was 
  thus 
  reduced 
  by 
  Lamarck 
  in 
  area, 
  and 
  

   made 
  to 
  comprise 
  only 
  the 
  six-legged, 
  wing-bearing 
  " 
  In- 
  

   secta." 
  For 
  these 
  Lamarck 
  proposed 
  the 
  name 
  Hexapoda; 
  

   but 
  that 
  name 
  has 
  been 
  little 
  used, 
  and 
  they 
  have 
  retained 
  

   to 
  this 
  day 
  the 
  title 
  of 
  the 
  much 
  larger 
  Linnasan 
  group, 
  viz. 
  

   Insecta. 
  The 
  position 
  of 
  the 
  Arachnida 
  in 
  the 
  great 
  sub- 
  

   phylum 
  Arthropoda, 
  according 
  to 
  recent 
  anatomical 
  and 
  

   embryological 
  researches, 
  is 
  explained 
  in 
  another 
  article 
  

   ( 
  Aetheopoda) 
  . 
  The 
  Arachnida 
  form 
  a 
  distinct 
  class 
  or 
  line 
  

   of 
  descent 
  in 
  the 
  grade 
  Euartliropoda, 
  diverging 
  (perhaps 
  in 
  

   common 
  at 
  the 
  start 
  with 
  the 
  Crustacea) 
  from 
  primitive 
  

   Euarthropods, 
  which 
  gave 
  rise 
  also 
  to 
  the 
  separate 
  lines 
  of 
  

  

  VOL. 
  48, 
  PAET 
  2. 
  — 
  NFAV 
  SEEIES. 
  12 
  

  

  