﻿STRUCTURK 
  AND 
  CLASSIFICATION 
  OF 
  THE 
  ARACHNIDA. 
  251 
  

  

  Moggridge 
  (32). 
  Refei'ences 
  to 
  systematic 
  works 
  will 
  also 
  

   be 
  found 
  at 
  the 
  end 
  of 
  this 
  article 
  (33). 
  

  

  Order 
  4. 
  Palpigradi 
  = 
  Microthelyphonida 
  (see 
  Fig. 
  65). 
  — 
  Pro- 
  

   soma 
  covered 
  above 
  by 
  three 
  plates, 
  a 
  larger 
  representing 
  

   the 
  dorsal 
  elements 
  of 
  the 
  first 
  four 
  somites, 
  and 
  two 
  smaller 
  

   representing 
  the 
  dorsal 
  elements 
  of 
  the 
  fifth 
  and 
  sixth. 
  

  

  Its 
  ventral 
  surface 
  provided 
  with 
  one 
  prosternal, 
  two 
  meso- 
  

   sternal, 
  and 
  one 
  metasternal 
  plate. 
  Appendages 
  of 
  first 
  pair 
  

   consisting 
  of 
  three 
  segments, 
  completely 
  chelate, 
  without 
  

   poison 
  gland 
  ; 
  of 
  second 
  pair 
  slender, 
  leg-like, 
  tipped 
  with 
  

   three 
  claws, 
  the 
  basal 
  segment 
  without 
  sterno-coxal 
  process, 
  

   taking 
  no 
  share 
  in 
  mastication, 
  and 
  widely 
  separated 
  from 
  its 
  

   fellow 
  of 
  the 
  opposite 
  side 
  ; 
  third, 
  fourth, 
  fifth, 
  and 
  sixth 
  

   appendages 
  similar 
  in 
  form 
  to 
  the 
  second 
  and 
  to 
  each 
  other. 
  

  

  Proboscis 
  free, 
  not 
  supported 
  from 
  below 
  by 
  either 
  the 
  

   prosternum 
  or 
  the 
  basal 
  segments 
  of 
  the 
  appendages 
  of 
  the 
  

   second 
  pair. 
  

  

  Opisthosoma 
  consisting 
  of 
  only 
  ten 
  somites, 
  which 
  have 
  no 
  

   tergal 
  and 
  sternal 
  elements, 
  the 
  preegenital 
  somite 
  contracted 
  

   to 
  form 
  a 
  '' 
  waist," 
  as 
  in 
  the 
  Pedipalpi 
  ; 
  the 
  last 
  three 
  

   narrowed 
  to 
  form 
  a 
  caudal 
  support 
  for 
  the 
  many-jointed 
  

   flagelliform 
  telson, 
  as 
  in 
  the 
  Urotricha. 
  Respiratory 
  organs 
  

   atrophied. 
  

  

  Family 
  Koeneniid{\3 
  (Koenenia). 
  

  

  Remarks. 
  — 
  An 
  extremely 
  remarkable 
  minute 
  form 
  ori- 
  

   ginally 
  described 
  by 
  Grassi 
  (34) 
  from 
  Sicily, 
  and 
  since 
  

   further 
  described 
  by 
  Hansen 
  (35) 
  . 
  Recently 
  the 
  genus 
  has 
  

   been 
  found 
  in 
  Texas, 
  U.S.A. 
  Only 
  one 
  genus 
  of 
  the 
  order 
  is 
  

   known. 
  

  

  Order 
  5. 
  Solifugse 
  =: 
  Mycetophorse 
  (see 
  Figs. 
  ^^ 
  — 
  69). 
  — 
  Dorsal 
  

   area 
  of 
  prosoma 
  covered 
  with 
  three 
  distinct 
  plates, 
  two 
  

   smaller 
  representing 
  the 
  terga 
  of 
  the 
  fifth 
  and 
  sixth 
  somites, 
  

   and 
  a 
  larger 
  representing 
  those 
  of 
  the 
  anterior 
  four 
  somites, 
  

   although 
  the 
  reduced 
  terga 
  of 
  the 
  third 
  and 
  fourth 
  are 
  trace- 
  

   able 
  behind 
  the 
  larger 
  plate. 
  The 
  latter 
  bears 
  a 
  pair 
  of 
  

   median 
  eyes 
  and 
  obsolete 
  lateral 
  eyes 
  on 
  each 
  side. 
  Sternal 
  

   elements 
  of 
  prosoma 
  almost 
  entirely 
  absent, 
  traces 
  of 
  a 
  

  

  